Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/10/1996
Publication Date: N/A
Technical Abstract: Pesticides in surface runoff contaminate not only surface water bodies but also groundwater through macropore flow. This study evaluated the effects of rainfall pattern on surface-applied atrazine and metolachlor losses in surface runoff and to further model pesticide transfer from soil to runoff. Four storm patterns [uniform intensity(UI), advanced- peak(AP), intermediate-peak(IP), and delayed-peak(DP)] were used. A Cecil sandy loam and a Miami silt loam were studied under either initially dry or wet conditions. The dissolved atrazine and metolachlor losses from the AP storm were more than two times those from the other storms for Cecil soil. Although the difference was reduced for Miami soil, metolachlor losses from the AP storm was still significantly greater than from the DP storm. For adsorbed herbicide loss, no consistent trend across storm patterns was exhibited on both soils, but a significant increase was observed for the wet treatment as compared to the dry treatment. The overall results showed storm pattern should be considered in prediction models in order to better estimate pesticide loss in runoff.