ABSTRACT:
Label changes defining the correct use of atrazine (6-chloro-N-ethyl-N'-(-(1-methylethyl)-1,3,5-triazine-2,4-diamine) and cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-trianzin-2-yl]amino]-2-methylpropionitrile) have forced producers to place a buffer area or an application setback around standpipes or surface inlets in a tile-outlet terraced field. An alternative best management practice (BMP) to the setback requirement, in the way of soil incorporation, was evaluated for possible adoption without the perceived increased economic costs and hardship of the use of the setbacks. Both inflow to and outflow of runoff from tile-outlet terrace subwatersheds with different herbicide management practices were monitored under natural rainfall to determine how they affected the herbicide concentrations and losses in runoff being discharged. Results showed that the setback did not reduce off-site herbicide transport when compared to no-setback treatments beyond that expected due to the reduction in area treated. Incorporation of the herbicides without a setback were found to be just as effective in reducing the herbicides lost in outflow as when using a setback.
Footnotes
S.K. Mickelson is an assistant professor, J.L. Baker is a professor, and S. W. Melvin is a professor in agricultural and biosystems engineering at Iowa State University, Ames, Iowa; R.S. Fawcett is an independent consultant, Fawcett Consulting, Huxley, Iowa; D.P. Tierney, Ph.D., Novartis Corporation, Greensboro, North Carolina; C.J. Peter, Ph.D., DuPont Corporation, Wilmington, Delaware.
- Copyright 1998 by the Soil and Water Conservation Society
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