TY - CONF TI - A web-based advisory service for optimum irrigation management AU - Abourached, C. AU - Hillyer, C. AU - Sayde, C. AU - English, M. AU - Bush, J. T2 - 2007 ASABE Annual International Meeting C2 - 2007/// C3 - Proceedings of the 2007 ASABE Annual International Meeting CY - Minneapolis, Minnesota DA - 2007/// PY - 2007/6/2/ SP - 1–12 PB - American Society of Agricultural and Biological Engineers ER - TY - RPRT TI - Stormwater wetland design update AU - Hunt, W.F., III AU - Burchell, M.R. AU - Wright, J.D. AU - Bass, K.L. A3 - North Carolina State University Extension Service DA - 2007/// PY - 2007/// M1 - AGW-588-12 M3 - North Carolina Cooperative Extension Publication PB - North Carolina State University Extension Service SN - AGW-588-12 ER - TY - RPRT TI - Implementation of Two Priority Stormwater Best Management Practice (BMP) Projects for the New Hanover County, NC Local Watershed Plan AU - Burchell, M.R. AU - Hunt, W.F. A3 - New Hanover County Planning Department DA - 2007/4// PY - 2007/4// M3 - Final Report PB - New Hanover County Planning Department ER - TY - RPRT TI - Kure Beach Dune Infiltration System AU - Burchell, M.R. AU - Hunt, W.F. AU - Bright, T.M. A3 - NCDOT Research and Analysis Group DA - 2007/7// PY - 2007/7// M1 - Project 2005-29 M3 - Final Report PB - NCDOT Research and Analysis Group SN - Project 2005-29 ER - TY - CONF TI - Innovative Stormwater Treatment Practices in the Neuse and Tar-Pamlico Basins: A Partnership between the North Carolina Ecosystem Enhancement Program and the Biological and Agricultural Engineering Department at North Carolina State University AU - Hathaway, J. M. AU - Hunt, W. F. AU - Smith, R. A. AU - Bass, K. L. T2 - World Environmental and Water Resources Congress 2007 AB - Urbanization within North Carolina's watersheds and the need for proactive mitigation led to the establishment of the North Carolina Ecosystem Enhancement Program (EEP) in July 2003. The EEP is responsible for the majority of mitigation efforts throughout the state. These efforts include the restoration, enhancement, and preservation of streams and wetlands, as well as the creation of stormwater best management practices (BMPs) for the purpose of maintaining and improving water quality and riparian habitats across the state. This project involves a partnership between EEP and the Biological and Agricultural Engineering Department (BAE) at North Carolina State University for the purpose of locating, designing, and monitoring stormwater BMPs. In addition, local governments and the North Carolina Cooperative Extension Service assist in project site selection and development. Two large river basins in North Carolina, Neuse and Tar-Pamlico, have historic, significant degradation to water quality partially due to urbanization and agricultural practices. Primary pollutants within these basins include nitrogen and phosphorous. To change the trend of degradation, the State of North Carolina enacted regulations for nitrogen and phosphorous removal specifically for these basins. These regulations provided for the funding of the EEP Nutrient Reduction Program by authorizing impact fees. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)570 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)570 DB - Crossref ER - TY - JOUR TI - Low temperature catalytic oxidation of aldehydes using wood fly ash and molecular oxygen AU - Kolar, Praveen AU - Kastner, James R. AU - Miller, Joby T2 - Applied Catalysis B: Environmental AB - Aldehydes, such a 2-methylbutanal (2-MB) and 3-methylbutanal (3-MB), are odorous and regulated VOCs generated in the poultry rendering process that are ineffectively removed in chemical wet scrubbers. It was theorized that wood fly ash or selective crystalline phases in the ash could act to catalyze the oxidation of aldehydes at room temperature in the presence of ClO2, resulting in a low-cost/energy air pollution control method. Results indicate that wood fly ash catalyzed the oxidation (i.e., breakdown) of 2-MB and 3-MB both in the presence of ClO2 and with just O2 (i.e., air) itself, potentially via a free radical mechanism. Aldehyde oxidation did not occur at measurable rates without the wood fly ash or activated carbon. The presence of ClO2 did not increase the rate, but altered the end products of oxidation. Wood fly ash also catalyzed the oxidation of 2-MB in the presence of air, leading to the appearance of 2-butanone, compared to acetone from 3-MB. Contact times of 30 s reduced 3-MB levels by ∼40% in bench scale, batch reactors. Similar results were found using activated charcoal (i.e., in terms of contact times), except that higher molecular weight compounds appeared to be formed. Continuous catalytic oxidation of 3-MB using wood fly ash was also demonstrated in a fixed-bed reactor at room temperature; the overall oxidation rate appeared to be first order with respect to 3-MB and a representative conversion of 20% at an inlet concentration of 67 ppmv and 2 s residence time (GHSV 1800 1/h, 25 °C, 1 atm) was measured. Results indicate the potential of using inexpensive solid waste materials to breakdown C5 aldehydes in rendering emissions to CO2, H2O, and less odor offensive compounds, but a carbon balance on the reaction and complete identification of end products are required for implementation. DA - 2007/11// PY - 2007/11// DO - 10.1016/j.apcatb.2007.05.022 VL - 76 IS - 3-4 SP - 203-217 J2 - Applied Catalysis B: Environmental LA - en OP - SN - 0926-3373 UR - http://dx.doi.org/10.1016/j.apcatb.2007.05.022 DB - Crossref KW - catalytic autoxidation KW - room temperature KW - activated carbon KW - wood fly ash KW - aldehydes ER - TY - CONF TI - Conversion of a Drainage Ditch to Constructed Wetlands to Treat Stormwater Runoff AU - Burchell, M. R. AU - Line, D. AU - Hunt, III, W. F. AU - Wright, J. T2 - World Environmental and Water Resources Congress 2007 AB - A drainage ditch near Laney High School in Wilmington, N.C., designed to collect runoff from athletic fields and parking lots and deliver it to Smith Creek, was converted to a constructed wetland in August 2005: The approximately 0.1 ha wetland collects and treats drainage water from a 12 ha watershed, 2.4 ha of which is impervious surface. The wetland was designed with a variety of elevation features and planted with over 15 species of wetland plants, to encourage sedimentation, biogeochemical transformations of nutrients associated with runoff, and ecological diversity. Retention times are estimated to be 3–4 days. As of summer 2006, the wetland was vegetated and on-line. Preliminary nutrient data indicate a 50% reduction in TN and TP concentrations, and a 40% reduction in TSS. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)246 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)246 DB - Crossref ER - TY - CONF TI - Comparing Design Methods for Restoring Small Streams in NC's Coastal Plain AU - Bass, K. L. AU - Evans, R. O. AU - Burchell, M. R. T2 - World Environmental and Water Resources Congress 2007 AB - Two stream restoration projects were recently designed and constructed in the coastal plain of NC. Several popular design approaches were implemented to develop plan parameters. Traditional engineering methods, natural channel design methods, and analytical approaches were utilized. The results of each approach were compiled for comparison and to improve design confidence. This paper includes a description of the methods employed, the limitations encountered, and an evaluation of the results. Each method presents challenges in terms of data collection, effort, and the experience required. Information on these limitations should be incorporated in design approach and application decisions. Based on initial findings, it appears that design differences for small streams with relatively stable watersheds may not exceed expected variability. However, this may not be the case for larger streams as differences increased with watershed size and complexity. It is suggested that completing similar initial estimates will improve design decisions, confidence, and reduce risk. As the science of stream restoration progresses, more quantitative comparisons of this type will provide designers with the information needed to guide complex approach decisions. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)235 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)235 DB - Crossref ER - TY - CONF TI - Addition of Organic Matter to Agricultural Ditch Soils to be Used as Constructed Wetlands for Nitrate Treatment AU - Burchell, M. R. AU - Skaggs, R. W. AU - Evans, R. O. AU - Lee, C. R. AU - Broome, S. W. T2 - World Environmental and Water Resources Congress 2007 AB - A wetland mesocosm experiment was conducted in eastern N.C. to determine if organic matter (OM) addition to soils existing in ditches that are to be retrofitted into constructed wetlands would improve NO3–-N treatment. Not all soils are suitable for wetland substrate, so OM addition can provide a carbon and nutrient source to the wetland early in its development to enhance denitrification and biomass growth. Batch studies, with various initial NO3–-N concentrations were conducted in surface-flow wetland mesocosms. The results indicated that increasing the organic matter content of a Cape Fear loam soil from 50 g kg–1 (5% d.w.) to 110 g kg–1 (11% d.w.) enhanced NO3–-N wetland treatment efficiency in spring and summer batch studies, but increases to 160 g kg–1 (16% d.w.) OM did not. Increased OM addition and biosolids to the soil significantly increased biomass growth in the second growing season, when compared to no OM addition. Based on the first-order kinetic constants for nitrate reduction calculated from these mesocosm studies, increased OM in the substrate will reduce the area required for wetlands constructed in ditches to treat nitrate-laden drainage water. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)233 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)233 DB - Crossref ER - TY - CONF TI - Pollutant Removal in Bioretention Cells with Grass Cover AU - Smith, Ryan A. AU - Hunt, William F. T2 - World Environmental and Water Resources Congress 2007 AB - North Carolina has spent considerable effort to improve water quality in the State and its estuaries. One area of focus has been stormwater runoff quality. Bioretention is often used to treat runoff from new developments and is retrofitted in areas where development has already occurred. Typical designs have trees and shrubs planted and mulch cover, which has become the design standard. There is significant interest in bioretention with grassed cover because maintenance could be less costly and because some owners consider them to be more aesthetically pleasing and usable. Some regulators are reluctant to allow grassed systems because of a lack of research data proving that they meet current standards for pollutant removal. The goals of this study were (1) to test the performance of grassed bioretention cells in removing nitrogen, phosphorous, metals and sediment and (2) to compare the pollutant removal between 2 identical grassed cells using induced storage zones with different fill media depths. An induced storage zone is a water storage layer at the bottom of the bioretention cell created by elevating the underdrain outlet above the bottom of the cell. A field system was built in the Piedmont of North Carolina for the study. Both cells lost volume during storm events through exfiltration, which decreased the volume of outflow through the underdrains. The induced storage zone caused an increase in the exfiltration volume, in some cases preventing any outflow from the underdrains, which improved the pollutant load reduction by the cells. Nutrient load reductions for TN were approximately 70 to 80%. Phosphorus load reductions were 35 to 50%. The higher load reduction estimates were associated with the cell with a greater media depth. Fecal conform concentration removal was excellent for one cell, 97%. However, due to a limited number of storms collected (6), there was not a statistically significant finding. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)581 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)581 DB - Crossref ER - TY - CONF TI - Field Evaluation of Level Spreaders in the Piedmont of North Carolina AU - Hathaway, J. M. AU - Hunt, W. F. T2 - World Environmental and Water Resources Congress 2007 AB - Level Spreaders are commonly used in combination with riparian buffers as a stormwater Best Management Practice (BMP) in many parts of the United States. These systems have not been extensively studied in urban environments to determine if they can provide a long term water quality benefit. In winter 2005, 24 level spreaders were evaluated in the Piedmont of North Carolina. Detailed observations were made at 20 of these locations. The results of the study indicate that level spreaders may not be the versatile structure they are perceived to be. No level spreader — riparian buffer system was able to provide diffuse flow through the riparian buffer from the level spreader to the stream. Common causes for failure to maintain diffuse flow included: lack of maintenance (12 cases), poor design (11), riparian topography / content (11), level spreader lip not level (7), built with easily eroded materials (6), poor construction methods (3), and human interference (2). This field evaluation indicates that level spreader systems may need design revisions, construction guidance, and maintenance requirements before they continue to be used en masse. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)579 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)579 DB - Crossref ER - TY - CONF TI - The Effect of Urban Stormwater BMPs on Runoff Temperature in Trout Sensitive Waters AU - Jones, Matthew P. AU - Hunt, William F. AU - Smith, Jonathan T. T2 - World Environmental and Water Resources Congress 2007 AB - Urbanization can increase the temperature of coldwater stream environments by transferring heat from solar radiation, captured by pavement materials, to receiving water bodies through stormwater runoff. A number of aquatic organisms, including trout, are sensitive to elevated stream temperatures and temperature increases associated with urbanization have been shown to have a negative impact on the aquatic ecosystem. Research was conducted in regions of trout sensitive waters in Western North Carolina to determine, the effect that urban stormwater BMPs have on the thermal load of stormwater runoff at 4 bioretention areas, 1 stormwater wetland, and 1 wet pond. Water temperature and associated flows were remotely logged every 5 minutes at all BMP inlets and outlets, with additional temperature sensors located at specified depths and receiving waters. Analysis focused on flow and temperature reductions between inlets and outlets, as well as temperature changes within the BMPs due to diurnal fluctuations and storm events. Variations in temperature throughout the soil and water columns suggest the opportunity for modified outlet structures to reduce the thermal load discharged from BMPs. Results have also indicated the possibility of lowering runoff temperatures through conveyance in buried pipes. A comparison of the effect shading within the BMPs has on thermal load is also presented. An understanding of the temperature reduction mechanisms involved in urban stormwater BMPs should provide engineers with design criteria tos effectively mitigate the effect of thermal loads from stormwater runoff. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)438 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)438 DB - Crossref ER - TY - CONF TI - Evaluation of Various Types of Permeable Pavements with Respect to Water Quality Improvement and Flood Control AU - Collins, Kelly A. AU - Hunt, William F. AU - Hathaway, Jon M. T2 - World Environmental and Water Resources Congress 2007 AB - In many U.S. states, different permeable pavement types are considered to have the same capabilities in reducing runoff, and they are not credited with improving water quality. To test various permeable pavement designs, a parking lot consisting of four different types of permeable pavements and standard asphalt was constructed in Kinston, NC. The permeable pavement sections consist of pervious concrete (PC), permeable interlocking concrete pavers (PICP) with 8.5 % void space, PICP with 12.9 % void space, and concrete grid pavers (CGP), each covering a 1200 sq. ft. area with a 10 in. gravel storage layer. The purpose of this study is to evaluate and compare the effects of each pavement type on water quality and runoff reduction. Site analyses on every rainfall event began in March, 2006, and will continue through March, 2007. Preliminary results indicate significant (p<0.05) peak flow and volume reductions from all permeable pavements. Additionally, there has been little to no runoff observed from any of the pervious sections. Pollutant removal performance by the pavements has widely varied. As a result of this study, it is expected that the state of North Carolina will make a judgment on how much pollutant removal credit permeable pavement types should receive. Also, this study may be used to determine whether or not stormwater credit should vary based on pavement type. