根据研究区土地利用方式,划分流域非点源源类,建立不同源类的代表性径流观N4,区,研究不同源类土壤基本理化性质和营养盐荷载空间异质性以及降雨径流作用下营养盐流失特征。结果表明:不同源类土壤有机质与中值粒径和阳离子代换量存在较好的相关性,相关系数R。分别为0.623和0.555,营养盐荷载存在一定的空间异质性,变异系数的大小为NO,-N(0.43)〉P04-P(0.32)〉TP(0.22)〉TN(0.17)〉NH4-N(0.16),降雨动力作用下氮磷流失量表现出耕地〉果地〉茶地〉林地,黄棕壤〉黄壤〉紫色土〉石灰土等规律,耕地和果园是研究区内的高风险源类,非点源TN的源强大小与降雨量、径流系数和侵蚀泥沙浓度的关联系数为0.465、0.706和0.712;非点源TP的源强大小与降雨量、径流系数和侵蚀泥沙浓度的关联系数为0.653、0.829和0.646,因此防治水土流失是控制氮磷流失的关键。
Based on land use type in the studied area, different non-point sources are classified, and soil physical and chemical properties, nutrient content, and nitrogen and phosphorus loss in representative runoff plots of different sources are studied. The research results indicate that soil organic matter is directly proportional to median diameter and inversely proportional to CEC, and R2 are 0.623 and 0.555, respectively, and the spatial variation coefficients of nitrogen and phosphorus order as NO3-N (0.43) 〉 POa-P (0.32) 〉 TP (0.22) 〉 TN (0.17) 〉 NH4-N (0.16). Surface runoff yield orders as yellow brown soil 〉 on yellow soil 〉 on purple soil 〉 on limestone soil, and on cultivated land 〉 on orchard land 〉 on forest land 〉 on tea land. Soil and nutrient erosion modulus order as cultivated land 〉 on orchard land 〉 on tea land〉 on forest land, grey associative coefficients between TN and precipitation, runoff and soil erosion are separately 0.465, 0.706 and 0.712, and TP and precipitation, runoff and soil erosion are 0.653, 0.829 and 0.646, respectively. Thus, controlling water and soil loss are the key measure to decrease N and P loss.