Full TGIF Record # 63047
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Publication Type:
Content Type:Abstract or Summary only
Author(s):Dozier, M. C.; Senseman, S. A.; Hoffman, D. W.; Potter, K. N.; Wolfe, J. E. III
Author Affiliation:Texas Agricultural Experiment Station, College Station, TX; Texas Agricultural Experiment Station, Temple, TX.; USDAARS, Blackland Research Center, Temple, TX
Title:Effectiveness of bermudagrass (Cynodon Dactylon) filter strips in herbicide removal from simulated surface runoff
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Meeting Info.:52nd Annual Meeting, Greensboro, NC, January 25-27, 1999
Source:Southern Weed Science Society Proceedings. Vol. 52, 1999, p. 224.
# of Pages:1
Publishing Information:Champaign, IL: Southern Weed Science Society.
Keywords:TIC Keywords: Cynodon dactylon; Filter strips; Herbicides; Surface runoff; Atrazine; Metolachlor; Tank mix; Sorghum
Abstract/Contents:"Combinations of atrazine and metolachlor, applied individually and together as a tank-mix, have proven to be invaluable and economical for control of annual broadleaves and annual grasses of corn and grain sorghum production. Though beneficial, the use of these herbicides pose a risk to surface and groundwater associated with the off-target movement of these herbicides in surface runoff. However, banning the use of atrazine has been projected to adversely impact producer income nationally by $342 million dollars. With this in mind, research is warranted to study better methods of managing the use and off-target losses of atrazine and metolachlor. One such practice to reduce off-target losses of herbicides is the use of grass filter strips. To better understand the benefits of grass filter strips, a series of experiments were conducted at the Blackland Research Center (BRC) in Temple, TX and the Texas A&M University Farm (TAMUF) in College Station, TX. These experiments included: micro-watershed surface runoff studies at BRC, 1996, and TAMF, 1997; a soil column study at TAMUF, 1998 and a single point adsorption study in 1998. It should be noted that these experiments were conducted under saturated soil conditions to focus the research on the contributions of reducing off-target losses of the two compounds by the bermudagrass. The micro-watershed runoff study was designed to determine the effectiveness of bermudagrass filter strips in removing atrazine and metolachlor from surface runoff. The two herbicides were added individually and as a tank mix to runoff water and allowed to uniformly flow across small, self-contained watersheds. Nine of the watersheds were composed of bermudagrass and nine were bare, conventional-tilled soil. Each watershed was 1 m by 3 m and enclosed with 18-gauge galvanized steel berms. Runoff was introduced upslope by a calibrated system utilizing flat-fan spray nozzles and a dispersion device designed to produce a sheet flow effect. After crossing the entire plot, runoff was collected at the lower end by a collection device. The runoff was then pumped to a small bucket for sampling at pre-determined time intervals. Next, the runoff was transferred to a larger tank equipped with a pressure transducer wired with a data logger to quantify the volume of runnoff collected. Treatments were replicated three times and runoff samples were extracted using solid phase extraction and analyzed for atrazine and metolachlor concentrations using gas chromatography-mass spectromerty. The soil column study was conducted by extracting intact soil columns from areas covered in bermudagrass and bare, convetional-tilled soil at the TAMUF. Runoff spiked with known concentrations of atrazine and metolachlor were applied individually and together as a tank-mix to each of the soil columns. Treatments were replicated three times and the volume of runoff and leachate measured. Composite samples of the runoff and leachate were extracted and analyzed as outlined above. Soil samples were collected and analyzed for atrazine and metolachlor concentrations. The final study, of this series, was determining the adsorptive capacity of bermudagrass and the two soils involved in the micro-watershed studies. These soils were Houston Black (BRC) and Weswood (TAMUF). Radio-labeled atrazine and metolachlor, individually and together as a tank-mix, were incubated with one gram of bermudagrass and two grams each of the two soils. Each treatment was replicated four times and the amount of radioactivity for each sample was determined using a Beckman liquid scintillation counter. Kds were then calculated. Results from the TAMUF micro-watershed exhibited no significant difference in % total herbicide load retained by either the bermudagrass or soil plots when the compounds were applied alone or togehter as a tank-mix. The soil column study revealed that a significantly greater amount of runoff leached through the soil columns covered in adsorb both atrazine and metolachlor and the Kds for both compounds were significantly greater for the bermudagrass verses the Weswood soil."
Note:This item is an abstract only!
ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Dozier, M. C., S. A. Senseman, D. W. Hoffman, K. N. Potter, and J. E. III Wolfe. 1999. Effectiveness of bermudagrass (Cynodon Dactylon) filter strips in herbicide removal from simulated surface runoff. South. Weed Sci. Soc. Proc. 52:p. 224.
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MSU catalog number: SB 611 .S6 v.52
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