Study On Balanced Fertilization On Rice To Control And Prevent Non-point Source Pollution In Longxi River Basin Of Ya'an

In this paper,using "3414" optimal design of quadratic regression test program in Longxi River basin of Ya'an,a field experiment was conducted to study the effect of nitrogen,phosphorus,potash fertilizer on dynamic tillering of rice,plant height,yield,yield components,nutritional quality,nitrogen,phosphorus,potassium uptake and utilization,the changes of soil nutrients and the relationship between yield and the highest tiller number,plant height,yield components,protein content,nutrient content of rice organ,in order to explore one set of balance fertilization for high yield and high quality models to control and prevent agriculture non-point source pollution. The results show that:Increasing nitrogenous fertilizers applying amount can significantly increase the quantity of rice tillers,make population size expand rapidly,also accompanied by increasing plant height. At a certain scope of phosphorus,the number of tiller increase with the increasing of phosphate fertilizer consumption.However,excessive application of nitrogen,phosphorus and potassium fertilizer have led to declining in the number of tillers. There was extremely significant quadratic regression relationship between the highest tiller number and the rice yield. There was significant quadratic regression relationship between plant height and rice yield.Among the 14 treatments,the highest rice yield treatment is 7th( N₂P₃K₂).Compared with the non-fertilization treatment,this treatment increased yield by 32.04%.It is the the best combination of fertilize which can increase rice yield under the experimental conditions. Application of nitrogen,phosphorus and potassium fertilizer can increase the rice yield. The level of application nitrogen is a primary factor that affected the rice yield,followed by potassium,phosphorus is the smallest factor. Calculating the code value of fertilization program and the results of yield,I set up the regression model between the amount of nitrogen(x₁),phosphorus(x₂),potassium(x₃)fertilizer and yield:y = 4351.93+ 10.90887x₁ - 3.91039x₂ + 6.711812x₃ - 0.02022x₁² + 0.003387x₂² - 0.01909x₃² + 0.008194x₁x₂ - 0.02628x₁x₃+0.010788x₂x₃. In order to obtain rice yield more than 5 600 kg/hm² ,the suitable fertilization program is as follows:pure nitrogenous 259.18～265.82 kg /hm²,pure phosphorus 165.13～170.87 kg/hm²,pure potassium 43.12～46.88 kg/hm². The yield component which was impact mostly by nitrogen is the 1000-grain weight,followed by grain number per panicle. The grain number per panicle affected most significantly by phosphorus. The yield component which were impact mostly by potassium were effective panicle and filled grain rate. There was extremely significant quadratic regression relationship between the effective panicle and yield. There was extremely significant quadratic regression relationship between the 1000-grain weight and yield.Among the 14 treatments,the treatment whose protein content of rice is highest is 11th(N₃P₂K₂).Nitrogen is conducive to improve rice protein content. Increasing phosphate and potash applying amount,protein content increased at first and then declined. The relationship between protein content of rice and yield is highly significant quadratic function. The Fe content of 6th treatment was the highest. The Cu content of 1th treatment was the highest. The content of Mn,Zn,Ca,Mg reached the highest level at 5th treatment. The mean content of the six mineral elements in rice was Mg> Ca> Zn> Mn> Fe> Cu. Variant coefficient of Fe content was the biggest,the second was Cu and the variant coefficient of Mg content was.the lowest of rice among different treatments. With increasing application rate of N fertilizer, Mn content of rice first decreased and then increased,but Fe, Cu, Zn, Ca and Mg content of rice increased first and then decreased. With increasing application rate of P fertilizer,Fe,Zn,Ca and Mg content of rice increased first and then decreased,but the impact of P fertilizer on Mn and Cu content of rice was not obvious. With increasing application rate of K fertilizer,Fe,Zn,Ca and Mg content of rice increased first and then decreased. Using appropriate potassium fertilizer will help improve Mn and Cu content of rice.With increasing application rate of nitrogen,phosphorus,potassium fertilizer,the total amount of nitrogen,phosphorus and potassium which the rice absorbed increased basically,while the fertilizer recovery decreased. With increasing application rate of nitrogen,dry matter production efficiency of nitrogen and phosphorus decreased. With increasing the application of nitrogen,the dry matter production efficiency of nitrogen and phosphorus decreased. The use of phosphorus fertilizer had no significant effect on absorption and utilization of nitrogen and potassium is conducive to the uptake and accumulation of potassium in rice,but there is no significant effect on rice nitrogen absorption. In addition,the relationship between the rice yield and the nitrogen rates of leaf sheath,the nitrogen rate of leaf, the phosphorus rate of leaf sheath,the phosphorus rate of haulm were quadratic regression model.After planting,the content of available nitrogen and available potassium in the test treatments soil were increased in varying degrees. The content of total phosphorus in soil was reduced in varying degrees. Beside the total nitrogen content of number 5,6,7,8,11,12 treatments' soil increased,the total nitrogen content of another treatments decreased in varying degrees. The changes of soil's available phosphorus content were in different. There was extremely significant positive correlation between the content of available nitrogen in soil and the application of nitrogen. There was extremely significant positive correlation between the content of available phosphorus in soil and the application of phosphorus. Nitrogen application had a significant effect on the content of available phosphorus in soil. There was extremely significant positive correlation between the content of available potassium in soil and the application of potassium.The rice planting area is about 1 059.33hm² in Longxi River Basin of Ya'an. According to our optimization of fertilization on rice research program,if this model can be carried out in the area,26.90 tons urea, 80.59 tons calcium super phosphate and 4.55 tons potassium chloride will be less used to reduce the source of eutrophication of the river,so as to control and prevent non-point source pollution.