TY - RPRT TI - Use of Mutant-assisted Gene Identification and Characterization (MAGIC) to Identify Useful Alleles for Crop Improvement AU - Balint-Kurti, P.J. AU - Johal, G.S. A3 - ISB News Reports DA - 2011/1// PY - 2011/1// PB - ISB News Reports ER - TY - SOUND TI - Microbes and Stormwater 101: An Introduction to Pathogens and Indicator Bacteria in Urban Stormwater Runoff AU - Hathaway, J. AU - Simmons, O.D., III AU - Hunt, W.F., III DA - 2011/// PY - 2011/// ER - TY - SOUND TI - Water Testing Updates for Tier 2 Good Agricultural Practices (GAP) Training AU - Simmons, O.D., III DA - 2011/// PY - 2011/// ER - TY - SOUND TI - Water Management for Safe Strawberries AU - Simmons, O.D., III AU - Gunter, C.G. DA - 2011/11/6/ PY - 2011/11/6/ ER - TY - SOUND TI - In-Service Good Agricultural Practices (GAP) Training AU - Ducharme, D. AU - Simmons, O.D., III AU - Turner, L. DA - 2011/12// PY - 2011/12// ER - TY - CONF TI - Concentration of bioaerosols in the vicinity of a commercial egg production farm in Southeast U.S AU - Hu, D. AU - Wang-Li, L. AU - Simmons, O.D., III AU - Osborne, J.A. AU - Classen, J.J. T2 - American Society of Agricultural and Biological Engineers Annual Meeting C2 - 2011/8/7/ CY - Louisville, KY DA - 2011/8/7/ PY - 2011/8/7/ ER - TY - CHAP TI - Vermicomposting for businesses and institutions AU - Sherman, R. T2 - Vermiculture Technology: Earthworms, Organic Waste, and Environmental Management A2 - Edwards, C.A. A2 - Aracon, N.Q. A2 - Sherman, R.L. PY - 2011/// SP - 369–390 PB - CRC Press SN - 9781439809877 ER - TY - BOOK TI - Vermiculture Technology: Earthworms, Organic Waste, and Environmental Management A3 - Edwards, C. A3 - Arancon, N. A3 - Sherman, R. DA - 2011/// PY - 2011/// PB - CRC Press SN - 9781439809877 ER - TY - RPRT TI - Long-term Water Quality Performance of a Coastal Dune Infiltration System AU - Price, W.D. AU - Burchell, M.R. AU - Hunt, W.F. AU - Chescheir, G.M. AU - Graves, A. A3 - North Carolina Department of Transportation DA - 2011/8// PY - 2011/8// M3 - Final Report PB - North Carolina Department of Transportation ER - TY - SOUND TI - In-Service Good Agricultural Practices (GAP) Training AU - Ducharne, D. AU - Simmons, O.D., III DA - 2011/// PY - 2011/// ER - TY - JOUR TI - Conservation Reserve Enhancement Program (CREP) Environmental Monitoring AU - Burchell, M.R. AU - Line, D. AU - Osmond, D. AU - Duckworth, O. AU - Moorman, C. AU - Hall, K. AU - Spooner, J. AU - Grabow, G. AU - Youssef, M. AU - Penrose, D. AU - Huffman, R. T2 - NCDENR - Division of Soil and Water DA - 2011/10// PY - 2011/10// M3 - Final Report ER - TY - JOUR TI - Restoration of PC croplands: How long does it take to observe water quality improvement? AU - Burchell, M.R. AU - Etheridge, J.R. AU - Evans, R.O., Jr T2 - Wetlands Science and Practice DA - 2011/// PY - 2011/// VL - 28 IS - 1 SP - 28–32 ER - TY - CONF TI - Relating Stormwater Control Measure (SCM) Discharge Design Standards to Stream Erosion in Piedmont North Carolina: Case Studies in Raleigh and Chapel Hill, North Carolina AU - Tillinghast, E. D. AU - Hunt, W. F. AU - Jennings, G. D. T2 - World Environmental and Water Resources Congress 2011 AB - As rural watersheds become urbanized, the percent imperviousness increases, altering the hydraulics of stormwater runoff. To restore urbanized watersheds, stormwater control measures (SCMs) are often implemented and designed through water quality measures to return peak flow attenuation to a pre-developed state; however, the affect of release rates on the geomorphic stability of streams are often neglected. The SCMs reduce peak flow rates, but increase duration of sub-bankfull flows within channels, extending periods of erosion. Nineteen rural reference streams along with PCSWMM were used to 1) develop a power regression equation controlling maximum release rate of SCMs based on critical shear stresses of bed sediment and 2) develop annual allowable erosional hours and excess stream power standards. These standards were then applied to 2 urbanized watersheds, House Creek in Raleigh, NC and Tanyard Branch in Chapel Hill, NC to assess the practicality of using the developed standards in an urbanized watershed and determine the geomorphic impact of using LID practices instead of a wet pond on a stream. C2 - 2011/5/19/ C3 - World Environmental and Water Resources Congress 2011 DA - 2011/5/19/ DO - 10.1061/41173(414)54 PB - American Society of Civil Engineers SN - 9780784411735 UR - http://dx.doi.org/10.1061/41173(414)54 DB - Crossref ER - TY - CONF TI - Residential Irrigation and Water Conservation Potential of Smart Irrigation Technologies in the Catawba River Basin AU - Vick, Jr., R. L. AU - Grabow, G. L. AU - Huffman, R. L. AU - Miller, G. L. T2 - World Environmental and Water Resources Congress 2011 AB - A three year residential lake water use study in the Catawba River Basin was initiated in 2009 to assess current water withdrawals for landscape irrigation and the water conservation potential of "smart irrigation" technologies. The study is being conducted by North Carolina State University, on properties bordering Duke Energy managed lakes, in North Carolina and South Carolina, that withdraw lake water for landscape irrigation. Assessment of current irrigation water use began in 2009 with a survey to which over 1,400 residences responded (reflecting a 7.4% return rate). Survey results were used to select thirty-six residences (twelve on each of three lakes along the Catawba River) for further evaluation. Water meters with loggers were installed on the main lines of irrigation systems of the selected residences in the summer of 2009 to monitor lake water withdrawals for landscape irrigation under current practices. Two weather stations and four atmometers were also installed in the region to monitor reference evapotransporation during the study. Three types of smart irrigation technologies (two ET-based controllers and one soil-moisture sensor system) were installed at twenty-seven of the study sites at the beginning of the 2010 irrigation season. The technologies were distributed such that each lake had six sites with ET-based controllers, three sites with soil-moisture sensors, and three sites with no intervention, which would serve as a comparison group. Metering of irrigation water withdrawals continued throughout the 2010 irrigation season after installation of smart irrigation technologies. Turf quality assessments were made throughout the year using a visual turf quality rating and a Normalized Difference Vegetative Index (NDVI) obtained with a turf color meter. The study will conclude with data collected in the 2011 irrigation season. C2 - 2011/5/19/ C3 - World Environmental and Water Resources Congress 2011 DA - 2011/5/19/ DO - 10.1061/41173(414)282 PB - American Society of Civil Engineers SN - 9780784411735 UR - http://dx.doi.org/10.1061/41173(414)282 DB - Crossref ER - TY - JOUR TI - Thermal Mitigation of Urban Storm Water by Level Spreader–Vegetative Filter Strips AU - Winston, R. J. AU - Hunt, W. F. AU - Lord, W. G. T2 - Journal of Environmental Engineering AB - A study was conducted in Louisburg, North Carolina, to determine the effect of level spreader–vegetative filter strip (LS-VFS) storm-water control measures (SCMs) on runoff temperature and thermal loading. Two LS-VFS systems draining an urban catchment were monitored during the summers of 2008 and 2009. The first VFS was 7.6 m wide and entirely grassed. The second was 15.2 m wide, with the first-half grassed and the second-half wooded. Runoff temperatures and thermal loads from the urban catchment tended to peak toward the beginning of a storm event. Median and maximum storm temperatures were significantly reduced across both the 7.6-m and 15.2-m LS-VFSs. However, median and maximum effluent temperatures for both filter strip lengths were significantly greater than the 21°C trout threshold. Mean and median effluent temperatures from the 15.2-m LS-VFS were slightly lower (<1°C) than those from the 7.6-m LS-VFS, which may show the impact of increased filter strip width and/or the shading from wooded vegetation on effluent temperatures. Expected differences between influent and effluent temperatures (both median and maximum) were greater as the influent temperature increased. Substantial and statistically significant (α=0.05) thermal load reductions were observed in both LS-VFSs because of measured reductions in both temperature and flow volume. Thermal load was eliminated in seven of 38 storm events because of infiltration of the entire runoff volume in the filter strips. The ability of LS-VFS systems to reduce storm-water temperatures and thermal loads supports their use in thermally sensitive watersheds. DA - 2011/8// PY - 2011/8// DO - 10.1061/(ASCE)EE.1943-7870.0000367 VL - 137 IS - 8 SP - 707-716 J2 - J. Environ. Eng. LA - en OP - SN - 0733-9372 1943-7870 UR - http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000367 DB - Crossref KW - Storm-water management KW - Temperature KW - Thermal pollution KW - Urbanization KW - SCM KW - BMP KW - Level spreader KW - Filter strip ER - TY - CONF TI - Hydraulic and Hydrologic Modelling of Permeable Pavement AU - Hohaia, Nick AU - Fassman, Elizabeth AU - Hunt, William F. AU - Collins, Kelly A. T2 - World Environmental and Water Resources Congress 2011 AB - This current paper outlines the investigation procedures used to calibrate and verify a new hydrologic model on five permeable pavement structures in two different climates: Birkdale, New Zealand and North Carolina, USA. A beta version computer modelling package designed by the United States (US) Environmental Protection Agency (EPA), the Storm Water Management Model for Low Impact Design (SWMM5-LID(beta)), was used for the procedure. The calibrated model for the Birkdale site demonstrated accurate prediction of the system's response for both individual storms and continuous simulation (long-term). The model accurately predicts the peak flow response of the system for the highly frequent events (> 30% exceedance probability) with the measured and modelled flow frequency curves matching over this range. Volume control prediction is less accurate as the model over predicts retention for events greater than 10% exceedance by an average 4.7 mm. The calibrated model for the four North Carolina pavements (except for CGP) demonstrated accurate prediction for storms between 10 mm and 30 mm. The sand fill of the CGP provided additional storage which reduced peak underdrain outflow and volume. Modelling of this relationship requires significant modification of the fixed parameters in the model, which was not attempted. Simulated outflow hydrographs for storms <10 mm followed a similar shape to the measured hydrographs but over predicted the response. Simulated outflow hydrographs for storms >30 mm again had very similar shapes to the measured hydrographs but could not predict peak flows. Two parameters governed the response of the permeable pavement model: the drain coefficient and the drain exponent. A drain exponent of 3 is used in all of the models. A higher drain exponent increases the accuracy of the model but the corresponding drain coefficient becomes smaller and smaller. A calibrated drain coefficient of 0.000006 is used for the Birkdale site, and for the sites in North Carolina (PICP1, PICP2, CGP and PC) 0.00024, 0.001175, 0.00013 and 0.000725 respectively, were determined. C2 - 2011/5/19/ C3 - World Environmental and Water Resources Congress 2011 DA - 2011/5/19/ DO - 10.1061/41173(414)61 PB - American Society of Civil Engineers SN - 9780784411735 UR - http://dx.doi.org/10.1061/41173(414)61 DB - Crossref ER - TY - CONF TI - Evaluating Media Depth, Surface Storage Volume, and Presence of an Internal Water Storage Zone on Four Sets of Bioretention Cells in North Carolina AU - Brown, Robert A. AU - Hunt, William F. T2 - World Environmental and Water Resources Congress 2011 AB - Bioretention is becoming a widely used stormwater control measure (SCM) to achieve stringent stormwater regulations. This field study describes research performed on two sites in eastern North Carolina, where monitoring occurred for just over two years. At each site, there were two hydrologically separate bioretention cells. After the first year of research, a design specification was altered for both cells at each study site. Analysis for all cells included: (1) an annual runoff balance and (2) a calculation of concentration and pollutant load reductions for nitrogen species, phosphorus species, and total suspended solids. The bioretention cells in Rocky Mount, NC, were designed with an internal water storage (IWS) zone. The underdrain outlet was 0.3 and 0.6 m from the surface of the media in the first and second year, respectively. This feature had a major impact on runoff volume reduction. Each cell had a different underlying soil type; one was sand and the other sandy clay loam. Out of 151 monitored rainfall events over two years, outflow only occurred in 6 and 21 events, respectively. More drainage occurred in the cell with the tighter underlying soil and when the IWS zone was shallower due to less storage volume availability. The bioretention cells in Nashville, NC, were conventionally drained. They had varying media depths (0.6-m versus 0.9-m). During construction, they were severely undersized and clogged with fine sediment. After one year, the clogging layer was removed, which nearly doubled the surface storage volume and increased the infiltration rate by almost a factor of ten. The bioretention cells pre-repair were treating nearly 65 percent of annual runoff. After the repair, an additional 25 percent of annual runoff was treated. This improved the water quality treatment, reduced peak outflow rates, and reduced the duration of high outflow rates. Both sites demonstrated the impact that changing one of the design parameters has on the overall performance. For incorporating an IWS zone, the hydrologic and water quality performance appear dependent upon underlying soils and IWS zone depth. Results from the other site highlighted the importance of properly constructing and maintaining bioretention cells. C2 - 2011/5/19/ C3 - World Environmental and Water Resources Congress 2011 DA - 2011/5/19/ DO - 10.1061/41173(414)44 PB - American Society of Civil Engineers SN - 9780784411735 UR - http://dx.doi.org/10.1061/41173(414)44 DB - Crossref ER - TY - CONF TI - Bioretention Outflow: Does It Mimic Rural Water Interflow? AU - DeBusk, Kathy M. AU - Hunt, William F. T2 - World Environmental and Water Resources Congress 2011 AB - Bioretention, a key structural practice of Low Impact Development (LID), has been proven to decrease peak flow rates and volumes, promote infiltration and evapotranspiration and improve water quality. Exactly how well bioretention mimics pre-development (or "natural") hydrology is an important research question. Do bioretention outflow rates mirror shallow groundwater inter-event stream recharge flow associated with natural or non-urban watersheds? Streamflow from three small, non-urban watersheds, located in the Piedmont of central North Carolina, was compared to bioretention outflow from four cells also in North Carolina's Piedmont region. Each benchmark watershed drained to a small stream, where flow rate was monitored for an extended period of time. After normalizing the flow rates and volumes by watershed size, data were combined to form two data sets: bioretention outflow and stream inter-event flow. Results indicate that there is no statistical difference between flow rates in streams draining undeveloped watersheds and bioretention outflow rates for the first 24 hours following the commencement of flow. Similarly, there is no statistical difference between the cumulative volumes released by the two systems during the 48 hours following the start of flow. These results indicate that bioretention cells behave comparably to watersheds in natural or non-urban conditions with respect to both flow rates and flow volumes and suggest that bioretention outflows may mirror post storm event shallow groundwater inter-event stream recharge flow. Solely considering bioretention outflow as a conjugate to runoff may be a misinterpretation of a flowrate that actually resembles shallow interflow. C2 - 2011/5/19/ C3 - World Environmental and Water Resources Congress 2011 DA - 2011/5/19/ DO - 10.1061/41173(414)41 PB - American Society of Civil Engineers SN - 9780784411735 UR - http://dx.doi.org/10.1061/41173(414)41 DB - Crossref ER - TY - CONF TI - Treating Highway Bridge Deck Runoff Using Bioretention and a Swale AU - Luell, S. K. AU - Hunt, W. F. AU - Winston, R. J. T2 - World Environmental and Water Resources Congress 2011 AB - A full sized bioretention cell, an undersized bioretention cell, and a swale were constructed in a bridge deck easement of I-540 in Knightdale, NC to treat bridge deck runoff. Runoff was piped from the northbound and southbound lanes to the bioretention cells and swale, respectively. Flow-weighted, composite water quality samples were collected at the inlets and outlets of the cells and the swale and were tested for nutrients, TSS, and heavy metals. The mean effluent concentration of TN released by the large cell, small cell, and swale were 0.38, 0.54, and 1.00 mg/L, respectively, while effluent TP concentrations were 0.10, 0.13, and 0.15 mg/L, respectively. Median TSS effluent concentrations were 16, 21, and 29 mg/L in the large cell, small cell, and swale, respectively. The large and small cells reduced runoff volumes by about 50% and 31%, respectively, for storms less than 2.54 cm. The swale reduced volumes by 3% for storms less than 2.54 cm. While both bioretention cells substantially reduced nutrient and sediment loads, the large cell outperformed the small cell. The small cell provided support for retrofitting undersized systems in areas with limited space. Both cells achieved greater pollutant and volume reductions than the swale. C2 - 2011/5/19/ C3 - World Environmental and Water Resources Congress 2011 DA - 2011/5/19/ DO - 10.1061/41173(414)40 PB - American Society of Civil Engineers SN - 9780784411735 UR - http://dx.doi.org/10.1061/41173(414)40 DB - Crossref ER - TY - CONF TI - Assessing the Accuracy of Bioretention Installation in North Carolina AU - Wardynski, B. J. AU - Hunt, W. F. T2 - World Environmental and Water Resources Congress 2011 AB - The performance of bioretention cells (BRCs) depends upon their capacity to store an adequate amount of runoff such that the desired stormwater volume and pollutant load are retained. Performance is also dependent upon the use of a suitable soil media that can provide storage within the void space, adequate infiltration between storm events, and substrate for plant and microbial interactions. Widespread construction of improperly designed cells could have substantial environmental consequences because of frequent overflow events. To determine if this is indeed a problem, 20 BRCs throughout North Carolina were assessed. Topographic surveys were performed and the as-built surface storage (ponding within the basin below the outlet elevation) was calculated using CAD software. Visual inspections of the soil profile were used to identify hydric soils and moisture regime. Particle-size distribution of the soil media at various depths was determined using the hydrometer method and permeability was estimated with constant-head saturated hydraulic conductivity tests. Results were compared to the intended storage volumes and soil specifications from original design calculations and construction plans. Preliminary findings show that 82% and 44% of BRC soil media failed to satisfy particle-size distribution and permeability specifications, respectively. Additionally, 50% of surveyed BRCs were either moderately or severely undersized. Continuing research will confirm whether BRCs throughout North Carolina are improperly installed and maintained. Research findings will be used to evaluate state requirements and provide recommendations to ensure that installed BRCs satisfy water quality and flood control regulations. C2 - 2011/5/19/ C3 - World Environmental and Water Resources Congress 2011 DA - 2011/5/19/ DO - 10.1061/41173(414)38 PB - American Society of Civil Engineers SN - 9780784411735 UR - http://dx.doi.org/10.1061/41173(414)38 DB - Crossref ER - TY - JOUR TI - Constructed Storm-Water Wetland Installation and Maintenance: Are We Getting It Right? AU - Hunt, W. F. AU - Greenway, M. AU - Moore, T. C. AU - Brown, R. A. AU - Kennedy, S. G. AU - Line, D. E. AU - Lord, W. G. T2 - Journal of Irrigation and Drainage Engineering AB - Constructed storm-water wetlands (CSWs) have become one of the more popular storm-water control measures (SCMs). CSWs offer a hybrid between larger detention technologies like storm-water wet ponds and newer green infrastructure technologies. The systems are characterized as being predominately shallow retention practices, with water elevations sufficiently low to support diverse flora and fauna. Figs. 1(a–c) illustrate several successful examples of CSWs. Many researchers have found that CSWs remove sediment, nutrients, and metals from storm-water runoff (Greenway 2004; Hathaway and Hunt 2010; Line et al. 2008; Kohler et al. 2004; Wadzuk et al. 2010). One of the principal drivers for the use of storm-water wetlands is the amount of credit awarded to them by various governmental agencies with respect to nutrient removal and sequestration [North Carolina Department of Environment and Natural Resources (NCDENR) 2009]. The apparent improvement in nutrient capture from storm-water runoff over that of storm-water wet ponds is one of the main reasons designers choose CSWs over the more traditional wet pond. Extensive coverage of vegetation allows for several pollutant removal mechanisms: filtration of particles, stabilization of sediments, nutrient uptake, microbialrhizophere interaction to promote nitrification and denitrification, and the provision of increased surface area for biofilm/periphyton growth (Greenway 2004). In regions where thermal loads threaten cold water fisheries, CSWs have been shown to release cooler water to streams than do wet ponds because of the shading caused by the vegetation—but absent from wet ponds (Jones and Hunt 2010). Some concerns have also presented themselves with respect to CSWs, which have prevented the practice from outright replacing the wet pond. Foremost among them is the threat of mosquito infestation that wetlands invariably face in relation to the public (QDNR 2000). Research has shown that exorbitantly high mosquito populations need not accompany CSWs, provided they are diversely vegetated (Greenway et al. 2003; Hunt et al. 2006). However, if wetlands are allowed to become monocultures