Effects Of Nitrogen Fertilizer Regulation On Vegetables Nitrogen Utilization And Soil Nitrate-N Residue

In recent years, with the increase in the amount of nitrogen fertilizer,environmental pollution is increasingly worsening. In vegetable production, excessive inputs of nitrogen results in a large number of nitrogen accumulated in the soil, leading to soil nutrient imbalances: on the one hand, it lead to decline in the quality of vegetable, high nitrate content in vegetables and endanger human health; On the other hand, nitrate in the water through runoff and leaching into the surface and groundwater sources, as a major source of nitrate, indirectly harm to human health.Considering the accumulation of nitrate in vegetables and soil nitrate leaching into environment issues, to take the combination of methods of field in situ monitoring the nitrogen leaching in open vegetables field and nitrogen physiological and biochemical regulation and control indoor tests, the Migration and transformation laws of nitrogen in the soil - plant - water system under conditions of growing Common vegetables in Beijing, and then the adoption of different physiological, biochemical and fertilization control measures regulates the release of soil nitrogen, and promote nutrient reasonably cycling and efficient use, to achieve the reducing nitrogen fertilizer inputs and soil nitrogen levels, reducing nitrate accumulation in vegetables, the goal of reducing the risk of environmental pollution. Specific research results are as follows:The leaching in situ monitoring test under the conditions of different nitrogen fertilization was carried out. The results showed that chemical nitrogen fertilizer, phosphate fertilizer, potash fertilizer consumption were 120kgN/hm~2, 90kg P2O5/hm~2, 135kgK2O/hm~2, the amount of organic fertilizer was 7500kg/hm~2, there was the better economic benefits of planting celeric, and at the same time, it can significantly reduce the nitrate content of vegetables. in a relatively short period in planting celeric and under normal conditions, soil nitrogen can be leached to 90cm, the leaching of nitrate content in water at the depth of 90cm ranges from 3.07-8.87mg/kg, the changes in the rate of total nitrogen leaching is 0.06 -19.94 kg/hm~2. it is suggested that Applied nitrogen fertilizer in soil has the greater risk of leaching into the groundwater pollution in the Chao soil with high fertility.R & D in the early stage, R & D products-control pilot study under the conditions of application of nitrogen fertilizer by half was carried out, results showed that the regulation and control agent measures can maintain the stable yield of rape, it can be significantly reduced nitrate content, but also is a significant improvement in Vc content, soluble sugar content and other quality indicators. It is suggested that appropriate application of control technology ensure that maintain crop yield stability in low-fertility soil and produce low nitrate content and high-quality indicators of vegetables, to reduce the nitrate residue accumulation in the soil, contribute significantly reduce the risk of the loss of nitrogen in vegetable fields to the environment.