SOIL-EROSION CONTRIBUTION TO PESTICIDE TRANSPORT BY FURROW IRRIGATION

Movement of pesticides from fields in runoff water and on sediment can degrade surface waters. Research typically found that because of the high water-to-sediment ratio, the total amount of pesticide in water greatly exceeded that associated with sediment. These observations suggested that erosion control would have little effect in reducing pesticide transport from the field. A laboratory study was conducted in a miniature furrow system to determine whether reduction in erosion would contribute to a reduction of napropamide [2-alpha-naphthoxy)-N,N-diethylpropionamide] transport. Variable erosion was created by polymer addition to the water combined with using variable water flow rates, Bromide was used as a nonsorbing independent tracer. Napropamide transport was linearly related to the amount of fine soil particulates eroded, Bromide transport was independent of the amount of erosion, and the percentage of the applied Br- removed in the runoff was less than that of napropamide. The results indicate that reduction in erosion of fine particulates will result in reduced transport of sorbed pesticides from the field.