昆明市水源区不同利用类型坡地径流氮和磷的输出特征

采用径流小区法对昆明市松华坝水源区牧羊河中游5种不同利用类型坡地2007年雨季地表径流氮和磷的输出情况进行观测分析.结果表明，随着雨季降雨次数的增加，径流小区产生的水样中，输出的ρ(TN)和ρ(TP)逐渐下降，在7月3日—9月17日的7次采样中，裸地、黄豆地、林地、土豆地和草地径流输出的ρ(TN)分别下降83.2%，79.8%，78.4%，75.9%和75.3%；输出的ρ(TP)分别下降74.6%，62.2%，54.2%，75.3%和72.1%，由此说明氮和磷的输出与地表径流及土壤侵蚀具有一致性.在氮和磷的输出过程中，强降雨对输出影响较大，施肥对输出影响明显.输出的可溶态氮素主要以NO₃--N为主. 

Nitrogen and Phosphorus Loss Characterstics in Runoff from Slopes with Different Land Uses in Songhua Dam Reservoir of Kunming

The nitrogen and phosphorus content and transformation in the runoff from slopes of different land uses was observed during a rainy season in the middle reaches of Muyang river of Songhua dam reservoir in Kunming.The results showed that the concentration of nitrogen and phosphorus in the runoff plot decreased with the increase of rainfall time.The concentration of total nitrogen decreased 83.2%,79.8%,78.4%,75.9%,and 75.3% in bare,bean,forest,tomato and grass plots,respectively,while the total phosphorus con...