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)435 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)435 DB - Crossref ER - TY - JOUR TI - Research needs for automated oyster shucking AU - Wheaton, Fred AU - Hall, Steven T2 - Aquacultural Engineering AB - Oyster shucking has been the focus of research and development for over 100 years, but to date there is no low cost automated oyster shucking machine commercially available. Automating oyster shucking is a difficult task due to the construction of the oyster shell and meat, the wide variation in oyster shell shape, and the effects of environmental parameters on oyster growth and shell shape. This paper describes areas where additional research is needed that will advance the science of oyster shucking. Oyster physical and thermal properties, various methods of applying energy to shuck oysters, automated oyster orientation, and oyster meat grading are discussed. Research needs are described and ideas are provided to stimulate further research on automation of oyster shucking and oyster orientation. DA - 2007/7// PY - 2007/7// DO - 10.1016/j.aquaeng.2007.02.002 VL - 37 IS - 1 SP - 67-72 J2 - Aquacultural Engineering LA - en OP - SN - 0144-8609 UR - http://dx.doi.org/10.1016/j.aquaeng.2007.02.002 DB - Crossref KW - automated oyster shucking KW - shellfish processing KW - research directions KW - seafood processing KW - automated oyster orientation KW - mechanization oyster processing KW - oyster processing research needs ER - TY - JOUR TI - Preface AU - Wheaton, Fred AU - Hall, Steven T2 - Aquacultural Engineering DA - 2007/7// PY - 2007/7// DO - 10.1016/j.aquaeng.2007.02.003 VL - 37 IS - 1 SP - 1-2 J2 - Aquacultural Engineering LA - en OP - SN - 0144-8609 UR - http://dx.doi.org/10.1016/j.aquaeng.2007.02.003 DB - Crossref ER - TY - JOUR TI - Effectiveness of a heat/cool technique for shucking oysters AU - Martin, Daniel E. AU - Supan, John AU - Nadimpalli, Uma AU - Hall, Steven G. T2 - Aquacultural Engineering AB - A method was developed to use heat/cool processes to effectively shuck oysters. The optimal method devised required only low-pressure steam and chilled water, thus providing a low cost and readily available solution to processors. A series of treatments were devised, and instrumentation installed to monitor process temperatures. Steam injection was used for heating, a vacuum pump was used to increase heating and chilling rates and an ice water solution was used for chilling. Sixty-seven different treatment combinations of both time–temperature and oyster location were tested on a total of 697 oysters. Release rates of up to 85% were observed. Coupling release rates with acceptable meat quality suggests optimal time–temperature combinations for the oysters studied (primarily from Louisiana and Mississippi coasts of the Gulf of Mexico) of 30 s pre-heat; 30 s steam injection at 30 psi; 30 s hold and 240 s ice water chill for these oysters. Variations among treatments suggest that this method of evaluation would be needed for different localities and oyster types, but still suggests that this methodology may potentially provide effective and inexpensive methods for automating oyster shucking. DA - 2007/7// PY - 2007/7// DO - 10.1016/j.aquaeng.2006.12.008 VL - 37 IS - 1 SP - 61-66 J2 - Aquacultural Engineering LA - en OP - SN - 0144-8609 UR - http://dx.doi.org/10.1016/j.aquaeng.2006.12.008 DB - Crossref KW - oyster shucking KW - food processing KW - temperature control KW - heat treatment KW - process optimization ER - TY - JOUR TI - Development and testing of a heat–cool methodology to automate oyster shucking AU - Martin, Daniel E. AU - Supan, John AU - Theriot, Jeremy AU - Hall, Steven G. T2 - Aquacultural Engineering AB - A heat/cool methodology was developed to facilitate oyster shucking. Eastern oysters Crassostrea virginica from several locations were used. Two methods were designed to shuck oysters, which incorporated various heat–cool regimes. The first was a combination of low-pressure steam and cryogenic CO2, the second a combination of steam and cooling, either from cryogenic N2 or ice water. The oysters were instrumented with T-type thermocouples connected to a datalogger to monitor and record process temperatures. Methods also were developed to quantify meat detachment, shelf-life and textural changes. The methods developed allowed for the measurement and optimization of the shucking process. Advantages of the steam–ice water combination include availability of facilities and low cost. Additionally, under selected regimes, meat quality was similar to that of raw oysters, while some reduction in microbial activity was recorded. Results indicated quantifiable methods, which yielded oyster meat detachments in excess of 85%. DA - 2007/7// PY - 2007/7// DO - 10.1016/j.aquaeng.2006.12.006 VL - 37 IS - 1 SP - 53-60 J2 - Aquacultural Engineering LA - en OP - SN - 0144-8609 UR - http://dx.doi.org/10.1016/j.aquaeng.2006.12.006 DB - Crossref KW - oyster shucking KW - methodology KW - temperature control KW - process engineering KW - instrumentation ER - TY - CONF TI - Controlled-temperature effects on biofilteration of recirculation systems for oyster studies AU - Saidu, M. AU - Hall, S. C2 - 2007/// C3 - 2007 ASABE Annual International Meeting, Technical Papers DA - 2007/// VL - 15 BOOK UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35648967173&partnerID=MN8TOARS ER - TY - CONF TI - Experimental investigation of direct connectivity between macropores and subsurface drains during infiltration AU - Akay, O. AU - Fox, G.A. AB - Laboratory experiments are commonly utilized for investigating the effect of macropore flow on contaminant transport. Most research to date has focused on lateral water and solute diffusion between macropores and the soil matrix with controlled bottom flux or specified pressure head boundary conditions as opposed to simulating local drainage flux to tile drains. Furthermore, recent research indicates immediate breakthrough of solutes and pesticides in subsurface drainage by extraordinarily efficient transport through directly connected macropores. Macropores, such as those created by earthworm burrows, have been documented to transfer water and solutes directly to subsurface drains. In this study, this "direct connectivity" phenomenon was verified by conducting infiltration experiments in a laboratory column (28 cm by 50 cm rectangular cross-section with length of 95 cm) with an artificial macropore directly connected to the subsurface drain. A novel design of the experimental setup allowed open surface and buried macropore lengths to be varied from the subsurface drain to the surface without unpacking/disturbing the soil column between experiments. Experiments were completed for various buried macropore lengths ranging from zero (no macropore effect) to 75 cm (surface connected macropore). The column was packed with a sandy loam soil with bulk density of 1.6 g/cm3. For each experiment, a 1-cm ponded boundary condition was maintained at the soil surface. Breakthrough curves were plotted for both matrix and macropore flow at the outlet. The movement of the wave front down the column was observed with pencil size tensiometers mounted on the side of the column at various depths. The macropore and soil matrix outflow revealed hydraulic nonequilibrium between soil matrix and macropore domains. It was observed that the longer the buried macropore length (i.e., as the macropore approached the soil surface), the more rapid response occurred at the drain outlet in addition to an increased percentage of total drain flow through the macropore. Breakthrough times with the surface connected macropore decreased significantly compared to buried macropores. This research also suggests that "drain connected" macropores may not necessarily have to possess a direct physical connection to subsurface drainage. C2 - 2007/// C3 - Examining the Confluence of Environmental and Water Concerns - Proceedings of the World Environmental and Water Resources Congress 2006 DA - 2007/// DO - 10.1061/40856(200)301 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84855161198&partnerID=MN8TOARS ER - TY - JOUR TI - Modeling parent and metabolite fate and transport in subsurface drained fields with directly connected macropores AU - Fox, G.A. AU - Sabbagh, G.J. AU - Malone, R.W. AU - Rojas, K. T2 - Journal of the American Water Resources Association AB - Abstract: Few studies exist that evaluate or apply pesticide transport models based on measured parent and metabolite concentrations in fields with subsurface drainage. Furthermore, recent research suggests pesticide transport through exceedingly efficient direct connections, which occur when macropores are hydrologically connected to subsurface drains, but this connectivity has been simulated at only one field site in Allen County, Indiana. This research evaluates the Root Zone Water Quality Model (RZWQM) in simulating the transport of a parent compound and its metabolite at two subsurface drained field sites. Previous research used one of the field sites to test the original modification of the RZWQM to simulate directly connected macropores for bromide and the parent compound, but not for the metabolite. This research will evaluate RZWQM for parent/metabolite transformation and transport at this first field site, along with evaluating the model at an additional field site to evaluate whether the parameters for direct connectivity are transferable and whether model performance is consistent for the two field sites with unique soil, hydrologic, and environmental conditions. Isoxaflutole, the active ingredient in BALANCE ® herbicide, was applied to both fields. Isoxaflutole rapidly degrades into a metabolite (RPA 202248). This research used calibrated RZWQM models for each field based on observed subsurface drain flow and/or edge of field conservative tracer concentrations in subsurface flow. The calibrated models for both field sites required a portion (approximately 2% but this fraction may require calibration) of the available water and chemical in macropore flow to be routed directly into the subsurface drains to simulate peak concentrations in edge of field subsurface drain flow shortly after chemical applications. Confirming the results from the first field site, the existing modification for directly connected macropores continually failed to predict pesticide concentrations on the recession limbs of drainage hydrographs, suggesting that the current strategy only partially accounts for direct connectivity. Thirty‐year distributions of annual mass (drainage) loss of parent and metabolite in terms of percent of isoxaflutole applied suggested annual simulated percent losses of parent and metabolite (3.04 and 1.31%) no greater in drainage than losses in runoff on nondrained fields as reported in the literature. DA - 2007/// PY - 2007/// DO - 10.1111/j.1752-1688.2007.00116.x VL - 43 IS - 6 SP - 1359-1372 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35648974021&partnerID=MN8TOARS ER - TY - JOUR TI - Influence of Rainfall Distribution on Simulations of Atrazine, Metolachlor, and Isoxaflutole/Metabolite Transport in Subsurface Drained Fields AU - Fox, Garey A. AU - Pulijala, Sri H. AU - Sabbagh, George J. T2 - Journal of Agricultural and Food Chemistry AB - This research investigated the impact of modeling atrazine, metolachlor, and isoxaflutole/metabolite transport in artificially subsurface drained sites with temporally discrete rainfall data. Differences in considering rainfall distribution are unknown in regard to estimating agrochemical fluxes in the subsurface. The Root Zone Water Quality Model (RZWQM) simulated pesticide fate and transport at three subsurface drained sites: metolachlor/atrazine field experiment in Baton Rouge, LA (1987), and two isoxaflutole/metabolite field experiments in Allen County and Owen County, Indiana (2000). The modeling assumed linear, equilibrium sorption based on average reported physicochemical and environmental fate properties. Assumed rainfall intensity and duration influenced transport by runoff more than transport by subsurface drainage. As the importance of macropore flow increased, the necessity for using temporally discrete rainfall data became more critical. Long-term simulations indicated no significant difference between average or upper percentile (i.e., <2% difference in percent loss as a function of mass applied) atrazine, metolachlor, or isoxaflutole/metabolite loss through subsurface drainage among the three different rainfall assumptions. It was necessary (i.e., within 7% of predicted loss) to use hourly or average duration storm events as opposed to daily rainfall data for total (i.e., runoff and subsurface drainage) pesticide loss over the long term. Keywords: Atrazine; environmental exposure; isoxaflutole; metabolite; metolachlor; modeling; rainfall distribution DA - 2007/7// PY - 2007/7// DO - 10.1021/jf063753z VL - 55 IS - 14 SP - 5399-5407 J2 - J. Agric. Food Chem. LA - en OP - SN - 0021-8561 1520-5118 UR - http://dx.doi.org/10.1021/jf063753z DB - Crossref KW - atrazine KW - environmental exposure KW - isoxaflutole KW - metabolite KW - metolachlor KW - modeling KW - rainfall distribution ER - TY - JOUR TI - Experimental investigation of direct connectivity between macropores and subsurface drains during infiltration AU - Akay, O. AU - Fox, G.A. T2 - Soil Science Society of America Journal AB - Recent research indicates immediate breakthrough of surface‐applied contaminants in subsurface drainage by transport through macropores directly connected to the surface. This “direct connectivity” phenomenon was verified and investigated by conducting infiltration experiments (1‐cm ponded water at the soil surface) in a laboratory soil column (sandy loam soil with bulk density of 1.6 g cm −3 ) with a vertical artificial macropore placed directly above or shifted away from a lateral subsurface drain. The experimental setup allowed surface‐connected and buried macropore lengths to be varied from the surface to the subsurface drain depth without unpacking or disturbing the soil column between experiments. It was observed that the longer the buried macropore length (i.e., as the macropore approached the soil surface), the more rapid the response at the drain outlet in addition to an increased percentage of total drain flow through the macropore (35–40%). Breakthrough with surface‐connected macropores was significantly faster than with buried macropores, suggesting that breaking surface connectivity of macropores by tillage may be an important management strategy. For surface‐connected macropore experiments, the average ratio of steady‐state total (macropore and matrix) to matrix flow rates decreased as the distance from the drain increased: 2.4, 2.1, and 1.6 for distances of 0, 6.25, and 12.5 cm, respectively. Extrapolating this data to distances beyond 12.5 cm suggested that macropores located within 20 to 25 cm of the drain act as though directly connected in this sandy loam soil. This research verifies the “contributing area” concept hypothesized in previous field and numerical modeling studies. DA - 2007/// PY - 2007/// DO - 10.2136/sssaj2006.0359 VL - 71 IS - 5 SP - 1600-1606 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35649011237&partnerID=MN8TOARS ER - TY - CONF TI - Seepage Erosion: A Significant Mechanism of Stream Bank Failure AU - Fox, G. A. AU - Chu-Agor, M. L. AU - Wilson, G. V. T2 - World Environmental and Water Resources Congress 2007 AB - The role of seepage undercutting on mass failure of stream banks is not well defined relative to other streambank failure mechanisms. Seepage flow initiates undercutting, similar to development and headward migration of internal gullies, by liquefaction of soil particles, followed by mass wasting of the stream