The Studies Of Different Fertilization On Yield And Quality Of Brassica Juncea

Fertilizer application plays an important role in the formations of the yield and quality of Brassica juncea. In order to explore the optimum fertilization strategies and provide technical supports for high-yield, high-quality and high-efficient production of Brassica juncea, the effects of different fertilization techniques on the yield and quality of Brassica juncea were studied through the field experiments of nitrogen, phosphorus, potash and the trace fertilizer applications.Firstly, the effects of nitrogen fertilizer application on the yield, nitrate content, vitamin C content and other quality indices of Brassica juncea were studied by different rates of nitrogen fertilizer and ratios between organic nitrogen and inorganic nitrogen, so as to determine the optimum range of nitrogen application and the optimum ratio between organic nitrogen and inorganic nitrogen. The results showed that, if the nitrogen fertilizer range is around0-600kg N/hm2, the yield of Brassica juncea will exhibit a highly significant quadratic regression relationship with the increase of nitrogen fertilizer. With the increasing rate of nitrogen fertilizer, the yield was increased from42.8%to131.1%. However, when the rate of nitrogen fertilizer was greater than300kg N/hm2, the yield was increased not significant. In addition with the continuous increase of nitrogen fertilizer, the plant nitrate content was significantly raised. Moreover, when the rate of fertilizer was less than300kg N/hm, the plant nitrate content of Brassica juncea was577.4mg/kg which satisfies the secondary salinity standard However, if the rate of fertilizer was more than450kg N/hm2, the plant nitrate content of Brassica juncea was higher than the secondary salinity standard. Another finding in this research is that the contents of crude protein, soluble sugar, crude fiber, and total acid increased firstly and then decreased as the rates of nitrogen fertilizer were increased, among which the highest contents were at the treatments of N3,N1, N1, and N2respectively. While, the Vc content showed a gradual downward trend with no significant difference between N2and N3treatments. Meanwhile, on the basis of300kg/hm2nitrogen fertilizer, when the organic nitrogen/inorganic nitrogen ratio were applied as3:7, the contents of VC, crude protein and soluble sugar and the yield of of Brassica juncea were increased by1.4%,2.3%,26.5%and30.5%respectively in comparison with pure inorganic nitrogen. However, the nitrate content was decreased by3.3%. To sum up, by summarizing and integrating the impacts on the yield and quality from the nitrogen levels and the ratio of organic/inorganic nitrogen, the optimum nitrogen application of Brassica juncea was300-450kg/hm2with the organic/inorganic nitrogen ratio of3:7.Secondly, the impacts of phosphate and potash fertilizer application on the yield and quality of Brassica juncea were studied in this research to determine the optimum ranges of phosphate and potash application by different phosphate and potash fertilizer application experiments. The results indicated that the yield of Brassica juncea had no significant difference with different rates of phosphate and potash fertilizer when the rates of nitrogen fertilizer were same. By applying the phosphate fertilizer at the range of0-60kg N/hm2and the potash fertilizer at the range of0-100kg/hm2, increasing the rates of phosphate and potash fertilizers could effectively reduce the nitrate contents of Brassica juncea, among which the lowest contents were at60kg/hm with phosphate fertilizer and100kg/hm2with potash fertilizer. When the phosphate fertilizer ranges from0to90kg N/hm2, the Vc content present a downward trend with the increase of phosphate application, while the crude protein content showed an upward trend. In addition, the total soluble sugar decreased firstly and then increased as the increase of phosphate fertilizer, while the crude fiber content increased firstly and then decreased. Moreover, when the rate of phosphate fertilizer went down to60kg/hm, the total soluble sugar content was lowest, but the crude fiber content was highest at that moment. When the potash fertilizer ranged from0to150kg N/hm2, the Vc content increased firstly and then decreased with the increase of ph potash application, while the total soluble sugar content decreased firstly and then increased. When the rate of potash fertilizer went up to100kg/hm2, the total soluble sugar content was lowest and the Vc content was highest at that moment. Besides, when the rate of potash fertilizer was150kg/hm2, the crude protein content and the crude fiber content were all highest. To sum up, by summarizing and integrating the factors of yield, quality and safety, the optimal application quantity of phosphate fertilizer (P2O5) and potash fertilizer (K2O) were60kg/hm2and100kg/hm2respectively.Meanwhile, the results of trace fertilizers experiment indicated that the yields of Brassica juncea were increased by8.3%and1.5%respectively after spraying the zinc and molybdenum fertilizers. While the yeilds of Brassica juncea were reduced by43.4%and 41.1%respectively for foliage spray of boron and magnesium fertilizers. The crude protein content and vitamin C content were increased effectively by foliage spray of boron, zinc, magnesium and molybdenum fertilizers, with the decrease of crude fiber content of Brassica juncea. However, the nitrate content of Brassica juncea was decreased effectively by foliage spray of magnesium and molybdenum fertilizers. Therefore, the rational application of trace fertilizers plays an important role in the high-yield, high-quality and high-efficient production of Brassica juncea.