Study About The Effects Of Fertilizing Skills On The Control Of Nitrate Accumulation In The Flowering Chinese Cabbage

In order to control the nitrate accumulation in vegetable effectively, using the bagasse in greenhouse, studies were carried on about the effects of different N application, different N fertilization forms, urea arranged different percentages of ammonium chloride with equal N, and N-P-K-C1 compound treatment with optimal compound design"416-B" on the yield and nitrate content of the flowering Chinese cabbage. So the optimal nutrient formulation of N-P-K-C1 compound treatment was found. The results are as follows:1. With the increase of N (Urea) application, economical yield of the flowering Chinese cabbage enhances too. But the extent of increasing in economical yield become smaller when the N (Urea) application is increased. The content of total N and nitrate follow the raise of N (Urea)applied. Increasing lower level N application ( 15.5g-treatment~') can highen the NRA. But, increasing higher level N application ( 15.5g-treatment~') can change the NRA little.2. Among the three treatments with equal N application, the treatments of [60%(NH4)2SO4+40%NH4C1] and NHtCl would reduce nitrate content in economical yield part of the same vegetable obviously compared to the treatment of Urea. But at the same time, the economical yield drop too likely because of the redundant NH4+ or Cl content. The total N, P content of the flowering Chinese cabbage are no obvious differences under all treatments of different N fertilization forms, it shows that the treatments of different N fertilization forms can't bring about distinct changes about the content of total N, P.3. The use of Urea- NH4Cl compound treatment will read to evident cut down of nitrate content in the flowering Chinese cabbage, the bigger the percentige of NH4C1 is used, the bigger the extent of drop about nitrate content become. The reason lies in the Cl. It would reduce the number of nitrous acid bacterium and then hold back the nitrification in bagasse obviously. The yields of the flowering Chinese cabbage are no obvious differences between the treatments of [60%Urea +40% NH4C1] and single urea. The treatment of [20%Urea +80% NH4Cl] could not result in evident change about the yield during the early lifetime. But on the harvest day, the yield cut down evidently, the extent of drop is 5.6%compared to the treatment of urea.4. The reasonable use of N, P, K, Cl coupund treatment can make the economical yield become bigger while the nitrate content in economical yield part become smaller. The increase of N, P, K applied can enhance the economical yield, but the increase of Cl application can reduce it; Besides, the use of N can increases the nitrate content in economical yield part, but the use of P, K, Cl can make the nitrate content in economical yield part become smaller. For the consideration of the yield, nitrate content and Vc content in economical yield part, The optimal nutrient formulation has been drafted, the coded date (true date) of N, P, K, Cl are listed separately: 0.49 (18.58 g-treatment-1) , 1.49 (8.95 g treatment-1) , 1.16 (22.11 g-treatment-1 ), 0.23 (33.31 g-treatment-1) . At the same time, the economical yield is 707.12 g-treatment-1, the nitrate content in economical yield part is 612.01 mg-kg-1FW, the Vc content is 170.42 mg-kg-1FW.