Study On Nitrogen Fate And Balance In Vegetable Field Under Greenhouse

The Protected vegetable fields have some characteristics of large quantity of fertilizer, the high strength of land use, The effect on balanced supply and utilization of nitrogen fertilizer in different fertilization patterns by condition of long-term continuous cultivation. In order to clarify the effect of different fertilizer application to, different fertilization methods, the study aim to three plant of Cauliflower in Beijing fangshan,research the fate of nitrogen, yield and quality of vegetable through planting three crops (Cauliflower) experiment by designing signal application of organic fertilizer, reduce nitrogen fertilization, slow-release nitrogen fertilizer, straw and other agricultural measures.1. In the nitrogen reduction30%, the vegetable production has remained stable, but there is an obvious effect in reducing nitrate accumulated and nitrogen losses in soil, The production of reducing nitrogen fertilizer is no different compare with conventional fertilization; at the same time, the efficiency of nitrogen use of reduce nitrogen fertilization of Cauliflower is higher3%, the nitrate content reduced47.4mg.kg-1compare with conventional fertilization, Vc tend to high; The research results from three stubble Cauliflower show that N loss rate of reduction nitrogen fertilization reduced11.3%than conventional fertilization.2. Using straw return could in reducing nitrate accumulated and nitrogen losses in soil. The yield of Cauliflower of conventional+straw (7500kg.hm-2) are no different compare with conventional fertilization. The nitrogen use rate of conventional+straw tend to high, and decrease the nitrate content of Cauliflower but increase Vc.The research results from three Cauliflower show that nitrogen accumulation in soil (0-60cm) of Conventional+straw less489.6kg.hm-2than Conventional fertilization, loss rate of fertilizer nitrogen reduced above27.5%compared with the Conventional fertilization.3. Slow control fertilizer in condition of nitrogen reduction about5%and64%,and field up to12.5%. At the same time, decreasing the nitrate content of Cauliflower increasing Vc.The overall accumulation of nitrate nitrogen of Controlled-release fertilizer1and2in soil (0-60cm) reduced304.5kg.hm-2and577.2kg.hm-2than Conventional fertilization. To sum up, reduce nitrogen application, planted fallow crop, increasing straw application, using controlled release fertilizer resin coated urea fertilization could maintain level of crop production, could improve use efficiency of nitrogen, Less nitrogen fertilizer could reduce the accumulation of nitrate nitrogen in soil, using straw could improve quality of vegetable, using controlled release fertilizer2could reducing the loss of nitrogen fertilizer in soil.