of specific mosquito-protective plants, such as Typha spp. (commonly referred to as cattails in the United States), they can become the very mosquito breeding grounds that the public fears (Greenway et al. 2003; Hunt et al. 2005). If storm-water wetlands are to be constructed, they must both (1) meet their intended water quality (and hydrologic) design goals and (2) not be a public nuisance. Anecdotal observation of CSWs constructed worldwide shows how many well-intended CSW designs fail. Two principal reasons were identified: One appears to be that not enough care was taken to ensure the storm-water wetlands’ normal pool elevation was appropriately shallow (that is, often the elevation of water in CSWs is too deep). The cause has been previously identified by Greenway et al. (2007). The second is clogging of the outlet structure that artificially raises the elevation above normal pool for extended periods of time. In both cases, simple preventative actions could be taken to ensure constructed storm-water wetlands maintain their designed integrity. The purpose of this forum is to document how poor design and inadequate management of two CSWs caused each to effectively become wet ponds, which results in (1) a reduced efficiency in the removal of some pollutants; (2) a degradation of biodiversity, which leads to an increased risk of having the wetlands become mosquito breeding grounds; and (3) degraded aesthetics. DA - 2011/8// PY - 2011/8// DO - 10.1061/(ASCE)IR.1943-4774.0000326 VL - 137 IS - 8 SP - 469-474 J2 - J. Irrig. Drain Eng. LA - en OP - SN - 0733-9437 1943-4774 UR - http://dx.doi.org/10.1061/(ASCE)IR.1943-4774.0000326 DB - Crossref ER - TY - JOUR TI - Char and char-supported nickel catalysts for secondary syngas cleanup and conditioning AU - Wang, Duo AU - Yuan, Wenqiao AU - Ji, Wei T2 - Applied Energy AB - Tars in biomass gasification systems need to be removed to avoid damaging and clogging downstream pipes or equipment. In this study, Ni-based catalysts were made by mechanically mixing NiO and char particles at various ratios. Catalytic performance of the Ni/char catalysts was studied and compared with performance of wood char and coal char without Ni for syngas cleanup in a laboratory-scale updraft biomass gasifier. Reforming parameters investigated were reaction temperature (650–850 °C), NiO loading (5–20% of the weight of char support), and gas residence time (0.1–1.2 s). The Ni/coalchar and Ni/woodchar catalysts removed more than 97% of tars in syngas at 800 °C reforming temperature, 15% NiO loading, and 0.3 s gas residence time. Analysis of syngas composition indicated that concentrations of H2 and CO in syngas significantly. Furthermore, performance of the Ni/coalchar catalyst was continuously tested for 8 h. There was slight deactivation of the catalyst in the early stage of tar/syngas reforming; however, the catalyst was able to stabilize soon after. It was concluded that chars especially coal char can be an effective and inexpensive support of NiO for biomass gasification tar removal and syngas conditioning. DA - 2011/5// PY - 2011/5// DO - 10.1016/j.apenergy.2010.11.041 VL - 88 IS - 5 SP - 1656-1663 J2 - Applied Energy LA - en OP - SN - 0306-2619 UR - http://dx.doi.org/10.1016/j.apenergy.2010.11.041 DB - Crossref KW - Biomass KW - Char KW - Gasification KW - Nickel oxide catalyst KW - Syngas reforming KW - Tar removal ER - TY - CONF TI - Autonomous aquatic vehicle fleet development: Sensors, communications and software AU - Hall, S.G. AU - Smith, D.D. AU - Thompson, B. C2 - 2011/// C3 - American Society of Agricultural and Biological Engineers Annual International Meeting 2011, ASABE 2011 DA - 2011/// VL - 3 SP - 1950-1960 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-81255142496&partnerID=MN8TOARS ER - TY - CONF TI - Ecological engineering of artificial oyster reefs to enhance carbon sequestration via the algae-oyster complex AU - Hall, S.G. AU - Risinger, J. AU - Lutz, A. AU - Farlow, J. C2 - 2011/// C3 - American Society of Agricultural and Biological Engineers Annual International Meeting 2011, ASABE 2011 DA - 2011/// VL - 3 SP - 2336-2344 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-81255168689&partnerID=MN8TOARS ER - TY - JOUR TI - Influence of Juice Preparations on the Fermentability of Sweet Sorghum AU - Bridgers, E. N. AU - Chinn, M. S. AU - Veal, M. W. AU - Stikeleather, L. F. T2 - Biological Engineering Transactions AB - Agricultural biomass has shown potential to aid in the solution to the rising need for biofuels and other biobased products. This study focused on sweet sorghum, a crop that produces relatively high quantities of easy to process, directly fermentable aqueous sugar. Sweet sorghum is desirable because of the reduced steps and inputs required for complete conversion to ethanol compared to starch and lignocellulosic biomass, as well as its adaptability to temperate regions, drought tolerance, and photosynthetic efficiency. Laboratory fermentation studies were conducted to evaluate the processing parameters for ethanol production on fresh and frozen sorghum juice. The effects of pH level, yeast type, incubation time, and sterilization were investigated. Ethanol and individual sugar concentrations (sucrose, fructose, and glucose) were measured over time. Fresh sorghum juice stocks on average contained 50% w/w sucrose, 24% w/w glucose, and 26% w/w fructose of total initial sugars, while frozen sorghum juice stocks contained 27% w/w sucrose, 37% w/w glucose, and 36% w/w fructose of total initial sugars. Ethanol yields were higher for sterile treatments, with 7.86% v/v ethanol (62 g L-1) and 6.24% v/v ethanol (49.3 g L-1) within 3 days on average for fresh sterile and non-sterile treatments, respectively. Frozen juice samples resulted in 7.81% v/v ethanol (61.6 g L-1) and 7.10% v/v ethanol (56.1 g L-1) for sterile and non-sterile treatments, respectively, after 3 days of incubation. Sterile treatments typically resulted in >84% conversion of sugars to ethanol, while non-sterile treatments ranged between 60% and 75% conversion. Overall, sweet sorghum juice is capable of supporting yeast fermentation with minimal input, making it a suitable substrate for development of on-farm and large-scale industrial ethanol conversion. DA - 2011/// PY - 2011/// DO - 10.13031/2013.38507 VL - 4 IS - 2 SP - 57-67 LA - en OP - SN - 2330-0337 UR - http://dx.doi.org/10.13031/2013.38507 DB - Crossref ER - TY - JOUR TI - Gasification and synthesis gas fermentation: an alternative route to biofuel production AU - Slivka, Rachel M AU - Chinn, Mari S AU - Grunden, Amy M T2 - Biofuels AB - Lignocellulosic biomass has been identified among the renewable energy sources to have the highest potential to minimize dependency on dwindling supplies of fossil fuels. Conversion of this biomass to biofuels by microorganisms through direct hydrolysis and fermentation can be challenging. Alternatively, biomass can be converted to synthesis gas (a mixture of CO, CO2, N2 and H2) through gasification and transformed to fuels using microbial catalysts that can convert the CO, H2 and CO2 to fuels such as ethanol, butanol and hydrogen. Biomass gasification–fermentation processing systems have shown promise and companies are now entering the marketplace for commercial-scale ethanol production from synthesis gas. Isolation of new organisms capable of higher product yield, as well as functional implementation of bioreactors that enhance gas solubility for microbial fermentation, make this technology an attractive option for reducing our dependency on fossil fuels. DA - 2011/7// PY - 2011/7// DO - 10.4155/bfs.11.108 VL - 2 IS - 4 SP - 405-419 J2 - Biofuels LA - en OP - SN - 1759-7269 1759-7277 UR - http://dx.doi.org/10.4155/bfs.11.108 DB - Crossref ER - TY - JOUR TI - Influence of Carbon Source Pre-Adaptation on Clostridium ljungdahlii Growth and Product Formation AU - Tirado-Acevedo, Oscar AU - L. Cotter, Jacqueline AU - S. Chinn, Mari AU - M. Grunden, Amy T2 - Journal of Bioprocessing & Biotechniques AB - Syngas fermentation is considered an alternate processing method for biofuel and biochemical production as part of thermochemical biomass conversion. Exposure of syngas fermenting microorganisms to sugars, either in the primary syngas fermentation or through pre-adaptation in the seed culture, has the potential to enhance overall fermentation performance and stress tolerance. In this rapid communication, Clostridium ljungdahlii was grown on different carbon sources including syngas only, syngas-fructose and fructose only to identify ideal pre-adaptation conditions for ethanol and acetate production from subsequent cultures grown in reactors containing syngas only or fructose-syngas substrates. In syngas only reactors, cultures pre-adapted to fructose had faster cell production rates (2X) and at least 83% higher ethanol and 16% higher acetate formation than cells pre-adapted on syngas or syngas-fructose. In syngas- fructose reactors, cultures did not show significant growth or acetate production differences under pre-adaptation treatments. Nevertheless, in these syngas-fructose reactors, cultures pre-adapted on syngas and syngas-fructose had nearly 20% higher ethanol production than those pre-adapted on fructose. Among pre-adaptation treatments, fructose had better results in syngas only reactors than syngas-fructose reactors. However, the presence of syngas in pre- adaptation cultures was better overall for ethanol production. DA - 2011/// PY - 2011/// DO - 10.4172/2155-9821.S2-001 VL - 01 IS - S2 J2 - J Bioprocess Biotech OP - SN - 2155-9821 UR - http://dx.doi.org/10.4172/2155-9821.S2-001 DB - Crossref ER - TY - JOUR TI - Effects of Grain Bag Storage on Post-Harvest Quality AU - Ward, Jason K AU - Davis, Jeremiah D T2 - 2011 Louisville, Kentucky, August 7 - August 10, 2011 AB - Abstract Polyethylene grain storage bags are one type of alternative grain storage systems available to producers. Very little is known regarding the internal environment of grain bags and its effect on grain quality while in storage. The objectives of this study were to develop tools and practices to measure internal environmental parameters of grain stored in bags, and to characterize its effect on grain quality. Internal storage conditions were monitored in four 25-ft long by 9-ft diameter grain bags across their center cross-section using specially designed linear sensor arrays pushed into the bags. Each bag was filled with 600 bu of dry, well-conditioned grain. Internal temperature and relative humidity as well as external weather conditions were continuously monitored for 20 weeks of storage. Simultaneously, grain samples were collected to determine changes in moisture content. Results indicate that the peripheral grain layer will track ambient temperatures, while grain temperatures in the center respond slowly to fluctuations. Changes in peripheral layer conditions do not significantly alter grain moisture content. Mean moisture content will change with time, most likely with major ambient condition changes. Further analysis is on-going. DA - 2011/// PY - 2011/// DO - 10.13031/2013.37389 ER - TY - CONF TI - Streambank erosion and instability induced by groundwater seepage AU - Midgley, T.L. AU - Fox, G.A. AU - Wilson, G.V. AU - Heeren, D.M. AU - Simon, A. AU - Langendoen, E.J. C2 - 2011/// C3 - American Society of Agricultural and Biological Engineers Annual International Meeting 2011, ASABE 2011 DA - 2011/// VL - 4 SP - 3009-3029 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-81255185841&partnerID=MN8TOARS ER - TY - JOUR TI - Streambank Erosion and Instability Induced by Groundwater Seepage AU - Midgley, Taber Leon AU - Fox, Garey A AU - Wilson, Glenn V AU - Heeren, Derek M AU - Simon, Andrew AU - Langendoen, Eddy J T2 - 2011 Louisville, Kentucky, August 7 - August 10, 2011 AB - Excessive sediment is one of the most common surface water pollutants. It diminishes water quality and destroys aquatic habitat. Streambank erosion is known to be a major source of sediment in streams and rivers, contributing as much as 80% of the total sediment load in some watersheds. Little work has been done to study the effects of seepage on streambank erosion and failure. Prior research, primarily in the laboratory under well-defined and controlled conditions, has examined seepage as a mechanism for bank erosion, but more needs to be done to validate conclusions derived from the laboratory with field data. This project studied a streambank on Dry Creek (a tributary to Little Topashaw Creek) located in Chickasaw County, Mississippi. The bank was previously observed to produce seepage even during dry summer months. This creek is a deeply incised stream in the Yalobusha Watershed with near 90 degree banks. The creek flows through alluvial plains under cultivation and surrounded by forested areas. Excess sediment has been identified as the main water quality issue in the watershed with gullies and banks being the main sources. Watershed geology is characterized by silt loam and clay loam with a more conductive loamy sand between the loam and an underlying cohesive layer. The site was initially instrumented with a network of tensiometers and observation wells. Groundwater conditions and bank erosion were monitored for several weeks, followed by an induced seepage experiment. A trench installed 2.8 m from the edge of the bank and approximately 2 m below ground surface was used to provide a constant head for groundwater flow in the near-bank area. The bank face was outfitted with a seepage collection device that measured seepage flow rate and sediment transport. Groundwater conditions were again monitored by the tensiometer and observation well network. Experiments consisted of a trench injection at a constant head and observations of flow rates, erosion rates, soil-water pressures, and water table elevations. Flow rates varied from 0.004 L/min to 1.16 L/min at different locations on the bank. It was observed that the seeps experienced self-healing erosion in which upper layer cohesive soil failures blocked further particle mobilization. One experiment simulated fluvial erosion removing the failed material, thereby, resulting in combined erosion rates of over 6000 g/min. Seepage erosion could be a dominate mechanism of streambank failure where the self-healing process is not occurring. DA - 2011/// PY - 2011/// DO - 10.13031/2013.37385 ER - TY - CONF TI - Measuring erodibility of cohesive soils using laboratory jet erosion tests AU - Al-Madhhachi, A.T. AU - Hanson, G.J. AU - Fox, G.A. AU - Tyagi, A.K. AU - Bulut, R. AB - Many factors affect the erodibility of cohesive soils, such as the soil characteristics, soil moisture content, and properties of the eroding fluid. Typically the erosion rate of cohesive soils is quantified using an excess shear stress equation, dependent on two major soil parameters: the critical shear stress (τc) and the erodibility coefficient (kd). A submerged jet test (JET — Jet Erosion Test) is one method for measuring these parameters. In this study, a laboratory JET and a new miniature version of the device ("mini" JET), with the advantage of being easier to use in the field, were used to measure τc and kd for various soils. The objective of this study was to determine if the "mini" JET estimated equivalent values for τc and kd. Two different soils types (silty sand and clayey sand) were used in comparing the performance of the two devices. Sieve analysis, hydrometer, and plasticity index tests were also performed to characterize these two soils. Test samples of the soils were prepared at three to seven different water contents with equivalent compaction effort (25 blows per layer). In-order to compare the performance and repeatability of both JET devices, tests were performed on paired samples prepared in the same way and tested at the same time. Reasonably equivalent measured kd were obtained with the two JET devices for both soils. Results indicated some variability in measuring τc and kd due to variability in the subsamples of the cohesive soil and differences in soil moisture levels. These results also indicated that settling back of some of the eroded soil into the scour area of the new "mini" JET device may have caused differences in measured τc relative to the original JET device. Even though there was an observed difference in the observed τc, the differences were consistent. The relationships between measured τc and kd obtained from both JET devices also compared reasonably well with those observed in previous field research. C2 - 2011/// C3 - World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability - Proceedings of the 2011 World Environmental and Water Resources Congress DA - 2011/// DO - 10.1061/41173(414)244 SP - 2350-2359 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79960437161&partnerID=MN8TOARS ER - TY - JOUR TI - Flow and transport experiments for a streambank seep originating from a preferential flow pathway AU - Fox, G.A. AU - Heeren, D.M. AU - Miller, R.B. AU - Mittelstet, A.R. AU - Storm, D.E. T2 - Journal of Hydrology AB - Streambank seeps commonly originate from localized heterogeneity or preferential flow pathways (PFPs) in riparian floodplains. However, limited field data have been reported on ground water seep flows and solute transport to seeps from PFPs. The objective of this research was to build upon previous floodplain-scale investigations of PFPs by analyzing seep discharge and transport characteristics through a single PFP. An important research question was whether this PFP could be conceptualized as a homogeneous, one-dimensional flow path. Streambank seep discharge measurements were obtained by inducing a hydraulic head in a trench injection system. Also, co-injection of Rhodamine WT (RhWT) and a potassium chloride (KCl) tracer over a 60-min period was used to investigate transport dynamics. Seep discharge and breakthrough curves for electrical conductivity (EC) and RhWT were measured at the streambank using a lateral flow collection device. The breakthrough curves were fit to one-dimensional convective-dispersion equations (CDEs) to inversely estimate solute transport parameters. The PFP from which the seep originated was clean, coarse gravel (6% by mass less than 2.0 mm) surrounded by gravel with finer particles (20% by mass less than 2.0 mm). Located approximately 2 m from the trench, the seep (50 cm by 10 cm area) required at least 40 cm of hydraulic head for flow to emerge at the streambank. At a higher hydraulic head of 125 cm, seep discharge peaked at 3.5 L/min. This research verified that localized PFPs can result in the rapid transport of water (hydraulic conductivity on the order of 400 m/d) and solutes once reaching a sufficient near-bank hydraulic head. A one-dimensional equilibrium CDE was capable of simulating the EC (R2 = 0.94) and RhWT (R2 = 0.91) breakthrough curves with minimal RhWT sorption (distribution coefficient, Kd, equal to 0.1 cm3/g). Therefore, the PFP could be conceptualized as a one-dimensional, homogenous flow and transport pathway. These results are consistent with previous research observing larger-scale phosphorus transport. DA - 2011/// PY - 2011/// DO - 10.1016/j.jhydrol.2011.04.014 VL - 403 IS - 3-4 SP - 360-366 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79956341660&partnerID=MN8TOARS KW - Contaminant transport KW - Preferential flow KW - Rhodamine WT KW - Riparian floodplain KW - Seepage ER - TY - JOUR TI - Escherichia coli Load Reduction from Runoff by Vegetative Filter Strips: A Laboratory-Scale Study AU - Fox, Garey A. AU - Matlock, Emily M. AU - Guzman, Jorge A. AU - Sahoo, Debabrata AU - Stunkel, Kevin B. T2 - Journal of Environmental Quality AB - Vegetative filter strips (VFS) are commonly used best management practices for removing contaminants from runoff. Additional research is warranted to determine their efficiency and the most appropriate metrics for predicting fecal bacteria reductions. The objective of this research was to determine VFS effectiveness in removing from runoff relative to inflow rate, infiltration capacity, and flow concentration. This research also investigated the presence of in runoff from clean water runon after diluted manure runon events. A laboratory-scale VFS soil box (200 cm long, 100 cm wide, 7.5% slope) was packed with a sandy loam soil. Ten constant-flow VFS experiments were conducted with and without vegetation (8-10 cm ryegrass [ L.]) at low (20-40 cm s), medium (40-60 cm s), and high (85-120 cm s) flow rates and for a full (100 cm) or concentrated (40 cm) VFS flow width to simulate a channelizing flow condition. Two runon events were investigated for each experimental condition: (i) diluted liquid swine manure runon and (ii) clean water runon 48 h afterward. was used as an indicator of fecal contamination and was quantified by the most probable number (MPN) technique. No concentration reductions were observed based on peak outflow concentrations, and only small concentration reductions were observed based on outflow event mean concentrations. The mass reductions ranged from 22 to 71% and were strongly correlated to infiltration or runoff reduction ( = 0.88), which was dependent on the degree of flow concentration. Little to no effect of sedimentation on transport was observed, hypothesized to be due to minimum attachment to sediment particles because the bacteria originated from manure sources. Therefore, the design of VFS for bacteria removal should be based on the infiltration capacity in the VFS and should prevent concentrated flow, which limits total infiltration. The event mean concentrations in clean water runon experiments were between 10 and 100 MPN per 100 mL; therefore, under these conditions, VFS served as a source of residual from previous runon events. DA - 2011/5// PY - 2011/5// DO - 10.2134/jeq2010.0391 VL - 40 IS - 3 SP - 980-988 J2 - J. Environ. Qual. LA - en OP - SN - 0047-2425 UR - http://dx.doi.org/10.2134/jeq2010.0391 DB - Crossref ER - TY - JOUR TI - Stage-dependent transient storage of phosphorus in alluvial floodplains AU - Heeren, D.M. AU - Fox, G.A. AU - Miller, R.B. AU - Storm, D.E. AU - Fox, A.K. AU - Penn, C.J. AU - Halihan, T. AU - Mittelstet, A.R. T2 - Hydrological Processes AB - Abstract Models for contaminant transport in streams commonly idealize transient storage as a well mixed but immobile system. These transient storage models capture rapid (near‐stream) hyporheic storage and transport, but do not account for large‐scale, stage‐dependent interaction with the alluvial aquifer. The objective of this research was to document transient storage of phosphorus (P) in coarse gravel alluvium potentially influenced by large‐scale, stage‐dependent preferential flow pathways (PFPs). Long‐term monitoring was