GLEAMS COMPUTER MODEL PESTICIDE PREDICTION IN TWO SOILS
Recent concerns about the presence of pesticide residues in surface and groundwater have resulted in a need for computer model simulation to assess the impacts of agrichemicals on potential surface and groundwater contamination. GLEAMS (Groundwater Loading Effects of Agricultural Management Systems), is a mathematical model developed for fieldsize areas to evaluate the effects of agricultural management systems on the movement of agrichemicals. It can be used as a tool to evaluate the effects of different tillage systems on pesticide, and nutrient losses. Agriculture is being increasingly criticized for the deterioration of surface and subsurface water resources all over the world. In the Balochistan province of Pakistan, almost all the urban and rural population depend on groundwater resources for drinking water, irrigation, and the water for livestock use. The objective of this study was to simulate pesticide (Metolachlor) losses from conventional tillage and no-till systems using the GLEAMS pesticide submodel. The pesticide submodel simulated results showed that the runoff losses of Metolachlor from convectional tillage were 94%, and by sediment, the losses were 92% higher than that for the no-till system. However, the percolation losses of Metolachlor were 61%, and the total Metolachlor losses were 39% higher from no-till system as compared to conventional tillage system. The total Metolachlor losses were higher for no-till system because 91 to 99% of the annual total no-till losses were by percolation as compared to 41 to 90% for conventional tillage.