bank. The objectives of this research were to quantify the impact of seepage undercutting on streambank stability based upon seepage flow and erosion measurements from two deeply incised streams in northern Mississippi: Little Topashaw Creek (LTC) and Goodwin Creek (GC). Stream bank soil properties characterized from disturbed and undisturbed soil cores suggested that the type of seepage erosion (seepage erosion of a conductive layer and undercutting of layers underneath the seepage layer) at LTC and GC was a function of the bank stratigraphy. At LTC, seepage eroded sediment from the conductive, relatively noncohesive loamy sand layer. The GC seeps originated from the conductive concretion layer, but the flow eroded a less cohesive loamy sand layer below the seepage layer. Subsurface flow and sediment concentrations commonly exceeded 0.1 m3 d–1 and 10 g L–1, respectively, as quantified using collection flumes installed into the stream banks. A bank stability model, SLOPE/W, was used to simulate the bank profiles of both LTC and GC based on field measured streambank stratigraphy, soil hydraulic properties and soil strength parameters. Model simulations included numerous bank angles, ground water table elevations, and distances of seepage undercutting. SLOPE/W simulations suggested a 200-mm critical distance of seepage undercutting at which the error in neglecting seepage undercutting became greater than the error in neglecting soil-water pressure effects. C2 - 2007/5/11/ C3 - World Environmental and Water Resources Congress 2007 DA - 2007/5/11/ DO - 10.1061/40927(243)350 PB - American Society of Civil Engineers SN - 9780784409275 UR - http://dx.doi.org/10.1061/40927(243)350 DB - Crossref ER - TY - CONF TI - Modeling streambank instability by seepage undercutting AU - Chu-Agor, M.L. AU - Wilson, G. AU - Fox, G.A. C2 - 2007/// C3 - 2007 ASABE Annual International Meeting, Technical Papers DA - 2007/// VL - 4 BOOK UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35649019650&partnerID=MN8TOARS ER - TY - JOUR TI - Modeling pesticide fate and nonideal transport from seeds treated with a slow-release pesticide in a laboratory soil column AU - Sabbagh, G.J. AU - Fox, G.A. AU - Ma, L. AU - Malone, R.W. AU - Arthur, E.L. AU - Dyer, D.G. T2 - Transactions of the ASABE DA - 2007/// PY - 2007/// VL - 50 IS - 2 SP - 523-532 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-34347229430&partnerID=MN8TOARS ER - TY - JOUR TI - Estimating streambed conductivity: Guidelines for stream-aquifer analysis tests AU - Fox, G.A. T2 - Transactions of the ASABE DA - 2007/// PY - 2007/// VL - 50 IS - 1 SP - 107-113 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33947717890&partnerID=MN8TOARS ER - TY - CONF TI - Numerical modeling of bank instability by groundwater seepage flow AU - Chu-Agor, M.L. AU - Wilson, G.V. AU - Fox, G.A. T2 - 2007 ASABE Annual Meeting. AB - Predicting bank collapse due to seepage erosion undercutting has not been fully studied or modeled, even though its role in streambank erosion may be important. The limitation originates from the lack of field measurements or laboratory experiments as well as the unavailability of discrete element models that can effectively simulate seepage erosion. The objective of this research was to demonstrate a procedure for incorporating seepage undercutting into two-dimensional variably-saturated flow and bank stability models and to investigate the role of seepage undercutting on bank instability. Integrated flow and bank stability models were used to simulate soil-water pressure variations and bank stability with and without seepage erosion with regard to input parameter uncertainty using Monte Carlo analysis. The percentage decrease in the mean factor of safety, Fs, ranged between 42 and 91% as the depth of undercutting increased, dependent upon the initial stability of the bank. For stable banks, the probability of failure reached 100% when the depth of the undercutting reached 30 to 50 mm. The propensity of streambanks to fail during the recession limb of hydrographs may be the combined result of seepage undercutting and reduced cohesion. C2 - 2007/// C3 - 2007 Minneapolis, Minnesota, June 17-20, 2007 CY - Minneapolis, Minnesota DA - 2007/// PY - 2007/6/17/ DO - 10.13031/2013.23228 M1 - 072117 PB - American Society of Agricultural and Biological Engineers ER - TY - JOUR TI - Consideration for unsaturated flow beneath a streambed during alluvial well depletion AU - Fox, G.A. AU - Gordji, L. T2 - Journal of Hydrologic Engineering AB - Unsaturated flow transforms streams from constant head boundaries to constant flux boundaries, impacting the quantity of stream recharge to groundwater. The objective of this research was to analyze the impact of unsaturated flow on stream/aquifer exchange by incorporating a three-regime, saturated/unsaturated flow, stream recharge model into MODFLOW, the most commonly used numerical flow model in ground water hydrology. This three-regime model extends prior research by accounting for a transition regime between fully saturated and gravity-driven unsaturated flow. Accounting for unsaturated flow between a stream and aquifer is necessary to adequately simulate stream depletion. Sensitivity analyses of steady stream recharge versus drawdown demonstrated that the transition regime became more important for cases with small stream stages, smaller streambed thicknesses, and larger entry pressure heads. Based on coarse sand and fine sand hypothetical scenarios, the transition regime in the proposed three-regime model could generally be neglected with minor error for most stream/aquifer scenarios. However, the transition regime became important when: (1) the drawdown stabilized near the range of drawdowns that represented the transition regime; and (2) there must be a significant difference (i.e., 0.2m ) in the entry and ultimate capillary pressure heads, which occurred with larger entry pressure heads (i.e., equal to or greater than 1.0m ) and a smaller pore size distribution index (i.e., approximately 1.0). DA - 2007/// PY - 2007/// DO - 10.1061/(ASCE)1084-0699(2007)12:2(139) VL - 12 IS - 2 SP - 139-145 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33847177625&partnerID=MN8TOARS ER - TY - CONF TI - Erosion of noncohesive sediment by groundwater seepage: Lysimeter experiments and modeling AU - Fox, G.A. AU - Chu-Agor, M. AU - Wilson, G. C2 - 2007/// C3 - 2007 ASABE Annual International Meeting, Technical Papers DA - 2007/// VL - 5 BOOK UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35648961784&partnerID=MN8TOARS ER - TY - JOUR TI - Erosion of noncohesive sediment by ground water seepage: Lysimeter experiments and stability modeling AU - Fox, G.A. AU - Chu-Agor, Ma.L. AU - Wilson, G.V. T2 - Soil Science Society of America Journal AB - Seepage may be a significant mechanism of streambank erosion and failure in numerous geographical locations. Previous research investigated erosion by lateral subsurface flow and developed a sediment transport model similar to an excess shear stress equation. As a continuation of this earlier research, slope destabilization driven by lateral, subsurface flow was studied to further verify the recently proposed sediment transport model. Laboratory experiments were performed using a two‐dimensional soil lysimeter. The experiments were conducted on two sandy soils: a field soil (loamy sand) and sieved sand with greater sand content and less cohesion. A series of seven lysimeter experiments were performed for the two different sands by varying the bank slope (90, 60, 45, 36, and 26°). Flow and sediment concentrations were measured at the outflow flume. Pencil‐size tensiometers were used to measure soil pore‐water pressure. A slight modification of the existing seepage sediment transport model adequately simulated lysimeter experiments for both noncohesive soils without modifying the seepage parameters of the excess shear stress equation, especially for bank angles >45°. The research then determined whether integrated finite element and bank stability models were capable of capturing both small‐ and large‐scale sapping failures. The models predicted large‐scale failures for bank angles >45° in which tension cracks formed on the bank surface. The models failed to predict collapses for bank angles <45° in which tension cracks formed on the seepage face. The failure to predict collapse was hypothesized to be due to the assumption of circular arc slip surfaces. More analytically complex stability approaches are needed to capture bank slope undermining. DA - 2007/// PY - 2007/// DO - 10.2136/sssaj2007.0090 VL - 71 IS - 6 SP - 1822-1830 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-36448981038&partnerID=MN8TOARS ER - TY - JOUR TI - Capture of airborne particulate using surface applied emulsions: Potential for postdetonation dirty bomb cleanup AU - Fox, G.A. AU - Fuchs, J.W. AU - Medina, V.F. AU - Atapattu, K. T2 - Journal of Environmental Engineering AB - Recent research has proposed the use of asphalt and tall-oil-pitch emulsions for stabilizing radioactive contamination deposited on surfaces in urban areas. The objective of this project was to investigate whether surface applied emulsions could capture airborne radioactive particulate. Laboratory experiments included wind-blown particulate capture studies using an acrylic column and particulate retainment experiments using a wind box capable of producing wind speeds of 96km∕h. A probe methodology was developed to relate particulate retainment to a tack force on the emulsion surface. Experiments were also performed to determine the potential for such emulsions to absorb particulate matter into their emulsion matrix. Tall-oil-pitch emulsions outperformed asphalt emulsions in terms of particulate retention, tack force, and the ability to absorb magnesium silicate. Both tall-oil-pitch and asphalt emulsions were capable of extracting 22–24gm−2 of powder from particulate-laden airflow. Tall-oil-pitch emulsions were capable of retaining as much as 5–10% of magnesium silicate powder applied (i.e., retainment densities of 10–20gm−2) even after sevendays of curing and after applying 96.5km∕h(60mph) wind. Tall-oil-pitch emulsions were able to absorb surface-applied magnesium silicate (approximately 0.1–0.2g of magnesium silicate per 1.0g of emulsion within threedays) into their emulsion matrix, preventing the magnesium silicate from being exposed to the external environment. Initial results with these five different emulsion formulations suggested particulate capture was feasible. Future emulsion formulations (i.e., longer curing times with greater acid concentrations) should be tested to optimize this postdetonation response strategy. DA - 2007/// PY - 2007/// DO - 10.1061/(ASCE)0733-9372(2007)133:3(255) VL - 133 IS - 3 SP - 255-262 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33847204998&partnerID=MN8TOARS ER - TY - CONF TI - An improved express fraction for modeling macropore/subsurface drain interconnectivity AU - Fox, G.A. AU - Akay, O. AU - Malone, R. AU - Ma, L. AU - Sabbagh, G. C2 - 2007/// C3 - 2007 ASABE Annual International Meeting, Technical Papers DA - 2007/// VL - 4 BOOK UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35648947771&partnerID=MN8TOARS ER - TY - JOUR TI - Soil properties controlling seepage erosion contributions to streambank failure AU - Wilson, G.V. AU - Periketi, R.K. AU - Fox, G.A. AU - Dabney, S.M. AU - Shields, F.D. AU - Cullum, R.F. T2 - Earth Surface Processes and Landforms AB - Abstract The majority of sediment leaving catchments may be from streambank failure. Seepage erosion of unconsolidated sand above a restrictive layer is an important erosion process in incised streams that leads to streambank failure by undercutting banks. The objective of this study was to determine the impact of soil properties on seepage erosion and the resulting streambank failure. Seepage flow and sediment concentrations were measured in situ at eight locations along the banks of a deeply incised stream in northern Mississippi. Using field observations as a guide, the soil profile conditions of a shallow (45 cm) streambank, consisting of 30 cm of topsoil, a 10 cm conductive layer, and a 5 cm restrictive layer, were mimicked in laboratory lysimeter experiments to quantify the hydrologic properties controlling seepage erosion and bank failure under a 40 cm head. The time to flow initiation and the flow rate were linearly related to the slope of the restrictive layer. Seepage erosion began within minutes of flow initiation and resulted in substantial (3 to 34 cm) undercutting of the bank. Sediment concentrations of seeps were as high as 660 g l −1 in situ and 4500 g l −1 in the lysimeters. Sediment concentrations were related to the layer slope, thereby indicating the importance of detailed site characterization. The USDA‐ARS Streambank Stability model demonstrated the increase in instability of banks due to undercutting by seepage erosion, but failed to account for the sediment loss due to sapping for stable banks and overestimated the sediment loads for failed banks. Published in 2006 by John Wiley & Sons, Ltd. DA - 2007/3// PY - 2007/3// DO - 10.1002/esp.1405 VL - 32 IS - 3 SP - 447-459 UR - http://dx.doi.org/10.1002/esp.1405 KW - sapping KW - seepage erosion KW - streambank failure KW - undercutting KW - subsurface flow ER - TY - JOUR TI - Erosion of Noncohesive Sediment by Groundwater Seepage: Lysimeter Experiments and Modeling AU - Fox, Garey A AU - Chu-Agor, Maria AU - Wilson, Glenn V T2 - 2007 Minneapolis, Minnesota, June 17-20, 2007 AB - Seepage may be a significant mechanism of streambank erosion and failure in numerous geographical locations. Previous research has investigated erosion by lateral subsurface flow and developed a sediment transport model similar to an excess shear stress equation. As a continuation of this earlier research, slope destabilization driven by lateral, subsurface flow was studied to further verify the recently proposed sediment transport model. Laboratory experiments were performed using a two-dimensional soil lysimeter. The experiments were conducted on two sandy soils: a field soil (loamy sand) and a sieved sand with greater sand content and less cohesion. A series of seven lysimeter experiments were performed for the two different sands by varying the bank slope (90o, 60o, 45o, 36o, and 26o). Flow and sediment concentrations were measured at the outflow flume. Pencil-size tensiometers were used to measure soil pore-water pressure. Results indicate that a slight modification of the existing seepage sediment transport model adequately simulates lysimeter experiments for both noncohesive soils without modifying the seepage parameters of the excess shear stress equation, especially for bank angles greater than 45o. The research then determined whether integrated finite element and bank stability models were capable of capturing both small and large scale sapping failures. The models predicted large-scale failures for bank angles greater than 45o in which tension cracks formed on the bank surface. The models failed to predict collapses for bank angles less than 45o in which tension cracks formed on the seepage face. The failure to predict collapse was hypothesized to be due to the assumption of circular arc slip surfaces. DA - 2007/// PY - 2007/// DO - 10.13031/2013.23422 ER - TY - JOUR TI - An Improved Express Fraction for Modeling Macropore/Subsurface Drain Interconnectivity AU - Fox, Garey A AU - Akay, Onur AU - Malone, Rob W AU - Ma, Liwang AU - Sabbagh, George J T2 - 2007 Minneapolis, Minnesota, June 17-20, 2007 AB - The rapid transport of contaminants through macropores and into subsurface drains is a concern. Recent research has proposed methods for incorporating this direct connectivity into contaminant transport models. For example, the one-dimensional pesticide fate and transport model, Root Zone Water Quality Model (RZWQM), was modified to include an express fraction parameter based on the percentage of macropores in direct hydraulic connection to subsurface drains. When macropore flow first reached the top of the water table (point midway between the drains), a macropore express fraction of water and chemical was routed directly into the subsurface drain, which improved predictions of concentration peaks. The remaining water and chemical was allowed to fill and mix with the water table, resulting in a concentration bulge at the water table. This research proposes an updated express fraction for RZWQM, which distributes water across all