Pesticides enter soil either by direct application, drift, or by washing off plant surfaces during rainfall or irrigation. Soil erosion and runoff are some of the major means by which pesticides enter streams, ponds, or lakes. The Water Quality Project at Kentucky State University (KSU) is evaluating best management practices for the growing of vegetable crops on highly erodible land (10% slope). A research study was conducted at KSU Research Farm to determine the influence of landscape features and soil amendments on runoff and infiltration water quality. Three soil treatments on a Lowell silty loam soil (pH 6.7, 2% organic matter) were used to reduce soil erosion and surface water runoff. Living turf mulch (tall fescue) 30 cm wide was planted to create multiple barriers to runoff between every cropping row, turf every other row, and no mulch treatments (rototilled bare soil) were compared. Pepper and tomato transplants, each in row, were spaced every 0.37 m with 10 plants per row. Plots contained 10 rows oriented on the contour of the slope, and each plot contained one of the three soil management practices. Endosulfan (Thiodan 3 EC) was used as foliar spray on tomato and pepper at the rate of 0.61 kg AI/ha. The impact of soil mulches on movement of endosulfan was measured under field conditions. Endosulfan infiltration through the vadose zone was monitored using pressure-vacuum lysimeters (n=27). A tipping bucket metering apparatus was used to collect runoff water. Studies were also undertaken to determine the magnitude and dissipation of endosulfan isomers (alpha- and beta-endosulfan) and the main metabolite, endosulfan sulfate.
Residues of carbofuran (Furadan) and its non-conjugated toxic metabolites; 3-hydroxy carbofuran and 3-keto carbofuran and the water soluble conjugated form of carbofuran; 3-hydroxy carbofuran glycoside were analysed individually in bean plants. Acephate (Orthene) deacetylation to methamidophos (Monitor) was monitored in tomato, pepper and cucumber. Chemical control of agricultural pests emphasized on the protection of aerial plant parts of vegetable crops against leaf feeding insects is a major goal.