@article{hazel_franklin_thomas_2008, title={Best management practices for reducing sediment loss from tobacco fields}, volume={63}, DOI={10.2489/jswc.63.3.91a}, abstractNote={Storm runoff from agricultural fields remains a significant source of pollutants to surface water. Use of best management practices in recent years has reduced these off-site impacts, especially for sediments. We evaluated a combination of best management practices on two agricultural Piedmont watersheds in North Carolina to estimate the combined reductions that can be achieved for tobacco cultivation. We evaluated the effectiveness of three best management practices for flue-cured tobacco production—reduced-till versus conventional tillage, grassed field-side filter zones, and forested filter zones—to determine the total reduction in suspended solids from storm runoff.}, number={3}, journal={Journal of Soil & Water Conservation}, author={Hazel, D. W. and Franklin, E. C. and Thomas, K. T.}, year={2008}, pages={91A} }
 @article{hazel_franklin_thomas_jennings_2008, title={Integrated practices for reducing sediment loss from Piedmont tobacco fields}, volume={63}, ISSN={["0022-4561"]}, DOI={10.2489/jswc.63.3.143}, abstractNote={We evaluated the effectiveness of three best management practices for flue-cured tobacco production—reduced tillage, grassed field-side filter zones, and forested filter zones—to determine the total reduction in suspended solids from storm water runoff. Use of reduced tillage in comparison with conventional tillage decreased total suspended solids leaving tobacco fields by 82%. Grassed field-side filter zones functioned very well in retaining solids in early summer but were overloaded by late summer. Forested filter zones were able to back up the grassed filter zones when they overloaded and exported total suspended solids to the forested filter zones. In combination, grassed filter zones and forested filter zones retained 68% to 69% of total suspended solids, respectively. Dense vegetation in the cutover forested filter zone more than doubled its capacity to detain solids, compared to the same forested filter zone when it was covered by mature mixed pine-hardwood. Use of these best management practices in series can significantly reduce sediment loss from tobacco; however, use of reduced-till may reduce tobacco yield and quality.}, number={3}, journal={JOURNAL OF SOIL AND WATER CONSERVATION}, author={Hazel, D. W. and Franklin, E. C. and Thomas, K. T. and Jennings, G. D.}, year={2008}, pages={143–152} }
 @article{holland_riordan_franklin_2006, title={A simple model for simulating tornado damage in forests}, volume={45}, ISSN={["1558-8424"]}, DOI={10.1175/JAM2413.1}, abstractNote={Abstract An analytical model is presented to describe patterns of downed trees produced by tornadic winds. The model uses a combined Rankine vortex of specified tangential and radial components to describe a simple tornado circulation. A total wind field is then computed by adding the forward motion of the vortex. The lateral and vertical forces on modeled tree stands are then computed and are compared with physical characteristics of Scots and loblolly pine. From this model, patterns of windfall are computed and are compared to reveal three basic damage patterns: cross-track symmetric, along-track asymmetric, and crisscross asymmetric. These patterns are shown to depend on forward speed, radial speed, and tree resistance. It is anticipated that this model will prove to be useful in assessing storm characteristics from damage patterns observed in forested areas.}, number={12}, journal={JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY}, author={Holland, Andrew P. and Riordan, Allen J. and Franklin, E. C.}, year={2006}, month={Dec}, pages={1597–1611} }
 @article{verchot_franklin_gilliam_1998, title={Effects of agricultural runoff dispersion on nitrate reduction in forested filter zone soils}, volume={62}, ISSN={["0361-5995"]}, DOI={10.2136/sssaj1998.03615995006200060033x}, abstractNote={Forested filter zones (FFZ) are being used more frequently for remediation of agricultural non-point source pollution. The objective of this study was to determine the effects of short-term dispersal (1-2 yr) of agricultural runoff on the denitrification potential of the soil microbial population and denitrification rates, to a depth of 1 m, in forest soils in two small watersheds (W1 and W2) in the Piedmont of North Carolina. Each watershed consisted of a field and a FFZ. Denitrification potential was measured in a series of soil slurry incubations of soils from inside the FFZ that received agricultural runoff and from soils immediately adjacent to the FFZ that received no runoff (control). Soils were amended with both glucose and nitrate (G +NO 3 ) to ensure adequate supply of substrate and energy source. Denitrification rates were measured at ambient C conditions in a similar incuhation with only NO 3 -N amendment (NO 3 ). We measured NO 3 -N disappearance in both incubations and reported loss as a percentage of initial concentrations. For the FFZ soils, >80% of the added NO 3 -N was lost in the G + NO 3 incubation from soils from the upper 50 cm