saturated layers between the drain and water table. Implicitly assumed is a uniform spatial distribution of macropores. This updated express fraction is evaluated using data from two isoxaflutole/metabolite field experiments in Allen County and Owen County IN (2000), where concentrations of parent and metabolite were measured in the drain flow. The results showed a slight improvement in the prediction of chemical concentrations on the recession limbs of drainage hydrographs. DA - 2007/// PY - 2007/// DO - 10.13031/2013.23235 ER - TY - JOUR TI - Measuring streambank erosion due to ground water seepage: correlation to bank pore water pressure, precipitation and stream stage AU - Fox, G.A. AU - Wilson, G.V. AU - Simon, A. AU - Langendoen, E.J. AU - Akay, O. AU - Fuchs, J.W. T2 - Earth Surface Processes and Landforms AB - Abstract Limited information exists on one of the mechanisms governing sediment input to streams: streambank erosion by ground water seepage. The objective of this research was to demonstrate the importance of streambank composition and stratigraphy in controlling seepage flow and to quantify correlation of seepage flow/erosion with precipitation, stream stage and soil pore water pressure. The streambank site was located in Northern Mississippi in the Goodwin Creek watershed. Soil samples from layers on the streambank face suggested less than an order of magnitude difference in vertical hydraulic conductivity ( K s ) with depth, but differences between lateral K s of a concretion layer and the vertical K s of the underlying layers contributed to the propensity for lateral flow. Goodwin Creek seeps were not similar to other seeps reported in the literature, in that eroded sediment originated from layers underneath the primary seepage layer. Subsurface flow and sediment load, quantified using 50 cm wide collection pans, were dependent on the type of seep: intermittent low‐flow (LF) seeps (flow rates typically less than 0·05 L min −1 ), persistent high‐flow (HF) seeps (average flow rate of 0·39 L min −1 ) and buried seeps, which eroded unconsolidated bank material from previous bank failures. The timing of LF seeps correlated to river stage and precipitation. The HF seeps at Goodwin Creek began after rainfall events resulted in the adjacent streambank reaching near saturation (i.e. soil pore water pressures greater than −5 kPa). Seep discharge from HF seeps reached a maximum of 1·0 L min −1 and sediment concentrations commonly approached 100 g L −1 . Buried seeps were intermittent but exhibited the most significant erosion rates (738 g min −1 ) and sediment concentrations (989 g L −1 ). In cases where perched water table conditions exist and persistent HF seeps occur, seepage erosion and bank collapse of streambank sediment may be significant. Copyright © 2007 John Wiley & Sons, Ltd. DA - 2007/9// PY - 2007/9// DO - 10.1002/esp.1490 VL - 32 IS - 10 SP - 1558-1573 UR - http://dx.doi.org/10.1002/esp.1490 KW - bank stability KW - interflow KW - ground water seepage KW - soil pore water pressure KW - streambank erosion ER - TY - JOUR TI - Comparative use of field and laboratory mesocosms for in-stream nitrate uptake measurement AU - Turlan, T. AU - Birgand, F. AU - Marmonier, P. T2 - Annales de Limnologie - International Journal of Limnology AB - Recent publications suggest that in large watersheds a large proportion (20 to 70%) of the net nitrogen input to the aquatic environment may be removed during water’s downstream path towards the outlet. In small watersheds there are few to no evaluations of the importance of in-stream processes in the overall nitrogen budget due in part to the lack of simple and robust methods for measuring in-stream nitrate uptake. We propose a comparative study for laboratory and field measurements on open mesocosms, 30 cm in diameter. Nitrate uptake was evaluated from the kinetics of disappearance of nitrate in water overlying undisturbed sediment cores, both in the laboratory and in-situ. Using both laboratory and in-situ mesocosms was an effort to determine whether the methods were comparable and applicable on a routine basis. Nitrate disappearance kinetics in the laboratory yielded expected results, which are that nitrate uptake rates are linearly correlated to nitrate concentration in the water column. In such conditions, our results show that the potential for nitrate uptake in streams can be calculated from the mass transfer coefficient. Our comparative study shows that incubations conducted in the laboratory intrinsically limit hyporheic exchanges, associated with small water level fluctuations, which may in fact prevail in the field as the in-situ incubations have shown. In-situ experiments yielded unexpected results, such as the succession of disappearance and gain of nitrate in the mesocosms through time. This was attributed to hyporheic exchanges, both natural and artificially induced by the design of the mesocosms. Both methods should be considered for future nitrate uptake studies as they yield complementary results, provided that some simple changes are made in the design of in-situ mesocosms. DA - 2007/// PY - 2007/// DO - 10.1051/limn/2007026 VL - 43 IS - 1 SP - 41-51 J2 - Ann. Limnol. - Int. J. Lim. OP - SN - 0003-4088 UR - http://dx.doi.org/10.1051/limn/2007026 DB - Crossref KW - in-stream processes KW - nitrate uptake KW - mesocosm KW - method KW - mass transfer coefficient ER - TY - JOUR TI - Long term fate of slurry derived nitrogen in soil: A case study with a macro-lysimeter experiment having received high loads of pig slurry (Solepur) AU - Peu, P. AU - Birgand, F. AU - Martinez, J. T2 - Bioresource Technology AB - In intensive livestock production areas, land application remains the traditional management of manure and slurries for nutrient recycling. For sustainable agriculture there is fear, however, that this practice may have detrimental effects, particularly on the depletion of Soil Organic Matter associated with pig slurry applications. We investigated the long-term fate of nitrogen in a reconstituted soil having received high doses of pig slurry during 5 years (1991-1995). After 5 years of intensive application rates (nearly 1000 m(3)yr(-1)), the N and C content of the soil profile (0-20 cm) had increased by about 60% and 50%, respectively. These results confirm previous findings although it seems that the particularly high rates of application may explain, in part, the relatively important N incorporation in soil. Pig slurry applications ceased in 1995 and nitrogen content in soil and drainage water have been monitored. Apparent mineralization rates were calculated from the decrease in N content of the soil. This analysis indicated that more than 50% of the added N stored in the soil at the end of the applications would eventually be mineralized, leaving nearly 50% of the stored N to be immobilized in the soil. These results are the first published of their kinds, as most reports never examine the fate of applied pig slurry N after halting applications. In addition the few reports on long-term experiments suggest that Soil Organic Matter following pig slurry applications may be unstable. Our analysis tends to show the contrary. However, this conclusion must be tempered because data on nitrate leachate patterns suggest that soil management such as ploughing and sowing may actually trigger mineralization that could eventually deplete nitrogen stored following applications. DA - 2007/12// PY - 2007/12// DO - 10.1016/j.biortech.2006.07.019 VL - 98 IS - 17 SP - 3228-3234 J2 - Bioresource Technology LA - en OP - SN - 0960-8524 UR - http://dx.doi.org/10.1016/j.biortech.2006.07.019 DB - Crossref KW - pig slurry KW - lysimeter KW - nitrogen fate ER - TY - JOUR TI - Chain management issues and good housekeeping procedures to minimise food processing waste AU - Sherman, R. T2 - HANDBOOK OF WASTE MANAGEMENT AND CO-PRODUCT RECOVERY IN FOOD PROCESSING, VOLUME 1 AB - This chapter explains that minimizing the volume of pre- and post-production organic and nonorganic waste is vital to companies in the food processing supply chain. Essential business objectives for minimizing solid waste throughout the supply chain are to minimize inputs and reduce the potential for waste, and to contemplate re-engineering or creating co-products to add value. Waste minimization is an efficient and up-front solution to waste management that can significantly alter the way a business thinks about and treats waste. Although recycling is the solution that is usually embraced by those concerned about waste, waste minimization is a superior approach because it aims to eliminate or reduce the quantity or toxicity of manufacturing wastes in addition to waste generated by products at the end of their useful life. The food supply chain is a network of companies that handle food, from the farmer to the retailer. Supply-chain management is a relatively new concept that first appeared in the 1980s in the Japanese motor industry. A crucial factor in supply-chain waste reduction programs is the partnership based on trust between each of the participating members. The chapter also explains that housekeeping is a general term used to describe how a facility's daily activities are carried out. Housekeeping measures include storage, inventory control, cleaning, maintenance, and record keeping. Therefore, good housekeeping is crucial for ensuring that a company is run efficiently. It is also the first and most essential step to minimizing waste and saving resources. Good housekeeping procedures can be applied to all activities in food processing facilities, including purchasing, materials accounting, inventory control, receiving, delivery, storage, proper labeling, optimizing operations and processes, preventive maintenance, and recovery/reuse/recycling. DA - 2007/// PY - 2007/// DO - 10.1533/9781845692520.2.39 IS - 141 SP - 39-58 SN - 2042-8049 ER - TY - CONF TI - Alkaline pretreatment of switchgrass for bioconversion to ethanol AU - Xu, J. AU - Chen, Y. AU - Wang, Z. AU - Sharma-Shivappa, R. R. AU - Burns, J. C. AU - Cheng, J. J. C2 - 2007/// C3 - 2007 ASABE Regional Annual Conference (Fletcher, North Carolina) DA - 2007/// ER - TY - PAT TI - Dynamic radiant food preparation methods and systems AU - Farkas, B. E. AU - Lloyd, B. J. AU - Keener, K. M. C2 - 2007/// DA - 2007/// PY - 2007/// ER - TY - JOUR TI - Development of environmentally superior treatment system to replace anaerobic swine lagoons in the USA AU - Vanotti, Matias B. AU - Szogi, Ariel A. AU - Hunt, Patrick G. AU - Millner, Patricia D. AU - Humenik, Frank J. T2 - BIORESOURCE TECHNOLOGY AB - A full-scale treatment system for swine manure was developed to eliminate discharge to surface and ground waters and contamination of soil and groundwater by nutrients and heavy metals, along with related release of ammonia, odor, and pathogens. The system greatly increased the efficiency of liquid-solid separation by polymer injection to increase solids flocculation. Nitrogen management to reduce ammonia emissions was accomplished by passing the liquid through a module where bacteria transformed ammonia into harmless nitrogen gas. Subsequent alkaline treatment of the wastewater in a phosphorus module precipitated phosphorus and killed pathogens. Treated wastewater was recycled to clean swine houses and for crop irrigation. The system was tested during one year in a 4400-head finishing farm as part of the Agreement between the Attorney General of North Carolina and swine producers Smithfield Foods, Premium Standard Farms and Frontline Farmers to replace traditional waste treatment anaerobic lagoons with environmentally superior technology. The on-farm system removed 97.6% of the suspended solids, 99.7% of BOD, 98.5% of TKN, 98.7% of soluble ammonia (NH(4)(+)-N), 95.0% of total P, 98.7% of copper and 99.0% of zinc. It also removed 97.9% of odor compounds in the liquid and reduced pathogen indicators to non-detectable levels. Based on performance obtained, it was determined that the treatment system met the Agreement's technical performance standards that define an environmentally superior technology. These findings overall showed that cleaner alternative technologies are technically and operationally feasible and that they can have significant positive impacts on the environment and the livestock industry. DA - 2007/12// PY - 2007/12// DO - 10.1016/j.biortech.2006.07.009 VL - 98 IS - 17 SP - 3184-3194 SN - 0960-8524 KW - manure treatment KW - pathogen inactivation nitrification-denitrification KW - phosphorous and ammonia removal KW - confined swine producion KW - piggery ER - TY - JOUR TI - Agricultural drainage management, quality and disposal issues in North America AU - Madramootoo, Chandra A. AU - Johnston, William R. AU - Ayars, James E. AU - Evans, Robert O. AU - Fausey, Norman R. T2 - IRRIGATION AND DRAINAGE AB - The North American continent, comprising Canada and the United States of America, has a wide range of climatic, soils and cropping conditions. Surface and subsurface drainage is required to remove excess soil water in the wetter regions of the continent, as well as to maintain a favorable salt and water balance in the crop root zone in the drier irrigated regions. Drainage and water table management practices are essential for the production of food and fiber. However, these practices may sometimes cause third-party impacts, which are largely of a water quality nature. Drainage practices have therefore evolved from removal of water for increased crop productivity, to a method of environmental control. Consequently, much effort over recent years has been in designing and installing drainage systems, which have multiple objectives. A very recent notable institutional development is the formation of the Agricultural Drainage Management Systems (ADMS) Coalition, comprised of farmers, drainage contractors and the drainage industry, government advisors, and water management and agricultural specialists, to promote research, education and adoption of drainage water management as a practice that can reduce the delivery of pollutants to streams. This paper describes the need, extent and status of drainage in North America, including water quality issues, drainage water management and disposal problems. Copyright © 2007 John Wiley & Sons, Ltd. L'Amérique du Nord, composée du Canada et des États-Unis d'Amérique, présente un large éventail de conditions climatiques, de sols et de cultures. Le drainage, de surface et souterrain, est nécessaire pour enlever l'excédent d'eau contenu dans le sol des régions les plus humides, de même que pour maintenir un bilan d'eau et de sels minéraux dans la zone racinaire propice aux cultures dans les régions irriguées plus sèches du continent. Le drainage et la gestion de la nappe phréatique sont, par conséquent, des pratiques essentielles à la production de nourriture et de fibres textiles. Toutefois, ces pratiques de drainage ne peuvent pas toujours être effectuées sans causer d'impacts sur une tierce partie. Les pratiques de drainage ont évolué à partir du simple prélèvement d'eau afin d'augmenter la production des cultures à une méthode de maîtrise environnementale visant à réduire les impacts sur la qualité de l'eau causés par ces pratiques. Par conséquent, au cours des dernières années, les efforts se sont concentrés sur le développement et l'installation de systèmes de drainage à objectifs multiples, prenant en considération la plante, l'hydrologie, le sol et l'environnement. La création de la Coalition sur la Gestion des Systèmes de Drainage Agricole (Agricultural Drainage Management Systems (ADMS) Coalition), composée d'agriculteurs, d'entrepreneurs de drainage, d'experts gouvernementaux, et de spécialistes de la gestion de l'eau et du monde agricole, afin de promouvoir la recherche, l'éducation, et l'adoption de la gestion de l'eau par le drainage comme une pratique innovante qui peut réduire les polluants dans les cours d'eau, constitue une avancée récente du monde institutionnel. Cet article décrit les besoins, l'étendue et la situation du drainage en Amérique du Nord, incluant les problématiques de qualité, de gestion et d'élimination de l'eau. Copyright © 2007 John Wiley & Sons, Ltd. DA - 2007/12// PY - 2007/12// DO - 10.1002/ird.343 VL - 56 SP - S35-S45 SN - 1531-0353 KW - agricultural drainage KW - management KW - quality KW - disposal KW - North America ER - TY - JOUR TI - Wood chips and wheat straw as alternative biofilter media for denitrification reactors treating aquaculture and other wastewaters with high nitrate concentrations