The Studies On Regulation Of Nitrogen And Vegetable Quality

In recently, the cultivate area of Chinese vegetable has increased rapidly, it has reached 13,347,000hm2, total yield has reached 405,140 kt in 1999. It is serious that nitrogen input rates are unreasonable high in vegetable production in China, which may increase nitrate accumulation in vegetable and ground water contamination. In result, these will be harmful to people's health.The objectives of this paper were to study nitrogen supply and nitrate accumulation in vegetable. The result are as follows:Vegetable growth and nitrogen contention was strongly affected by nitrogen supply in pot culture experiments and field experiments. The economically optimal usage of nitrogen in cabbage is 430.0kg/hm2. However, it was 226.4 in rape. For further counting, if the highest N fertilizer was lower than 92.5 kg/hm2, nitrate contention in rape couldn't pass 1000.0 mg/kg.Nitrogen is the most restrictive element in vegetable growth, the second is Phosphorus. The effect of Potassium is little to biomass in field experiment. The experiment of confined element in soil showed that, using N, P, K, Zn, B fertilizer could increase the top yield in cabbage production. The capability to offer nutrition in soil was related to N, P, K. In addition, adding nitrogen fertilizer couldn't affect tomato's yield.Compared with inorganic nitrogen fertilizer, organic fertilizer can make vegetable to grow well and obviously improve its qualities. There was no significant difference between adding fertilizer treat and no adding fertilizer treat. But nitrate concentration in vegetables was significantly decreased, about 45.7%~49.8%.If adding more nitrogen fertilizer, the yield had no significantly changed, however, nitrate contention with organic fertilizer was reducing between 9.0%~~45.6%.