Influence of Rainfall Distribution on Simulations of Atrazine, Metolachlor, and Isoxaflutole/Metabolite Transport in Subsurface Drained Fields

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• 作者：Garey A. Fox ; Sri H. Pulijala ; George J. Sabbagh
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2007
• 出版时间：July 11, 2007
• 年：2007
• 卷：55
• 期：14
• 页码：5399 - 5407
• 全文大小：167K
• 年卷期：v.55,no.14(July 11, 2007)
• ISSN：1520-5118

文摘

This research investigated the impact of modeling atrazine, metolachlor, and isoxaflutole/metabolitetransport in artificially subsurface drained sites with temporally discrete rainfall data. Differences inconsidering rainfall distribution are unknown in regard to estimating agrochemical fluxes in thesubsurface. The Root Zone Water Quality Model (RZWQM) simulated pesticide fate and transport atthree subsurface drained sites: metolachlor/atrazine field experiment in Baton Rouge, LA (1987),and two isoxaflutole/metabolite field experiments in Allen County and Owen County, Indiana (2000).The modeling assumed linear, equilibrium sorption based on average reported physicochemical andenvironmental fate properties. Assumed rainfall intensity and duration influenced transport by runoffmore than transport by subsurface drainage. As the importance of macropore flow increased, thenecessity for using temporally discrete rainfall data became more critical. Long-term simulationsindicated no significant difference between average or upper percentile (i.e., <2% difference in percentloss as a function of mass applied) atrazine, metolachlor, or isoxaflutole/metabolite loss throughsubsurface drainage among the three different rainfall assumptions. It was necessary (i.e., within7% of predicted loss) to use hourly or average duration storm events as opposed to daily rainfalldata for total (i.e., runoff and subsurface drainage) pesticide loss over the long term.