中文摘要：

通过对居民点、林地、坡耕地等土地利用类型的小型集水区（亚流域）径流磷形态与通量的定位监测,研究了紫色丘陵典型小流域的非点源磷流失特征。结果表明,居民点在降雨量4 mm即可产流,林地与坡耕地的产流临界降雨量为20 mm。居民点的降雨径流响应迅速,径流与降雨峰值基本同步;林地和坡耕地产流时间延迟,径流峰值较降雨延迟20-120 min。居民点、坡耕地和林地的次降雨平均径流深分别为22.4、12.3、9.5 mm,径流系数分别为0.36、0.17和0.09,泥沙流失量分别为136.2、73.5和48.6 kg/hm2。居民点和林地径流的总磷（Total P-TP）、颗粒态磷（Particulate P-PP）浓度在径流过程中迅速达到峰值后陡然下降;坡耕地径流的TP、PP浓度呈多峰变化。居民点径流的可溶性磷（Dissolved P-DP）浓度随径流量增大而减少;林地径流的DP浓度逐渐增加;坡耕地DP、磷酸盐（PO3-4-P）浓度较低且波动较小。居民点小雨、中雨、大雨和暴雨等雨型下的TP流失负荷分别为42.6、136.3、190.0、1 245.6 g/hm2,平均负荷为403.6 g/hm2,林地与坡耕地在中雨、大雨和暴雨等雨型下的TP流失负荷分别为3.5、3.9、90.6和6.6、10.2、210.6 g/hm2,二者的平均负荷为32.7和75.8 g/hm2。降雨量越大,磷流失负荷越高,暴雨条件下的TP流失负荷最高。居民点的磷流失负荷远高于坡耕地和林地,表明居民点的径流污染是非点源污染控制的关键源。

英文摘要：

Phosphorus forms and fluxes via hydrological pathways in typical rainfall events from different land uses in the hilly area of purple soil had been conducted by in-situ monitoring in some sub-catchments so as to understand＂hotspot＂and＂critical time＂for control of non-point-source pollution of phosphorus in a catchment. Rainfall-runoff process along with sediment yield,total phosphorus（ TP）,dissolved phosphorus（ DP） and particulate phosphorus（ PP） concentrations and loadings were monitored in representative rain（ small,medium,heavy and storm）events from sub-catchment of residence,forestland and cropland. The results showed that rainfall-runoff processes responded with land uses. In the residence sub-catchment,runoff started while rainfall reached 4mm,whereas,that started in much higher rainfall（ 20 mm） in the forestland and cropland sub-catchment,respectively. Runoff responded to rainfall rapidly at almost the same peak in the residence sub-catchment in medium,heavy and storm rain,while runoff delayed 20- 90 and 20- 120 min after rainfall in cropland and forestland sub-catchment,respectively. The mean runoff depth,runoff coefficient and sediment yield from residence sub-catchment were 22. 4mm,0. 36 and 136. 2 kg / hm2; while those were 9. 5 mm,0. 09 and 48. 6 kg /hm2 from forestland and 12. 3mm,0. 17 and 73. 5 kg / hm2 from cropland,respectively. The water and soil loss from the residence is the most serious in the hilly area of purple soil. The concentration of total P（ TP） and particulate phosphorus（ PP） of runoff water from the residence and forestland sub-catchment reached peak quickly and decreased sharply,whereas,TP and PP of runoff water from cropland turned into a process with multi-peaks. The concentration of dissolved P（ DP） of runoff water from the residence sub-catchment decreased when runoff discharge increased. DP of runoff water from the forestland sub-catchment increased during the runoff process. DP and phosphate（ PO3-4- P） concentrations of runoff from