AU - Saliling, Willie Jones B. AU - Westerman, Philip W. AU - Losordo, Thomas M. T2 - AQUACULTURAL ENGINEERING AB - This study evaluated wood chips and wheat straw as inexpensive and readily available alternatives to more expensive plastic media for denitrification processes in treating aquaculture wastewaters or other high nitrate waters. Nine 3.8-L laboratory scale reactors (40 cm packed height × 10 cm diameter) were used to compare the performance of wood chips, wheat straw, and Kaldnes plastic media in the removal of nitrate from synthetic aquaculture wastewater. These upflow bioreactors were loaded at a constant flow rate and three influent NO3–N concentrations of 50, 120, and 200 mg/L each for at least 4 weeks, in sequence. These experiments showed that both wood chips and wheat straw produced comparable denitrification rates to the Kaldnes plastic media. As much as 99% of nitrate was removed from the wastewater of 200 mg NO3–N/L influent concentration. Pseudo-steady state denitrification rates for 200 mg NO3–N/L influent concentrations averaged (1360 ± 40) g N/(m3 d) for wood chips, (1360 ± 80) g N/(m3 d) for wheat straw, and (1330 ± 70) g N/(m3 d) for Kaldnes media. These values were not the maximum potential of the reactors as nitrate profiles up through the reactors indicated that nitrate reductions in the lower half of the reactors were more than double the averages for the whole reactor. COD consumption per unit of NO3–N removed was highest with the Kaldnes media (3.41–3.95) compared to wood chips (3.34–3.64) and wheat straw (3.26–3.46). Effluent ammonia concentrations were near zero while nitrites were around 2.0 mg NO2–N/L for all reactor types and loading rates. During the denitrification process, alkalinity and pH increased while the oxidation–reduction potential decreased with nitrate removal. Wood chips and wheat straw lost 16.2% and 37.7% of their masses, respectively, during the 140-day experiment. There were signs of physical degradation that included discoloration and structural transformation. The carbon to nitrogen ratio of the media also decreased. Both wood chips and wheat straw can be used as filter media for biological denitrification, but time limitations for the life of both materials must be considered. DA - 2007/11// PY - 2007/11// DO - 10.1016/j.aquaeng.2007.06.003 VL - 37 IS - 3 SP - 222-233 SN - 1873-5614 KW - wheat straw KW - wood chips KW - denitrification KW - aquaculture KW - media degradation KW - biofilter ER - TY - JOUR TI - Winter wheat and maize response to urea ammonium nitrate and a new urea formaldehyde polymer fertilizer AU - Cahill, S. AU - Osmond, Deanna AU - Crozier, C. AU - Israel, D. AU - Weisz, R. T2 - Agronomy Journal DA - 2007/// PY - 2007/// DO - 10.2134/agronj2OO7.0132 VL - 99 IS - 6 SP - 1645–1653 ER - TY - JOUR TI - Viewpoint-the problems of teaching practical design to today's engineering students-the agricultural engineering experience AU - Boyette, M. D. T2 - International Journal of Engineering Education DA - 2007/// PY - 2007/// VL - 23 IS - 4 SP - 631-635 ER - TY - JOUR TI - Simulating nitrogen leaching and turnover in a subsurface-drained grassland receiving animal manure in Northern Germany using DRAINMOD-N II AU - Bechtold, Iris AU - Koehne, Sigrid AU - Youssef, Mohamed A. AU - Lennartz, Bernd AU - Skaggs, R. Wayne T2 - AGRICULTURAL WATER MANAGEMENT AB - The primary objective of this study was to evaluate the nitrogen fate and transport simulation model DRAINMOD-N II for drained permanent grassland soils. Since the plant component of DRAINMOD-N II was developed for annual row crop systems, it was modified using an empirical approach to consider perennial grasses. The model was field-tested using a 12-year (1989–2000) data set of field hydrology, non-reactive tracer transport, and carbon (C) and nitrogen (N) dynamics from a tile drained grassland research site (Infeld, North-West Germany). Model calibration was performed using the first half of the data set, followed by validation using the second half. Model simulations were visually and statistically compared to field measurements. Modified DRAINMOD-N II successfully predicted drain flow during the validation period. The model could also simulate the observed dynamics of weakly preferential tracer transport by using a high longitudinal dispersivity. Furthermore, the model well described organic carbon (OC) dynamics during calibration. Since there were no OC measurements during the second half of the study, OC model predictions were not validated. Simulated and measured N losses via drain flow were in agreement during model calibration. The model, however, substantially under-predicted N loads during the validation period. Two reasons were hypothesized for the relatively poor performance of DRAINMOD-N II during the validation period. First, the simplistic approach used in the modified DRAINMOD-N II to quantify grass biomass yield did not take into account the effect of soil water dry or wet stresses on plant growth and biomass yield. This hypothesis could not be tested since there were no measurements of grass biomass yield. Secondly, the effect of the calibration errors in N process rates increased with the difference in precipitation patterns between the calibration and validation periods. This is despite the fact that calibrated transformation rates were within published ranges. While inconclusive, these results indicates that a more robust approach for quantifying grass biomass and N uptake may be needed for the current version of DRAINMOD-N II in order to successfully simulate C and N dynamics in drained grassland. DA - 2007/10/16/ PY - 2007/10/16/ DO - 10.1016/j.agwat.2007.06.001 VL - 93 IS - 1-2 SP - 30-44 SN - 1873-2283 KW - nitrate leaching KW - turnover processes KW - subsurface drainage KW - modelling ER - TY - JOUR TI - Potential of agricultural residues and hay for bioethanol production AU - Chen, Ye AU - Sharma-Shivappa, Ratna R. AU - Keshwani, Deepak AU - Chen, Chengci T2 - APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY AB - Production of bioethanol from agricultural residues and hays (wheat, barley, and triticale straws, and barley, triticale, pearl millet, and sweet sorghum hays) through a series of chemical pretreatment, enzymatic hydrolysis, and fermentation processes was investigated in this study. Composition analysis suggested that the agricultural straws and hays studied contained approximately 28.62-38.58% glucan, 11.19-20.78% xylan, and 22.01-27.57% lignin, making them good candidates for bioethanol production. Chemical pretreatment with sulfuric acid or sodium hydroxide at concentrations of 0.5, 1.0, and 2.0% indicated that concentration and treatment agent play a significant role during pretreatment. After 2.0% sulfuric acid pretreatment at 121 degrees C/15 psi for 60 min, 78.10-81.27% of the xylan in untreated feedstocks was solubilized, while 75.09-84.52% of the lignin was reduced after 2.0% sodium hydroxide pretreatment under similar conditions. Enzymatic hydrolysis of chemically pretreated (2.0% NaOH or H2SO4) solids with Celluclast 1.5 L-Novozym 188 (cellobiase) enzyme combination resulted in equal or higher glucan and xylan conversion than with Spezyme(R) CP- xylanase combination. The glucan and xylan conversions during hydrolysis with Celluclast 1.5 L-cellobiase at 40 FPU/g glucan were 78.09 to 100.36% and 74.03 to 84.89%, respectively. Increasing the enzyme loading from 40 to 60 FPU/g glucan did not significantly increase sugar yield. The ethanol yield after fermentation of the hydrolyzate from different feedstocks with Saccharomyces cerevisiae ranged from 0.27 to 0.34 g/g glucose or 52.00-65.82% of the theoretical maximum ethanol yield. DA - 2007/9// PY - 2007/9// DO - 10.1007/s12010-007-0026-3 VL - 142 IS - 3 SP - 276-290 SN - 1559-0291 KW - chemical pretreatment KW - enzymatic hydrolysis KW - feedstocks KW - fermentation KW - glucan KW - lignin KW - xylan ER - TY - JOUR TI - Planning for water allocation and water quality using a spreadsheet-based model AU - Grabow, G. L. AU - McCornick, P. G. T2 - Journal of Water Resources Planning and Management AB - An integrated planning activity was undertaken for the Amman-Zarqa Basin in Jordan to account for present and future uses of water resources including reclaimed water. Upgrades to existing wastewater treatment plants mean that new reclaimed water resources will be available in the future. To evaluate the impact of current and potential future uses on basin stakeholders, a spreadsheet-based model was developed to predict water quantity and quality at several key locations. The model consists of a flow component and a water quality component. The model was used to screen various water-use scenarios and to formulate feasible alternatives including the sequencing of future water demands. The use of a spreadsheet model allowed engineers and scientists within the Ministry of Water and Irrigation, and members of the consulting team who had limited modeling experience to be involved in the planning activity. DA - 2007/// PY - 2007/// DO - 10.1061/(ASCE)0733-9496(2007)133:6(560) VL - 133 IS - 6 SP - 560-564 ER - TY - JOUR TI - Ensiling agricultural residues for bioethanol production AU - Chen, Ye AU - Sharma-Shivappa, Ratna R. AU - Chen, Chengci T2 - APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY DA - 2007/10// PY - 2007/10// DO - 10.1007/s12010-007-0030-7 VL - 143 IS - 1 SP - 80-92 SN - 1559-0291 KW - carbohydrate KW - ensiling KW - enzyme KW - feedstocks KW - fermentation KW - hydrolysis KW - lignin KW - pretreatment ER - TY - JOUR TI - Plant nitrogen acquisition and interactions under elevated carbon dioxide: impact of endophytes and mycorrhizae AU - Chen, Xin AU - Tu, Cong AU - Burton, Michael G. AU - Watson, Dorothy M. AU - Burkey, Kent O. AU - Hu, Shuijin T2 - GLOBAL CHANGE BIOLOGY AB - Abstract Both endophytic and mycorrhizal fungi interact with plants to form symbiosis in which the fungal partners rely on, and sometimes compete for, carbon (C) sources from their hosts. Changes in photosynthesis in host plants caused by atmospheric carbon dioxide (CO 2 ) enrichment may, therefore, influence those mutualistic interactions, potentially modifying plant nutrient acquisition and interactions with other coexisting plant species. However, few studies have so far examined the interactive controls of endophytes and mycorrhizae over plant responses to atmospheric CO 2 enrichment. Using Festuca arundinacea Schreb and Plantago lanceolata L. as model plants, we examined the effects of elevated CO 2 on mycorrhizae and endophyte ( Neotyphodium coenophialum) and plant nitrogen (N) acquisition in two microcosm experiments, and determined whether and how mycorrhizae and endophytes mediate interactions between their host plant species. Endophyte‐free and endophyte‐infected F. arundinacea varieties, P. lanceolata L., and their combination with or without mycorrhizal inocula were grown under ambient (400 μmol mol −1 ) and elevated CO 2 (ambient + 330 μmol mol −1 ). A 15 N isotope tracer was used to quantify the mycorrhiza‐mediated plant acquisition of N from soil. Elevated CO 2 stimulated the growth of P. lanceolata greater than F. arundinacea , increasing the shoot biomass ratio of P. lanceolata to F. arundinacea in all the mixtures. Elevated CO 2 also increased mycorrhizal root colonization of P. lanceolata , but had no impact on that of F. arundinacea . Mycorrhizae increased the shoot biomass ratio of P. lanceolata to F. arundinacea under elevated CO 2 . In the absence of endophytes, both elevated CO 2 and mycorrhizae enhanced 15 N and total N uptake of P. lanceolata but had either no or even negative effects on N acquisition of F. arundinacea , altering N distribution between these two species in the mixture. The presence of endophytes in F. arundinacea , however, reduced the CO 2 effect on N acquisition in P. lanceolata , although it did not affect growth responses of their host plants to elevated CO 2 . These results suggest that mycorrhizal fungi and endophytes might interactively affect the responses of their host plants and their coexisting species to elevated CO 2 . DA - 2007/6// PY - 2007/6// DO - 10.1111/j.1365-2486.2007.01347.x VL - 13 IS - 6 SP - 1238-1249 SN - 1365-2486 KW - elevated CO2 KW - endophyte KW - Festuca arundinacea KW - mycorrhizae KW - N-15 tracer KW - plant N acquisition KW - Plantago lanceolata ER - TY - JOUR TI - Phosphate bonding configuration on ferrihydrite based on molecular orbital calculations and XANES fingerprinting AU - Khare, Nidhi AU - Martin, James D. AU - Hesterberg, Dean T2 - GEOCHIMICA ET COSMOCHIMICA ACTA AB - Sorption of phosphate by Fe(III)- and Al(III)-(hydr)oxide minerals regulates the mobility of this potential water pollutant in the environment. The objective of this research was to determine the molecular configuration of phosphate bound on ferrihydrite at pH 6 by interpreting P K-edge XANES spectra in terms of bonding mode. XANES and UV–visible absorption spectra for aqueous Fe(III)–PO4 solutions (Fe/P molar ratio = 0–2.0) provided experimental trends for energies of P(3p)–O(2p) and Fe(3d)–O(2p) antibonding molecular orbitals. Molecular orbitals for Fe(III)–PO4 or Al(III)–PO4 complexes in idealized monodentate or bidentate bonding mode were generated by conceptual bonding arguments, and Extended-Hückel molecular orbital computations were used to understand and assign XANES spectral features to bound electronic states. The strong white line at the absorption edge in P K-edge XANES spectra for Fe–PO4 or Al–PO4 systems is attributable to an electronic transition from a P 1s atomic orbital into P(3p)–O(2p) or P(3p)–O(2p)–Al(3p) antibonding molecular orbitals, respectively. For Fe–PO4 systems, a XANES peak at 2–5 eV below the edge was assigned to a P 1s electron transition into Fe(4p)–O(2p) antibonding molecular orbitals. Similarly, a shoulder on the low-energy side of the white line for variscite corresponds to a transition into Al(3p)–O(2p) orbitals. In monodentate-bonded phosphate, Fe–O bonding is optimized and P–O bonding is weakened, and the converse is true of bidentate-bonded phosphate. These differences explained an inverse correlation between energies of P(3p)–O(2p) and Fe(3d)–O(2p) antibonding molecular orbitals consistent with a monodentate-to-bidentate transition in aqueous Fe(III)–PO4 solutions. The intensity of the XANES pre-edge feature in Fe(III)-bonded systems increased with increasing number of Fe(III)–O–P bonds. Based on the similarity of intensity and splitting of the pre-edge feature for phosphate sorbed on ferrihydrite at 750 mmol/kg at pH 6 and aqueous Fe–PO4 solutions containing predominantly bidentate complexes, XANES results indicated that phosphate adsorbed on ferrihydrite was predominantly a bidentate–binuclear surface complex. DA - 2007/9/15/ PY - 2007/9/15/ DO - 10.1016/j.gca.2007.07.008 VL - 71 IS - 18 SP - 4405-4415 SN - 0016-7037 ER - TY - JOUR TI - Evaluation of four permeable pavement sites in eastern North Carolina for runoff reduction and water quality impacts AU - Bean, E. Z. AU - Hunt, W. F. AU - Bidelspach, D. A. T2 - Journal of Irrigation and Drainage Engineering AB - Four permeable pavement applications in North Carolina’s Coastal Plain were constructed and monitored to determine their effectiveness of reducing runoff quantity and improving water quality. Sites were either constructed of permeable interlocking concrete pavers (2), porous concrete (1), or concrete grid pavers (1). One site of each pavement type was monitored for runoff reduction for periods ranging from 10 to 26 months. Measured runoff depths from rainfall events over 50mm were used to determine permeable pavement equivalent curve numbers for the sites, which ranged from 45 to 85. Only the two permeable interlocking concrete pavement (PICP) sites were monitored for water quality. Runoff and exfiltrate samples were intended to be collected, in addition to runoff monitoring, from the Swansboro PICP site. However, no runoff was produced during this study from the Swansboro PICP site for rainfall events up to 88mm. From exfiltrate concentrations, nutrient retention was estimated to be 3.4 and 0.4kg∕ha∕year for total nitrogen and total phosphorus, respectively. For the Goldsboro PICP site, water quality of asphalt runoff and PICP exfiltrate were compared. Analysis of water quality samples from the second site determined that concentrations of total Kjeldahl nitrogen, ammonia, total phosphorus, and zinc were significantly (p⩽0.05) lower in permeable pavement exfiltrate than asphalt runoff. DA - 