A SCREENING METHOD TO IDENTIFY THE PROBABILITIES OF PESTICIDE LEACHING

The research reported applied Monte Carlo simulation techniques to eva luate the probabilities of pesticide leaching beneath Oklahoma's winte r wheat, dry-land farming areas where monitoring data were either miss ing or incomplete. Random variables describing soil conditions and fix ed or management variables which identified pesticide and cropping pra ctice effects were utilized. Data were reported which showed that half of an annual unit pesticide application could be expected to leach pa st 178 cm of soil core in 3-5% of the occurrences. Graphs and a linear interpolation method are presented to extend the comparisons to other pesticides or to additional settings. It was found that pesticide sel ection rather than cropping practice was more effective in eliminating pesticide leaching.