Optimal Management of Fertilizer Application in Agricultural Production for Higher Efficiency and Better Water Quality-a Case Study in Taihu Lake Region.

Optimal management of fertilizer application in agricultural production for higher efficiency and better water quality-a case study in Taihu lake region Weiming Shi State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing210008, China wmshi@issas.ac.cn Chinese water pollution problem is serious, eutrophication that caused by excessive nitrogen and phosphorus is the key point of the water pollution in China. The agricultural non-point source pollution is one of the main sources. According to the estimation, TN entering into Taihu Lake is approximately 30-40% from the point source pollution, and 60-70% from the non-point source pollution. The amount of fertilizer usage has increased several decuples in key valleys in China since 60's; The quantity of farming nitrogen, and phosphorus in important basins has obviously increased; The non-point source pollution in intensive agricultural areas caused nitrate pollution in ground water. Rice is an important staple crop in China as well as in the world, fertilizer nitrogen is used in high amount, but with low efficiency at 30-41% in average. Moreover, vegetable cultivation is widely distributed nearby river in the Taihu lake region, fertilizer nitrogen and phosphate is also used in high amount, but with low efficiency below 20%. Therefore, nitrogen and phosphate loss from agricultural field threat to environmental quality is becoming big concern. A case study was conducted in Yixing city nearby Taihu lake. Our results showed that: 1) To optimize fertilizer application is important both for agriculture and environment; 2) Technology for optimal management of fertilizer use in rice and vegetable production for higher efficiency and better environmental quality has been developed; 3) Policy and social issues are as important as technology; 4) More technologies, simple, easy-to-use need to be developed.