in W1 and from the upper 30 cm in W2. In control soils, high levels of NO 3 -N loss were observed in only the upper 20 cm of the profile in W1, and in W2 surface soils had significantly lower denitrification potential than FFZ soils at all depths. Denitrification potential was greatly enhanced (P = 0.05) throughout the entire first 100 cm in the first FFZ and in the surface 40 cm in the second FFZ. Denitrification rates under ambient C conditions were higher (>40%) in the surface 20 cm of the profile of the FFZ in W1, compared with the unexposed control (∼20%), but no enhancement was observed on W2. Exposure of soil to agricultural runoff had a significant impact on the soil microbial community. Denitrification potential in subsoil was limited by the absence of denitrifiers in unexposed soils, but subsoils exposed to agricultural runoff had a significant denitrifier population. The fact that higher denitrification potential did not translate to higher denitrification rates in these incubations indicates that C availability limited the denitrification process at all depths in these Piedmont forest soils.}, number={6}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Verchot, LV and Franklin, EC and Gilliam, JW}, year={1998}, pages={1719–1724} }
 @article{verchot_franklin_gilliam_1997, title={Nitrogen cycling in piedmont vegetated filter zones .1. Surface soil processes}, volume={26}, ISSN={["0047-2425"]}, DOI={10.2134/jeq1997.00472425002600020002x}, abstractNote={Surface runoff is a major transport mechanism for particulate-bound and dissolved N species from agricultural fields. One means of reducing nutrient loading in surface waters is the use of vegetative filter zones. The objective of this study was to evaluate the effectiveness of two forested filter zones (FFZ) for removing N from runoff in the Piedmont region of North Carolina. We used a spreading device to ensure dispersed flow in the FFZ. In addition to measuring inputs and outputs from each FFZ, we characterized the N cycle in the surface 30 cm of the soil profile to determine the fate of different N species retained in the FFZ. N loading increased as water passed through FFZ1: NO3-N increased by 1.6 kg ha−1 yr−1, organic-N increased by 13.4 kg ha−1 yr−1 and NH4-N decreased by 0.2 kg ha−1 yr−1. The second FFZ was more effective with net retention of 0.2 kg ha−1 yr−1 for NO3-N, 0.5 kg ha−1 yr−1 for organic-N and 0.2 kg ha−1 yr−1 for NH4-N. The FFZ were ineffective during the winter and spring when water filled pore space exceeded 35% in FFZ1 and 25% in FFZ2, and infiltration was low. Infiltration was the key factor controlling N pollutant removal from surface runoff. Therefore, the clayey soils of the Piedmont may not be as effective as the sandy coastal plain soils studied by other authors. Results from the analysis of the N cycle suggest that both uptake by the vegetation and leaching to deeper soil layers were the dominant fates of inorganic-N.}, number={2}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Verchot, LV and Franklin, EC and Gilliam, JW}, year={1997}, pages={327–336} }
 @article{verchot_franklin_gilliam_1997, title={Nitrogen cycling in piedmont vegetated filter zones .2. Subsurface nitrate removal}, volume={26}, ISSN={["0047-2425"]}, DOI={10.2134/jeq1997.00472425002600020003x}, abstractNote={Subsurface flow often constitutes the major pathway for movement of dissolved nutrients such as NO3-N from agricultural fields. The objectives of this study were (i) to determine the changes in shallow groundwater chemistry along a piezometric gradient from agricultural fields, across grass-vegetated field edges and through adjacent forest on two Piedmont watersheds and (ii) determine the relative importance of dilution, denitrification, and plant uptake in subsurface NO3 attenuation. We monitored changes in groundwater chemistry at three depths along a piezometric gradient from an agricultural field through a grass field edge and through a forested filter zone (FFZ). We measured marked decrease in nitrate concentrations from 8 to 10 mg L−1 at the field edge to almost 0 at the forest edge; Cl concentrations remained within the range of 8 to 10 mg L−1, suggesting that dilution was not an important factor in NO3 concentration reductions. At a third site, we introduced NO3-N and a conservative tracer, bromide, into the soil profile at both the grass-vegetated field border and the forested area, to determine mechanisms responsible for the observed decrease in NO3-N concentrations. Using ion concentration ratios we determined that nitrate attenuation in the grass-vegetated field edge was low compared to the forest. Nitrate loss in the forest was almost exclusively through denitrification; plant uptake was insignificant in these experiments. Although grass-vegetated field borders were less effective than riparian forests at NO3-N removal, considerable reductions were observed in these areas on the experimental watersheds. Similar reductions would be expected over shorter distances in riparian forests.}, number={2}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Verchot, LV and Franklin, EC and Gilliam, JW}, year={1997}, pages={337–347} }