2007/// PY - 2007/// DO - 10.1061/(ASCE)0733-9437(2007)133:6(583) VL - 133 IS - 6 SP - 583-592 ER - TY - JOUR TI - Effect of a metabolic stimulant on ammonia volatilization from broiler litter AU - Shah, S. B. AU - Baird, C. L. AU - Rice, J. M. T2 - JOURNAL OF APPLIED POULTRY RESEARCH AB - High NH3 concentrations in broiler and turkey houses can adversely affect bird performance and the environment when exhausted into the atmosphere. Acidifying amendments have been used in poultry houses to reduce NH3 levels, but the acidifiers are caustic and may not be effective for the entire growout of 8 to 9 wk. In this 45-d study, the effect of a metabolic stimulant (biostimulant), Bio-Kat, on exhaust NH3 concentrations from chambers containing broiler litter (supplemented daily with layer manure slurry) was evaluated. Average NH3 concentration in the exhaust air from the chambers containing Bio-Kat-treated litter was reduced by 61% compared with untreated litter. Also, ammoniacal-N concentration in the Bio-Kat-treated litter was double that of untreated litter at the end of the study. The Bio-Kat amendment was most effective during the first 10 to 12 d, and its efficacy decreased over time. Additional work is required to evaluate the more concentrated formulation (for duration of effectiveness and application rate) and identify the proper method of application (i.e., incorporation vs. broadcasting on the surface). DA - 2007/// PY - 2007/// DO - 10.1093/japr/16.2.240 VL - 16 IS - 2 SP - 240-247 SN - 1537-0437 KW - acidifier KW - amendment KW - bio-kat KW - biostimulant KW - chamber KW - poultry KW - concentration KW - emission ER - TY - JOUR TI - Challenges in quantification of ligninolytic enzymes from Phanerochaete chrysosporium cultivation for pretreatment of cotton stalks AU - Shi, J. AU - Sharma-Shivappa, R. R. AU - Chinn, Mari AU - Dean, R. A. AU - Shivappa, R. B. T2 - Transactions of the ASABE AB - Enzymes play an important role in the breakdown of lignin during microbial pretreatment of lignocellulosic feedstocks. However, quantification of the various enzyme activities with assays developed for enzyme extracts from pure cultures can be challenging. In this study, spectrophotometric assays used for the quantification of peroxidases in enzyme extracts from submerged (SmC) and solid-state (SSC) cultivation of P. chrysosporium on cotton stalks during 14 days pretreatment failed to detect lignin peroxidase (LiP) and manganese peroxidase (MnP) activities. However, results from sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) suggested presence of protein bands with molecular weights corresponding to MnP and LiP in the enzyme extracts from fungal pretreatment cultures. Addition of crude enzyme extracts from SmC and SSC treated samples to fresh cotton stalks showed 3.42% and 7.45% increase in lignin content, respectively. This slight increase may be attributed to components within crude extracts that polymerize the phenolic compounds instead of resulting in delignification. It can be inferred from this study that although qualitative methods for ligninolytic enzyme estimation provide useful information, it is essential to investigate alternative approaches to quantify ligninolytic enzymes during cultivation on natural lignocellulosic materials to overcome the limitations of existing assays. DA - 2007/// PY - 2007/// DO - 10.13031/2013.24071 VL - 50 IS - 6 SP - 2347–2354 ER - TY - JOUR TI - A comparison of two exposure systems to apply malathion to Lumbricus terrestris L AU - Henson-Ramsey, H. AU - Kennedy-Stoskopf, S. AU - Levine, J. AU - Shea, D. AU - Taylor, S. K. AU - Stoskopf, M. K. T2 - BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY DA - 2007/6// PY - 2007/6// DO - 10.1007/s00128-007-9194-7 VL - 78 IS - 6 SP - 427-431 SN - 0007-4861 ER - TY - JOUR TI - Effect of organnic, sustainable, and conventional management strategies in grower fields on soil physical, chemical, and biological factors and the incidence of Southern blight AU - Liu, Bo AU - Tu, Cong AU - Hu, Shuijin AU - Gumpertz, Marcia AU - Ristaino, Jean Beagle T2 - APPLIED SOIL ECOLOGY AB - The objectives of our research were to evaluate the impact of organic, sustainable, and conventional management strategies in grower fields on soil physical, chemical, and biological factors including soil microbial species and functional diversity and their effect on the Basidiomycete plant pathogen Sclerotium rolfsii, causal agent of Southern blight. Soils from 10 field locations including conventional, organic and sustainable farms were sampled and assayed for disease suppressiveness in greenhouse assays, and soil quality indicators. Soils from organic and sustainable farms were more suppressive to Southern blight than soils from conventional farms. Soils from organic farms had improved soil chemical factors and higher levels of extractable C and N, higher microbial biomass carbon and nitrogen, and net mineralizable N. In addition, soil microbial respiration was higher in soils from organic than sustainable or conventional farms, indicating that microbial activity was greater in these soils. Populations of fungi and thermophiles were significantly higher in soils from organic and sustainable than conventional fields. The diversity of bacterial functional communities was also greater in soils from organic farms, while species diversity was similar. Soils from organic and sustainable farms had improved soil health as indicated by a number of soil physical, chemical and biological factors and reduced disease. DA - 2007/11// PY - 2007/11// DO - 10.1016/j.apsoil.2007.06.007 VL - 37 IS - 3 SP - 202-214 SN - 1873-0272 KW - chemical and biological properties KW - organic and conventional farms KW - microbial communities KW - functional diversity KW - species diversity KW - biolog KW - DGGE ER - TY - JOUR TI - Criteria for calculating drain spacing and depth AU - Skaggs, R. W. T2 - Transactions of the ASABE AB - Agricultural and biological engineers have had a leading role in developing drainage design methods that span the range from simple drainage equations to complex computer simulation models. While current efforts are focused on development of complex models to quantify crop and drainage water quality response to design and management alternatives, there is still a place for simple drainage equations. Application of drainage design equations is limited by lack of design criteria for most locations in the U.S. This article reports results of a simulation study to determine design criteria for the steady-state Hooghoudt equation and the transient van Schilfgaarde equation. Simulations were conducted to determine drain spacings that maximize profit for three drain depths on four soils at five locations in eastern U.S. Drainage design rates (DDR) for the Hooghoudt equation and the time required for 30 cm water table drawdown (TDD30) were determined for each of the optimum drain spacings. Results were analyzed to develop equations for predicting design criteria (DDR and TDD30) in terms of growing season rainfall, drain depth, profile transmissivity, and drainable porosity for the humid region of the U.S. These criteria may be used, with their respective equations, to estimate drain depth and spacing for any location in eastern U.S. DA - 2007/// PY - 2007/// DO - 10.13031/2013.23971 VL - 50 IS - 5 SP - 1657-1662 ER - TY - JOUR TI - Anaerobic waste treatment processes AU - Chen, Y. AU - Cheng, Jay T2 - Water Environment Research AB - Water Environment ResearchVolume 79, Issue 10 p. 1430-1450 Treatment SystemFree Access Anaerobic Waste Treatment Processes Ye Chen, Ye ChenSearch for more papers by this authorJay J. Cheng, Jay J. ChengSearch for more papers by this author Ye Chen, Ye ChenSearch for more papers by this authorJay J. Cheng, Jay J. ChengSearch for more papers by this author First published: 01 October 2007 https://doi.org/10.2175/106143007X218430AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume79, Issue102007 Literature ReviewSeptember 2007Pages 1430-1450 RelatedInformation DA - 2007/// PY - 2007/// DO - 10.2175/106143007x218430 VL - 79 IS - 10 SP - 1430–1450 ER - TY - JOUR TI - Simulating the water budgets of natural Carolina bay wetlands AU - Caldwell, Peter V. AU - Vepraskas, Michael J. AU - Skaggs, R. Wayne AU - Gregory, James D. T2 - WETLANDS DA - 2007/12// PY - 2007/12// DO - 10.1672/0277-5212(2007)27[1112:stwbon]2.0.co;2 VL - 27 IS - 4 SP - 1112-1123 SN - 0277-5212 KW - DRAINMOD KW - hydrology KW - modeling KW - water balance ER - TY - JOUR TI - Exact equations for critical depth in a trapezoidal canal - Discussion by Prabhata K. Swamee and Pushpa N. Rathie AU - Srivastava, Rajesh T2 - JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING DA - 2007/// PY - 2007/// DO - 10.1061/(ASCE)0733-9437 VL - 133 IS - 5 SP - 509-509 SN - 1943-4774 ER - TY - JOUR TI - Sampling hazelnuts for aflatoxin: Effect of sample size and accept/reject limit on reducing the risk of misclassifying lots AU - Ozay, G. AU - Seyhan, F. AU - Yilmaz, A. AU - Whitaker, T. B. AU - Slate, A. B. AU - Giesbrecht, F. C. T2 - Journal of AOAC International DA - 2007/// PY - 2007/// VL - 90 IS - 4 SP - 1028-1035 ER - TY - JOUR TI - Management alternatives to enhance water quality and ecological function of channelized streams and drainage canals AU - Evans, R. O. AU - Bass, K. L. AU - Burchell, M. R. AU - Hinson, R. D. AU - Johnson, R. AU - Doxey, M. T2 - Journal of Soil & Water Conservation DA - 2007/// PY - 2007/// VL - 62 IS - 4 SP - 308-320 ER - TY - JOUR TI - Kinetic evaluation of normal walking and jumping in cats, using a pressure-sensitive walkway AU - Lascelles, B. D. X. AU - Findley, K. AU - Correa, M. AU - Marcellin-Little, D. AU - Roe, S. T2 - VETERINARY RECORD AB - The kinetic parameters of the limbs of 23 normal, client‐owned cats were evaluated by encouraging them to walk and jump normally on a pressure‐sensitive walkway. Each cat was encouraged to walk across the walkway five times over a period of 30 to 45 minutes (by using food, toys, the owner's presence and a purpose‐built tunnel) at a target speed of 0·6 m/s (and an acceleration of less than ± 0·1 m/s 2 ). They were then encouraged to jump on to the walkway from a height of 1 m five times at five‐minute intervals. The kinetic parameters of peak vertical force ( pvf ) and vertical impulse ( vi ) were measured for each limb (the forelimbs only for the jumps), and expressed as a percentage of bodyweight ( pvf %bw and vi %bw/s ). Fifteen of the 23 cats satisfactorily completed three to five walks and two to five jumps that could be analysed. There were no significant differences between the pvf or vi of the left and right limbs, but both parameters were significantly greater for the forelimbs than the hindlimbs (P<0·001) for the walking data. The mean (sd) pvf %bw for the forelimbs and hindlimbs were 48·2 (6·0) and 38·3 (4·0), respectively, and the mean vi % bw/s were 16·9 (3·2) and 13·3 (2·8). Jumping down generated significantly greater pvf (P<0·01) and slightly greater vi than during walking; there were no significant differences between the left and right forelimbs. The mean pvf %bw was 148·9 (16·4) and the mean vi %bw/s was 18·1 (4·3). DA - 2007/4/14/ PY - 2007/4/14/ DO - 10.1136/vr.160.15.512 VL - 160 IS - 15 SP - 512-+ SN - 2042-7670 ER - TY - JOUR TI - Expression and characterization of Acidothermus cellulolyticus E1 endoglucanase in transgenic duckweed Lemna minor 8627 AU - Sun, Ye AU - Cheng, Jay J. AU - Himmel, Michael E. AU - Skory, Christopher D. AU - Adney, William S. AU - Thomas, Steven R. AU - Tisserat, Brent AU - Nishimura, Yufuko AU - Yamamoto, Yuri T. T2 - BIORESOURCE TECHNOLOGY AB - Endoglucanase E1 from Acidothermus cellulolyticus was expressed cytosolically under control of the cauliflower mosaic virus 35S promoter in transgenic duckweed, Lemna minor 8627 without any obvious observable phenotypic effects on morphology or rate of growth. The recombinant enzyme co-migrated with the purified catalytic domain fraction of the native E1 protein on western blot analysis, revealing that the cellulose-binding domain was cleaved near or in the linker region. The duckweed-expressed enzyme was biologically active and the expression level was up to 0.24% of total soluble protein. The endoglucanase activity with carboxymethylcellulose averaged 0.2 units mg protein−1 extracted from fresh duckweed. The optimal temperature and pH for E1 enzyme activity were about 80 °C and pH 5, respectively. While extraction with HEPES (N-[2-hydroxyethyl]piperazine-N′-[2-ethanesulfonic acid]) buffer (pH 8) resulted in the highest recovery of total soluble proteins and E1 enzyme, extraction with citrate buffer (pH 4.8) at 65 °C enriched relative amounts of E1 enzyme in the extract. This study demonstrates that duckweed may offer new options for the expression of cellulolytic enzymes in transgenic plants. DA - 2007/11// PY - 2007/11// DO - 10.1016/j.biortech.2006.09.055 VL - 98 IS - 15 SP - 2866-2872 SN - 0960-8524 KW - Acidothermus cellulolyticus KW - endoglucanase E1 KW - gene expression KW - Lemna minor KW - transgenic duckweed ER - TY - JOUR TI - Evaluating the performance of sampling plans to detect hypoglycin A in ackee fruit shipments imported into the United States AU - Whitaker, T. B. AU - Saltsman, J. J. AU - Ware, G. M. AU - Slate, A. B. T2 - Journal of AOAC International DA - 2007/// PY - 2007/// VL - 90 IS - 4 SP - 1060-1072 ER - TY - JOUR TI - Evaluating the performance of sampling plans to detect fumonisin B-1 in maize lots marketed in Nigeria AU - Whitaker, T. B. AU - Doko, M. B. AU - Maestroni, B. M. AU - Slate, A. B. AU - Ogunbanwo, B. F. T2 - Journal of AOAC International DA - 2007/// PY - 2007/// VL - 90 IS - 4 SP - 1050-1059 ER - TY - JOUR TI - Effect of moisture content on ammonia emissions from broiler litter: A laboratory study AU - Liu, Zifei AU - Wang, Lingjuan AU - Beasley, David AU - Oviedo, Edgar T2 - JOURNAL OF ATMOSPHERIC CHEMISTRY DA - 2007/9// PY - 2007/9// DO - 10.1007/s10874-007-9076-8 VL - 58 IS - 1 SP - 41-53 SN - 1573-0662 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-34548108638&partnerID=MN8TOARS KW - ammonia emissions KW - broiler litter ER - TY - JOUR TI - Determining the variability associated with testing shelled corn for aflatoxin using different analytical procedures in Louisiana in 1998 AU - Park, D. L. AU - Whitaker, T. B. AU - Simonson, J. AU - Morris, H. F. AU - Durr, B. AU - Njapau, H. T2 - Journal of AOAC International DA - 2007/// PY - 2007/// VL - 90 IS - 4 SP - 1036-1041 ER - TY - JOUR TI - Asymptotic analysis on the interaction between spatial diversity and multiuser diversity in wireless networks AU - Zhou, Quan AU - Dai, Huaiyu T2 - IEEE TRANSACTIONS ON SIGNAL PROCESSING AB - Spatial diversity and multiuser diversity attract much research interest recently. In this paper, through asymptotic analysis of the average system capacity and scheduling gain, we investigate the cross-layer interaction between these two forms of diversity in wireless networks. Rigorous proofs and necessarily stronger results in terms of convergence are provided for some intuitions in this area. Equally important, explicit expressions of scheduling gain and average system capacity in various circumstances that reveal interconnections and fundamental tradeoffs among key system parameters are given, which afford us some insights in system design. Our results are general enough to cover many practical scenarios of interest. DA - 2007/8// PY - 2007/8// DO - 10.1109/TSP.2007.896059 VL - 55 IS - 8 SP - 4271-4283 SN - 1941-0476 KW - average system capacity KW - multiple-input multiple-output (MIMO) KW - multiuser diversity KW - scheduling gain KW - spatial diversity ER - TY - JOUR TI - Sampling almonds for aflatoxin, Part II: Estimating risks associated with various sampling plan designs AU - Whitaker, T. B. AU - Slate, A. B. AU - Hurley, J. M. AU - Giesbrecht, F. G. T2 - Journal of AOAC International DA - 2007/// PY - 2007/// VL - 90 IS - 3 SP - 778-785 ER - TY - JOUR TI - Nitrogen Removal in Streams of Agricultural Catchments—A Literature Review AU - Birgand, Françoisx AU - Skaggs, R. Wayne AU - Chescheir, George M. AU - Gilliam, J. Wendell T2 - Critical Reviews in Environmental Science and Technology AB - Excess nutrient loads have been recognized to be the major cause of serious water quality problems recently encountered in many estuaries and coastal waters of the world. Agriculture has been recognized in many regions of the world to be the largest single source of nitrogen emissions to the aquatic environments, and best management