YanhuaWanga,c,d, ZucongCaia,c,d, Xiaoyuan Yanb, HaoYanga,c,d
aSchool of Geography Science, Nanjing Normal University, 1 Wenyuan Road, Qixia, Nanjing 210023, China;
bInstitute of Soil Science, Chinese Academy ofSciences, Nanjing 210008, China;
cJiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing, China;
dJiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, China
Abstract
Nitrogen limits primary productivity in ecosystems. To overcome this limitation and maintain food security, densely populated agricultural regions in developing nations now use synthetic nitrogen fertilizers to boost yields. However, nitrogen saturation of aquatic ecosystems was observed here and there, i.e. Taihu Lake, Dianchi Lake and lots of rivers in the watershed. Human activities have more than doubled the annual amount of reactive nitrogen (Nr) entering terrestrial ecosystems since the preindustrial era (Galloway 1998; Green et al 2004). Increased gradually Nr emitted to the atmosphere resulting in the haze, greenhouse effects, acid rain and so on. In this study, we assessed the fate of Nr in the rural area of the Taihu watershed, China. A detailed quantification of Crop Production-Livestock Breeding System (CLS) was constructed in this study. Material flow analysis method and the principle of conservation of mass were used.