performed at floodplain sites adjacent to the Barren Fork Creek and Honey Creek in northeastern Oklahoma. Based on results from subsurface electrical resistivity mapping which was correlated to hydraulic conductivity data, observation wells were installed both in higher hydraulic conductivity and lower hydraulic conductivity subsoils. Water levels in the wells were monitored over time, and water samples were obtained from the observation wells and the stream to document P concentrations at multiple times during high flow events. Contour plots indicating direction of flow were developed using water table elevation data. Contour plots of total P concentrations showed the alluvial aquifer acting as a transient storage zone, with P‐laden stream water heterogeneously entering the aquifer during the passage of a storm pulse, and subsequently re‐entering the stream during baseflow conditions. Some groundwater in the alluvial floodplains had total P concentrations that mirrored the streams' total P concentrations. A detailed analysis of P forms indicated that particulate P (i.e. P attached to particulates greater than 0·45 µm) was a significant portion of the P transport. This research suggests the need for more controlled studies on stage‐dependent transient storage in alluvial systems. Copyright © 2011 John Wiley & Sons, Ltd. DA - 2011/// PY - 2011/// DO - 10.1002/hyp.8054 VL - 25 IS - 20 SP - 3230-3243 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80052952199&partnerID=MN8TOARS KW - alluvial floodplains KW - phosphorus KW - preferential flow KW - subsurface transport KW - transient storage ER - TY - JOUR TI - Option-specific student outcomes to meet biological engineering program criteria AU - Fox, G.A. AU - Elliott, R.L. AU - Bellmer, D. T2 - Applied Engineering in Agriculture DA - 2011/// PY - 2011/// VL - 27 IS - 5 SP - 857-860 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80053937677&partnerID=MN8TOARS ER - TY - CONF TI - Evaluation of the Bank Stability and Toe Erosion Model (BSTEM) for predicting lateral streambank retreat on ozark streams AU - Midgley, T.L. AU - Fox, G.A. AU - Heeren, D.M. AB - Streambank erosion is known to be a major source of sediment in streams and rivers. The Bank Stability and Toe Erosion Model (BSTEM) was developed by the USDA-ARS National Sedimentation Laboratory in order to predict streambank retreat due to both fluvial erosion and geotechnical failure. Few model evaluations for bank retreat have been performed to date. The objective of this research was to evaluate BSTEM's ability to predict bank retreat on Ozark ecoregion streams, assess the importance of accurate geotechnical and fluvial erosion soil parameter values, and evaluate the importance of the near bank water table elevation on bank stability. The model was applied to a streambank on the Barren Fork Creek in northeastern Oklahoma. This site experienced significant bank retreat (between 7.8 and 20.9 m over a 100-m length of stream) between April and October 2009 based on regular surveys of the bank profile. BSTEM (version 5.2) was not originally programmed to run multiple hydrographs iteratively, so an additional subroutine was written which automatically input the stream stage. The new subroutine was also written to lag the water table response in the near-bank ground water depending on user settings. Eight BSTEM simulations were performed using combinations of the following input data: with and without a water table lag; default BSTEM geotechnical parameters (moderate silt loam) versus laboratory measured geotechnical parameters for the silt loam layer based on direct shear tests on saturated soil samples; and default BSTEM fluvial erosion parameters versus field measured fluvial erosion parameters from submerged jet tests on the silt loam layer. Using default BSTEM input values underestimated the actual erosion that occurred. Lagging the water table predicted more geotechnical failures resulting in greater bank retreat. Using measured fluvial and geotechnical parameters and a water table lag also under predicted bank retreat (approximately 4.0 m), but did predict the appropriate timing of bank collapses. C2 - 2011/// C3 - World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability - Proceedings of the 2011 World Environmental and Water Resources Congress DA - 2011/// DO - 10.1061/41173(414)209 SP - 1991-2000 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79960424136&partnerID=MN8TOARS ER - TY - JOUR TI - Evaluation of a stream-aquifer analysis test for deriving reach-scale streambed conductance AU - Fox, G.A. AU - Heeren, D.M. AU - Kizer, M.A. T2 - Transactions of the ASABE DA - 2011/// PY - 2011/// VL - 54 IS - 2 SP - 473-479 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79954527847&partnerID=MN8TOARS ER - TY - CONF TI - Measuring the erodibility of cohesive soils influenced by seepage forces using a laboratory jet erosion test device AU - Al-Madhhachi, A.-S.T. AU - Fox, G.A. AU - Tyagi, A.K. AU - Hanson, G.J. AU - Bulut, R. C2 - 2011/// C3 - American Society of Agricultural and Biological Engineers Annual International Meeting 2011, ASABE 2011 DA - 2011/// VL - 4 SP - 3030-3041 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-81255171946&partnerID=MN8TOARS ER - TY - CONF TI - Groundwater seepage mechanisms of streambank erosion and failure AU - Fox, G.A. AU - Wilson, G.V. AU - Midgley, T. AU - Almadhhachi, A. AU - Carson, R. C2 - 2011/// C3 - ASABE - International Symposium on Erosion and Landscape Evolution 2011 DA - 2011/// SP - 25-33 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84861644621&partnerID=MN8TOARS ER - TY - JOUR TI - Groundwater Seepage Mechanisms of Streambank Erosion and Failure AU - Fox, Garey A AU - Wilson, Glenn V AU - Midgley, Taber AU - Almadhhachi, Abdulsahib AU - Carson, Rachel T2 - International Symposium on Erosion and Landscape Evolution (ISELE), 18-21 September 2011, Anchorage, Alaska AB - The importance of groundwater seepage and pipeflow is unknown with respect to other fundamental processes of streambank erosion and failure, although seepage and pipeflow features are observed on streambanks throughout the world that span a range of geomorphologic conditions. Previous field and laboratory research on seepage erosion has demonstrated that groundwater seepage and pipeflow play an important role in the erosion and failure of streambanks. This previous research pointed to seepage forces and undercutting as causes, independent of fluvial forces, of bank failures in some stream systems. Specific seepage and pipeflow mechanisms that cause bank failure may never manifest themselves as transparent features on unstable banks. The objective of this research was to conduct more in-depth laboratory and field experiments to determine how groundwater flow mechanisms, potentially in combination with fluvial processes, affect the occurrence and timing of streambank erosion and failure. Current research activities include conducting three-dimensional soil column experiments to determine the occurrence and prevalence of different seepage erosion mechanisms (i.e., seepage gradient forces and undercutting) across a range of soil textures and cohesions and to identify typical undercut formations when seepage undercutting occurs. Seepage undercuts only formed in sands with a bulk density greater than 1.35 g/cm3 and in loamy sands with a bulk density greater than 1.50 g/cm3. For soils with greater clay content, seepage erosion undercuts may not occur under typical bulk densities. This research also monitored pore-water pressures in a streambank on Dry Creek, a tributary to Little Topashaw Creek located in Chickasaw County, Mississippi, before and during an induced seepage experiment. Seepage flow and erosion rates were measured in four separate experiments on three seeps and demonstrated the capability of seepage to rapidly destabilize streambanks, especially when acting in concert with processes that remove deposited material from the seepage undercut. Usually the erosion rate of cohesive soils from fluvial forces is computed using an excess shear stress equation, dependent on two major soil parameters: the critical shear stress and the erodibility coefficient. A submerged jet test apparatus is one method for measuring these parameters. In this study, a new miniature version of the jet test device and a seepage column were utilized to measure the erodibility of cohesive soils influenced by seepage. Erodibility of cohesive soils exponentially increased with higher seepage gradients. These laboratory and field experiments have further demonstrated the importance of considering seepage mechanisms relative to bank and hillslope stability. Groundwater forces can act over extended periods to destabilize banks between flow events, but specific seepage mechanisms become prevalent under certain streambank stratigraphy and hydrologic conditions. DA - 2011/// PY - 2011/// DO - 10.13031/2013.39206 ER - TY - JOUR TI - Comparison of subsurface and surface runoff phosphorus transport rates in alluvial floodplains AU - Mittelstet, Aaron R. AU - Heeren, Derek M. AU - Fox, Garey A. AU - Storm, Daniel E. AU - White, Michael J. AU - Miller, Ronald B. T2 - Agriculture, Ecosystems & Environment AB - Phosphorus (P) loading to streams can occur by both surface runoff and subsurface transport, with subsurface P transport often assumed negligible. Groundwater P concentrations in alluvial aquifers can be significant, especially in preferential flow paths (PFPs). The objectives of this research were to quantify subsurface P transport rates at two sites in northeastern Oklahoma and to compare them with surface runoff P transport rates derived from a hydrologic model, the Pasture Phosphorus Management Calculator (PPM Plus). Ozark ecoregion study sites were adjacent to the Barren Fork Creek and Honey Creek in northeastern OK, USA. Each site, instrumented with 24 observation wells, was monitored for several months for both groundwater levels and P concentrations. Using the flow and P concentration data, Monte Carlo simulations with Darcy's Law and a P transport rate equation were used to calculate the distributions of subsurface P transport rates across a transect within the well field containing a single identified PFP. Total subsurface P transport rates, through both the non-PFP flow domain and a single PFP, were estimated to be 0.04 kg year−1 and 0.03 kg year−1 for the Barren Fork Creek and Honey Creek field sites, respectively. Monte Carlo simulations for surface runoff P transport rates with PPM Plus resulted in average total P surface runoff transport rates of 0.07 kg year−1 for the Barren Fork Creek site and 0.08 kg year−1 for the Honey Creek site. For the groundwater at these floodplains, the P source was P-laden stream water flowing into the alluvial aquifer and a minimal quantity of P leaching from the surface. Results indicated that the subsurface P transport rates for small (3 ha) alluvial floodplain sites in the Ozark ecoregion were at least 0.03–0.04 kg year−1, although subsurface P transport rates may be higher in cases with greater numbers of PFPs and where the subsurface is connected to a larger P source. DA - 2011/5// PY - 2011/5// DO - 10.1016/j.agee.2011.04.006 VL - 141 IS - 3-4 SP - 417-425 J2 - Agriculture, Ecosystems & Environment LA - en OP - SN - 0167-8809 UR - http://dx.doi.org/10.1016/j.agee.2011.04.006 DB - Crossref KW - Alluvial floodplains KW - Hydrologic modeling KW - Phosphorus management KW - Preferential flow KW - Subsurface transport ER - TY - JOUR TI - Design and Application of a Direct-Push Vadose Zone Gravel Permeameter AU - Miller, R.B. AU - Heeren, D.M. AU - Fox, G.A. AU - Storm, D.E. AU - Halihan, T. T2 - Ground Water AB - A borehole permeameter is well suited for testing saturated hydraulic conductivity ( K sat ) at specific depths in the vadose zone. Most applications of the method involve fine‐grained soils that allow hand auguring of test holes and require a small water reservoir to maintain a constant head. In non‐cohesive gravels, hand‐dug test holes are difficult to excavate, holes are prone to collapse, and large volumes of water are necessary to maintain a constant head for the duration of the test. For coarse alluvial gravels, a direct‐push steel permeameter was designed to place a slotted pipe at a specific sampling depth. Measurements can be made at successive depths at the same location. A 3790 L (1000 gallons) trailer‐mounted water tank maintained a constant head in the permeameter. Head in the portable tank was measured with a pressure transducer and flow was calculated based on a volumetric rating curve. A U.S. Bureau of Reclamation analytical method was utilized to calculate K sat . Measurements with the permeameter at a field site were similar to those reported from falling‐head tests. DA - 2011/// PY - 2011/// DO - 10.1111/j.1745-6584.2010.00796.x VL - 49 IS - 6 SP - 920-925 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80052945273&partnerID=MN8TOARS ER - TY - JOUR TI - Comparison of Aquifer Sustainability Under Groundwater Administrations in Oklahoma and Texas1 AU - Mittelstet, Aaron R. AU - Smolen, Michael D. AU - Fox, Garey A. AU - Adams, Damian C. T2 - JAWRA Journal of the American Water Resources Association AB - Mittelstet, Aaron R., Michael D. Smolen, Garey A. Fox, and Damian C. Adams, 2011. Comparison of Aquifer Sustainability Under Groundwater Administrations in Oklahoma and Texas. Journal of the American Water Resources Association (JAWRA) 1-8. DOI: 10.1111/j.1752-1688.2011.00524.x Abstract: We compared two approaches to administration of groundwater law on a hydrologic model of the North Canadian River, an alluvial aquifer in northwestern Oklahoma. Oklahoma limits pumping rates to retain 50% aquifer saturated thickness after 20 years of groundwater use. The Texas Panhandle Groundwater Conservation District’s (GCD) rules limit pumping to a rate that consumes no more than 50% of saturated thickness in 50 years, with reevaluation and readjustment of permits every 5 years. Using a hydrologic model (MODFLOW), we simulated river-groundwater interaction and aquifer dynamics under increasing levels of “development” (i.e., increasing groundwater withdrawals). Oklahoma’s approach initially would limit groundwater extraction more than the GCD approach, but the GCD approach would be more protective in the long run. Under Oklahoma rules more than half of aquifer storage would be depleted when development reaches 65%. Reevaluation of permits under the Texas Panhandle GCD approach would severely limit pumping as the 50% level is approached. Both Oklahoma and Texas Panhandle GCD approaches would deplete alluvial base flow at approximately 10% development. Results suggest periodic review of permits could protect aquifer storage and river base flow. Modeling total aquifer storage is more sensitive to recharge rate and aquifer hydraulic conductivity than to specific yield, while river leakage is most sensitive to aquifer hydraulic conductivity followed by specific yield. DA - 2011/3/4/ PY - 2011/3/4/ DO - 10.1111/j.1752-1688.2011.00524.x VL - 47 IS - 2 SP - 424-431 LA - en OP - SN - 1093-474X UR - http://dx.doi.org/10.1111/j.1752-1688.2011.00524.x DB - Crossref KW - alluvial aquifer KW - water law KW - water policy KW - groundwater management KW - MODFLOW KW - groundwater model KW - groundwater-river interaction KW - conjunctive use ER - TY - CONF TI - Assessing streambank stability of oklahoma ozark streams with rapid geomorphic assessments AU - Heeren, D.M. AU - Mittelstet, A.R. AU - Fox, G.A. AU - Storm, D.E. AB - Streams in the Ozark Ecoregion naturally meander and have a high degree of sinuosity. Changes in land use have resulted in accelerated rates of streambank erosion. Numerous benefits may be achieved from streambank stabilization, but more information is needed on the most critical locations for investing limited funds. Rapid geomorphic assessments (RGAs) are indices proposed to aid in prioritizing sites. This research (1) evaluated two RGAs, the Bank Erosion Hazard Index (BEHI) and the Channel Stability Index (CSI), on several stream sites along the Barren Fork Creek and Spavinaw Creek, and (2) developed a new RGA specific to the ecoregion. The performance of the RGAs was assessed based on lateral bank erosion estimated from five years of aerial photography. Correlations between the existing RGAs and lateral bank erosion were relatively low with coefficients of determination, R2, of 0.23 and 0.19 for CSI and BEHI, respectively. The two RGAs failed to indicate the same reaches as the most unstable. Primary limitations were not considering the streambank's cohesion and the difficulty in accurately assessing some metrics. Therefore, the Ozark Stream Erosion Potential Index (OSEPI) was developed by including parameters to account for bank cohesion and stream curvature. The OSEPI had the highest correlation (R2 of 0.31 for all sites; R2 of 0.46 for sites with similar soils) to measured streambank erosion and aided in prioritizing sites. C2 - 2011/// C3 - World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability - Proceedings of the 2011 World Environmental and Water Resources Congress DA - 2011/// DO - 10.1061/41173(414)408 SP - 3907-3916 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79960395760&partnerID=MN8TOARS ER - TY - JOUR TI - Nitrate dynamics in artificially drained nested watersheds AU - Billy, C. AU - Birgand, F. AU - Sebilo, M. AU - Billen, G. AU - Tournebize, J. AU - Kao, C. T2 - Physics and Chemistry of the Earth, Parts A/B/C AB - There is concern that subsurface drainage, by destroying or by-passing active denitrification areas, may prevent nitrate retention processes and enhance nitrate contamination of surface water by agriculture. To address this question, we studied the flow and concentration signatures of drainage waters and their transformations in a series of 5 nested watersheds, from 1 to 100 km2 area, in the Brie region near Paris (France). At all scales, nitrate concentrations are generally higher during the winter drainage season compared to the low flow periods (late spring to early fall). High nitrate concentrations characterizing drainage waters are visible at the 1st, 2nd and 3rd stream order but are “diluted” by surface runoff from forested zones and buffered by groundwater contributions. The analysis of nitrate chemographs and nitrate budgets established for the different nested watersheds show significant nitrogen retention. Isotopic measurements indicate that the nitrate pool is enriched in δ15N–NO3- as its concentration decreases. Direct estimation of benthic denitrification with benthic chambers allowed concluding that benthic denitrification is not the only retention mechanism and that “underground” denitrification, affecting nitrate on its way from the base of the root zone down to the limit of the river bed, may in fact dominate nitrogen retention processes even in this intensively drained watershed. DA - 2011/1// PY - 2011/1// DO - 10.1016/j.pce.2008.09.007 VL - 36 IS - 12 SP - 506-514 J2 - Physics and Chemistry of the Earth, Parts A/B/C LA - en OP - SN - 1474-7065 UR - http://dx.doi.org/10.1016/j.pce.2008.09.007 DB - Crossref KW - Drainage KW - Nitrate retention KW - Denitrification KW - Nitrate-nitrogen isotopic composition ER - TY - JOUR TI - Composting for biodrying organic materials AU - Sadaka, Sammy AU - VanDevender, Karl AU - Costello, Tom AU - Sharara, Mahmoud DA - 2011/// PY - 2011/// ER - TY - BOOK TI - Application of an antibiotic resets the maize leaf phyllosphere community and increases resistance to southern leaf blight AU - Balint-Kurti, P. AU - Pridgen, P. AU - Stapleton, A.E. DA - 2011/// PY - 2011/// VL - 905 SE - 57-62 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80053399393&partnerID=MN8TOARS ER - TY - JOUR TI - Analysis of quantitative disease resistance to southern leaf blight and of multiple disease resistance in maize, using near-isogenic lines AU - Belcher, Araby R. AU - Zwonitzer, John C. AU - Cruz, Jose Santa AU - Krakowsky, Mathew D. AU - Chung, Chia-Lin AU - Nelson, Rebecca AU - Arellano, Consuelo AU - Balint-Kurti, Peter J. T2 - Theor Appl Genet DA - 2011/10// PY - 2011/10// DO - 10.1007/s00122-011-1718-1 VL - 124 IS - 3 SP - 433-445 ER - TY - CHAP TI - The status of vermicomposting in North America: A rapidly developing technology. AU - Sherman, R. AU - Bogdanov, P. T2 - Vermiculture Technology: Earthworms, Organic Waste, and Environmental Management PY - 2011/// SP - 391–408 PB - CRC Press ER - TY - JOUR TI - Long-term hydrology and water quality of a drained pine plantation in North Carolina AU - Amatya, D. M. AU - Skaggs, R. W. T2 - Transactions of the ASABE AB - Long-term data provide a basis for understanding natural variability, reducing uncertainty in model inputs and parameter estimation, and developing new hypotheses. This article evaluates 21 years (1988-2008) of hydrologic data and 17 years (1988-2005) of water quality data from a drained pine plantation in eastern North Carolina. The plantation age was 14 years at the beginning of the investigation (1988) and 34 years at the end (2008). The 21-year average rainfall of 1517 mm was 9% higher than the 50-year (1951-2000) long-term average of 1391 mm observed at the nearest U.S. Weather Bureau station in Morehead City, North Carolina. Annual rainfall varied from 852 mm in the driest year (2001) to 2331 mm in the wettest year (2003) during the study period and was affected by several hurricanes and tropical storms. The runoff coefficient (ROC; drainage outflow expressed as a fraction of rainfall) varied from 0.05 in the driest year to as high as 0.56 in the wettest year (2003), with an average ROC of 0.32. Annual outflow (runoff) on this watershed was primarily subsurface flow to drainage ditches and was strongly correlated with rainfall (R2 = 0.81). Outflows were greater, more continuous, and longer in winter than in other seasons. Outflow in winter was 59% of rainfall on average. March was the only month that never produced zero outflow. The lowest mean outflow occurred in the spring and was significantly different from the other three seasons. Consistent with theory for subsurface drainage, outflow from this poorly drained land is dependent on water table elevation and occurs when the water table is within about 1.1 m of the surface. The water table tended to be close to the surface during the winter and early spring with low ET demands, and during summer with hurricanes and tropical storms producing large outflows, but was drawn down to depths much deeper than the drains during long dry periods in summer and fall. As a result, annual outflow and annual average water table depth were only weakly correlated (R2 = 0.52). There was no relationship (R2 = 0.01) between the annual average water table depth and the annual average evapotranspiration (ET), calculated as the difference between annual rainfall and outflow. The estimated average annual ET of 1005 mm was close to the Penman-Monteith based average annual potential ET (PET) of 1010 mm for a grass reference. Although nitrogen (N) levels in the drainage water were elevated after fertilization of the stand in late 1988, these elevated levels declined substantially by 1995. Average annual concentrations of total N ranged from 0.51 to 2.23 mg L-1 with a long-term average of 1.10 mg L-1. Annual average values for total P ranged from 0.01 to 0.12 mg L-1 with an average of 0.04 mg L-1. The highest average annual concentrations for N and P occurred in 1989 (N) and 1990 (P) following fertilization in spring of 1989. The average annual total N and P loadings were 6.5 5.3 kg ha-1 and 0.17 0.11 kg ha-1, respectively. Both concentrations and annual loadings were similar to other forested sites in the region. These long-term data should be useful for assessing the effects of land use change and management treatments on the hydrology and water quality of similar lands in the coastal region. