@article{gannon_hixson_weber_shi_yelverton_rufty_2013, title={Sorption of Simazine and S-Metolachlor to Soils from a Chronosequence of Turfgrass Systems}, volume={61}, ISSN={["1550-2759"]}, DOI={10.1614/ws-d-12-00173.1}, abstractNote={Pesticide sorption by soil is among the most sensitive input parameters in many pesticide-leaching models. For many pesticides, organic matter is the most important soil constituent influencing pesticide sorption. Increased fertility, irrigation, and mowing associated with highly maintained turfgrass areas result in constant deposition of organic material, creating a soil system that can change drastically with time. Changes in soil characteristics could affect the environmental fate of pesticides applied to turfgrass systems of varying ages. Sorption characteristics of simazine andS-metolachlor were determined on five soils from bermudagrass systems of increasing ages (1, 4, 10, 21, and 99 yr) and compared to adjacent native pine and bare-ground areas. Surface soil (0 to 5 cm) and subsurface soil (5 to 15 cm) from all sites were air-dried and passed through a 4-mm sieve for separation from plant material. Using a batch-equilibrium method, sorption isotherms were determined for each soil. Data were fit to the Freundlich equation, andKd(soil sorption coefficient) andKoc(organic carbon sorption coefficient) values were determined. Sorption and soil system age were directly related to organic matter content in the soil. Sorption of both herbicides increased with age of the soil system and was greatest on the surface soil from the oldest bermudagrass soil system. Herbicide sorption decreased at greater soil depths with lower organic matter. Greater amount of14C–simazine sorbed to subsurface soil of the oldest turfgrass system compared to14C–S-metolachlor. Results indicate that as bermudagrass systems age and accumulate higher organic matter levels increased herbicide sorption may decrease the leaching potential and bioavailability of simazine andS-metolachlor.}, number={3}, journal={WEED SCIENCE}, author={Gannon, Travis W. and Hixson, Adam C. and Weber, Jerome B. and Shi, Wei and Yelverton, Fred H. and Rufty, Thomas W.}, year={2013}, pages={508–514} }
 @article{hixson_shi_weber_yelverton_rufty_2009, title={Soil Organic Matter Changes in Turfgrass Systems Affect Binding and Biodegradation of Simazine}, volume={49}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2008.09.0541}, abstractNote={Concern about pesticide losses from maintained turfgrass areas led us to examine the fate of the triazine herbicide simazine in turfgrass systems and, specifically, interactions between simazine binding to soil organic matter and biodegradation. Soil samples were removed from turfgrass systems of different ages, placed in microcosms, conditioned as sterile or nonsterile, and exposed to 14C‐simazine. At seven sampling intervals, the soil was extracted and 14C was separated into three pools; bound, extractable, and CO2 With sterilized surface soil (0–5 cm), 52, 70, and 71% of applied 14C‐simazine was bound to soil from the 4‐, 21‐, and 99‐yr‐old turfgrass systems, respectively, after 16 wk. With nonsterile conditions, biodegradation became dominant, as 60 to 80% of the 14C was recovered in the CO2 fraction and binding was held at ∼20%. Among all soils evaluated, bound 14C and 14CO2 production was lower in subsurface soil (5–15 cm) from the 4‐ and 21‐yr‐old turfgrass systems. 14C‐simazine disappearance time (DT50) values under nonsterile conditions ranged from 0.9 to 5.8 wk. Results indicate that turfgrass systems have a relatively low amount of simazine available for leaching as the systems age due to a large capacity for biodegradation and binding to organic matter.}, number={4}, journal={CROP SCIENCE}, author={Hixson, Adam C. and Shi, Wei and Weber, Jerome B. and Yelverton, Fred H. and Rufty, Thomas W.}, year={2009}, pages={1481–1488} }
 @article{hixson_gannon_yelverton_2007, title={Efficacy of application placement equipment for tall fescue (Lolium arundinaceum) growth and seedhead suppression}, volume={21}, ISSN={["1550-2740"]}, DOI={10.1614/WT-06-108.1}, abstractNote={Field research was conducted to evaluate plant growth-regulator efficacy for tall fescue growth and seedhead suppression applied using application placement equipment. Specially designed equipment outfitted with fluid application systems applies low-volume plant growth regulator directly on plant foliage, reducing opportunity for drift and visible application. Wet-blade mowers are equipped to apply plant growth regulators and mow in a single pass, whereas rotary-wick applicators simply wipe chemicals directly on uncut vegetation. Therefore, a wet-blade, rotary-wick, and broadcast sprayer system were chosen to apply imazapic at three rates (9, 35, and 53 g ai/ha), and a mefluidide + chlorsulfuron tank mix at 7 + 140 g ai/ha to tall fescue roadsides for vegetative growth and seedhead suppression. Experiments were conducted during the spring and summer of 2004 in central and western North Carolina. Tall fescue was slightly injured and discolored by all treatments but fully recovered by 2 mo after treatment. Imazapic suppressed new vegetative growth 3 mo after treatment compared with the nonmowed–nontreated control (16.1 cm of growth) and the mowed–nontreated control (21.1 cm) when applied with the rotary-wick applicator (8.5 cm) and broadcast sprayer (6.2 cm). However, differences in vegetative height primarily occurred when application placement equipment treatments were compared with nontreated vegetation as opposed to mowed–nontreated plants. Although mowed–nontreated and wet-blade–treated plots had more new vegetative growth, nonmowed–nontreated plots still consistently had the greatest vegetative height. Seedhead suppression ranged from 87 to 100% when compared with the nonmowed–nontreated control, with wet-blade treatments consistently providing the least-effective seedhead suppression. Overall, application placement equipment did not improve plant growth-regulator efficacy when compared with the foliar broadcast spray. Nomenclature: Chlorsulfuron; imazapic; mefluidide; tall fescue, Lolium arundinaceum (Schreb.) S.J. Darbyshire, ‘Kentucky 31’}, number={3}, journal={WEED TECHNOLOGY}, author={Hixson, Adam C. and Gannon, Travis W. and Yelverton, Fred H.}, year={2007}, pages={801–806} }
 @article{hixson_crow_mcsorley_trenholm_2005, title={Saline irrigation affects Belonolaimus longicaudatus and Hoplolaimus galeatus on seashore paspalum}, volume={37}, number={1}, journal={Journal of Nematology}, author={Hixson, A. C. and Crow, W. T. and McSorley, R. and Trenholm, L. E.}, year={2005}, pages={37–44} }