practices have been proposed to reduce nutrient losses at the field edge. As a result, there is growing awareness that nutrient management must be handled at the watershed scale. However, the key to nutrient management at the watershed scale is the understanding and quantification of the fate of nutrients both at the field scale and after they enter the aquatic environment. There has been widespread evidence since the late 1970s that nitrogen can be removed from water during its downstream transport in watersheds or basins. Although this information is becoming crucial, no overview has been proposed, so far, to qualitatively as well as quantitatively summarize available information in the literature. For this reason, we propose a review on the biogeochemical processes involved in nitrogen removal in streams, the rates of removal reported, and the factors influencing those rates. Nitrogen removal rates in agricultural streams should be expected to vary between 350 and 1250 mg N m−2 day−1. Mass transfer coefficients (coefficient evaluating intrinsic ability of a stream to remove nitrogen) values in agricultural streams may vary between 0.07 and 0.25 m day−1, although these values correspond to values obtained from reach scale studies. Reviewing values obtained from different measurement scales has revealed that results from incubations or experiments performed in the laboratory clearly underestimate mass transfer coefficients compared to those reported at the reach scale, from severalfold to more than one order of magnitude. Nitrogen removal rates and efficiency in streams are the highest in the summer, and this is critical for receiving ecosystems, which are most sensitive to external inputs at this period of the year. Removal efficiency is the lowest in winter in temperate climates due to high flow and loading combined with lowest removal rates. In-stream processes, on an annual basis, may remove at the watershed scale as much as 10 to 70% of the total N load to the drainage network. DA - 2007/6/19/ PY - 2007/6/19/ DO - 10.1080/10643380600966426 VL - 37 IS - 5 SP - 381-487 J2 - Critical Reviews in Environmental Science and Technology LA - en OP - SN - 1064-3389 1547-6537 UR - http://dx.doi.org/10.1080/10643380600966426 DB - Crossref ER - TY - JOUR TI - Effects of development on runoff and pollutant export AU - Line, D. E. AU - White, N. M. T2 - WATER ENVIRONMENT RESEARCH AB - Runoff from two similar drainage areas in the Piedmont physiographic region of North Carolina was monitored simultaneously for 5.6 years. One of the drainage areas was developed as part of a large residential subdivision, while the other remained in woods and agricultural fields. Runoff volume was 68% greater for the developed compared with the undeveloped area, and baseflow as a percentage of overall discharge was approximately 0% compared with 25% for the undeveloped area. Overall annual export of sediment was 95% greater for the developed area, while export of nitrogen and phosphorus forms was 66 to 88% greater for the developed area. These results document the significant increases in runoff, sediment, and nutrient export associated with residential development. DA - 2007/2// PY - 2007/2// DO - 10.2175/106143006X111736 VL - 79 IS - 2 SP - 185-190 SN - 1554-7531 KW - urban hydrology KW - water quality KW - water resources planning ER - TY - JOUR TI - Effect of potassium inhibition on the thermophilic anaerobic digestion of swine waste AU - Chen, Ye AU - Cheng, Jay J. T2 - WATER ENVIRONMENT RESEARCH AB - The inhibition effects of high potassium concentration on thermophilic anaerobic digestion of swine waste were studied. A continuous stirred tank reactor (CSTR), operated at a hydraulic retention time of 10 days and chemical oxygen demand loading of 7.2 to 7.5 g/L/d, was used to digest swine waste and cultivate thermophilic anaerobic microorganisms. To evaluate the toxicity of potassium, batch inhibition tests were also conducted. Without acclimation to potassium, the inhibition threshold beyond which methane production decreased significantly was 3 g K+/L. Volatile fatty acids accumulation was observed during the decline of methane production. Propionic acid was the dominant fatty acid, indicating that propionic acid utilizers were more sensitive to potassium inhibition than acetoclastic methanogens. To test the effect of acclimation on potassium inhibition, the potassium concentration in the CSTR was increased to 6 and 9 g K+/L. Acclimation to 6 g K+/L increased the tolerance of anaerobic inocula to potassium inhibition without significantly reducing the methanogenic activity. The inhibition threshold was increased from 3 g K+/L for unacclimated inocula, to 6 g K+/L for inocula acclimated to 6 g/L of potassium. Acclimation of inocula to 9 g/L potassium further increased the inhibition threshold to 7.5 g K+/L. However, the overall methanogenic activity in the last case was lower than that of unacclimated and 6 g K+/L acclimated inocula. DA - 2007/6// PY - 2007/6// DO - 10.2175/106143007X156853 VL - 79 IS - 6 SP - 667-674 SN - 1061-4303 KW - anaerobic digestion KW - continuous stirred tank reactor KW - inhibition KW - potassium KW - swine waste KW - thermophilic digestion ER - TY - JOUR TI - Disruption of a maize 9-lipoxygenase results in increased resistance to fungal pathogens and reduced levels of contamination with mycotoxin fumonisin AU - Gao, Xiquan AU - Shim, Won-Bo AU - Goebel, Cornelia AU - Kunze, Susan AU - Feussner, Ivo AU - Meeley, Robert AU - Balint-Kurti, Peter AU - Kolomiets, Michael T2 - MOLECULAR PLANT-MICROBE INTERACTIONS AB - Plant oxylipins, produced via the lipoxygenase (LOX) pathway, function as signals in defense and development. In fungi, oxylipins are potent regulators of mycotoxin biosynthesis and sporogenesis. Previous studies showed that plant 9-LOX-derived fatty acid hydroperoxides induce conidiation and mycotoxin production. Here, we tested the hypothesis that oxylipins produced by the maize 9-LOX pathway are required by pathogens to produce spores and mycotoxins and to successfully colonize the host. Maize mutants were generated in which the function of a 9-LOX gene, ZmLOX3, was abolished by an insertion of a Mutator transposon in its coding sequence, which resulted in reduced levels of several 9-LOX-derived hydroperoxides. Supporting our hypothesis, conidiation and production of the mycotoxin fumonisin B1 by Fusarium verticillioides were drastically reduced in kernels of the lox3 mutants compared with near-isogenic wild types. Similarly, conidia production and disease severity of anthracnose leaf blight caused by Colletotrichum graminicola were significantly reduced in the lox3 mutants. Moreover, lox3 mutants displayed increased resistance to southern leaf blight caused by Cochliobolus heterostrophus and stalk rots caused by both F. verticillioides and C. graminicola. These data strongly suggest that oxylipin metabolism mediated by a specific plant 9-LOX isoform is required for fungal pathogenesis, including disease development and production of spores and mycotoxins. DA - 2007/8// PY - 2007/8// DO - 10.1094/MPMI-20-8-0922 VL - 20 IS - 8 SP - 922-933 SN - 1943-7706 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-34547106821&partnerID=MN8TOARS KW - lipid peroxidation ER - TY - JOUR TI - A review of gaseous ammonia emissions from slurry pits in pig production systems AU - Griffing, E. M. AU - Overcash, M. AU - Westerman, P. T2 - BIOSYSTEMS ENGINEERING AB - Twenty-six experimental studies of ammonia emissions from pig buildings that utilise some form of pit/slurry system have been analysed and compared. Using standard values for pig weight and total Kjeldahl nitrogen (TKN) content in the waste when these quantities were unspecified, experimental ammonia emissions were compared on a per cent loss (of excreted TKN) basis. Correction factors were determined for measurements made during specific parts of the year, with corresponding differences in temperature, or time of day, and adjustments were made to put emission data on an annual average basis, when applicable. When corrected in this way, measurements made in the United States and in Europe were 22% and 21%, respectively. The standard deviation and standard error of the mean were 9% and 1.8%, respectively. The 95% confidence interval of the mean was 17.6–24.9%. The proposed emission factor data are reasonably consistent and emission factors higher or lower must be critically compared to the existing experimental base. DA - 2007/7// PY - 2007/7// DO - 10.1016/j.biosystemseng.2007.02.012 VL - 97 IS - 3 SP - 295-312 SN - 1537-5110 ER - TY - JOUR TI - Fruity fermented off-flavor distribution in samples from large peanut lots AU - Greene, J. L. AU - Whitaker, T. B. AU - Hendrix, K. W. AU - Sanders, T. H. T2 - JOURNAL OF SENSORY STUDIES AB - ABSTRACT Fruity fermented (FF) off‐flavor develops when immature peanuts are cured at excessive temperatures ( > 35C). The objective of this study was to characterize FF distributions and determine the variability among samples from large peanut lots. Twenty peanut lots identified as having a range of FF off‐flavor were sampled. Twenty samples from each lot were roasted and processed into paste for descriptive sensory analysis. Differences in FF intensity were noted within and among lots. The FF intensity mean of the lots was either greater or less than the median value for the samples, indicating that the distributions were skewed. The skewed distributions and the variation among samples from a single lot demonstrated the need to develop a sampling plan for FF off‐flavor. PRACTICAL APPLICATIONS The peanut manufacturing industry has a stated concern for fruity fermented (FF) off‐flavor in peanuts purchased for use in peanut products, but there is difficulty in obtaining a truly uniform sample of all peanuts in a large lot. This study measured the variability and characterized the FF distribution among samples from bulk peanut lots, and will be used to estimate the components contributing to FF variation within peanut lots and aid in the development of sampling plans for accurate FF intensity determination. This type of research has relevance to a wide range of food factors where the factor of interest is not homogeneously distributed in a commodity or product. DA - 2007/8// PY - 2007/8// DO - 10.1111/j.1745-459X.2007.00119.x VL - 22 IS - 4 SP - 453-461 SN - 0887-8250 ER - TY - JOUR TI - Detection and quantification of species authenticity and adulteration in crabmeat using visible and near-infrared spectroscopy AU - Gayo, Javier AU - Hale, Scott A. T2 - JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY AB - Seafood processing often removes morphological properties of seafood species that enable the consumer to distinguish one type of organism from another. For this reason, species substitution is the most common form of economic adulteration in the seafood industry. Visible and near-infrared spectroscopy (Vis/NIR) has been used to detect and quantify species authenticity and adulteration in crabmeat samples. Atlantic blue crabmeat was adulterated with blue swimmer crabmeat in 10% increments. Water absorption bands dominated the main features in the crabmeat spectra, with a decrease in sample absorbance with increasing adulteration percentage. Several data pretreatments, i.e., moving average, combing, first and second derivatives, and multiplicative scatter correction, in addition to the raw data, were investigated for prediction and quantitative data analysis using partial least-squares. In addition, quantitative analysis was done using the full spectrum and a sequential approach in which 50 wavelengths were added sequentially to determine a new model and find an optimal solution. The results suggest that Vis/NIR spectroscopy is a suitable technology that can be applied to detect and quantify species authenticity and adulteration in crabmeat. DA - 2007/2/7/ PY - 2007/2/7/ DO - 10.1021/jf061801+ VL - 55 IS - 3 SP - 585-592 SN - 1520-5118 KW - species authenticity KW - adulteration KW - VIS/NIR spectroscopy KW - PLS ER - TY - JOUR TI - A comparison of chemical pretreatment methods for improving saccharification of cotton stalks AU - Silverstein, Rebecca A. AU - Chen, Ye AU - Sharma-Shivappa, Ratna R. AU - Boyette, Michael D. AU - Osborne, Jason T2 - BIORESOURCE TECHNOLOGY AB - The effectiveness of sulfuric acid (H(2)SO(4)), sodium hydroxide (NaOH), hydrogen peroxide (H(2)O(2)), and ozone pretreatments for conversion of cotton stalks to ethanol was investigated. Ground cotton stalks at a solid loading of 10% (w/v) were pretreated with H(2)SO(4), NaOH, and H(2)O(2) at concentrations of 0.5%, 1%, and 2% (w/v). Treatment temperatures of 90 degrees C and 121 degrees C at 15 psi were investigated for residence times of 30, 60, and 90 min. Ozone pretreatment was performed at 4 degrees C with constant sparging of stalks in water. Solids from H(2)SO(4), NaOH, and H(2)O(2) pretreatments (at 2%, 60 min, 121 degrees C/15 psi) showed significant lignin degradation and/or high sugar availability and hence were hydrolyzed by Celluclast 1.5L and Novozym 188 at 50 degrees C. Sulfuric acid pretreatment resulted in the highest xylan reduction (95.23% for 2% acid, 90 min, 121 degrees C/15 psi) but the lowest cellulose to glucose conversion during hydrolysis (23.85%). Sodium hydroxide pretreatment resulted in the highest level of delignification (65.63% for 2% NaOH, 90 min, 121 degrees C/15 psi) and cellulose conversion (60.8%). Hydrogen peroxide pretreatment resulted in significantly lower (p 0.50 regarded as satisfactory performance. We were able to generate runoff and sediment yields comparable to observed values by replacing soil surface properties with subsoil properties, in conjunction with the cutslope management parameter file in WEPP. We found a similar agreement between predicted and observed values for stabilized conditions by increasing critical shear stress from 0.3 to 10 Pa for the soil input layer. In addition, changes to the model source code to reduce the lower limit of effective hydraulic conductivity (Kef) for impermeable surfaces resulted in improved runoff NSE, but consequently increased sediment yield on areas with higher Kef values. WEPP has great potential for modeling applications on construction sites; however, more validation studies are needed to confirm and expand upon our findings. DA - 2007/// PY - 2007/// DO - 10.13031/2013.22639 VL - 50 IS - 2 SP - 507-516 ER - TY - JOUR TI - Application of DRAINMOD-GIS to a lower coastal plain watershed AU - Fernandez, G. AU - Chescheir, G. M. AU - Skaggs, R. W. AU - Amatya, D. M. T2 - Transactions of the ASABE AB - This article reports a case study for applying DRAINMOD-GIS, a DRAINMOD-based lumped parameter watershed model, to Chicod Creek watershed, a 11100 ha coastal plain watershed in North Carolina that is not intensively instrumented or documented. The study utilized the current database of land use, topography, stream network, soil, and weather data available to state and federal agencies. Methods for collecting, evaluating, and formatting watershed data for model input are described. The study demonstrated that the lumped parameter model may be used to characterize the hydrology and water quality of Chicod Creek. Hydrology predictions were within 5% of the measured data. Predicted mean monthly nitrate-nitrogen (NO3-N) loads compared well with the measured data. Mean annual delivery ratios of each field ranged from 81% to 99% with a watershed mean of 90%. Application of the model to evaluate the effects of changing land use is presented. DA - 2007/// PY - 2007/// DO - 10.13031/2013.22635 VL - 50 IS - 2 SP - 439-447 ER - TY - JOUR TI - Theoretical study of the impact of particulate matter gravitational settling on ambient coarse particulate matter monitoring for agricultural emissions AU - Wang, Lingjuan AU - Parnell, Calvin B., Jr. AU - Buser, Michael D. T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - Abstract The particle size distributions (PSDs) of particulate matter (PM) in the downwind plume from simulated sources of a cotton gin were analyzed to determine the impact of PM settling on PM monitoring. The PSD of PM in a plume varies as a function of gravitational settling. Gravitational settling has a greater impact on the downwind PSD from sources with PSDs having larger mass median diameters (MMDs). The change in PSD is a function of the source PSD of emitted PM, wind speed, and downwind distance. Both MMD and geometric standard deviation (GSD) in the downwind plume decrease with an increase