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40667 VL - 54 IS - 6 SP - 2087-2098 ER - TY - JOUR TI - Linking plant ecology and long-term hydrology to improve wetland restoration success AU - Caldwell, P. V. AU - Vepraskas, M. J. AU - Gregory, J. D. AU - Skaggs, R. W. AU - Huffman, R. L. T2 - Transactions of the ASABE AB - Although millions of dollars are spent restoring wetlands, failures are common, in part because the planted vegetation cannot survive in the restored hydrology. Wetland restoration would be more successful if the hydrologic requirements of wetland plant communities were known so that the most appropriate plants could be selected for the range of projected hydrology at the site. Here we describe how hydrologic models can be used to characterize the long-term hydrology of wetland plant communities, and we show how these results can be used to define wetland design criteria. In our study, we quantified differences in long-term (40-year) hydrologic characteristics of the pond pine woodland (PPW), nonriverine swamp forest (NRSF), high pocosin (HP), and bay forest (BF) plant communities native to the North Carolina Coastal Plain. We found that the median water level was 8 cm below the land surface in PPW and 9, 2, and 8 cm above the land surface for NRSF, HP, and BF, respectively. When the land surface was inundated, the median duration of inundation was 91 d year-1 for PPW and 317, 243, and 307 d year-1 for NRSF, HP, and BF, respectively. Our models suggested that the PPW received an average of 15% of its water input from groundwater inflow, whereas the other communities we modeled did not appear to receive groundwater inflow. Using these results and soil organic layer thickness, we developed and propose design criteria linking soil, vegetation, and hydrology parameters that should contribute to improved restoration success. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40662 VL - 54 IS - 6 SP - 2129-2137 ER - TY - JOUR TI - Leaf area index (lai) of loblolly pine and emergent vegetation following a harvest AU - Sampson, D. A. AU - Amatya, D. M. AU - Lawson, C. D. B. AU - Skaggs, R. W. T2 - Transactions of the ASABE AB - Forests provide goods and services to society and, often, refugia for plants and animals; forest managers utilize silviculture to provide ecosystem services and to create habitat. On the Coastal Plain of North Carolina, forest management objectives typically include wood fiber production but may also include the maintenance of environmental quality and, sometimes, species diversity. Silvicultural prescriptions alter stand structure and development trajectories by influencing the competitive interactions among plant species for site resources. Early site intervention may include nutrient additions and/or vegetation control; in coastal loblolly pine (Pinus taeda L.) stands, herbaceous and arborescent species can dominate the site leaf area index (LAI) for many years after a harvest (followed by planting). LAI is an important structural and functional component of a forest stand. Many eco-hydrologic and water quality models do not accurately account for LAI as the process driver to evapotranspiration (ET), and thus they ignore the ecophysiological effects of LAI on site water balance and nutrient loading. We measured LAI of emergent vegetation following a harvest, mechanical site preparation, and then pine planting for a drained loblolly pine plantation in coastal North Carolina. For six years monthly, growing season estimates of LAI were obtained using a LI-COR LAI 2000 Plant Canopy Analyzer (PCA) for control (D1), thinned (D3), and harvested (D2) watersheds. In this article, we present results from the D2 treatment. In D2, we harvested all emergent vegetation in 18 randomly placed 1 m2 clip plots for three growing seasons where we estimated LAI using species-pooled estimates of specific leaf area and total leaf dry mass (i.e., LAICLIP); PCA measurements were recorded prior to clipping (LAIPCA). We also simulated loblolly pine seedling growth and development using the biogeochemical process model SECRETS-3PG to examine site differentiation in LAI. Four years post-harvest maximum LAICLIP exceeded 8 m2 m-2 (projected area basis). LAIPCA underestimated LAICLIP; LAICLIP = 1.436 LAIPCA (r2 = 0.53; p < 0.0001; n = 195). Corrected LAIPCA estimates exceeded simulated pine LAI (LAISIM) for ~4.5 years post-planting. Emergent vegetation dominated the site for nearly five years and likely exerted a strong influence over site water balance and nutrient use during early stand development. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40664 VL - 54 IS - 6 SP - 2057-2066 ER - TY - JOUR TI - Estimating Nitrogen, Phosphorus, and Carbon Fluxes in Forested and Mixed-Use Watersheds of the Lower Coastal Plain of North Carolina: Uncertainties Associated with Infrequent Sampling AU - Birgand, F. AU - Appelboom, T. W. AU - Chescheir, G. M. AU - Skaggs, R. W. T2 - Transactions of the ASABE AB - Assessing the impact of a land use change or the water quality improvement provided by a treatment system almost always involves computation of the difference in nutrient loads before and after implementation, or upstream and downstream of the system studied. Reporting meaningful values on mass balance or differences in nutrient loads implies that the uncertainty in the computed loads is several times smaller than the difference itself. This may imply very small uncertainties for the nutrient load measurements. The level of uncertainty induced by infrequent sampling on annual loads was investigated for a suite of nutrients in runoff from a forested watershed and a mixed land use watershed in the lower coastal plain of North Carolina. Reference data were used to simulate discrete sampling and to calculate new annual load estimators, which were then compared to the reference loads to calculate the level of uncertainty. Uncertainties depended on the watershed and the nutrients and other constituents, but their level was generally found to be high, around 20% and 40% or more for weekly and monthly sampling for most nutrients. This was generally attributed to the short periods of active flow in these watersheds and the flashiness of flow associated with subsurface drainage. The results suggest that to obtain uncertainties of 2% or 5% for nitrogen forms, 100 or more than 200 samples over six months of the year might be necessary in the forested and mixed-use watersheds of the lower coastal plain. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40668 VL - 54 IS - 6 SP - 2099-2110 LA - en OP - SN - 2151-0040 UR - http://dx.doi.org/10.13031/2013.40668 DB - Crossref ER - TY - JOUR TI - Effects of land use on soil properties and hydrology of drained coastal plain watersheds AU - Skaggs, R. W. AU - Chescheir, G. M. AU - Fernandez, G. P. AU - Amatya, D. M. AU - Diggs, J. T2 - Transactions of the ASABE AB - Some of the world's most productive cropland requires artificial or improved drainage for efficient agricultural production. Soil hydraulic properties, such as hydraulic conductivity and drainable porosity, are conventionally used in design of drainage systems. While it is recognized that these soil properties vary over a relatively wide range within a given soil series, it is generally assumed they can be approximated based on soil type, independent of crop or land use. Effects of land use on hydrology of drained soils in the North Carolina lower coastal plain were investigated by comparing hydrologic measurements on drained agricultural cropland, drained forest land (Loblolly pine), and an undrained forested wetland. Higher ET on the drained pine forest site resulted in reduced drainage outflow and deeper water tables compared to the agricultural site. Measurements for the wetland site showed water tables near the surface but annual outflows similar to the drained forest site. Field effective hydraulic conductivity in the top 70 cm of the drained forest site was more than two orders of magnitude greater than that of corresponding layers of the soil on the agricultural site. Drainable porosity, based on measured soil water characteristics, was also much higher for the forested sites. Long term (50-year) DRAINMOD simulations predicted average annual drainage outflow of 51.4 cm for the agricultural field as compared to 37.6 cm for the forested site. The difference resulted primarily from greater ET predicted for the forested site. Because of the high hydraulic conductivity of the surface layers and large surface depressional storage, predicted surface runoff from the forested site was nil, compared to an average annual runoff of 13 cm for the drained cropland site. Results of long-term simulations were used to analyze these effects for the widely variable seasonal and annual weather conditions of eastern North Carolina. DA - 2011/// PY - 2011/// DO - 10.13031/2013.39037 VL - 54 IS - 4 SP - 1357-1365 ER - TY - JOUR TI - Effect of minor drainage on hydrology of forested wetlands AU - Skaggs, R. W. AU - Phillips, B. D. AU - Chescheir, G. M. AU - Trettin, C. C. T2 - Transactions of the ASABE AB - Results of a simulation study to determine the impacts of minor drainage for silviculture on wetland hydrology are presented in this article. Long-term DRAINMOD simulations were conducted to determine the threshold drainage intensity (ditch depth and spacing) that removes wetland hydrology from forested wetlands. Analyses were conducted for 13 soil series and profile combinations at ten locations from Norfolk, Virginia, to Baton Rouge, Louisiana, in the Atlantic and Gulf coastal states. Threshold ditch spacings (LT) were obtained for five ditch depths for all combinations of soil profiles and locations. Analysis of the results showed that LT can be approximated as LT = , where T is the horizontal hydraulic transmissivity of the soil profile, and C is a coefficient dependent on ditch depth and geographic location. The C values for all combinations of ditch depth and location are given in this article. The threshold spacings can be used as benchmarks to directly evaluate the impact of drainage alternatives on wetland hydrology. They were also used herein to determine T25 inputs for previously developed methods to predict the lateral impact of a single ditch on wetland hydrology. Lateral impacts were determined and presented for a 0.9 m (3 ft) deep drainage ditch for all soils and locations considered. The T25 values presented can be used to determine lateral impacts for other ditch depths and soils. The analyses in this study were conducted for a surface depressional storage of 5 cm. More work is needed to define T25 values for smaller surface storages, including those smaller values needed for application to agricultural cropland. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40665 VL - 54 IS - 6 SP - 2139-2149 ER - TY - JOUR TI - Determination of aflatoxin risk components for in-shell Brazil nuts AU - Vargas, E. A. AU - Santos, E. A. AU - Whitaker, T. B. AU - Slate, A. B. T2 - FOOD ADDITIVES AND CONTAMINANTS PART A-CHEMISTRY ANALYSIS CONTROL EXPOSURE & RISK ASSESSMENT AB - A study was conducted on the risk from aflatoxins associated with the kernels and shells of Brazil nuts. Samples were collected from processing plants in Amazonia, Brazil. A total of 54 test samples (40 kg) were taken from 13 in-shell Brazil nut lots ready for market. Each in-shell sample was shelled and the kernels and shells were sorted in five fractions: good kernels, rotten kernels, good shells with kernel residue, good shells without kernel residue, and rotten shells, and analysed for aflatoxins. The kernel:shell ratio mass (w/w) was 50.2/49.8%. The Brazil nut shell was found to be contaminated with aflatoxin. Rotten nuts were found to be a high-risk fraction for aflatoxin in in-shell Brazil nut lots. Rotten nuts contributed only 4.2% of the sample mass (kg), but contributed 76.6% of the total aflatoxin mass (µg) in the in-shell test sample. The highest correlations were found between the aflatoxin concentration in in-shell Brazil nuts samples and the aflatoxin concentration in all defective fractions (R(2)=0.97). The aflatoxin mass of all defective fractions (R(2)=0.90) as well as that of the rotten nut (R(2)=0.88) were also strongly correlated with the aflatoxin concentration of the in-shell test samples. Process factors of 0.17, 0.16 and 0.24 were respectively calculated to estimate the aflatoxin concentration in the good kernels (edible) and good nuts by measuring the aflatoxin concentration in the in-shell test sample and in all kernels, respectively. DA - 2011/// PY - 2011/// DO - 10.1080/19440049.2011.596488 VL - 28 IS - 9 SP - 1242-1260 SN - 1944-0057 KW - survey KW - exposure KW - risk assessment KW - mycotoxins KW - aflatoxins ER - TY - JOUR TI - Advances in forest hydrology: Challenges and opportunities AU - Amatya, D. M. AU - Douglas-Mankin, K. R. AU - Williams, T. M. AU - Skaggs, R. W. AU - Nettles, J. E. T2 - Transactions of the ASABE AB - Forests are an integral component of the landscape, and maintaining their functional integrity is fundamental for the sustainability of ecosystems and societies alike. Tools, innovations, and practices, analogous to those developed to improve agricultural production and quantify environmental impacts, are needed to ensure the sustainability of these forested landscapes as well as the ecosystem goods and services they produce. This article introduces ten technical articles on critical ecohydrologic processes, protection and restoration, and the effects of management practices on the hydrology and water quality of forests and forested wetlands, using both monitoring and modeling approaches. Prepared by experts in forest science, forest and agricultural hydrology, and water management, the studies reported in this special collection are concentrated in the Atlantic Coastal plain and focus on forests with shallow water tables. Experimental studies describe the effects of riparian vegetation harvest, human disturbance, and future climatic change on groundwater, the significance of emergent vegetation after harvest, and long-term hydrologic water balance of a managed pine forest. Modeling studies use the SWAT model to predict streamflow dynamics of a less disturbed, coastal forested watershed, and DRAINMOD to determine the impacts of minor silvicultural drainage on wetland hydrology and to improve wetland restoration. Finally, a study describes potential uncertainties associated with infrequent water sampling of nutrient loads from drained forested watersheds. This introductory article summarizes these studies of shallow water table forests and relates them to the broader field of forest hydrology, including its challenges and opportunities, while identifying pressing issues of land use and climate change. The results from these studies should help guide management and restoration of forest wetland ecosystems and direct future forest hydrologic research, including research in large prior converted agricultural landscapes. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40672 VL - 54 IS - 6 SP - 2049-2056 ER - TY - JOUR TI - Suppression of the 2010 Alexandrium fundyense bloom by changes in physical, biological, and chemical properties of the Gulf of Maine AU - McGillicuddy, D. J., Jr. AU - Townsend, D. W. AU - He, R. AU - Keafer, B. A. AU - Kleindinst, J. L. AU - Li, Y. AU - Manning, J. P. AU - Mountain, D. G. AU - Thomas, M. A. AU - Anderson, D. M. T2 - LIMNOLOGY AND OCEANOGRAPHY AB - For the period 2005–2009, the abundance of resting cysts in bottom sediments from the preceding autumn was a first‐order predictor of the overall severity of spring–summer blooms of Alexandrium fundyense in the western Gulf of Maine and southern New England. Cyst abundance off mid‐coast Maine was significantly higher in autumn 2009 than it was preceding a major regional bloom in 2005. A seasonal ensemble forecast was computed using a range of forcing conditions for the period 2004–2009, suggesting that a large bloom was likely in the western Gulf of Maine in 2010. This did not materialize, perhaps because environmental conditions in spring–summer 2010 were not favorable for growth of A. fundyense . Water mass anomalies indicate a regional‐scale change in circulation with direct influence on A. fundyense 's niche. Specifically, near‐surface waters were warmer, fresher, more stratified, and had lower nutrients than during the period of observations used to construct the ensemble forecast. Moreover, a weaker‐than‐normal coastal current lessened A. fundyense transport into the western Gulf of Maine and Massachusetts Bay. Satellite ocean color observations indicate the 2010 spring phytoplankton bloom was more intense than usual. Early season nutrient depletion may have caused a temporal mismatch with A. fundyense 's endogenous clock that regulates the timing of cyst germination. These findings highlight the difficulties of ecological forecasting in a changing oceanographic environment, and underscore the need for a sustained observational network to drive such forecasts. DA - 2011/11// PY - 2011/11// DO - 10.4319/lo.2011.56.6.2411 VL - 56 IS - 6 SP - 2411-2426 SN - 0024-3590 ER - TY - JOUR TI - Fine particulate matter in a high-rise layer house and its vicinity AU - Li, Q. AU - Wang-Li, L. AU - Shah, S.B. AU - Jayanty, R.K.M. AU - Bloomfield, P. T2 - Transactions of the ASABE DA - 2011/// PY - 2011/// VL - 54 IS - 6 SP - 2299-2310 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84862921384&partnerID=MN8TOARS ER - TY - JOUR TI - Field Evaluation of Bioretention Indicator Bacteria Sequestration in Wilmington, North Carolina AU - Hathaway, J. M. AU - Hunt, W. F. AU - Graves, A. K. AU - Wright, J. D. T2 - JOURNAL OF ENVIRONMENTAL ENGINEERING AB - Although bioretention has been shown to remove or sequester a wide range of pollutants, relatively little study has been performed to evaluate its ability to sequester indicator bacteria. Two adjacent bioretention areas in Wilmington, North Carolina, were studied. The primary difference in the design of the two systems was soil depth. One bioretention cell was constructed with 25 cm of fill soil (Bioretention-S) and one with 60 cm of fill soil (Bioretention-D). The systems performed differently for indicator bacteria on the basis of multiple performance evaluation metrics. Bioretention-D showed concentration reductions of 70% and 89% for E. coli and enterococci, respectively. Effluent concentrations from Bioretention-D compared well to US EPA target values and other studies in literature. Conversely, Bioretention-S showed concentration “reductions” of -119% and -102% for E. coli and enterococci, respectively. Effluent concentrations from Bioretention-S were substantially higher than USEPA target values and other studies in literature. Multiple factors were evaluated to determine the cause of performance differences between the two cells. The 25 cm of fill soil in Bioretention-S exhibited poorer runoff detention, likely because of higher soil water flux and decreased contact time relative to Bioretention-D. These differences seemingly led to diminished indicator bacteria sequestration. The results of this study suggest soil depth and hydraulic loading are important design parameters for bioretention implemented to sequester microbes. DA - 2011/12// PY - 2011/12// DO - 10.1061/(asce)ee.1943-7870.0000444 VL - 137 IS - 12 SP - 1103-1113 SN - 1943-7870 KW - Storm water KW - Bioretention KW - Biofiltration KW - Indicator bacteria KW - E. coli KW - Enterococci ER - TY - JOUR TI - Use of mutant-assisted gene identification and characterization (MAGIC) to identify novel genetic loci that modify the maize hypersensitive response AU - Chaikam, Vijay AU - Negeri, Adisu AU - Dhawan, Rahul AU - Puchaka, Bala AU - Ji, Jiabing AU - Chintamanani, Satya AU - Gachomo, Emma W. AU - Zillmer, Allen AU - Doran, Timothy AU - Weil, Cliff AU - Balint-Kurti, Peter AU - Johal, Guri T2 - THEORETICAL AND APPLIED GENETICS DA - 2011/10// PY - 2011/10// DO - 10.1007/s00122-011-1641-5 VL - 123 IS - 6 SP - 985-997 SN - 1432-2242 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84857082490&partnerID=MN8TOARS ER - TY - JOUR TI - Pretreatment of Corn Stover for Sugar Production with Combined Alkaline Reagents AU - Zhang, Ximing AU - Xu, Jiele AU - Cheng, Jay J. T2 - ENERGY & FUELS AB - Corn stover pretreatment using a combination of sodium hydroxide (NaOH) and calcium oxide (CaO) at room temperature was investigated for improved cost-effectiveness of biomass-to-sugar conversion in this study. The effects of NaOH loading, CaO loading, and residence time on enzymatic hydrolysis were studied, and the total reducing sugar yield in the enzymatic hydrolysis was used to evaluate the pretreatment conditions. Compared with NaOH pretreatment, pretreatment with the combination of NaOH and CaO resulted in a similar sugar production rate but at a potentially lower cost. The addition of CaO not only increased the alkalinity, which favored biomass digestibility improvement, but also contributed to better biomass preservation in the pretreatment. On the basis of the sugar production rate and cost-benefit considerations, the two recommended pretreatment conditions were 3 h, 0.05 g NaOH g–1 raw biomass, 0.1 g CaO g–1 raw biomass and 6 h, 0.05 g NaOH g–1 raw biomass, 0.05 g CaO g–1 raw biomass, at which the total reducing sugar yields were 529.0 and 538.9 mg g–1 raw biomass, respectively, with overall carbohydrate conversions of 75.6 and 77.0%, respectively. DA - 2011/10// PY - 2011/10// DO - 10.1021/ef201130d