澄江尖山河小流域不同土地利用类型地表径流氮、磷的流失特征

根据径流小区观测, 对澄江尖山河小流域不同土地利用类型地表径流中氮、磷的流失特征进行了研究. 结果表明:灌草丛和次生林都有较好的调节径流和减少土壤流失的作用，在相同的降水量下，坡耕地总产流量分别是人工林、次生林、灌草丛的1.58，12.45和5.52倍；而从产沙量来看，坡耕地的产沙量也远大于其余几种土地利用类型，坡耕地的总产沙量分别是人工林、次生林和灌草丛的8.41，53.06和41.90倍. 不同土地利用类型径流中的总氮、总磷的输出量差异显著，总氮、总磷输出趋势都表现为坡耕地＞人工林＞灌草丛＞次生林；不同土地利用类型径流小区侵蚀泥沙中的总氮、总磷输出量同样为坡耕地＞人工林＞灌草丛＞次生林，且坡耕地的输出量远大于其余几种土地利用类型. 相关分析表明，径流中带走的总氮量大于泥沙，磷的输出主要是以泥沙结合态为主，泥沙是磷的主要载体. 

Phosphorous and Nitrogen Loss Characteristics with Runoff on Different Lands UsePattern in Small Watersheds in Jianshan River, Chengjiang

Phosphorous and nitrogen loss characteristic in runoff on four different soil types in watersheds in Jianshan River, Chengjiang were studied based on runoff observations. It showed that both the secondary forest and shrub-grassland were good at reducing runoff and soil erosion. Under the same amount of rain, total runoff in slope farmland was 1.58 times of planted forest, 12.45 times ofnatural secondary forest, and 5.52 times of shrub-grassland. Sediment productionon slope farmland was bigger than other landuse patterns, being respectively 8.41, 53.06 times of planted forests, natural secondary forests, and 41.90 times of shrub-grassland. Phosphorous and nitrogen outputs in runoff were significant in different land use patterns, total phosphorous and nitrogen outputs in the runoff in different land use patterns were in the order of slope farmland > planted forest > shrub-grassland > secondary forest. It is the same as phosphorous and nitrogen outputs in the sediments, and outputs in the slope farmland were far higher than others. Correlation analysis showed total nitrogen amounts in the runoffwere greater than in sediment, phosphorous mainly loses with sediment, and sediment is the main carrier of phosphorus.