Wednesday, 9 November 2005
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Evaluating Effectiveness of Three Grass Buffer Designs in Reducing Atrazine, Metolachlor and Glyphosate Transport in Surface Runoff.

Chung-Ho Lin1, Robert N. Lerch2, Harold E. Garrett1, Clark J. Gantzer3, Stephen H. Anderson4, and Milon F. George1. (1) Center for Agroforestry, University of Missouri-Columbia, 203 ABNR Natural Resources Building, Columbia, MO 65211, (2) USDA-ARS, Cropping Systems and Water Quality Research Unit, 265 Agricultural Engineering Building, Columbia, MO 65211-0001, (3) Department of Soil, Environmental and Atmospheric Sciences, University of Missouri-Columbia, 302 ABNR Natural Resources Building, Columbia, MO 65211, (4) Department of Soil, Environmental and Atmospheric Sciences, University of Missouri-Columbia, 302 ABNR Building, Columbia, MO 65211

Multiple species riparian grass buffers have been recommended as a cost-effective approach to mitigate herbicide transport in surface runoff derived from agronomic operations. However, the effectiveness of different buffer designs, such as species selection, combinations of different species, and buffer length, on reductions in herbicide transport have not been well documented. An experiment consisting of three grass buffer designs and one cultivated fallow control with three replications was conducted to assess effectiveness in reducing herbicide transport for claypan soils. The four vegetative filter strip treatments include: 1) tall fescue, 2) switchgrass hedge in combination with tall fescue, 3) switchgrass hedge in combination with native grass and forbs species, and 4) continuous cultivated fallow as a control. Rainfall simulation was used to create uniform antecedent soil moisture content in the plots and to generate runoff. Runoff collection equipment was installed at 1 m above the buffers and within the buffers at 1, 4, and 8 m below the upslope end. Grass buffers significantly reduced the transport of atrazine, metolachlor and glyphosate in surface runoff. Grass buffers with native species were most consistently effective at reducing herbicide transport. The 8-m native species buffers removed about 75-80% of the atrazine, metolachlor and glyphosate in surface runoff. Four meters of buffer resulted in similar or equivalent reductions in transport of atrazine and metolachlor as eight meters of buffer. Thus, the implementation of native species buffers could provide desired reductions in herbicide transport with less land taken out of production.

Handout (.pdf format, 629.0 kb)

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