VL - 25 IS - 10 SP - 4796-4802 SN - 0887-0624 ER - TY - JOUR TI - Ammonia emissions from broiler cake stockpiled in a naturally ventilated shed AU - Yao, H. AU - Shah, Sanjay AU - Willits, D. H. AU - Westerman, P. W. AU - Li, L. W. AU - Marshall, T. K. T2 - Transactions of the ASABE AB - Due to concerns about the negative environmental impacts of ammonia (NH3), the EPA may soon regulate NH3 emissions from livestock operations, including waste piles. This would require knowledge of NH3 emission rates, but there are very few field-scale studies on emission measurement from broiler waste stockpiles. This is the first study in which short-term NH3 fluxes from broiler cake stockpiled in a shed were measured, taking into account both forced and natural convection. Acid scrubbers were used to measure NH3 concentrations, while the integrated horizontal flux (IHF) method and Fick's law of diffusion were used to determine NH3 emissions due to forced and natural convection, respectively. Average daily air temperature and wind speed 0.75 m above the stockpile were 24.9C and 0.65 m s-1 in summer and 8.5C and 1.02 m s-1 in winter. Natural convection accounted for <0.01% of total emission, but not isolating gas concentrations during forced convection conditions generally led to overestimation of emission. In summer (7 d), NH3-N emission factors were 17 g m-2 d-1 (stockpile surface area), 30 g m-3 d-1 (stockpile volume), 1.8 g kg-1 N d-1 (initial cake N content), and 11 g AU-1 d-1 (where AU = 500 kg live weight marketed). During the first 7 d of the winter study, the emission factors were 27 g m-2 d-1, 43 g m-3 d-1, 2.1 g kg-1 N d-1, and 18 g AU-1 d-1, respectively. For the 15 d study, the emission factors changed very little. Higher emissions in winter were due to higher wind speeds, broiler cake total Kjeldahl N (TKN), and pH. While air temperature also affected emissions, stockpile temperatures (not measured) due to microbial activity were probably more important. Care should be taken in extrapolating this study's results to other stockpiles due to differences in stockpile dimensions, chemical properties, and environmental conditions. DA - 2011/// PY - 2011/// DO - 10.13031/2013.39830 VL - 54 IS - 5 SP - 1893–1904 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-81755163497&partnerID=MN8TOARS ER - TY - JOUR TI - Adsorption of ammonia on ozonated activated carbon AU - Love, C. D. AU - Kolar, P. AU - Classen, John AU - Das, L. T2 - Transactions of the ASABE AB - In this theoretical research, we investigated ozonated granular activated carbon (OGAC) as an ammonia adsorbent in aqueous systems. Research objectives were to determine the (1) effectiveness of ozone loading on adsorption capacity of activated carbon in aqueous ammonia solutions, (2) kinetics and adsorption isotherms of ammonia adsorption, and (3) effect of volatile organic compounds on adsorption of ammonia from the aqueous phase. Batch experiments indicated that ozonation for 30 min enhanced the adsorption capacity of granular activated carbon from 0.47 0.065 mg g-1 to 1.02 0.099 mg g-1 due to increased surface oxygen species on activated carbon. These results suggested that activated carbon could be chemically modified to enhance the adsorption of ammonia from aqueous systems. Analysis of the rate data suggested that the adsorption of ammonia on OGAC followed an Elovich model with initial adsorption rate (a) and desorption constants () between 0.146 and 1.06 mg g-1 min-1 and 5.5 and 7.75 g mg-1, respectively (25C to 45C). The effect of temperature (25C to 45C) on adsorption was not found to be significant, suggesting that adsorption on OGAC was non-activated. However, presence of volatile organic compounds (VOCs) such as p-cresol and acetic acid inhibited adsorption of ammonia on OGAC. Future research is needed to synthesize activated carbon that can absorb ammonia and VOCs simultaneously. DA - 2011/// PY - 2011/// DO - 10.13031/2013.39834 VL - 54 IS - 5 SP - 1931–1940 ER - TY - JOUR TI - Underdrain Configuration to Enhance Bioretention Exfiltration to Reduce Pollutant Loads AU - Brown, R. A. AU - Hunt, W. F. T2 - JOURNAL OF ENVIRONMENTAL ENGINEERING AB - The bioretention drainage configuration of raising the outlet to create an internal water storage (IWS) layer in the media was originally intended to promote denitrifying conditions. The goal was to reduce nitrate and total nitrogen concentrations in nutrient-sensitive watersheds. Two field studies in the Piedmont region of North Carolina, where the in situ soils typically have high clay content, showed this design feature had potential to enhance exfiltration and reduce drainage from bioretention. Two bioretention cells in Rocky Mount, North Carolina, were monitored for two year-long periods to measure the impact of varying IWS zone depths over sandier underlying soils. Nearly 99% of runoff entering the bioretention cell with sand underlying soil (sand cell) was never directly discharged to the storm water network. However, the hydraulic retention time (contact time) of runoff in the media was less than 3 h, and except for total suspended solids (TSS), minimal pollutant removal was achieved. The other bioretention cell had a sandy clay loam underlying soil (SCL cell); the percentage of runoff leaving via exfiltration and evapotranspiration from this cell was 87% during the monitoring period with a 1.03-m IWS zone depth and 75% when the IWS zone depth was 0.73 m. The underlying soil of the SCL cell had a lower hydraulic conductivity, so water would remain in the IWS zone for up to 7 days. The increased hydraulic retention time in the media resulted in lower outflow concentrations. For events monitored with drainage from the SCL cell, efficiency ratios of all the nitrogen species and TSS exceeded 0.5. As an additional metric of performance, the parking lot runoff and treated runoff from both the SCL and sand cells were compared to concentrations consistent with “good” and “fair” benthic macroinvertebrate health in streams. Using this metric, the parking lot runoff only met the “fair” standard for total nitrogen (TN) and total phosphorus (TP), and treated runoff from the SCL cell achieved the “good” standard for both TN and TP. However, because of the short hydraulic retention time of runoff in the media for the sand cell, this cell only maintained the “fair” standard for TN and did not achieve the “fair” standard for TP. DA - 2011/11// PY - 2011/11// DO - 10.1061/(asce)ee.1943-7870.0000437 VL - 137 IS - 11 SP - 1082-1091 SN - 1943-7870 KW - Internal water storage (IWS) zone KW - Bioretention KW - Hydrology KW - Water quality KW - Drainage configuration KW - Coastal plain KW - Exfiltration KW - Low impact development ER - TY - JOUR TI - Stormwater control measure (SCM) design standards to limit stream erosion for Piedmont North Carolina AU - Tillinghast, E. D. AU - Hunt, W. F. AU - Jennings, G. D. T2 - JOURNAL OF HYDROLOGY AB - This study evaluated the potential impacts of sub-bankfull flows produced by stormwater control measures (SCMs) on stream geomorphic stability. In part, design standards for SCMs include peak flow attenuation to maintain pre-development flow conditions to those of undeveloped watersheds or return urbanized, developed watersheds back to the pre-developed state. Most SCMs target lower frequency storms, usually the 2-and/or 10-year discharge events, but leave peak flows resulting from higher frequency storms uncontrolled. SCMs are possibly subjecting streams to longer and more frequent periods of erosion, increasing stream channel instability. The d65 substrate size, pattern, profile, and dimension of 33 reference stream cross-sections in Piedmont North Carolina were modeled using the continuous simulations program, SWMM, to develop (1) a unit critical discharge metric in L/s/ha, Qc = 0.0035(d65)1.5048, (2) allowable annual erosional hour standard, Log(AAEH) = −1.26Log(d65) + 1.21, and (3) allowable volume of eroded bedload standard, Log(AV) = −0.64(Qc) − 1.52, for watersheds containing SCMs discharging into surface waters. The unit critical discharge represents a threshold that, once exceeded, incipient motion of the d65 particle can occur. These standards represented benchmarks of stable, naturally eroding reference streams. Ninety-four percent of the unit critical discharges were less than the 2-year 24-h event, indicating the necessity of controlling higher frequency sub-bankfull flows. The standards were applied to an urbanized watershed (one sub-catchment containing a structural SCM and two sub-catchments without) in Raleigh, North Carolina. The unit critical discharge metric appeared to adequately represent urbanized stream geomorphic processes for the sub-catchment undergoing urbanization (4.5% difference) but not for the mature urbanized sub-catchments (47.5% and 68.8% difference). Depending on the long-term management goal of the unstable stream, this metric is not applicable for all urbanized watersheds due to the discrepancy between the field and calculated unit critical discharges. Standards developed from urbanized reference streams could possibly better represent SCMs in urbanized watersheds. All three sub-catchments failed to meet the erosional standards demonstrating the ability of the standards to predict unstable geomorphic processes in streams. The addition of a detention SCM (wet pond), in the urbanized sub-catchment extended the duration of erosive flows from 37 to 87 h/ha/yr, but reduced the estimated volume of eroded bedload from 1.81 to 0.99 m3/m/ha/yr when compared to uncontrolled urbanization (no wet pond). Alterations to the design of the wet pond, increased volume size and change in orifice diameter, were explored to see if erosional standards could be better met. This study demonstrated the effect of current SCM design standards on stream stability and why geomorphic processes of stream channels should be incorporated in SCM design standards. DA - 2011/12/9/ PY - 2011/12/9/ DO - 10.1016/j.jhydrol.2011.09.027 VL - 411 IS - 3-4 SP - 185-196 SN - 1879-2707 KW - Stormwater control measures KW - Stream geomorphology KW - Stream erosion KW - Erosional hours KW - Sediment transport KW - SWMM 5.0 ER - TY - JOUR TI - Solvent extraction and quantification of capsaicinoids from Capsicum chinense AU - Chinn, Mari S. AU - Sharma-Shivappa, Ratna R. AU - Cotter, Jacqueline L. T2 - FOOD AND BIOPRODUCTS PROCESSING AB - Capsaicinoid extraction from peppers is typically performed using organic solvents, however, the extraction efficiencies can vary with peppers, their parts and pre-extraction processing. In the absence of in depth information on capsaicinoid extraction from habañero peppers, this work was undertaken to examine the processing parameters for solvent extraction of capsaicinoids from whole habañero peppers (Capsicum chinense) and their various parts. The effects of solvent type (ethanol, acetone and acetonitrile), pepper part(s) (seeds, shells), tissue preparation (freeze and oven drying), and time on capsaicinoid recovery (capsaicin and dihydrocapsaicin) were evaluated. Across all solvents, capsaicin yields were on average 16, 5 and 8 mg/g dry pepper part for seeds, shells and whole peppers, respectively. Dihydrocapsaicin yield ranged from 0.65 to 9.17 mg/g dry pepper depending on interaction between parts and preparation. Overall, higher yields of capsacinoids were obtained from oven-dried peppers using acetone as the solvent. DA - 2011/10// PY - 2011/10// DO - 10.1016/j.fbp.2010.08.003 VL - 89 IS - C4 SP - 340-345 SN - 0960-3085 KW - Habanero peppers KW - Capsaicin KW - Dihydrocapsaicin KW - Extraction KW - Ethanol KW - Acetone KW - Acetonitrile ER - TY - JOUR TI - Nitrogen and Cutting Height Influence Root Development during Warm-Season Turfgrass Sod Establishment AU - Wherley, B. G. AU - Sinclair, T. R. AU - Dukes, M. D. AU - Schreffler, A. K. T2 - AGRONOMY JOURNAL AB - Effective water conservation in the landscape requires identification of cultural management practices that maximize the genetic rooting potential of establishing turfgrass sod. Nitrogen is critical for successful turfgrass establishment; however, there has recently been debate over whether to restrict N fertilization during summer periods in parts of Florida and the United States. This study was undertaken to examine within four warm‐season turfgrass species, the relative influences of cutting height and N fertility on the (i) rate of root extension and (ii) root biomass produced over a 10‐wk period. ‘Tifway 419’ bermudagrass ( Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy), ‘Empire’ zoysiagrass ( Zoysia japonica Steud.), ‘Argentine’ bahiagrass ( Paspalum notatum Flugge), and ‘Floratam’ St. Augustinegrass ( Stenotaphrum secundatum Walt. Kuntze) were established from 10‐cm diam. by 5‐cm deep plugs of turfgrass sod into 90‐cm tall, clear acrylic tubes. Experimental treatments were arranged in a complete factorial that was repeated over two growing seasons. Rates of root extension were calculated from weekly measures of the deepest visible root in each column. Root extension rates ranged from ∼1.0 to 1.8 cm d −1 during the studies, with bahiagrass exhibiting the most rapid root extension of the four species. The results demonstrated that increasing N fertility during establishment increased rates of root extension into deep soil, particularly in bermudagrass. Height of cut had no effect on rate of root extension for most species, but higher cutting height did promote more rapid root extension in bermudagrass. Although not significantly accelerating vertical root extension in most species, maintaining sod at the higher cutting heights resulted in significantly greater root proliferation within both upper and lower soil depths for all species. The results emphasize the importance of proper N fertility and cutting heights for optimizing root development of different turfgrass species during sod establishment. DA - 2011/// PY - 2011/// DO - 10.2134/agronj2011.0146 VL - 103 IS - 6 SP - 1629-1634 SN - 0002-1962 ER - TY - JOUR TI - Modeling biochemical conversion of lignocellulosic materials for sugar production: a Review AU - Wang, Z. Y. AU - Xu, J. L. AU - Cheng, J. J. T2 - BioResources DA - 2011/// PY - 2011/// VL - 6 IS - 4 SP - 5282-5306 ER - TY - JOUR TI - Long-term impact of farming practices on soil organic carbon and nitrogen pools and microbial biomass and activity AU - Wang, Yi AU - Tu, Cong AU - Cheng, Lei AU - Li, Chunyue AU - Gentry, Laura F. AU - Hoyt, Greg D. AU - Zhang, Xingchang AU - Hu, Shuijin T2 - SOIL & TILLAGE RESEARCH AB - Conventional agriculture with intensive tillage and high inputs of synthetic chemicals has critically depleted the soil C pools. Alternative practices such as no-tillage and organic inputs have been shown to increase soil C content. However, the long-term impact of these practices on soil C pools was not fully understood under humid and warm climate conditions such as the southeast USA. We hypothesized that a combination of sustainable production practices will result in greater microbial biomass and activity and soil organic C than any individual practice. To test this hypothesis, we conducted a long-term experiment examining how different farming practices affect soil C and N pools and microbial biomass and activities in a fine-sandy loam (FAO: Acrisol) in the southern Appalachian mountains of North Carolina, USA. The experiment was a randomized complete design with four replications. Six management treatments, i.e., tillage with no chemical or organic inputs (Control, TN), tillage with chemical inputs (TC), tillage with organic inputs (TO), no-tillage with chemical inputs (NC), no-tillage with organic inputs (NO), and fescue grasses (FG), were designed. Organic C and N pools and microbial properties in 0–15 cm soils were markedly different after 15 years of continuous treatments. Both no tillage and organic inputs significantly promoted soil microbial biomass by 63–139% and 54–126%; also microbial activity increased by 88–158% and 52–117%, respectively. Corresponding increases of soil organic C by 83–104% and 19–32%, and soil organic N by 77–94% and 20–32% were measured. The combination of no tillage and organic management increased soil organic C by 140% over the conventional tillage control, leading to a soil C content comparable to an un-disturbed grassland control. No tillage reduced the proportion of organic C in the light fraction with d < 1.0 g cm−3 (from 1.53–3.39% to 0.80–1.09%), and increased the very heavy fraction with d > 1.6 g cm−3 (from 95% to 98%). Organic inputs, however, had little impact on C distribution among different density fractions of the soil except light fraction in tillage treatment. Over all, no-tillage practices exerted greater influence on microbial biomass levels and activity and soil organic C levels and fractionations than organic inputs. Our results support the hypothesis and indicate that management decisions including reducing tillage and increasing organic C inputs can enhance transformation of soil organic C from the labile into stable pools, promote soil C accumulation, improve soil fertility and while mitigate atmospheric CO2 rise. DA - 2011/12// PY - 2011/12// DO - 10.1016/j.still.2011.08.002 VL - 117 SP - 8-16 SN - 0167-1987 KW - Microbial C and N KW - Microbial respiration KW - Reduced tillage KW - Soil C fractions KW - Soil C and N pools KW - Sustainable farming practice ER - TY - JOUR TI - Feasibility of a Dune Infiltration System to Protect North Carolina Beaches from Fecal Bacteria Contaminated Storm Water AU - Bright, Tiffany M. AU - Burchell, Michael R. AU - Hunt, William F. AU - Price, William T2 - JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE AB - Storm water ocean outfalls discharging into recreational waters pose a human health threat because of increased potential exposure to bacteria and other pathogens. The dune infiltration system (DIS) was designed and implemented at two ocean outfall sites in response to concerns by the North Carolina Department of Transportation and the town of Kure Beach, North Carolina The systems were designed to divert storm water runoff from 1.9 ha (4.7 acre) and 3.2 ha (8.0 acre) watersheds into the beach dunes. Following construction, data were collected from 25 storms during March through October 2006. The systems captured a combined total of nearly 1,800 m3 (63,500 ft3), or 95% of the influent storm water runoff—a significant reduction of runoff volume and peak flow discharging directly onto the beach (p<0.0001). Fecal coliform and enterococci concentrations were measured in the inflowing storm water runoff and groundwater downslope of the systems. Both groundwater bacteria concentrations near the systems were significantly lower than the bacteria concentrations in the inflowing storm water (p<0.001). Furthermore, groundwater fecal coliform concentrations after implementing the DISs were statistically similar to preconstruction levels (p<0.05). The initial results are promising, and the system should be considered for more widespread use. However, further comprehensive research is recommended to more thoroughly understand the viability of the DIS as a storm water best management practice and the fate and transport of the bacteria within the dunes. DA - 2011/10// PY - 2011/10// DO - 10.1061/(asce)ee.1943-7870.0000395 VL - 137 IS - 10 SP - 968-979 SN - 0733-9372 KW - Storm water KW - Coastal best management practice KW - Dunes KW - Infiltration KW - Fecal bacteria KW - Groundwater ER - TY - JOUR TI - Effects of harvest regime and water depth on nutrient recovery from swine wastewater by growing Spirodela oligorrhiza AU - Xu, J. L. AU - Shen, G. X. T2 - Water Environment Research DA - 2011/// PY - 2011/// VL - 83 IS - 11 SP - 2049-2056 ER - TY - JOUR TI - Influence of screw insertion order on compression generated by bone plates in a fracture model AU - Jermyn, K. AU - Roe, S. C. T2 - VETERINARY AND COMPARATIVE ORTHOPAEDICS AND TRAUMATOLOGY AB - Summary Present recommendations regarding order of screw insertion for compression plate osteo-synthesis in veterinary training are variable. We hypothesized that placement of a neutrally positioned screw would reduce the magnitude of compression that could be generated by a subsequently placed compression screw. Canine tibial diaphyseal segments were fixed to a plate attached to a bone surrogate and load cell, and the compression generated by screw tightening was measured. Three different screw insertion order patterns were evaluated using both dynamic compression plate (DCP) and limited contact dynamic compression plate (LC-DCP) implants. In group CN, the first screw was placed in compression mode and the second in neutral mode in group NC, the first screw was placed in neutral mode and the second in compression mode in group LNC, the first screw was placed partially tightened in neutral mode and the second in compression mode followed by complete tightening of the neutral screw. Screw insertion order significantly influenced the amount of compression generated with both groups CN and LNC demonstrating significantly greater compression generation when compared with group NC (p <0.0001). Compression generated by group CN constructs was also significantly greater than group LNC (p = 0.0013). Evaluation of group CN data to assess the influence of plate and drill guide combinations on compressive force generated did not demonstrate a statistically significant difference. To maximize compression using a load screw in a bone plate, following securement of the opposite bone fragment to the plate, it should be placed before a neutral screw is placed. DA - 2011/// PY - 2011/// DO - 10.3415/vcot-11-06-0081 VL - 24 IS - 6 SP - 403-407 SN - 0932-0814 KW - Fracture model KW - screw KW - bone plate KW - compression generated ER - TY - JOUR TI - Enzymatic hydrolysis of switchgrass and coastal bermuda grass pretreated using different chemical methods AU - Xu, J. L. AU - Wang, Z. Y. AU - Sharma-Shivappa, R. R. AU - Cheng, J. J. T2 - BioResources DA - 2011/// PY - 2011/// VL - 6 IS - 3 SP - 2990-3003 ER - TY - JOUR TI - Design and evaluation of a discreet sampler for waste treatment lagoons AU - Classen, John AU - Rice, J. M. AU - McNeill, J. P. AU - Simmons, Otto T2 - Applied Engineering in Agriculture AB - A lagoon sampler was designed to collect 300-mL samples from depths up to 2.82 m at 15.2-cm intervals. Design parameters required the device to collect discrete samples through the entire lagoon column without cross contamination during raising or lowering of the device through the lagoon and to leave the liquid column undisturbed so subsequent samples could be taken from lower depths at the same location. An evaluation protocol was developed to test the device in a 55.9-cm diameter, 3.35-m tall PVC test column. This test column was of sufficient depth to be representative of lagoons and of sufficient diameter to avoid interference, or edge effects, associated with the sampling device. The evaluation protocol used dissolved solids (sodium chloride) as the test parameter in 30.5-cm deep layers of sodium chloride of decreasing concentrations to fill the test column from the bottom and simulated different solids concentrations that may be found in a lagoon. Samples were collected at six depths from 122 to 198 cm. Based on electrical conductivity measurements, samples collected with the device were slightly more dilute than the expected value at all sample depths. Further tests showed that operation of the device did not cause mixing of the layered salt solutions. The sampler was used to collect samples from various depths in a lagoon; results suggested there was little interference among samples taken at specific locations through subsequent depths. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40621 VL - 27 IS - 6 SP - 1007–1014 ER - TY - JOUR TI - Coupled biofilter - heat exchanger prototype for a broiler house AU - Shah, Sanjay AU - Workman, D. J. AU - Yates, J. AU - Basden, T. J. AU - Merriner, C. T. AU - deGraft-Hanson, J. T2 - Applied Engineering in Agriculture AB - Biofiltration is effective in reducing air emissions from livestock barns but it increases the production cost. Coupling a biofilter with a heat exchanger may allow waste heat recovery to temper the fresh air going back into the livestock barn when supplemental heating is required. A proof-of-concept coupled biofilter - heat exchanger was evaluated for its ability to reduce ammonia emissions and recover heat in a 5,000-bird broiler house in Wardensville, West Virginia. The heat exchanger plenum was stacked on top of the biofilter with a corrugated aluminum sheet serving as the heat transfer surface. The biofilter was effective in treating very high inlet ammonia concentrations (>96 ppm) with removal efficiencies >79% for empty bed residence times ranging from 4.3 to 29.1 s. Accumulation of sulfur in the medium showed that the biofilter may have been effective in trapping some sulfurous gases emitted from the broiler house. Based on 13.5 h of monitoring, the heat exchanger had heat recoveries of 2.3 to 8.3 kW and overall heat transfer coefficients of 7.37 to 35.30 W m-2 K-1. The heat exchanger's performance was comparable to two commercially-available heat exchangers evaluated in published studies in livestock barns. The biofilter-heat exchanger system can improve air quality and reduce energy use in livestock production where supplemental heating is required but additional design improvements and testing are required for commercial application. DA - 2011/// PY - 2011/// DO - 10.13031/2013.40617 VL - 27 IS - 6 SP - 1039–1048 ER - TY - JOUR TI - Production of high-starch duckweed and its conversion to bioethanol AU - Xu, Jiele AU - Cui, Weihua AU - Cheng, Jay J. AU - Stomp, Anne-M. T2 - BIOSYSTEMS ENGINEERING AB - Growing high-starch duckweed for its conversion to bioethanol was investigated as a novel technology to supplement maize-based ethanol production. Under the fall (autumn) climate conditions of North Carolina, the biomass accumulation rate of Spirodela polyrrhiza grown in a pilot-scale culture pond using diluted pig effluent was 12.4 g dry weight m−2 day−1. Through simple transfer of duckweed plants into well water for 10 days, the duckweed starch content increased by 64.9%, resulting in a high annual starch yield of 9.42 × 103 kg ha−1. After enzymatic hydrolysis and yeast fermentation of high-starch duckweed biomass in a 14-l fermentor, 94.7% of the theoretical starch conversion was achieved. The ethanol yield of duckweed reached 6.42 × 103 l ha−1, about 50% higher than that of maize-based ethanol production, which makes duckweed a competitive starch source for fuel ethanol production. DA - 2011/10// PY - 2011/10// DO - 10.1016/j.biosystemseng.2011.06.007 VL - 110 IS - 2 SP - 67-72 SN - 1537-5110 ER - TY - JOUR TI - Status and barriers of advanced biofuel technologies: A review AU - Cheng, Jay J. AU - Timilsina, Govinda R. T2 - RENEWABLE ENERGY AB - Development of biofuels from renewable resources is critical to the sustainability of the world’s economy and to slow down the global climate change. Currently, a significant amount of bioethanol and biodiesel are produced as biofuels to partially replace gasoline and diesel, respectively, in the transportation sector worldwide. However, these biofuels represent a tiny portion (<4%) of the total fuels consumed. Furthermore, bioethanol is produced predominantly from sugarcane and corn, and biodiesel from crop and plant oils. Production of these raw materials is competing for the limited arable land against food and feed production. It is not feasible to tremendously increase biofuel production using the current technologies. Therefore, it is critical to investigate advanced or 2nd generation biofuel production technologies. This article is trying to summarize the current status of the 2nd generation biofuel technologies including bioethanol from lignocellulosic materials and biodiesel from microalgae. The summary includes the descriptions of the technologies, their advantages and challenges, feedstocks for the 2nd generation biofuels, the key barriers to their commercial applications, and future perspectives of the advanced technologies. DA - 2011/12// PY - 2011/12// DO - 10.1016/j.renene.2011.04.031 VL - 36 IS - 12 SP - 3541-3549 SN - 0960-1481 KW - Biofuel KW - Ethanol KW - Biodiesel KW - Lignocelluloses KW - Microalgae ER - TY - JOUR TI - Influent Pollutant Concentrations as Predictors of Effluent Pollutant Concentrations for Mid-Atlantic Bioretention AU - McNett, J. K. AU - Hunt, William F. AU - Davis, Allen P. T2 - JOURNAL OF ENVIRONMENTAL ENGINEERING AB - The water quality performance of best management practices (BMPs) has been frequently assessed by the removal efficiency metric. Recent findings show that the removal efficiency metric is flawed because it does not account for background water quality, eco-region differentiation, and background, or “irreducible,” concentrations. Additionally, the removal efficiency metric inherently assumes a definite association exists between influent and effluent pollutant concentrations. Such a relationship between influent and effluent concentrations has been minimally studied for bioretention, the most common storm-water control measure associated with low-impact development (LID). This study analyzes influent and effluent total nitrogen (TN) and total phosphorous (TP) concentrations from 11 bioretention cells in the mid-Atlantic United States. Pooled data showed only a slight association between influent and effluent TN. Essentially no relationship exists between influent and effluent TP concentration. Both findings indicate that the percent-removal metric is a faulty means of evaluating bioretention performance. Twelve general linear models (GLMs) were created where influent TN and TP were the predictors of respective effluent TN and TP concentrations. Only one GLM was considered to be “good,” defined as 67–90% of the variation in effluent concentrations being explained by respective influent concentrations (R2=0.72). In addition, there were two “fair” models, five “poor” models, and four “very poor” models. No “very good” models were found for TN or TP. Furthermore, as influent nutrient concentration in runoff increases, the removal efficiency increases for TN and TP. “Dirtier” influent TP concentrations were effectively reduced; conversely, “cleaner” TP influent concentrations increased, both tending toward a (possibly media-controlled) baseline effluent concentration (0.10 to 0.18 mg/l). TN effluent data also may have been tending toward a common concentration; however, the value was not as discernible. DA - 2011/9// PY - 2011/9// DO - 10.1061/(asce)ee.1943-7870.0000373 VL - 137 IS - 9 SP - 790-799 SN - 1943-7870 KW - Storm-water BMPs KW - Water quality KW - Bioretention KW - Removal efficiency ER - TY - JOUR TI - Evaluation of undersized bioretention stormwater control measures for treatment of highway bridge deck runoff AU - Luell, S. K. AU - Hunt, W. F. AU - Winston, R. J. T2 - WATER SCIENCE AND TECHNOLOGY AB - Two grassed bioretention cells were constructed in the easement of a bridge deck in Knightdale, North Carolina, USA, in October, 2009. One was intentionally undersized ('small'), while the other was full sized ('large') per current North Carolina standards. The large and small cells captured runoff from the 25- and 8-mm events, respectively. Both bioretention cells employed average fill media depths of 0.65 m and internal water storage (IWS) zones of 0.6 m. Flow-proportional, composite water quality samples were collected and analyzed for nitrogen species, phosphorus species, and TSS. During 13 months of data collection, the large cell's median effluent concentrations and loads were less than those from the small cell. The small cell's TN and TSS load reductions were 84 and 50%, respectively, of those achieved by the large cell, with both cells significantly reducing TN and TSS. TP loads were not significantly reduced by either cell, likely due to low TP concentrations in the highway runoff which may have approached irreducible levels. Outflow pollutant loads from the large and small cell were not significantly different from one another for any of the examined pollutants. The small cell's relative performance provides support for retrofitting undersized systems in urbanized areas where there is insufficient space available for conventional full-sized stormwater treatment systems. DA - 2011/// PY - 2011/// DO - 10.2166/wst.2011.736 VL - 64 IS - 4 SP - 974-979 SN - 1996-9732 KW - bioretention KW - bridge deck KW - highway runoff KW - retrofit KW - stormwater KW - undersized ER - TY - JOUR TI - Effects of urbanization and urban stream restoration on the physical and biological structure of stream ecosystems AU - Violin, C. R. AU - Cada, P. AU - Sudduth, E. B. AU - Hassett, B. A. AU - Penrose, D. L. AU - Bernhardt, E. S. T2 - Ecological Applications DA - 2011/// PY - 2011/// VL - 21 IS - 6 SP - 1932-1949 ER - TY - JOUR TI - Bermuda grass as feedstock for biofuel production: A review AU - Xu, Jiele AU - Wang, Ziyu AU - Cheng, Jay J. T2 - BIORESOURCE TECHNOLOGY AB - Bermuda grass is a promising feedstock for the production of fuel ethanol in the Southern United States. This paper presents a review of the significant amount of research on the conversion of Bermuda grass to ethanol and a brief discussion on the factors affecting the biomass production in the field. The biggest challenge of biomass conversion comes from the recalcitrance of lignocellulose. A variety of chemical, physico-chemical, and biological pretreatment methods have been investigated to improve the digestibility of Bermuda grass with encouraging results reported. The subsequent enzymatic hydrolysis and fermentation steps have also been extensively studied and effectively optimized. It is expected that the development of genetic engineering technologies for the grass and fermenting organisms has the potential to greatly improve the economic viability of Bermuda grass-based fuel ethanol production systems. Other energy applications of Bermuda grass include anaerobic digestion for biogas generation and pyrolysis for syngas production. DA - 2011/9// PY - 2011/9// DO - 10.1016/j.biortech.2011.05.070 VL - 102 IS - 17 SP - 7613-7620 SN - 1873-2976 KW - Bermuda grass KW - Enzymatic hydrolysis KW - Ethanol KW - Fermentation KW - Pretreatment ER - TY - JOUR TI - Organic nitrogen exports from urban stormwater wetlands in North Carolina AU - Moore, Trisha L. C. AU - Hunt, William F. AU - Burchell, Michael R. AU - Hathaway, Jon M. T2 - ECOLOGICAL ENGINEERING AB - Effluent organic nitrogen concentrations from seven constructed stormwater wetlands in North Carolina were examined to compare background organic nitrogen (ON) concentrations and the fraction of organic nitrogen relative to total nitrogen discharged. Seasonal influences on organic nitrogen concentrations were also examined. The median ON concentration from the stormwater wetlands was 0.78 mg l−1, and despite differences in wetland design and influent ON characteristics, outlet ON concentrations from all but one wetland were not significantly different. ON export from all stormwater wetlands was significantly less than untreated runoff entering the wetlands (p = 0.002). In addition, median organic:total nitrogen (ON:TN) ratios from stormwater wetlands (0.75) were significantly greater than from untreated urban runoff (0.66), comparing more closely to ON:TN ratios collected from a naturally occurring wetland and reported in the literature for natural landscapes. Seasonal differences in organic nitrogen concentrations were identified with significantly lower concentrations during the winter. Though stormwater wetlands will not (and perhaps should not be expected to) completely remove total nitrogen loads from runoff, these results suggest constructed wetlands can play a role in restoring the balance between organic and inorganic nitrogen forms closer to that of an undisturbed landscape. The presence of background organic nitrogen concentrations from stormwater wetlands similar to those from a naturally occurring wetland highlights the importance of choosing appropriate metrics (e.g., effluent concentrations) when assessing treatment performance. DA - 2011/4// PY - 2011/4// DO - 10.1016/j.ecoleng.2010.12.015 VL - 37 IS - 4 SP - 589-594 SN - 1872-6992 KW - Wetland KW - Stormwater KW - Organic nitrogen KW - Irreducible concentration KW - ON:TN ratio KW - Export ER - TY - JOUR TI - Multivariate analysis of maize disease resistances suggests a pleiotropic genetic basis and implicates a GST gene AU - Wisser, Randall J. AU - Kolkman, Judith M. AU - Patzoldt, Megan E. AU - Holland, James B. AU - Yu, Jianming AU - Krakowsky, Matthew AU - Nelson, Rebecca J. AU - Balint-Kurti, Peter J. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - Plants are attacked by pathogens representing diverse taxonomic groups, such that genes providing multiple disease resistance (MDR) are expected to be under positive selection pressure. To address the hypothesis that naturally occurring allelic variation conditions MDR, we extended the framework of structured association mapping to allow for the analysis of correlated complex traits and the identification of pleiotropic genes. The multivariate analytical approach used here is directly applicable to any species and set of traits exhibiting correlation. From our analysis of a diverse panel of maize inbred lines, we discovered high positive genetic correlations between resistances to three globally threatening fungal diseases. The maize panel studied exhibits rapidly decaying linkage disequilibrium that generally occurs within 1 or 2 kb, which is less than the average length of a maize gene. The positive correlations therefore suggested that functional allelic variation at specific genes for MDR exists in maize. Using a multivariate test statistic, a glutathione S-transferase (GST) gene was found to be associated with modest levels of resistance to all three diseases. Resequencing analysis pinpointed the association to a histidine (basic amino acid) for aspartic acid (acidic amino acid) substitution in the encoded protein domain that defines GST substrate specificity and biochemical activity. The known functions of GSTs suggested that variability in detoxification pathways underlie natural variation in maize MDR. DA - 2011/5/3/ PY - 2011/5/3/ DO - 10.1073/pnas.1011739108 VL - 108 IS - 18 SP - 7339-7344 SN - 0027-8424 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79956318799&partnerID=MN8TOARS KW - multivariate mixed model KW - pleiotropy KW - quantitative disease resistance KW - Zea mays (maize) ER - TY - JOUR TI - Lime Pretreatment of Coastal Bermudagrass for Bioethanol Production AU - Wang, Ziyu AU - Cheng, Jay J. T2 - ENERGY & FUELS AB - Coastal bermudagrass (CBG) is regarded as a potential lignocellulosic feedstock for bioethanol production in the southeast United States. Lime pretreatment of CBG for enhanced reducing sugar recovery was investigated in this study, which examined a variety of temperatures (21−121 °C) at a range of residence times with different lime loadings (0.02−0.20 g/g of dry biomass). During pretreatment, 10−20% lignin was removed. After enzymatic hydrolysis with excessive cellulases and cellobiase, the best total reducing sugar yield for the lime-pretreated CBG was 78% of the theoretical maximum, which is over 2 times more than that from the untreated CBG. The recommended condition is 100 °C for 15 min with a lime loading of 0.1 g/g of dry biomass, under which 87% glucan and 68% xylan were converted to glucose and xylose, respectively. Fermentation tests of the hydrolyzates indicated that more than 99% glucose in the hydrolyzate was used by the yeast during the fermentation, with ethanol yields of 95% of the theoretical maximum for the hydrolyzate and 83% of the theoretical maximum for the raw biomass. DA - 2011/4// PY - 2011/4// DO - 10.1021/ef2000932 VL - 25 IS - 4 SP - 1830-1836 SN - 1520-5029 ER - TY - JOUR TI - Functional, physiochemical, and rheological properties of duckweed (spirodela polyrhiza) protein AU - Yu, G. AU - Liu, H. AU - Venkateshan, K. AU - Yan, S. AU - Cheng, Jay AU - Sun, X. S. AU - Wang, D. T2 - Transactions of the ASABE AB - Duckweed contains mainly starch and protein, and protein is a coproduct of starch-based biofuel production. Plant proteins have a great potential for value-added products. However, the lack of information on duckweed protein as a bioenergy coproduct limits its use. In this study, duckweed protein was extracted, purified, and characterized for chemical composition, molecular weight, surface hydrophobicity, emulsion, thermal stability, and rheological properties. Duckweed (Spirodela polyrhiza) with an initial protein content of 34.5% was selected for this study, and the protein was extracted from fresh, frozen, and ambient temperature dried duckweed. The highest extraction rate (52.1%) was obtained from fresh duckweed, followed by ambient-dried duckweed (45.6%) and frozen duckweed (44.3%). The protein samples extracted from ambient-dried duckweed had the highest purity (67.8%) of the three prepared duckweed sources. Duckweed protein showed a low stability of the emulsion and poor emulsifying properties. Molecular weights of duckweed protein fractions ranged from 14 kDa to more than 160 kDa. FTIR showed five distinct absorption bands related to amide A and B, amide I and II, and the carbohydrate component. The melting peak of the duckweed protein sample was broad; it began below 50C, covered a range of about 120C, ended at 160C, and degraded at 250C. Duckweed protein is more hydrophobic than soy proteins at the same pH value, which suggests that duckweed protein has potential to improve water resistance of protein-based adhesives. DA - 2011/// PY - 2011/// DO - 10.13031/2013.36459 VL - 54 IS - 2 SP - 555–561 ER - TY - JOUR TI - Delignification of switchgrass cultivars for bioethanol production AU - Xu, J. L. AU - Chen, Y. AU - Cheng, J. J. AU - Sharma-Shivappa, R. R. AU - Burns, J. C. T2 - BioResources DA - 2011/// PY - 2011/// VL - 6 IS - 1 SP - 707-720 ER - TY - JOUR TI - Phosphorus leaching in a sandy soil as affected by organic and inorganic fertilizer sources AU - Kang, Jihoon AU - Amoozegar, Aziz AU - Hesterberg, Dean AU - Osmond, Deanna L. T2 - GEODERMA AB - Long-term application of phosphorus (P) to soils as fertilizer or manure can increase the potential for P loss to ground and surface waters. Vertical P transport was investigated in a sandy soil material receiving seven different P fertilizer sources: poultry compost, poultry litter, triple superphosphate [Ca(H2PO4)2·H2O], dairy lagoon liquid, swine lagoon liquid, swine lagoon sludge, and dissolved potassium dihydrogen phosphate (KH2PO4). The P sources were surface-applied to soil columns (6.35-cm diameter, 10-cm long) at two rates equivalent to 75 and 150 kg total P ha−1, and columns were intermittently leached with deionized (DI) water. Column effluents were collected for up to 23 pore volumes and analyzed for dissolved reactive phosphorus (DRP) and dissolved organic carbon (DOC). In addition, a P retardation factor was determined for the soil from a P adsorption isotherm. Transport of P through soil columns receiving liquid P sources was simulated by a one-dimensional equilibrium convective–dispersive equation (CDE) based on water-extractable P (WEP) concentrations. Cumulative amounts of DRP leached were linearly related to the amounts of WEP in P source materials (r2 = 0.87***). The recovery of DRP in the column effluents relative to WEP in the applied materials was 126 ± 15% (mean ± standard error) for organic P sources and 66 ± 2% for inorganic P sources. The use of WEP in the CDE model underpredicted P transport in the columns amended with lagoon liquids compared with dissolved KH2PO4. Results indicated that leaching losses of P from land-applied manures exceed the amounts of WEP in source materials because of organic P mineralization and competitive sorption of DOC. DA - 2011/3/15/ PY - 2011/3/15/ DO - 10.1016/j.geoderma.2010.12.019 VL - 161 IS - 3-4 SP - 194-201 SN - 0016-7061 KW - Adsorption KW - Leaching KW - Organic carbon KW - Phosphorus KW - Water quality ER - TY - JOUR TI - Mapping QTL Controlling Southern Leaf Blight Resistance by Joint Analysis of Three Related Recombinant Inbred Line Populations AU - Negeri, Adisu T. AU - Coles, Nathan D. AU - Holland, James B. AU - Balint-Kurti, Peter J. T2 - Crop Science AB - ABSTRACT Southern leaf blight (SLB) is a foliar necrotrophic disease of maize ( Zea mays L.) caused by the ascomycete fungus Cochliobolus heterostrophus (Drechs.) Drechs. It is particularly important in warm humid parts of the world where maize is cultivated, such as the southern Atlantic coast area of the United States and parts of India, Africa, and Western Europe. Quantitative trait loci (QTL) for resistance to SLB disease caused by C. heterostrophus race O were identified in three maize recombinant inbred populations assessed in two environments: Clayton, NC, in the summer and Homestead, FL, in the winter. The three populations were derived from the crosses B73 × CML254, CML254 × B97, and B97 × Ki14. Each of these populations was derived from a cross between a temperate maize line (B73 or B97) and a tropical maize line (Ki14 or CML254). Quantitative trait loci were identified by separate analysis of each population and by joint connected and disconnected analyses of all the populations. The