Effects Of Different Ratios Of Nitrogen Forms And Coated Controlled-release Fertilizers On Yield And Quality Of Several Vegetables

Under the same amount of nitrogen application, the experiment of different proportions of nitrogen forms including nitrate, ammonium and amide nitrogen in hydroponic and soilless culture cultivation were conducted, to explore the effects of different ratios of three nitrogen forms on yield and quality of several vegetables, and to explore the use of coated controlled release fertilizers(CRFs) instead of the traditional nutrient solution, which simplifies the configuration of nutrient solution cultivation and the application processes. The experiments of soilless culture of several vegetables cultivation proved that the coated CRFs should be encouraged as partial or all substitution of major elements in traditionnal nutrient solution. The yield and quality of vegetables were not affected by the appliacation of coated CRFs compared with the traditional nutrient solution. Meanwhile, some parts of the program not only increased the yield, but also improved the safety of edible fruit crop. The main results are as follows:1. Based on the leafy vegetables formulation of South China Agricultural University(B), the hydroponic spinach experienment was conductedby adjusting different ratio s of the ammonium, nitrate and amide nitrogen, with the same amount of nitrogen. The results showed that when the ratios were 55%:25%:20% and 45%:25%:30% of the three nitrogen forms, the biomass yield and total nitrogen, soluble protein and Vc content of the spinach plant were highest, and also the spinach quality was best. With the increase of ammonium nitrogen, the iron, manganese, zinc absorption of spinach was inhibited in a certain extent, However, the absorption of copper was pronoted as the presence of the amide nitrogen, in a certain extent, and the absorption of trace elements by spinach was improved by combined application of three nitrogen forms. Therefore, the combined application of three nitrogen forms and amide nitrogen was not less than 20%, the hydroponic spinachcould achieve optimal results, and could be extended demonstration in agricultural production.2. The soilless culture experiment of brassia based on the formulation of hydroponic spinach was conducted, and leafy vegetables formulation of South C hina Agricultural University(B) was as control. The results showed that the yield was highest in the treatments which contain 30% amide nitrogen in the nutrient solution, and the yield was significantly increased by 32.2-33.3% compared with the control treatment. The content of nitrate nitrogen was reduced by 22.3% in the treatment which ratios of three nitrogen forms was 45%: 25%:30%, compared with the traditional nutrient solution nitrate treatment However, there was no significant difference in Vc content and plant mineral elements content. Therefore, the above ratio of nutrient solution is more beneficial to obtain high yield and substrate cultivation of high quality brassia.3. The soilless culture experiments of tomato based on the ratios of nitrogen forms test matrix were conducted, and the Japanese Yamazaki tomato nutrient solution as a control. The results showed that the yield was significantly increased by 21.7%-55.2% in the treatment which containing ammonium, nitrate and amide nitrogen, compared with the control treatment; the yield was significantly increased by 21.7%-55.2% compared with single nitrogen form treatment; the yields were also significant increased by 19.5%-35.9% and 30.1%-49.0%, compared with the treatment which containing 25% ammonium and containing 10% or 30% of the amide nitrogen. The content of chlorophyll and photosynthetic rate showed no significant differences among all treatments; the tomato fruit sugar acid ratio was effectively increased, while fruit Vc content was decreased with the increase of ammonium nitrogen proportion. The amide nitrogen can significantly reduce the nitrate content of tomato fruit; when the three nitrogen forms exist, the quality of tomato fruit was ensured, the nitrate content of fruit was reduced and its edible security was increased. Therefore, the nutrient solution containing proper ratios of ammonium, nitrate and amide nitrogen can effectively improve the yield and quality of tomato cultivation matrix, also suitable for application on agricultural production.4. Japanese Yamazaki pepper nutrient solution as a control, matrix pepper cultivation trials by using different ratios of N forms under the same N amount application was conducted. The results showed that the coordination application of three nitrogen forms significant increase the yield by 60.0%, and the nitrate content in the pepper fruit was significantly reduced by 30.3% compared with the control treatment. However, the Vc and mineral nutrient contents in pepper fruits showed no significant difference. Therefore, the nutrient solution containing proper ratios of ammonium, nitrate and amide nitrogen forms in matrix can effectively improve the yield of pepper cultivation and food safety.5. Japanese Yamazaki pepper nutrient solution as a control, and coated controlled release urea(CRU), coated controlled release diammonium phosphate(C RP) and coated controlled release potassium chloride(CRK) substrate for the cultivation of pepper nutritional substances. The results show that regardless of a single one of coated nutrients with nutrient solution application, or controlled release of all three nutrients, no significant changes were found in fruit yield compared with traditional nutrient solution, and the nitrate content was significantly decreased by 30.0%-33.8% by the application of coated CRU and C RP, CRK treatments compared with the control treatment.. Therefore coated controlled release fertilizer to replace some or all the major element in the nutrient solution is feasible, the production is guaranteed and the food security of pepper fruit was improved, can promote the practical application of agricultural production.6. Japan Yamazaki tomato nutrient solution as a control, the effects of nitrogen in traditional nutrient solution replaced by CRU on yield and quality in substrate culture tomato was studied. The results showed that yield of the same amount nitrogen using C RU with P, K solution was not significantly different compared with traditional nutrient solution, but the yield of CRU with P, K solution was increased significantly by 22% compared with the same amount nitrogen using urea. The yield of the same amount nitrogen using CRU was significantly increased by 28.1% compared with the same amount nitrogen using urea when the N, P, K in solution was instead by fertilizer, and the yield of 1.5 times amount nitrogen using coated CRU was not significantly different compared with NS. The sugar-acid ratio of coated CRU with P, K solution was increased by 29.6% compared with the same amount nitrogen using urea, and the fruit NO3--N content of that was significantly reduced by 50% compared with traditional nutrient solution. Therefore, the yield of coated C RU was significantly increased and the quality was significantly improved compared with the water soluble nitrogen fertilizer. The production and quality could be guaranteed by using the controlled release nitrogen fertilizer with N, P solution, not only the formula and the constitute of traditional nutrient solution was simplified, but also the fruit NO 3--N content was reduced at the same time, which improved the edible safety of tomato fruit. N itrogen in traditional nutrient solution replaced by C RU could be extensively applied in substrate culture production.The study found that both leaf and solanaceous vegetables, combined application of the three kinds of ammonium, nitrate and amide nitrogen could achieve a better yield and quality. Besides, a part of nitrate nitrogen was replaced by the ammonium or amide nitrogen, so the nitrate content of vegetables was reduced, improve it’s the safety of edible was improved, the proportion of the nutrient solution worthy of promotion and application in agricultural production.The coated CRF with a more convenient, more science, more accurate advantage, will solve many bottlenecks of the application of nutrient solution which was limited by many factors. The results of this study demonstrated that whether a single coated CRU or CRP, CRK cooperated application, yield and quality are guaranteed, and also the nitrate content of the fruits was significantly reduced. Under the background of promoting agricultural facilities in China, the application of CRFs has broad prospects.