湖泊流域种植系统磷流特征及影响分析

湖泊流域中农业种植排放的磷污染是水体富营养化的主要污染来源。通过物质流分析方法，建立湖泊流域农业种植系统的静态磷物质流分析模型，并以巢湖流域为例，运用模型系统地量化并分析了2006年流域农业种植系统中的种子、化肥、农药、粪便、作物、秸秆等含磷物质的代谢过程。结果表明，系统对水体磷贡献为20．84 kg／亩，其中畜禽粪便还田和化肥施用是造成水体磷污染的主要原因，其含磷量分别占系统磷总输入量的74．68％和15．07％，并提出防治畜禽养殖污染和提高磷肥施用效率等减少系统对水体磷污染的主要措施。研究为高效控制农业面源污染，寻找治理水体富营养化的新途径提供依据。

Analysis of Phosphorus Flows and Influence Factors in Crop Farming System of Lake Watershed

The phosphorus （ P ） discharged from crop farming contributes the most to the eutrophication of the lake watershed.A static P flow analysis model of crop farming system was developed based on substance flow a-nalysis.Taking Chaohu Watershed as the studied area, the P flows relating with seeds, chemical fertilizers, pes-ticides, manures, crops, straws and so on were calculated and systemically analyzed.The results showed that the total P discharged from the crop farming system of Chaohu Watershed in 2006 is 311.04 kg/hm.The manure discharged by rural residents and livestocks and the applied chemical fertilizers contributes the most P to the sur-rounding water, which occupies 74.68%and 15.07%separately.Some measures were proposed aiming at re-ducing the P pollution caused by the crop farming system, such as preventing the pollution of livestock breeding, and improving the efficiency of fertilizer application, etc.The study results provide a basis to control agricultural non-point pollution source and find new ways to mitigate eutrophication.