滇池北岸居民-农田混合区土壤磷输入输出特征及表观平衡

Input and output Features of Phosphorus in the Mixed zone of Farmland and Suburban Villages in the Northern Bank of Dianchi Lake

以滇池北岸大清河下游典型农区韭菜田与花卉地为对象,通过野外采样观测与室内化学分析,研究了居民农田混合区土壤磷输入输出特征及表观平衡。结果表明:调查区总面积46.7hm^2,磷主要输入途径为化肥施用、附近居民生活污水排放、养殖废水排放、乡镇企业污水排放、韭菜原位腐解。磷输入以化肥施用为主,每年输入436.83kg/hm^2,占磷输入总量的89.51%。韭黄收获每年输出25.69kg/hm^2。调查区磷输入总量22.79t,输出总量1.21t,磷的表观平衡21.58t。在滇池流域化肥施用是混合区农田磷的主要来源,磷的表观平衡为462.1kg/hm^2。土壤磷易发生淋失,对附近水体构成威胁。

The characteristics of phosphorus input and outputin typical leek and flowers farmland on the downstreamof Daqing River on the north shore of Dianchi Lake was studied through sampling observation and chemical analy-sis. The results showed that the total area of the survey area is 46.7 hectares. The sources of phosphorus input werechemical fertilizer, the sewage water from the nearby residents, livestock wastes, wastewater from the enterprises,and leek decomposition. The chemical fertilizer was the major sources of phosphorus. The annual input amount was436. 83kg/km^2, which accounted for 89.51% of the total input. The leek contributed 25.69kg/km^2 of phosphoruseach year. The total phosphorus input was 22. 79t, and the total output was 1.21t. The phosphorus apparent equi-librium was 21.58t. Chemical fertilizer application in the Dianchi Lake basin was the main source of phosphorus in-soil. The phosphorus apparent equilibrium was 462. 1 kg/km^2. The phosphorus tended to be leached out of soil,which threatened the water.