[Present status, mechanisms, and control techniques of nitrogen and phosphorus non-point source pollution from vegetable fields].

Chemical fertilizers are often excessively applied on vegetable fields to pursue higher yields. In some areas, the fertilization rates are several times of those needed by vegetables. Nitrogen and phosphorous are obviously accumulated in the vegetable soils, resulting in the malnutrition, excessive nitrate, and poor quality of vegetables. Furthermore, a series of environmental problems, e.g., deterioration of vegetable soil physical and chemical properties, nitrate pollution of groundwater, and eutrophication of surface water, are produced. This paper reviewed the present status of nitrogen and phosphorous non-point source pollution from vegetable soils (accumulation characteristics of nitrogen and phosphorous and their pollution risks to water environment and vegetables), pollution mechanisms (sources, transformation, and losses of nitrogen and phosphorous), and control techniques (fertilization, chemical addition, nitrogen catch crop cultivation, optimal planting system, spatial matching of source and sink landscapes, and grass buffer strip technology), aimed to supply references for the further study on the nitrogen and phosphorous non-point source pollution from vegetable fields.