Study On The Technology Of Applying Silicon Fertilizer To Reduce Nitrogen In Greenhouse Vegetables

The silicon element is one of the beneficial elements for crop growth.It is the only element that can be absorbed by plants in large quantities without producing toxicity.It can promote crop growth,improve crop yield and quality of agricultural products,and improve crop resistance to environmental stress.Vegetables are an important part of human daily diet,China is a big consumer of vegetables.Greenhouse vegetables is an important way of planting,the development of facilities of vegetables achieving better economic benefits,is an important topic worth exploring.In this study,cherry tomatoes,cabbage and fruit cucumbers were selected to study the effects of silicon fertilizer application after nitrogen reduction on their yield,quality and nitrogen fertilizer use efficiency,and to explore the optimal amount of nitrogen application and the ratio of nitrogen to silicon,so as to provide new possibilities and theoretical basis for fertilizer reduction technology of f vegetables in facilities.The main conclusions are as follows:（1）Cherry tomato,cabbage and fruit cucumber were studied,and Si-Ca-K-Mg fertilizer was used as experimental fertilizer.Four groups of treatments were designed in solar greenhouse:control group,nitrogen reduction group,silicon application group and nitrogen reduction silicon application group.Under the conditions of this experiment,it was found that the application of Si-Ca-K-Mg fertilizer after nitrogen reduction increased the yield of cherry tomato,heading cabbage and fruit cucumber by 27.39%,22.94%and 24.60%,respectively,and the partial productivity of nitrogen fertilizer was 29.53%,13.27%and 21.60%,respectively.Nitrate content decreased significantly,33.56%,31.04%and 42.52%,respectively.To sum up,the application of Si-Ca-K-Mg fertilizer after reduced nitrogen fertilizer could increase the yield and nitrogen use efficiency of cherry tomato,cabbage and fruit cucumber,and significantly reduce the nitrate content in the edible part.Additionally,it can keep the quality index consistent with the normal level of nitrogen application.（2）Two varieties of fruit cucumber were studied,and micro-nano silicon fertilizer was used as experimental fertilizer.Four groups of treatments were designed in solar greenhouse:control group,nitrogen reduction group,silicon application group and nitrogen reduction silicon application group.Under the conditions of this experiment,it was found that with the application of micro-nano silicon fertilizer after nitrogen reduction,the yield of fruit-raising cucumber increased by 27.42%,the partial productivity of nitrogen fertilizer increased by 34.07%at most,and nitrate decreased by 50.03%at most.Plant height,stem diameter and leaf area increased significantly before growth,and other growth indexes also increased in varying degrees.To sum up,the application of micro-nano silicon fertilizer after nitrogen reduction could increase the stem diameter,plant height,leaf area,yield and nitrogen use efficiency of cucumber in the early and middle stages of nitrogen reduction,and significantly reduce the content of nitrate in fruit-type cucumber fruit.and can make the quality index consistent with the normal level of nitrogen application.（3）Taking the fruit cucumber as the research object and micro-nano silicon as the experimental fertilizer,the two-factor D-optimal pot experiment was designed in the solar greenhouse,and six groups of experiments were set up according to the coding level.The regression model of nitrogen-silicon interaction effect of fruit cucumber was established in the experiment.After the analysis of the model,it was found that nitrogen was the main factor of the model.When the application rate of N and Si O₂ was higher than that of 752 kg/hm² and 119kg/hm²,the yield per plant produced negative reward.When the application rate of N and Si O₂was higher than that of 741 kg/hm² and 121 kg/hm²,the comprehensive score of quality produced negative reward.The nitrogen and silicon fertilizer application rates for high yield of fruit cucumber were 722.66 kg/hm² and 113.93 kg/hm²,respectively.The best nitrogen and silicon fertilizer rates for fruit-type cucumber were 725.03 kg/hm² and 117.29 kg/hm²,respectively.The ratio of nitrogen to silicon is 1:0.14～1:0.18 in the scheme of N:701.92～748.67 kg/hm²,Si O₂:110.02～120.78 kg/hm²,for the highest yield and high quality.