Agricultural best management practices for water pollution control: current issues

From the first awareness of agricultural sources of water pollution in the US in the 1960s, we finally see in the 1990s a commitment at the national level for agricultural non-point source (NPS) pollution control. This has been occasioned by a growing awareness that, with point sources of some pollutants largely controlled by waste-water treatment, greater attention must be paid to NPS pollution control, a large percentage of which is agricultural. The 1985 Farm Security Act mandated several national erosion control programs that will have some impact on water quality, and there is opportunity to supplement these programs with best management practices (BMPs) specifically designed to address agricultural water pollutants, primarily nitrate, phosphorus and modern pesticides. This paper discusses fundamental processes affecting transport of agricultural pollutants in surface and ground water and suggests how knowledge of these processes can be used to evaluate existing agricultural NPS BMPs and to develop supplemental practices.