Effects of fertilizer reduction on Yield and non-point source pollution of Yongyou rice

In the main grain producing areas of China, there are still problems of agricultural non-point source pollution and eutrophication of surrounding surface water caused by excessive application of chemical fertilizers. In order to change the unreasonable traditional fertilization habits of farmers and minimize agricultural non-point source pollution, a fertilizer reduction fertilization project was carried out in Jiangshan City to study the effects of 10%~30% fertilizer reduction on the yield of rice Yongyou 15 and the loss of nutrients (total nitrogen, total phosphorus and total potassium) in surface runoff of paddy fields on the basis of farmers' conventional fertilization. The results showed that there was no significant change in rice yield by reducing the amount of conventional fertilizer by 10%~20%, and the yield by reducing 10% was the highest. The nutrient concentration in the drainage of paddy field quickly rose to the highest value 1h after fertilization, and then nitrogen, phosphorus and potassium quickly decreased by 25.9%~66.0%, 70.1%~88.3% and 25.0%~52.5% after 24h. After that, all nutrients decreased slowly until the end of the experiment. This shows that if the paddy field irrigation water outflow is caused by heavy rain or artificial drainage, the nutrient diversion loss risk period (also a high risk period of non-point source pollution) is within a few days after fertilization. The reduction of chemical fertilizer has a significant impact on the nutrient content in the drainage of paddy field, and the amount of conventional fertilization is reduced by 10%~30%\u one hour after fertilization, the contents of total nitrogen, total phosphorus and total potassium in the drainage decreased by 3.7%~68.2%, 26.3%~64.8% and 5.8%~57.5% respectively. It is of great significance to improve economic benefits and protect the ecological environment in rice production