most significant QTL identified were on chromosomes 3, 8, 9,and 10. Joint analysis led to more precise position estimates than separate analysis in each case. Results are discussed in the context of previous SLB QTL analysis studies and a recent flowering time QTL study that used the same populations. The chromosome 8 and 9 QTL colocalized with previously identified flowering time QTL which suggested that the perceived effect on SLB resistance at these QTL may have been mediated through an effect on flowering time DA - 2011/// PY - 2011/// DO - 10.2135/cropsci2010.12.0672 VL - 51 IS - 4 SP - 1571 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959615426&partnerID=MN8TOARS ER - TY - JOUR TI - IMPACTS OF LAND-COVER CHANGE ON SUSPENDED SEDIMENT TRANSPORT IN TWO AGRICULTURAL WATERSHEDS AU - Schilling, Keith E. AU - Isenhart, Thomas M. AU - Palmer, Jason A. AU - Wolter, Calvin F. AU - Spooner, Jean T2 - JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION AB - Schilling, Keith E., Thomas M. Isenhart, Jason A. Palmer, Calvin F. Wolter, and Jean Spooner, 2011. Impacts of Land-Cover Change on Suspended Sediment Transport in Two Agricultural Watersheds. Journal of the American Water Resources Association (JAWRA) 47(4):672-686. DOI: 10.1111/j.1752-1688.2011.00533.x Abstract: Suspended sediment is a major water quality problem, yet few monitoring studies have been of sufficient scale and duration to assess the effectiveness of land-use change or conservation practice implementation at a watershed scale. Daily discharge and suspended sediment export from two 5,000-ha watersheds in central Iowa were monitored over a 10-year period (water years 1996-2005). In Walnut Creek watershed, a large portion of land was converted from row crop to native prairie, whereas in Squaw Creek land use remained predominantly row crop agriculture. Suspended sediment loads were similar in both watersheds, exhibiting flashy behavior typical of incised channels. Modeling suggested that expected total soil erosion in Walnut Creek should have been reduced 46% relative to Squaw Creek due to changes in land use, yet measured suspended sediment loads showed no significant differences. Stream mapping indicated that Walnut Creek had three times more eroding streambank lengths than did Squaw Creek suggesting that streambank erosion dominated sediment sources in Walnut Creek and sheet and rill sources dominated sediment sources in Squaw Creek. Our results demonstrate that an accounting of all sources of sediment erosion and delivery is needed to characterize sediment reductions in watershed projects combined with long-term, intensive monitoring and modeling to account for possible lag times in the manifestation of the benefits of conservation practices on water quality. DA - 2011/8// PY - 2011/8// DO - 10.1111/j.1752-1688.2011.00533.x VL - 47 IS - 4 SP - 672-686 SN - 1093-474X KW - sediment KW - streambank erosion KW - nonpoint source pollution KW - land-use/land-cover change KW - watershed restoration KW - lag time ER - TY - JOUR TI - Exploring fecal indicator bacteria in a constructed stormwater wetland AU - Hathaway, J. M. AU - Hunt, W. F. AU - Graves, A. K. AU - Bass, K. L. AU - Caldwell, A. T2 - WATER SCIENCE AND TECHNOLOGY AB - Microbial pollution in surface waters is a concern throughout the world, with both public health and economic implications. One contributing source to such pollution is stormwater runoff, often treated using various types of stormwater control measures. However, relatively little is known regarding microbe sequestration in constructed stormwater wetlands (CSWs), one type of commonly installed stormwater control measure. In this study, indicator bacteria concentrations in both the water and sediment of a CSW were evaluated at multiple locations. Results suggested that fecal coliform concentrations in stormwater runoff decrease through the system, with relatively consistent concentrations noted throughout the second half of the wetland. This potentially indicates a baseline concentration of fecal coliform is present due to internal processes such as animal activity and microbial persistence. However, wetland sediments showed little E. coli present during most sampling events, with minimal patterns existing with respect to sediment sampling location. CSW designs should promote optimization of hydraulic retention time and minimization of stormwater velocities to promote sedimentation and degradation of microbes by way of wetland treatment functions. DA - 2011/// PY - 2011/// DO - 10.2166/wst.2011.539 VL - 63 IS - 11 SP - 2707-2712 SN - 1996-9732 KW - fecal coliform KW - microbe KW - sediment KW - stormwater KW - wetland ER - TY - JOUR TI - Cropland Edge, Forest Succession, and Landscape Affect Shrubland Bird Nest Predation AU - Shake, Corey S. AU - Moorman, Christopher E. AU - Burchell, Michael R., II T2 - JOURNAL OF WILDLIFE MANAGEMENT AB - Abstract The effects of habitat edges on nest survival of shrubland birds, many of which have experienced significant declines in the eastern United States, have not been thoroughly studied. In 2007 and 2008, we collected data on nests of 5 shrubland passerine species in 12 early successional forest patches in North Carolina, USA. We used model selection methods to assess the effect of distance to cropland and mature forest edge on nest predation rates and additionally accounted for temporal trends, nest stage, vegetation structure, and landscape context. For nests of all species combined, nest predation decreased with increasing distance to cropland edge, by nearly 50% at 250 m from the cropland edge. Nest predation of all species combined also was higher in patches with taller saplings and less understory vegetation, especially in the second year of our study when trees were 4–6 m tall. Predation of field sparrow ( Spizella pusilla ) nests was lower in landscapes with higher agricultural landcover. Nest predation risk for shrubland birds appears to be greater near agricultural edges than mature forest edges, and natural forest succession may drive patterns of local extirpation of shrubland birds in early successional forest patches. Thus, we suggest that habitat patches managed for shrubland bird populations should be considerably large or wide (>250 m) when adjacent to crop fields and maintained in structurally diverse early seral stages. © 2011 The Wildlife Society. DA - 2011/5// PY - 2011/5// DO - 10.1002/jwmg.101 VL - 75 IS - 4 SP - 825-835 SN - 0022-541X KW - agricultural landscapes KW - early successional KW - habitat edge KW - nest predation KW - shrubland birds ER - TY - JOUR TI - Constructed storm-water wetland installation and maintenance: are we getting it right? T2 - Journal of Irrigation and Drainage Engineering DA - 2011/// PY - 2011/// VL - 137 IS - 8 SP - 469-474 ER - TY - JOUR TI - Validation and uncertainty analysis of an ammonia emission model for broiler litter AU - Liu, Z. AU - Wang-Li, L. AU - Beasley, D. B. AU - Shah, Sanjay T2 - Transactions of the ASABE AB - A mechanistic emission model was previously developed at laboratory scale to estimate ammonia emission fluxes from broiler litter. The overall model inputs include air temperature, air velocity, and litter properties such as litter nitrogen content, moisture content, and pH. The model outputs are predicted ammonia emission fluxes from litter. Considerable uncertainties may exist in measurement values of model inputs and outputs as well as model parameters. The purpose of this study was to perform model validation in the presence of measurement and model parameter uncertainties. A validation metric based on the mean and covariance in the measurement and in the model parameters was used to validate the ammonia emission model of broiler litter. The core model was validated given the uncertainties in the model prediction due to uncertainties of parameters (the Freundlich partition coefficient Kf and the mass transfer coefficient KG) and the uncertainties in the measurements. The significant level for the core model validation was 17.8%. The Kf submodel was validated at the given uncertainties of pH and temperature, and the significant levels were from 12.0% to 49.4%, which provided high confidence on the Kf submodel. At the given uncertainty levels of air velocity and temperature, the KG submodel passed the validation test (p > 0.05) when air velocities were low and failed the validation test (p < 0.05) when air velocities were high. The failure of the KG submodel at high air velocity levels may have been caused by significant loss of nitrogen and moisture content from the litter surface. DA - 2011/// PY - 2011/// DO - 10.13031/2013.37096 VL - 54 IS - 3 SP - 1051–1057 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959799571&partnerID=MN8TOARS ER - TY - JOUR TI - Evaluation of First Flush for Indicator Bacteria and Total Suspended Solids in Urban Stormwater Runoff AU - Hathaway, Jon M. AU - Hunt, William F. T2 - WATER AIR AND SOIL POLLUTION DA - 2011/5// PY - 2011/5// DO - 10.1007/s11270-010-0574-y VL - 217 IS - 1-4 SP - 135-147 SN - 1573-2932 KW - Indicator bacteria KW - E. coli KW - enterococci KW - Fecal coliform KW - First flush KW - Stormwater ER - TY - JOUR TI - An Evaluation of the Toxicity of Accumulated Sediments in Forebays of Stormwater Wetlands and Wetponds AU - McNett, Jacquelyn K. AU - Hunt, William F. T2 - WATER AIR AND SOIL POLLUTION DA - 2011/6// PY - 2011/6// DO - 10.1007/s11270-010-0665-9 VL - 218 IS - 1-4 SP - 529-538 SN - 1573-2932 KW - Sediment KW - Forebays KW - Stormwater wetlands KW - Stormwater wetponds KW - Water quality KW - Land application ER - TY - JOUR TI - Thermal mitigation of urban storm water by level spreader-vegetative filter strips T2 - Journal of Environmental Engineering (New York, N.Y.) DA - 2011/// PY - 2011/// VL - 137 IS - 8 SP - 707-716 ER - TY - JOUR TI - The reactive oxidant potential of different types of aged atmospheric particles: An outdoor chamber study AU - Rattanavaraha, W. AU - Rosen, E. AU - Zhang, H. F. AU - Li, Q. F. AU - Pantong, K. AU - Kamens, R. M. T2 - Atmospheric Environment DA - 2011/// PY - 2011/// VL - 45 IS - 23 SP - 3848-3855 ER - TY - JOUR TI - Surface shading effects on soil C loss in a temperate muck soil AU - Taggart, Matthew J. AU - Heitman, Joshua L. AU - Vepraskas, Michael J. AU - Burchell, Michael R. T2 - GEODERMA AB - Histosols are a huge reservoir for C, covering < 1% of the world's land surface but storing up to 12% of total soil C. Thorough comprehension of factors controlling the rate of soil C loss from Histosols is critical for proper management of these C sinks. Two experiments evaluated how formerly cultivated, warm-climate Histosols undergoing wetland restoration respond to decreases in soil temperatures via vegetative shading, under different water table conditions. We compared temperature and soil CO2 efflux differences from intact soil cores under three levels of light reduction in a greenhouse: 0%, 70%, and 90%. Soil in full sun was consistently warmer and showed higher efflux rates than 70% and 90% shade treatments: 4.132, 3.438, and 2.054 μmol CO2 m−2 s−1, respectively. Shade treatments reached peak efflux rates at similar water potential, −2 to − 4 kPa. A field experiment subjected in-situ soil to full sun, 70% light reduction, and light reduction from naturally occurring herbaceous vegetation. Shade treatment effects on soil temperature and C mineralization were evident throughout the growing season. Vegetative shade effects on soil temperature were greatest in August and September when soil under vegetation was 5–11 °C cooler than unshaded soil. Soil CO2 efflux was correlated strongly with soil temperature; daily efflux rates were consistently highest from unshaded soil. Efflux across treatments showed a strong seasonal correlation to soil moisture, increasing as soil dried in response to water table decline. Soil water potential was unaffected by shade treatment, suggesting temperature effects were solely responsible for efflux differences between treatments. All results confirm that surface shading has a strong influence on soil temperatures and C mineralization rates. Management to enhance vegetative shading in wetland restoration projects may be an effective strategy for slowing soil C losses and promoting soil C sequestration when O2 is not limiting. DA - 2011/7/15/ PY - 2011/7/15/ DO - 10.1016/j.geoderma.2011.04.020 VL - 163 IS - 3-4 SP - 238-246 SN - 1872-6259 KW - Histosols KW - Wetland restoration KW - CO2 efflux KW - Mineralization KW - Soil temperature KW - Shading ER - TY - JOUR TI - A novel genetic framework for studying response to artificial selection AU - Wisser, Randall J. AU - Balint-Kurti, Peter J. AU - Holland, James B. T2 - PLANT GENETIC RESOURCES-CHARACTERIZATION AND UTILIZATION AB - Response to selection is fundamental to plant breeding. To gain insight into the genetic basis of response to selection, we propose a new experimental genetic framework allowing for the identification of trait-specific genomic loci underlying population improvement and the characterization of allelic frequency responses at those loci. This is achieved by employing a sampling scheme for recurrently selected populations that allows for the simultaneous application of genetic association mapping and analysis of allelic frequency change across generations of selection. The combined method unites advantages of the two approaches, permitting the estimation of trait-specific allelic effects by association mapping and the detection of rare favourable alleles by their significant enrichment over generations of selection. Our aim is to develop a framework applicable for many crop species in order to gain a broader and deeper understanding of the genetic architecture of response to artificial selection. DA - 2011/7// PY - 2011/7// DO - 10.1017/s1479262111000359 VL - 9 IS - 2 SP - 281-283 SN - 1479-2621 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79960130677&partnerID=MN8TOARS KW - adaptation KW - association mapping KW - plant breeding, quantitative trait KW - selection ER - TY - JOUR TI - Targeted discovery of quantitative trait loci for resistance to northern leaf blight and other diseases of maize AU - Chung, Chia-Lin AU - Poland, Jesse AU - Kump, Kristen AU - Benson, Jacqueline AU - Longfellow, Joy AU - Walsh, Ellie AU - Balint-Kurti, Peter AU - Nelson, Rebecca T2 - THEORETICAL AND APPLIED GENETICS DA - 2011/7// PY - 2011/7// DO - 10.1007/s00122-011-1585-9 VL - 123 IS - 2 SP - 307-326 SN - 1432-2242 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79961211155&partnerID=MN8TOARS ER - TY - JOUR TI - Special Issue on Urban Storm-Water Management in the 21st Century Introduction AU - Traver, Robert AU - Clark, Shirley AU - Hunt, William AU - Struck, Scott T2 - JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING AB - As the practice of storm-water management evolves, so has our understanding of the tools. As we move away from a myopic flood control perspective, new tools to include what we now call green infrastructure best management practices (BMPs) were developed. Green roofs, rain gardens, and porous pavements appeared, with much of the design elements based on reasonable estimates of performance, thus the term “best.” Now we as a profession are moving toward a more engineered approach, with designs based on scientific knowledge of the processes, from soil physics and chemistry to hydrology and hydraulics. Soon it may be time to retire BMPs and move forward with the term “storm-water control measures,” as recommended by the National Academies authors of Urban Stormwater in the United States (National Research Council 2008). This issue of the Journal of Irrigation and Drainage Engineering is devoted to this evolving field of storm-water sustainability, and the effort to predict performance of our storm-water control measures. The 10 papers in this special issue reflect this evolution. Papers range from evaluating the concentration of effluent scoured from catch basins to cost-estimation tools, plus the inclusion of green-infrastructure tools within the International Stormwater BMP Database. Green and stone roofs are represented as are level spreaders. Bioretention/bioinfiltration rain gardens, however, received the most attention with papers on media depth, phosphorus removal, process modeling, mounding, and fines accumulation. This collection truly demonstrates our increasing knowledge base. This effort is a result of collaboration between the Stormwater Infrastructure Committee and Urban Water Resources Research Council, together with the Journal of Irrigation and Drainage Engineering Publications Committee. Conference proceedings from recent Environmental and Water Resources Institute (EWRI) congresses and low-impact development (LID) conferences were reviewed, and a select group of authors was invited to expand and revise their work. These papers passed through the standard journal peer-review process. We hope that this set of papers is of use to the profession. We would like to thank all the contributing authors, the reviewers, and William Ritter, as editor, for their efforts in this special issue. DA - 2011/3// PY - 2011/3// DO - 10.1061/(asce)ir.1943-4774.0000325 VL - 137 IS - 3 SP - 113-113 SN - 1943-4774 ER - TY - JOUR TI - SDI Dripline Spacing Effect on Corn and Soybean Yield in a Piedmont Clay Soil AU - Grabow, G. L. AU - Huffman, R. L. AU - Evans, R. O. T2 - JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING AB - A subsurface drip irrigation (SDI) system was installed in the Piedmont of North Carolina in a clay soil in the fall of 2001 to test the effect of dripline spacing on corn and soybean yield. The system was zoned into three sections; each section was cropped to either corn (Zea mays L.), full-season soybean [Glycine max (L.) Merr.], or winter wheat (Triticum aestivum) double cropped to soybean representing any year of a typical crop rotation in the region. Each section had four plots; two SDI plots with dripline spacing at either 1.52 or 2.28 m, an overhead sprinkler irrigated plot, and an unirrigated plot. There was no difference in average corn grain yield for 2002–2005 between dripline spacings or between either dripline spacing and sprinkler. Irrigation water use efficiency (IWUE) was greater for sprinkler irrigated corn than for either SDI treatment and there was no difference in IWUE in soybean. Water typically moved laterally from the driplines 0.38 to 0.50 m. SDI yield and IWUE increased relative to sprinkler yields and water use efficiency in the second and third year of the study. This may suggest that initial fracturing of the heavy clay soil during SDI system installation and subsequent settling of the soil affected water distribution. DA - 2011/1// PY - 2011/1// DO - 10.1061/(asce)ir.1943-4774.0000277 VL - 137 IS - 1 SP - 27-36 SN - 1943-4774 KW - Irrigation systems KW - Trickle irrigation KW - Water management ER - TY - JOUR TI - Impacts of Media Depth on Effluent Water Quality and Hydrologic Performance of Undersized Bioretention Cells AU - Brown, Robert A. AU - Hunt, William F., III T2 - JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING AB - Fill media and excavation volume are the main costs in constructing bioretention cells, but the importance and impact of media depth in these systems is relatively unknown. Two sets of loamy-sand-filled bioretention cells of two media depths (0.6 m and 0.9 m), located in Nashville, North Carolina, were monitored from March 2008 to March 2009 to examine the impact of media depth on their performance with respect to hydrology and water quality. Construction and design errors resulted in the surface storage volume being undersized for the design event (2.5 cm). The actual surface storage volume was only 28% and 35% of the design volume for the 0.6-m and 0.9-m media depth cells, respectively. Overflow (bypass) occurred at least three times more frequently than intended. The exfiltration volume was much higher in the deeper media cells, presumably because of greater storage volume in the media and more exposure to side walls. Evapotranspiration (ET) plus exfiltration accounted for 42% of the inflow runoff in the 0.9-m media cells, while ET and exfiltration accounted for only 31% of the inflow runoff in the 0.6-m media cells. With the increase in exfiltration, the deeper media depth met a previously defined low-impact development (LID) hydrology goal of volume reduction more frequently than the shallower media system (44% of events compared to 21%). Larger outflow reduction consequently increased the reduction in pollutant loads. Estimated annual pollutant load reduction for total nitrogen, total phosphorus, and total suspended solids were 21, 10, and 71% for the 0.6-m media cells and 19, 44, and 82% for the 0.9-m media cells, respectively. Overall, nitrogen reduction was poor owing to suspected export of nitrate from the fertilizer use, and phosphorus removal was hampered because of irreducible concentrations in the inflow. Pollutant reduction was limited because the cells were undersized as a result of construction and design errors. DA - 2011/3// PY - 2011/3// DO - 10.1061/(asce)ir.1943-4774.0000167 VL - 137 IS - 3 SP - 132-143 SN - 1943-4774 KW - Biological processes KW - Sustainable development KW - Stormwater management KW - Water quality KW - Hydrology KW - North Carolina ER - TY - JOUR TI - Field Evaluation of Four Level Spreader-Vegetative Filter Strips to Improve Urban Storm-Water Quality AU - Winston, R. J. AU - Hunt, William F., III AU - Osmond, D. L. AU - Lord, W. G. AU - Woodward, M. D. T2 - JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING AB - An assessment of the performance of four level spreader–vegetative filter strip (LS-VFS) systems designed to treat urban storm-water runoff was undertaken at two sites in the Piedmont of North Carolina. At each site, a 7.6-m grassed filter strip and a 15.2-m half-grassed, half-forested filter strip were examined. Monitored parameters included rainfall, inflow to, and outflow from each LS-VFS system. A total of 21 and 22 flow-proportional water quality samples were collected and analyzed for the Apex and Louisburg sites, respectively. All studied LS-VFS systems significantly reduced mean total suspended solids (TSS) concentrations (p<0.05), with the 7.6 and 15.2-m buffers reducing TSS by at least 51 and 67%, respectively. Both 15.2-m VFSs significantly reduced the concentrations of total Kjeldahl nitrogen (TKN), total nitrogen (TN), organic nitrogen (Org-N), and NH4-N (p<0.05), whereas results were mixed for the 7.6-m VFSs. Significant pollutant mass reduction was observed (p<0.05) for all nine pollutant forms analyzed in Louisburg, which was caused by infiltration in the VFSs. The effects of VFS length and/or vegetation