利用 5～ 6a野外径流小区试验资料 ,研究 1 7种植被覆盖对土壤侵蚀和氮素流失的影响 ,结果表明 :1 9种作物、4种草地和 4种草灌间作小区年平均径流量为 2 7773、1 80 2 8和 1 31 4 9m3/ km2 · a,比相应裸地减少 2 7.5%、51 .1 %和64.3% ;侵蚀模数为 1 71 6、1 0 2 1和 81 2 t/ km2 · a,减少 73.0 %、92 .8%和 94 .3% ;全氮富集率为 1 .65、2 .4 8和 2 .59,比裸地增加 1 3.8%～ 1 1 4 % ;年平均土壤氮素流失量为 1 4 58、1 2 52、382 9和 966kg/ km2· a。 2植被通过调节径流流速来间接影响泥沙全氮富集 ,土壤侵蚀模数愈大 ,泥沙全氮富集率愈小。 3土壤氮素流失方程 SN=( 55.56-4 .87ln SL)· SL·TN ,可定量预测土壤氮素的流失。 Using 5 ~ 6a field runoff plots, the effects of 17 vegetation cover on soil erosion and nitrogen loss were studied. The results showed that the annual average runoff of 1 9 crops, 4 grasslands and 4 grass irrigations was 2 7773, 1 80 2 8 and 1 31 4 9m3 / km2 · a decreased by 21.5%, 51.1% and 64.3% respectively compared with corresponding bare land; erosion modulus was 1 71 6,1 0 2 1 and 81 2 t / km2 · a decreased by 73.0%, 92.8% and 94.3% respectively. The total nitrogen enrichment rate was 1.65, 2.48 and 2.59, which increased by 1.38% -1.14% compared with the bare land. The annual average amount of soil nitrogen loss was 1 4 58,1 2 52,382 9 and 966 kg / km2 · a. 2 Vegetation indirectly affected the total nitrogen enrichment by regulating the runoff velocity. The larger the soil erosion modulus, the smaller the total nitrogen enrichment rate. 3 soil nitrogen loss equation SN = (55.56-4. 87ln SL) · SL · TN, can predict the soil nitrogen loss quantitatively.