The Research Of Seaweed Fertilizer And Other Factors To Reduce Nitrate Content In Vegetables

Vegetable nitrate pollution is currently facing a grim situation, it is a serious threat to human health, and has attracted more and more attention of consumers and researchers. Many factors which influence vegetable growth will affect the nitrate content, such as nitrogen, fertilization period, light, temperature, moisture and other. At present, the measures to control the nitrate content in vegetables mainly include the control of fertilizing, improve the environment, food processing before cooking and so on. In our study, the most important purpose is to reduce the nitrate content of vegetables, to acquire a foliage fertilizer formulation which can reduce the nitrate content as effectively as possible on the premise of vegetable yield, and to provide certain theory and experiment foundation for the Agricultural sustainable development.1. Selecting model plant and founding high nitrogen modelFirstly, we selected a kind of plant which nitrate content was high as model plant. We detect ed several market vegetables finding that the nitrate content in leafy vegetables exceed the standard. The crowndaisy chrysanthemum nitrate content was higer than that of the other vegetables. Then we cultured crowndaisy chrysanthemum, pakchoi and rape in the same conditions. The result showed that the nitrate content of crowndaisy chrysanthemum was much higer than pakchoi and rape. At the time of harvest, the nitrate content of crowndaisy chrysanthemum was3.5times of rape and5times of pakchoi. It also showed that the nitrate reductase activity in the crowndaisy chrysanthemum was far lower than pakchoi and rape. Crowndaisy chrysanthemum tended to accumulate nitrate. Therefore we selected crowndaisy chrysanthemum as a model plant. Then we established high nitrogen model. We fertilized different qulity ureal to crowndaisy chrysanthemum to select a suitable concentration of ureal. In the concentration of ureal the nitrate concent was highest and the vegetable yield is not lower than then other teams. The result showed that the suitable ureal concentration was4g of every pot (The length of the pot was34cm. The width of the pot was25cm. The height of the pot was10cm).2. The influence of Seaweed fertilizer to nitrate content in crowndaisy chrysanthemumIn recent years, seaweed fertilizer has gradually attracted people’s attention. We used kelp root powder and kelp polysaccharide which was extracted from kelp root powder as objects in our study. The kelp root powder was added to the soil. The kelp polysaccharide was sprayed on the leaves. The result showed that both kelp root powder and kelp polysaccharide could reduce the nitrate content in crowndaisy chrysanthemum. The kelp polysaccharide’s effect was more obvious than the kelp root powder. When the kelp root powder was added80g every pot, the nitrate content was lowest and the yield was high. When the kelp polysaccharide’s concentration was10mg/ml, the nitrate content was lowest and the yield was high. In order to further realize the kelp polysaccharide, we studide the physicochemical property of kelp polysaccharide. The result showed that the surgar content of kelp polysaccharide was64.4%and the realative molecular mass include were165508Da,9110Da and2176Da.3. The influence of other factors to nitrate content in crowndaisy chrysanthemumWe also studied other factors including the phosphorus and kalium, molybdenum, manganese and dicyandiamide(DCD)effect on the content of nitrate in the crowndaisy chrysanthemum. All the experiments were caarried out in high nitrogen model. The result showed that all of the four factors can reduce the nitrate content in crowndaisy chrysanthemum. The optimical concentration of each factor were:0.8%monopotassium phosphate,300mg/L ammomium molybdate,0.08%manganese sulfate,DCD10%.4. The influence of synthesized factors to nitrate content in crowndaisy chrysanthemum and the experiment in fieldAfter the study of each factor, we synthesized all the factors together. The result showed that synthesized factors effect was more obvious than single factor. Then we reduced the ureal quality and found that when the ureal was2g every pot, the nitrate in crowndaisy chrysanthemum was lower but the yield was not less than the hign nitrogen model. So we find an effective method to reduce the nitrate content in crowndaisy chrysanthemum. It is as follows:2g ureal every pot,80g kelp root powder,10mg/ml kelp polysaccharide,0.8%monopotassium phosphate,300mg/L ammomium molybdate,0.08%manganese sulfate, nitrification inbitor DCD10%. This recipe worked well in field and it also has a good effect on rape and pakchoi.