type are very important for pollutant removal, as effluent pollutant concentrations were lower (with one exception) for the 15.2-m VFSs. The median effluent concentrations for TN and total phosphorus (TP) for the four LS-VFSs were nearly always better than fair water quality benchmarks for the Piedmont of North Carolina, but only met good water quality metrics in one-half of the studied storm events. DA - 2011/3// PY - 2011/3// DO - 10.1061/(asce)ir.1943-4774.0000173 VL - 137 IS - 3 SP - 170-182 SN - 1943-4774 KW - Vegetation KW - Filters KW - Sustainable development KW - Stormwater management KW - Water quality KW - Best Management Practice KW - Urban areas KW - North Carolina ER - TY - JOUR TI - Developments in mycotoxin analysis: an update for 2009-2010 AU - Shephard, G. S. AU - Berthiller, F. AU - Burdaspal, P. AU - Crews, C. AU - Jonker, M. A. AU - Krska, R. AU - MacDonald, S. AU - Malone, B. AU - Maragos, C. AU - Sabino, M. AU - Solfrizzo, M. AU - Egmond, H. P. AU - Whitaker, T. B. T2 - WORLD MYCOTOXIN JOURNAL AB - This review highlights developments in mycotoxin analysis and sampling over a period between mid-2009 and mid-2010. It covers the major mycotoxins aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. New and improved methods for mycotoxins continue to be published. Immunological-based method developments continue to be of wide interest in a broad range of formats. Multimycotoxin determination by LC-MS/MS is now being targeted at the specific ranges of mycotoxins and matrices of interest or concern to the individual laboratory. Although falling outside the main emphasis of the review, some aspects of natural occurrence have been mentioned, especially if linked to novel method developments. DA - 2011/2// PY - 2011/2// DO - 10.3920/wmj2010.1249 VL - 4 IS - 1 SP - 3-28 SN - 1875-0796 KW - aflatoxin KW - Alternaria KW - ergot KW - fumonisin KW - ochratoxin KW - patulin KW - trichothecenes KW - zearalenone KW - sampling ER - TY - JOUR TI - Registration of 'Bailey' Peanut AU - Isleib, Thomas G. AU - Milla-Lewis, Susana R. AU - Pattee, Harold E. AU - Copeland, Susan C. AU - Zuleta, M. Carolina AU - Shew, Barbara B. AU - Hollowell, Joyce E. AU - Sanders, Timothy H. AU - Dean, Lisa O. AU - Hendrix, Keith W. AU - Balota, Maria AU - Chapin, Jay W. T2 - JOURNAL OF PLANT REGISTRATIONS AB - ‘Bailey’ (Reg. No. CV‐111, PI 659502) is a large‐seeded virginia‐type peanut ( Arachis hypogaea L. subsp. hypogaea var. hypogaea ) with partial resistance to five diseases that occur commonly in the Virginia‐Carolina production area: early leaf spot (caused by Cercospora arachidicola Hori), late leaf spot [caused by Cercosporidium personatum (Berk. & M.A. Curtis) Deighton], Cylindrocladium black rot [caused by Cylindrocladium parasiticum Crous, M.J. Wingf. & Alfenas], Sclerotinia blight (caused by Sclerotinia minor Jagger), and tomato spotted wilt (caused by Tomato spotted wilt tospovirus ). It also has partial resistance to southern stem rot (caused by Sclerotium rolfsii Sacc.). Bailey was developed as part of a program of selection for multiple‐disease resistance funded by growers, seedsmen, shellers, and processors. Bailey was tested under the experimental designation N03081T and was released by the North Carolina Agricultural Research Service (NCARS) in 2008. Bailey was tested by the NCARS, the Virginia Agricultural Experimental Station, and five other state agricultural experiment stations and the USDA‐ARS units participating in the Uniform Peanut Performance Tests. Bailey has an alternate branching pattern, an intermediate runner growth habit, medium green foliage, and high contents of fancy pods and medium virginia‐type seeds. It has approximately 34% jumbo and 46% fancy pods, seeds with tan testas and an average weight of 823 mg seed −1 , and an extra large kernel content of approximately 42%. Bailey is named in honor of the late Dr. Jack E. Bailey, formerly the peanut breeding project's collaborating plant pathologist. DA - 2011/1// PY - 2011/1// DO - 10.3198/jpr2009.12.0742crc VL - 5 IS - 1 SP - 27-39 SN - 1940-3496 ER - TY - JOUR TI - Effects of fungicides and insecticides on feeding behavior and community dynamics of earthworms: Implications for casting control in turfgrass systems AU - Tu, Cong AU - Wang, Yi AU - Duan, Wenxia AU - Hertl, Peter AU - Tradway, Lane AU - Brandenburg, Rick AU - Lee, David AU - Snell, Mark AU - Hu, Shuijin T2 - APPLIED SOIL ECOLOGY AB - Earthworms play important roles in sustaining turfgrass systems through enhancing soil aeration, water filtration, and thatch mixing and decomposition. However, high surface activities of earthworms can lead to uneven playing surfaces, soil erosion and new niches favorable to weed invasion in the playing area of a golf course. Shifts from highly toxic and persistent to less toxic and easily degradable pesticides have been suggested to be largely responsible for high earthworm activities observed in turf systems worldwide. In this study, we examined the impact of fungicides and insecticides on earthworm behavior in controlled environments and on the dynamics of earthworm community in the field. Single application of insecticides Sevin (carbaryl) and Merit (imidacloprid) at the manufactures’ suggested doses significantly inhibited earthworm feeding activity for at least three weeks without leading to any earthworm death. Fungicides did not show significant toxicity to earthworms when applied only once, but their toxicities increased as application frequency increased. Consecutive weekly applications of Sevin, Merit and T-methyl for four times led to earthworm mortality of 35, 45 and 80%, respectively. In the field, six consecutive weekly applications of T-methyl and Sevin significantly reduced the abundance and biomass of earthworms with suppressive effects lasting for at least 6 weeks after the chemical application was terminated. Taken together, these findings suggest that the surface activities of earthworms in turfgrass systems may be managed through moderate application of pesticides at peak periods of earthworm activities. DA - 2011/1// PY - 2011/1// DO - 10.1016/j.apsoil.2010.11.002 VL - 47 IS - 1 SP - 31-36 SN - 1873-0272 KW - Earthworms KW - Fungicides KW - Insecticides KW - Turfgrass system ER - TY - JOUR TI - Uncertainties in Assessing Annual Nitrate Loads and Concentration Indicators: Part 2. Deriving Sampling Frequency Charts in Brittany, France AU - Birgand, F. AU - Faucheux, C. AU - Gruau, G. AU - Moatar, F. AU - Meybeck, M. T2 - Transactions of the ASABE AB - In water quality monitoring programs, standard sampling frequency schemes tend to be applied throughout entire regions or states. Ideally, the common standard among monitoring stations ought not to be the sampling frequency but instead the level of uncertainty of the estimated water quality indicators. Until now, there was no obvious way of doing this. This article proposes, for the first time, guidelines to select appropriate sampling frequencies to harmonize the level of uncertainty in the case of yearly nitrate indicators for the regional river water quality monitoring network in Brittany, France. A database of 50 watershed-year datasets (nine watersheds of 4 to 252 km2 in size) was used for which high temporal resolution data (hourly and daily) were available for flow and nitrate concentrations. For each dataset, the uncertainty levels were calculated by numerically simulating sampling intervals varying from 2 to 60 days. The precision limits of the uncertainties were successfully correlated to a hydrological reactivity index. The correlations were used to derive sampling frequency charts. These charts can be used by watershed managers to optimize the sampling frequency scheme for any watershed for a desired uncertainty level, provided that the dimensionless local hydrological reactivity can be calculated from previous records of continuous flow rates. The sampling frequency charts also suggest that, depending on the hydrological reactivity, expected uncertainties generated by monthly sampling range between 6% and 14% for the annual load and between -5% and +2.5% to +7.2% for the annual concentration average. DA - 2011/// PY - 2011/// DO - 10.13031/2013.36263 VL - 54 IS - 1 SP - 93-104 LA - en OP - SN - 2151-0040 UR - http://dx.doi.org/10.13031/2013.36263 DB - Crossref ER - TY - JOUR TI - Sediment export from a highway construction site in central North Carolina AU - Line, D. E. AU - Shaffer, M. B. AU - Blackwell, J. D. T2 - Transactions of the ASABE AB - Sediment export and turbid runoff from active construction sites continue to be a source of impairment to surface water resources. Few studies have been published that include monitoring data from construction sites, particularly highway construction sites. In this study, water quality monitoring of runoff originating from three sections of a highway construction corridor was conducted during a 4.5-year period. Two unnamed tributaries, referred to as Tilly and Ellery for this study, were monitored at two locations downstream of the highway corridor, and one tributary, referred to as King's Mill, was monitored upstream and downstream of the highway corridor. At each station, discharge was continuously monitored and flow-proportional samples were collected. Samples were analyzed for total suspended solids, total solids, and turbidity. A recording raingauge was also maintained at one of the highway monitoring stations. Monitoring data at all stations documented increased sediment export and turbidity levels during the construction period as compared to the pre- and post-construction periods. During construction, sediment export rates ranged from 2.7 to 17.7 Mg ha-1 year-1, while mean turbidity levels ranged from 466 to 1,607 NTU for the five stations downstream of the highway corridor. For the station with the greatest sediment export, about 32% of the export occurred during two back-to-back tropical storms. At this time, one section of the highway was particularly susceptible to erosion because more than 6 m of fill material had recently been added to bring the road surface to near grade and vegetation had not yet been established. Increases in sediment export and turbidity at the other four downstream stations during highway construction were less pronounced. Mean turbidity levels during construction at all downstream stations were greater than 50 NTU. Post-construction mean turbidity levels were much less than during construction but were still greater than pre-construction at four of the five stations. Post-construction turbidity levels on the King's Mill tributary downstream of the highway were not significantly different from upstream. DA - 2011/// PY - 2011/// DO - 10.13031/2013.36264 VL - 54 IS - 1 SP - 105-111 ER - TY - JOUR TI - Genome-wide association study of quantitative resistance to southern leaf blight in the maize nested association mapping population AU - Kump, Kristen L. AU - Bradbury, Peter J. AU - Wisser, Randall J. AU - Buckler, Edward S. AU - Belcher, Araby R. AU - Oropeza-Rosas, Marco A. AU - Zwonitzer, John C. AU - Kresovich, Stephen AU - McMullen, Michael D. AU - Ware, Doreen AU - Balint-Kurti, Peter J. AU - Holland, James B. T2 - NATURE GENETICS DA - 2011/2// PY - 2011/2// DO - 10.1038/ng.747 VL - 43 IS - 2 SP - 163-U120 SN - 1061-4036 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79251575784&partnerID=MN8TOARS ER - TY - JOUR TI - Evaluating the effects of organic carbon on biological filtration performance in a large scale recirculating aquaculture system AU - Guerdat, Todd C. AU - Losordo, Thomas M. AU - Classen, John J. AU - Osborne, Jason A. AU - DeLong, Dennis T2 - AQUACULTURAL ENGINEERING AB - Studies evaluating the impact of organic carbon on biological filters at the large scale for aquaculture production are lacking. Understanding the performance characteristics of different biofilters under actual production conditions will be the only means by which recirculating system designers may properly select and size biological filters for commercial production use. Previous studies have determined the impact of organic carbon on biofilter performance at the small lab scale often using artificial waste nutrients in the evaluation. Evaluations under actual production conditions using real wastewater produce vastly different results than previous lab scale studies using artificial nutrients. As such, this study is a preliminary step in evaluating the impact of organic carbon on three different commercially available biological filters at the large scale under actual recirculating aquaculture production conditions. The study was conducted at the North Carolina State University Fish Barn—a commercial scale research and demonstration recirculating aquaculture facility operated by the Biological and Agricultural Engineering department. The study was based on a 60 m3 Tilapia system with average daily feed rates of 45 kg using a 40% protein feed and an average biomass of 6750 kg. The system was dosed with sucrose (C12H22O11) to increase the concentration of biodegradable organic carbon in the system. The effect of elevated organic carbon concentrations on total ammoniacal nitrogen (TAN) removal rates was evaluated and determined based on biofilter media volume. Variability increased substantially in the volumetric TAN removal rate (VTR) for all three filters. VTR for all three filter types was reduced by approximately 50% as compared to normal production conditions. The results demonstrate the importance of controlling the concentration of biologically available organic carbon in a recirculating aquaculture system. DA - 2011/1// PY - 2011/1// DO - 10.1016/j.aquaeng.2010.10.002 VL - 44 IS - 1 SP - 10-18 SN - 1873-5614 KW - Biological filtration KW - Organic carbon KW - Nitrification KW - Recirculating aquaculture ER - TY - JOUR TI - Evaluating Four Storm-Water Performance Metrics with a North Carolina Coastal Plain Storm-Water Wetland AU - Lenhart, Hayes A. AU - Hunt, William F., III T2 - JOURNAL OF ENVIRONMENTAL ENGINEERING AB - Storm-water best management practices (BMPs) are typically assessed using the performance metric of pollutant concentration removal efficiencies. However, debate exists whether this is the most appropriate metric to use. In this study, a storm-water wetland constructed and monitored in the coastal plain of North Carolina is evaluated for water quality and hydrologic performance using four different metrics: concentration reduction, load reduction, comparison to nearby ambient water quality monitoring stations, and comparison to other wetlands studied in North Carolina. The River Bend storm-water wetland was constructed in spring 2007 and was monitored from June 2007 through May 2008. Twenty-four hydrologic and 11 water quality events were captured and evaluated. The wetland reduced peak flows and runoff volumes by 80 and 54%, respectively. Reductions were significant. Concentrations for the following pollutants increased: total kjeldahl nitrogen (TKN), NH4–N, total nitrogen (TN), and total suspended solids (TSS); inflow and outflow concentrations did not change for total phosphorus (TP), while only NO2–3–N and orthophosphorus (OP) concentrations were lower at the outlet. Using a load reduction metric, results were strikingly different, showing positive load reductions of 35, 41, 42, 36, 47, 61, and 49% for these respective pollutants: TKN, NO2–3–N , NH4–N , TN, TP, OP, and TSS. When comparing the effluent concentrations from the wetland to ambient water quality in the Trent River, all effluent nitrogen species concentration were either similar or lower. TP and TSS concentrations leaving the wetland were higher than ambient water quality data. Finally, by comparing pollutant concentrations among different North Carolina wetlands, it is apparent the River Bend wetland received relatively “clean” water and released water with pollutant concentrations comparable to all other studies examined. Major conclusions from this study include: (1) storm-water wetlands sited in sandier soils (such as those of the North Carolina coastal plain) should be considered a low impact development tool and (2) the selection of performance metric has a pronounced bearing on how a BMP’s performance is perceived. Sole reliance on a concentration reduction metric is discouraged. DA - 2011/2// PY - 2011/2// DO - 10.1061/(asce)ee.1943-7870.0000307 VL - 137 IS - 2 SP - 155-162 SN - 1943-7870 KW - Storm-water management KW - Runoff KW - Water quality KW - Watersheds KW - Wetlands KW - North Carolina ER - TY - JOUR TI - The Wheat Puroindoline Genes Confer Fungal Resistance in Transgenic Corn AU - Zhang, Jinrui AU - Martin, John M. AU - Balint-Kurti, Peter AU - Huang, Li AU - Giroux, Michael J. T2 - JOURNAL OF PHYTOPATHOLOGY AB - Puroindoline a and b (Pina and Pinb), together make up the functional components of the wheat grain hardness locus (Ha) and have antimicrobial properties. The antifungal activity of puroindoline proteins, PINA and PINB, has been demonstrated in vitro and in vivo. In this study, Pina and Pinb were introduced into corn under the control of a corn Ubiquitin promoter. Two Pina/Pinb expression–positive transgenic events were evaluated for resistance to Cochliobolus heterostrophus, the corn southern leaf blight (SLB) pathogen. Transgenic corn expressing Pins showed significantly increased tolerance to C. heterostrophus, averaging 42.1% reduction in symptoms. Pins are effective in vivo as antifungal proteins and could be valuable tools in corn SLB control. DA - 2011/3// PY - 2011/3// DO - 10.1111/j.1439-0434.2010.01744.x VL - 159 IS - 3 SP - 188-190 SN - 1439-0434 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79551503188&partnerID=MN8TOARS KW - Puroindolines KW - corn KW - southern leaf blight resistance ER - TY - JOUR TI - Pretreatment of switchgrass for sugar production with the combination of sodium hydroxide and lime AU - Xu, Jiele AU - Cheng, Jay J. T2 - BIORESOURCE TECHNOLOGY AB - Sodium hydroxide (NaOH) and lime (Ca(OH)(2)) were innovatively used together in this study to improve the cost-effectiveness of alkaline pretreatment of switchgrass at ambient temperature. Based on the sugar production in enzymatic hydrolysis, the best pretreatment conditions were determined as: residence time of 6h, NaOH loading of 0.10 g/g raw biomass, NaOH addition at the beginning, Ca(OH)(2) loading of 0.02 g/g raw biomass, and biomass wash intensity of 100ml water/g raw biomass, at which the glucose and xylose yields were respectively 59.4% and 57.3% of the theoretical yields. The sugar yield of the biomass pretreated using the combination of 0.10 g NaOH/g raw biomass and 0.02 g Ca(OH)(2)/g raw biomass was found comparable with that of the biomass pretreated using 0.20 g NaOH/g raw biomass at the same conditions, while the chemical expense was remarkably reduced due to the low cost of lime and the reduced loading of NaOH. DA - 2011/2// PY - 2011/2// DO - 10.1016/j.biortech.2010.12.038 VL - 102 IS - 4 SP - 3861-3868 SN - 1873-2976 KW - Biofuels KW - Biomass conversion KW - Lignocellulose KW - Lime KW - Sodium hydroxide ER - TY - JOUR TI - High temperature dilute acid pretreatment of coastal Bermuda grass for enzymatic hydrolysis AU - Redding, Arthur P. AU - Wang, Ziyu AU - Keshwani, Deepak R. AU - Cheng, Jay J. T2 - BIORESOURCE TECHNOLOGY AB - Dilute sulfuric acid was used to pretreat coastal Bermuda grass at high temperature prior to enzymatic hydrolysis. After both pretreatment and enzymatic hydrolysis processes, the highest yield of total sugars (combined xylose and glucose) was 97% of the theoretical value. The prehydrolyzate liquor was analyzed for inhibitory compounds (furfural, hydroxymethylfurfural (HMF)) in order to assess potential risk for inhibition during the following fermentation. Accounting for the formation of the inhibitory compounds, a pretreatment with 1.2% acid at 140 °C for 30 min with a total sugar yield of 94% of the theoretical value may be more favorable for fermentation. From this study, it can be concluded that dilute sulfuric acid pretreatment can be successfully applied to coastal Bermuda grass to achieve high yields of monomeric glucose and xylose with acceptable levels of inhibitory compound formation. DA - 2011/1// PY - 2011/1// DO - 10.1016/j.biortech.2010.09.053 VL - 102 IS - 2 SP - 1415-1424 SN - 1873-2976 KW - Coastal Bermuda grass KW - Dilute sulfuric acid pretreatment KW - Enzymatic hydrolysis KW - Furfural KW - Hydroxymethylfurfural ER - TY - JOUR TI - Growing duckweed in swine wastewater for nutrient recovery and biomass production AU - Xu, J. L. AU - Shen, G. X. T2 - Bioresource Technology DA - 2011/// PY - 2011/// VL - 102 IS - 2 SP - 848-853 ER - TY - JOUR TI - Bioretention Outflow: Does It Mimic Nonurban Watershed Shallow Interflow? AU - DeBusk, Kathy M. AU - Hunt, William F. AU - Line, Daniel E. T2 - JOURNAL OF HYDROLOGIC ENGINEERING AB - Bioretention, a key structural practice of low impact development (LID), has been proved to decrease peak flow rates and volumes, promote infiltration and evapotranspiration, and improve water quality. Exactly how well bioretention mimics predevelopment (or “natural”) hydrology is an important research question. Do bioretention outflow rates mirror shallow groundwater interevent stream recharge flow associated with natural or nonurban watersheds? Streamflow from three small, nonurban watersheds, located in Piedmont, part of central North Carolina, was compared with bioretention outflow from four cells also in North Carolina’s Piedmont region. Each benchmark watershed drained to a small stream, where flow rate was monitored for an extended period of time. After normalizing the flow rates and volumes by watershed size, data were combined to form two data sets: bioretention outflow and stream interevent flow. Results indicate that there is no statistical difference between flow rates in streams draining undeveloped watersheds and bioretention outflow rates for the first 24 h following the commencement of flow. Similarly, there is no statistical difference between the cumulative volumes released by the two systems during the 48 h following the start of flow. These results indicate that bioretention cells behave comparably to watersheds in natural or nonurban conditions, with respect to both flow rates and flow volumes, and suggest that bioretention outflows may mirror post–storm event shallow groundwater interevent stream recharge flow. Solely considering bioretention outflow as a conjugate to runoff may be a misinterpretation of a flowrate that actually resembles shallow interflow. DA - 2011/3// PY - 2011/3// DO - 10.1061/(asce)he.1943-5584.0000315 VL - 16 IS - 3 SP - 274-279 SN - 1943-5584 KW - Hydrology KW - Storm-water management KW - Streamflow KW - Best management practice ER -