Simulation Nitrogen Levels On Economic Yield And Global Warming Potentials Of Rice-wheat Rotation

Fertilizers are known as "food-food", has long been important material basis for food production. China becomes the world's leading countries in the consumption of nitrogen fertilizer, since the late1980of the20th century. China is the world's largest country in volume of nitrogenous fertilizer production and consumption today, and this will increase further. But the food production didn't coincide with the increased use of nitrogen fertilizer.There is an excessive nitrogen fertilizer application problem, and the efficiency decreased significantly in recent years. Application of nitrogen fertilizer in excess, it will cause nitrogen loss, reducing nitrogen use efficiency, and destruction of water features. On the other hand, it also increases the agricultural greenhouse gas emissions, resulting in new environmental problems. Therefore, researcher has focused on how to reduce nitrogen losses and improve nitrogen use efficiency.This paper studies of nitrogen fertilizer on farmland ecological system of greenhouse gas emissions and agricultural non-point source pollution risk. It provides technical support to low-carbon agricultural production, has important theoretical and practical significance.In this paper, field survey, field trial and the DNDC model was used, to study the environmental effects of different nitrogen application levels in the rice-wheat rotation agro-ecosystem. The main conclusions are as follows.Dongtan agricultural park is already in a mild state of pollution of water quality. The content of chemical oxygen demand, ammonium and total nitrogen seriously overweight, caused by agricultural fertilizer.In the rice-wheat rotation system, nitrogen fertilizer has a significant influence on the quality of surface and leakage water. Comprehensive pollution index of water leakage CK>N1>N2>N3, at the0.01level, CK and Ni,N2,N3were significantly different during wheat growing; When the rice grows, the surface and leakage water has been seriously polluted. Surface water pollution index size followed by the CK>3>N1>2>N2>l>N3; Comprehensive pollution index of field Leakage water followed by CK>N1>N2>N3>1.A field test had been done and used the biogeochemical model to simulate the crop yield and greenhouse gas emissions of rice-wheat rotation system at Chongming Island. There has an optimization unit crop yield GWP, when the nitrogen application rate reduced60.96%of the control, crop yield is12668.1kg/hm2/yr and the GWP reduced43.02%.This study shows, reducing the amount of nitrogen reasonability can to bring down the greenhouse gas emissions, reduce the nitrogen loss and keep the crop yield with the control together. This paper has an important theoretical and practical significance of construction of the ecological Chongming Island.