in down-wind distance and source MMD. The larger the source MMD, the greater the change in the downwind MMD and GSD. Also, the greater the distance from the source to the sampler, the greater the change in the downwind MMD and GSD. Variations of the PSD in the downwind plume significantly impact PM10 sampling errors associated with the U.S. Environmental Protection Agency (EPA) PM10 samplers. For the emission sources with MMD >10 µm, the PM10 oversampling rate increases with an increase in downwind distance caused by the decrease of GSD of the PSD in the downwind plume. Gravitational settling of particles does not help reduce the oversampling problems associated with the EPA PM10 sampler. Furthermore, over-sampling rates decrease with an increase of the wind speed. DA - 2007/1// PY - 2007/1// DO - 10.1080/10473289.2007.10465300 VL - 57 IS - 1 SP - 111-115 SN - 1047-3289 ER - TY - JOUR TI - Substrate organic matter to improve nitrate removal in surface-flow constructed wetlands AU - Burchell, Michael R., II AU - Skaggs, R. Wayne AU - Lee, Charles R. AU - Broome, Steven AU - Chescheir, George M. AU - Osborne, Jason T2 - JOURNAL OF ENVIRONMENTAL QUALITY AB - ABSTRACT A wetland mesocosm experiment was conducted in eastern North Carolina to determine if organic matter (OM) addition to soils used for in‐stream constructed wetlands would increase NO 3 − –N treatment. Not all soils are suitable for wetland substrate, so OM addition can provide a carbon and nutrient source to the wetland early in its development to enhance denitrification and biomass growth. Four batch studies, with initial NO 3 − –N concentrations ranging from 30 to 120 mg L −1 , were conducted in 2002 in 21 surface‐flow wetland mesocosms. The results indicated that increasing the OM content of a Cape Fear loam soil from 50 g kg −1 (5% dry wt.) to 110 g kg −1 (11% dry wt.) enhanced NO 3 − –N wetland treatment efficiency in spring and summer batch studies, but increases to 160 g kg −1 (16% dry wt.) OM did not. Wetlands constructed with dredged material from the USACE Eagle Island Confined Disposal Facility in Wilmington, NC, with initial OM of 120 g kg −1 (12% dry wt.), showed no improvement in NO 3 − –N treatment efficiency when increased to 180 g kg −1 (18% dry wt.), but did show increased NO 3 − –N treatment efficiency in all batch studies when increased to 220 g kg −1 (22% dry wt.). Increased OM addition and biosolids to the Cape Fear loam and dredged material blends significantly increased biomass growth in the second growing season when compared to no OM addition. Results of this research indicate that increased OM in the substrate will reduce the area required for in‐stream constructed wetlands to treat drainage water in humid regions. It also serves as a demonstration of how dredged material can be used successfully in constructed wetlands, as an alternative to costly storage by the USACE. DA - 2007/// PY - 2007/// DO - 10.2134/jeq2006.0022 VL - 36 IS - 1 SP - 194-207 SN - 0047-2425 ER - TY - JOUR TI - Precise mapping of quantitative trait loci for resistance to southern leaf blight, caused by Cochliobolus heterostrophus race O, and flowering time using advanced intercross maize lines AU - Balint-Kurti, P. J. AU - Zwonitzer, J. C. AU - Wisser, R. J. AU - Carson, M. L. AU - Oropeza-Rosas, M. A. AU - Holland, J. B. AU - Szalma, S. J. T2 - GENETICS AB - Abstract The intermated B73 × Mo17 (IBM) population, an advanced intercross recombinant inbred line population derived from a cross between the maize lines B73 (susceptible) and Mo17 (resistant), was evaluated in four environments for resistance to southern leaf blight (SLB) disease caused by Cochliobolus heterostrophus race O. Two environments were artificially inoculated, while two were not inoculated and consequently had substantially lower disease pressure. Four common SLB resistance quantitative trait loci (QTL) were identified in all environments, two in bin 3.04 and one each in bins 1.10 and 8.02/3. There was no significant correlation between disease resistance and days to anthesis. A direct comparison was made between SLB QTL detected in two populations, independently derived from the same parental cross: the IBM advanced intercross population and a conventional recombinant inbred line population. Several QTL for SLB resistance were detected in both populations, with the IBM providing between 5 and, in one case, 50 times greater mapping resolution. DA - 2007/5// PY - 2007/5// DO - 10.1534/genetics.106.067892 VL - 176 IS - 1 SP - 645-657 SN - 1943-2631 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-34548569322&partnerID=MN8TOARS ER - TY - JOUR TI - Influence of process conditions on end product formation from Clostridium thermocellum 27405 in solid substrate cultivation on paper pulp sludge AU - Chinn, Mari S. AU - Nokes, Sue E. AU - Strobel, Herbert J. T2 - BIORESOURCE TECHNOLOGY AB - Solid substrate cultivation of thermophilic, anaerobic bacteria offers an alternative production method for many bio-based chemicals; however the process must be optimized for each substrate-organism fermentation. The effects of initial substrate moisture content (SMC, 30%, 50% and 70% wet-basis), supplemental nutrient concentration (SNC, 12%, 50% and 100%) and duration of cultivation time (6, 10 and 14 days), on product formation (lactate, ethanol and acetate) by Clostridium thermocellum 27405 were examined during growth on paper pulp sludge. Water activities at moisture contents above 30% wet-basis were essentially identical (∼0.99), yet the water contents differed significantly, and affected the metabolic activity of C. thermocellum. Increases in initial substrate moisture content from 50% to 70% for cultures supplemented with 50% or 100% nutrients resulted in a 75–145 mM increase in total end products. At 70% SMC, the addition of 100% SNC generated a 56% increase in product formation above the addition of 50% nutrient supplementation. Increases in the quantity of free water present in the solid substrate cultivation system up to the water holding capacity of the paper pulp sludge led to improved performance of this anaerobic bacterium. While nutrient supplementation is common in the form of salts for many aerobic microorganisms, efficient metabolism for anaerobic C. thermocellum grown in SSC was highly dependent on added salts, vitamins and reducing agents. Further studies are needed to determine if this is a general effect for other anaerobes grown in solid substrate cultures. DA - 2007/8// PY - 2007/8// DO - 10.1016/j.biortech.2006.08.033 VL - 98 IS - 11 SP - 2184-2193 SN - 1873-2976 KW - solid substrate fermentation KW - anaerobic KW - thermophilic KW - solid-state fermentation KW - moisture content KW - nutrients KW - ethanol KW - acetate KW - lactate ER - TY - JOUR TI - Mapping resistance to Southern rust in a tropical by temperate maize recombinant inbred topcross population AU - Jines, M. P. AU - Balint-Kurti, P. AU - Robertson-Hoyt, L. A. AU - Molnar, T. AU - Holland, J. B. AU - Goodman, M. M. T2 - THEORETICAL AND APPLIED GENETICS DA - 2007/2// PY - 2007/2// DO - 10.1007/s00122-006-0466-0 VL - 114 IS - 4 SP - 659-667 SN - 1432-2242 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33846813838&partnerID=MN8TOARS ER - TY - JOUR TI - Potential impacts of implementation of the phosphorus loss assessment tool (PLAT) on the poultry industry in North Carolina: Case studies AU - Israel, D. W. AU - Osmond, D. L. AU - Roberts, J. C. T2 - Journal of Soil & Water Conservation DA - 2007/// PY - 2007/// VL - 62 IS - 1 SP - 48-54 ER - TY - JOUR TI - Effects of pelvic positioning and simulated dorsal acetabular rim remodeling on the radiographic shape of the dorsal acetabular edge AU - Thompson, Randall AU - Roe, Simon C. AU - Robertson, Ian D. T2 - VETERINARY RADIOLOGY & ULTRASOUND AB - A radiographic study was conducted to evaluate the effect of pelvic rotation and of simulated dorsal acetabular rim (DAR) remodeling on the radiographic appearance of the dorsal acetabular edge (DAE). The DAE is the line connecting the cranial and caudal rims of the acetabulum when viewing a pelvic radiograph made with the dog in the ventrodorsal position with the hind limbs extended. In this study, it was hypothesized that the DAE would change with pelvic rotation and simulated DAR damage. Ventrodorsal radiographs of eight canine pelves were made at 0°, 5°, and 10° of left and right pelvic rotation over its longitudinal axis. These radiographs were repeated following removal of 2, 4, and then 6 mm of bone from the right DAR of each pelvis. The ratio of acetabular width to maximum depth of the DAE was calculated. The area between the DAE and a straight line connecting the cranial and caudal acetabular rims was measured digitally. The DAE depth and area changed with pelvic rotation, and with increasing simulated DAR damage. A linear relationship between the obturator foramina width ratio and pelvic rotation allowed estimation of the degree and direction of pelvic rotation. Equations were developed from the data to assist with the estimation of the amount of DAR remodeling on a clinical radiograph. DA - 2007/// PY - 2007/// DO - 10.1111/j.1740-8261.2007.00196.x VL - 48 IS - 1 SP - 8-13 SN - 1740-8261 KW - canine hip dysplasia KW - defect area KW - dorsal acetabular edge KW - dorsal acetabular rim KW - pelvic rotation ER - TY - JOUR TI - Biomechanical comparison of dual interlocking single loop and double loop tension band techniques to the classic AO tension band technique for repair of olecranon osteotomies in dogs AU - Grafinger, Michael S. AU - Roe, Simon C. AU - Spodnick, Gary AU - Smith, Eric S. T2 - VETERINARY SURGERY AB - Objective— To compare olecranon fragment stability between the classic tension band wire (TBW) technique with the wire placed either in contact with ( Arbeitsgemeinschaft für Osteosynthesefragen [AO]), or not in contact with, a Kirschner (K)‐wire (AOW) to 2 novel wire patterns: a dual interlocking single loop (DISL) and a double loop (DL). Study Design— Ex vivo mechanical evaluation on cadaveric bones. Sample Population— Canine ulnae (n=40) with olecranon osteotomies repaired with 2 K‐wires and 1 of 4 TBW constructs. Methods— Single load to failure applied through the triceps tendon. Displacement was measured from images captured from digital video. Techniques were compared based on the load resisted when the olecranon fragment was displaced 0.5, 1, and 2 mm. Results— At 0.5 mm of displacement, the DISL construct resisted more load than the AOW construct (505 versus 350 N; P =.05). AO and DL constructs resisted an intermediate load (345 and 330 N, respectively). There was no significant difference between groups at 1 mm of displacement. At 2 mm of displacement, DL (785 N) resisted more load than AO (522 N, P =.01) and AOW (492 N, P =.03) groups. Conclusions— DISL constructs provided similar stability to classic TBW constructs whereas DL constructs were more stable at higher loads. Clinical Relevance— The DL construct is easy to perform, less bulky, and provides comparable fragment stability to standard TBW techniques at functional loads. Surgical method is important for optimal performance of all TBW constructs. DA - 2007/2// PY - 2007/2// DO - 10.1111/j.1532-950X.2007.00246.x VL - 36 IS - 2 SP - 141-148 SN - 0161-3499 ER - TY - JOUR TI - The effects of vermicompost on field turnips and rainfall runoff AU - Classen, John AU - Rice, J. M. AU - Sherman, R. T2 - Compost Science & Utilization AB - Vermicompost made from separated swine waste solids (0, 10, or 20% by volume of soil) was applied to turnips in small field plots during four growing seasons to determine the effect on plant growth, runoff volume and nutrients in runoff. The effect of nitrogen fertilizer was controlled by supplementing half the plots with inorganic nitrogen to balance the nitrogen fertilizer recommendations for turnips. Vermicompost addition increased fresh weight of fruit and foliage by a factor of two to five and increased dry weight by a factor of three with no increase in nitrogen but higher phosphorus in runoff. Runoff volume was lower in plots that received vermicompost compared to control plots. DA - 2007/// PY - 2007/// DO - 10.1080/1065657x.2007.10702308 VL - 15 IS - 1 SP - 34–39 ER - TY - JOUR TI - Entomopathogenic fungi detection and avoidance by mole crickets (Orthoptera : Gryllotalpidae) AU - Thompson, Sarah R. AU - Brandenburg, Rick L. AU - Roberson, Gary T. T2 - ENVIRONMENTAL ENTOMOLOGY AB - A chamber to monitor mole cricket behavior was designed using two different soil-filled containers and photosensors constructed from infrared emitters and detectors. Mole crickets (Scapteriscus spp.) were introduced into a center tube that allowed them to choose whether to enter and tunnel in untreated soil or soil treated with Beauveria bassiana (Balsamo) Vuillemin. Each time the cricket passed through the photosensor located near the entrance of soil-filled containers, the infrared light was blocked and the exact moment that this occurred was logged onto a computer using custom-written software. Data examined included the first photosensor trigger, total number of sensor triggers, presence of tunneling, and final location of the cricket after 18 h. These behaviors were analyzed to discern differences in mole cricket behavior in the presence of different treatments and to elucidate the mechanism that mole crickets use to detect fungal pathogens. The first study examined substrate selection and tunneling behavior of the southern mole cricket, Scapteriscus borellii Giglio-Tos, to the presence of five strains of B. bassiana relative to a control. There were no differences between the first sensor trigger and total number of triggers, indicating the mole crickets are not capable of detecting B. bassiana at a distance of 8 cm. Changes in mole cricket tunneling and residence time in treated soil occurred for some strains of B. bassiana but not others. One of the strains associated with behavioral changes in the southern mole cricket was used in a second experiment testing behavioral responses of the tawny mole cricket, S. vicinus Scudder. In addition to the formulated product of this strain, the two separate components of that product (conidia and carrier) and bifenthrin, an insecticide commonly used to control mole crickets, were tested. There were no differences in mole cricket behavior between treatments in this study. The differences in behavioral responses between the two species could suggest a more sensitive chemosensory recognition system for southern mole crickets. DA - 2007/2// PY - 2007/2// DO - 10.1603/0046-225X(2007)36[165:EFDAAB]2.0.CO;2 VL - 36 IS - 1 SP - 165-172 SN - 1938-2936 KW - infrared emitters and detectors KW - Beauveria bassiana KW - Scapteriscus borellii KW - S. vicinus KW - avoidance ER - TY - CONF TI - Duckweed: an alternative starch source for bioethanol production AU - Chen, Y. AU - Yablonski, M. AU - Ernst, E. AU - Stomp, A. -M. AU - Cheng, J. J. C2 - 2007/// C3 - 2007 ASABE Regional Annual Conference (Fletcher, North Carolina) DA - 2007/// ER - TY - CONF TI - Microwave pretreatment of switchgrass to enhance enzymatic hydrolysis AU - Keshwani, D. R. AU - Cheng, J. J. AU - Li, L. AU - Burns, J. C. AU - Chiang, V. AB - Switchgrass is a promising lignocellulosic biomass for fuel-ethanol production. However, pretreatment of lignocellulosic materials is necessary to improve its susceptibility to enzymatic hydrolysis. The objectives of this study were to examine the feasibility of microwave pretreatment to enhance enzymatic hydrolysis of switchgrass and to determine the optimal pretreatment conditions. Switchgrass samples immersed in water, dilute sulfuric acid and dilute sodium hydroxide solutions were exposed to microwave radiation at varying levels of radiation power and residence time. Pretreated solids were enzymatically hydrolyzed and reducing sugars in the hydrolysate were analyzed. Microwave radiation of switchgrass at lower power levels resulted in more efficient enzymatic hydrolysis. The application of microwave radiation for 10 minutes at 250 watts to switchgrass immersed in 3% sodium hydroxide solution (w/v) produced the highest yields of reducing sugar. Results were comparable to conventional 60 minute sodium hydroxide pretreatment of switchgrass. The findings suggest that combined microwave-alkali is a promising pretreatment method to enhance enzymatic hydrolysis of switchgrass. C2 - 2007/// C3 - Proceedings of the ASABE Annual International Meeting (Minneapolis, Minnesota) DA - 2007/// DO - 10.13031/2013.23472 VL - 077127 ER -