Effect Different Nitrogen Application On Yield And Quality Of Chinese Cabbage In Sichuan Province

With the rapid development of China’s economy, people’s living standard has been greatly improved and the quality of their life has undergone earth-shaking changes. Therefore, people has more and more high requirement of the quality of the vegetables, in other words, their requirement of vegetable has experienced a qualitative leap from quantity in the past to the quality at present. Compared with growing the food crops, the economic returns of growing the vegetables are much better; consequently, farmers invest a large amount of fertilizer at all costs, especially the nitrogen fertilizer, to improve the output of vegetables. The lack of scientific guidance, the backward modes of production, the weak standardization production as well as the commonly unreasonable fertilization result in a waste of fertilizer resources, environmental pollution. More seriously, these unreasonable fertilization phenomenons will lead to a series problems of reduction in vegetable quality such as nitric acid overweight, which will seriously damage the human health.This paper discusses that farmers in Sichuan Province have no clear fertilizer rate and definite fertilization structure in the process of planting cabbage. By means of peasant household sample investigation method, the paper has carried out an investigation of the basic situation of cabbage planting in Sichuan Province, problems of fertilization as well as problems encountered during the cabbage planting to grasp the best fertilizer variety, the best proportion between the organic nitrogenous fertilizer and the inorganic nitrogen fertilizer, the fertilizing time and the fertilizer rate of nitrogen as well as the fertilization methods and other issues. The fertilizer field experiments are expanded in the five typical vegetable production areas in Sichuan province to provide fertilizer guidance and compound formulations for cabbage planting in Sichuan Province. The main findings are as follows:(1)The cost of fertilizer and labor are the main planting inputs for the cabbage farmers in Sichuan province,3353-.1575 Yuan per hectare, accounting for 45% of the total. The farmers fertilize unreasonably, in details, excessive amounts of nitrogen fertilizer, phosphorus fertilization comes the second and potassium fertilizer is less. As to fertilization methods, the base fertilizer is based mainly on holeextruding, accounting for 65.4%, hole application is second, accounting for 28.3%, other fertilization methods accounting for 6.7%. The cabbage fertilizer mainly picks up the broadcasting application, accounting for 42.1%, hole application is complementary, accounting for 22.1%, other methods accounting for 35.8%. There are several factors which influence the production of cabbage, especially the insufficient soil fertility, extensive management, natural disasters, etc. Farmers’demands for national policies are mainly the science and technology support, the reduction of the farming material inputs, the government’s increase in its procurement prices for farm products, as well as provide sales channels and so on.(2) The nutrient absorption rules of cabbage performance in Sichuan shows that the trend of nitrogen absorption decreases after its first increase and reaches the maximum demand for nitrogen fertilizers from the rosette stage to be the early cabbage. The absorption of phosphorus is less than nitrogen, but with the continuous development of cabbage, it shows an increasing trend. The absorption of potassium is the most among the three nutrient elements, showing a trend of reducing before increasing and achieve maximum from rosette stage to early cabbage.(3) In the experiment, within the range of the total amount of nitrogen (0-531kg/hm2), the output of cabbage will increase as the nitrogen fertilizer rate rises. The fact is that the nitrate content of cabbage will increase with the increase of nitrogen, while the vitamin C of the cabbage reduces.(4) From the experiment of fertilizer between organic nitrogen and inorganic nitrogen, a conclusion can be achieved that the production of cabbage fertilized with organic nitrogen is lower than those fertilized with both organic fertilizer and inorganic nitrogen, accordingly, the production of cabbage fertilized with inorganic nitrogen is lower than those fertilized with both organic fertilizer and inorganic nitrogen. The nitrate content of the cabbage only fertilized with organic nitrogen is significantly higher than that fertilized with both organic nitrogen and inorganic nitrogen; besides, the vitamin C content in cabbage fertilized with both organic nitrogen and inorganic nitrogen is significantly higher than that totally fertilized with inorganic nitrogen. That also explains fertilization with both organic nitrogen and inorganic nitrogen not only increases the production of cabbage, but improves the quality of cabbage. The proportion of fertilizer between organic nitrogen and inorganic nitrogen within the scope of the 1:2-1:1 proportion is the best.(5)From these experiments mentioned above, we can see that the first batch of cabbage’s output increases with the rise of the nitrogen fertilizer rate. However,the second batch of cabbage’s output has decreased for the overuse of nitrogen fertilizer. Compared with cabbages with the N2 as fertilization, those cabbage fertilized by N3 has a relatively low output.All these experiments suggest that if we use a large amount of nitrogen fertilizer for a long time, the growth of the cabbage will be inhabited, which will lead to an unsatisfactory output.