洱海西部雨季地表径流氮磷污染特征及受土地利用类型的影响

云南高原平坝区地表径流是湖泊氮、磷的主要来源之一.为研究高原平坝区雨季地表径流氮、磷污染特征及受土地利用类型的影响，调查了洱海西部平坝区雨季的径流氮、磷形态特征，并结合遥感影像空间分析与SPSS等统计分析，从汇水区尺度和缓冲区尺度上研究土地利用类型与地表径流水质的关系.结果表明:①研究区雨季地表径流氮、磷质量浓度较高，ρ（TP）为0.16~0.77 mg/L，且以DIP（溶解性无机磷）为主（63.01%）；ρ（TN）为1.75~14.86 mg/L，且以NO₃--N为主（78.15%）.②汇水区尺度上城镇用地对ρ（TP）影响突出.环湖农村居民点对ρ（NH₄+-N）影响突出，耕地中的高施肥种植区对ρ（TN）、ρ（NO₃--N）影响突出；③在缓冲区500、1 000和2 000 m尺度下，随缓冲区距离增加，土地利用类型对地表径流水质的影响减小.研究显示，城镇用地与高施肥种植区对洱海西部雨季地表径流氮、磷质量浓度影响最大，土地利用类型随缓冲区距离增加对水质的影响逐渐减小. 

Nitrogen and Phosphorus Pollution Characteristics of Surface Runoff and the Impacts of Land Use on Runoff Water Quality in Rainy Season in the Western Erhai Lake Basin

Surface runoff is one of the main sources of nitrogen and phosphorus pollution for lakes in the plain area of the Yunnan plateau. To study the characteristics of nitrogen and phosphorus pollution of surface runoff and the impacts of land use on the water quality of the runoff in the rainy season in the plain area of the Yunnan plateau, the chemical speciation of nitrogen and phosphorus in the surface runoff was investigated during the rainy season in the western Erhai Lake basin. The relationship between the patterns of land use and the water quality was also studied using remote sensing image spatial analysis and SPSS statistical analysis at the catchment and riparian buffer scales. The results were as follows:(1) The nitrogen and phosphorus concentrations in surface runoff were relatively high; TP ranged from 0.16 to 0.77 mg/L with the dissolved inorganic phosphorus (DIP) as the major species accounting for 78.15%, and TN ranged from 1.75 to 14.86 mg/L with the NO₃^--N as the major species accounting for 63.01%. (2) In the catchment area, the influence of urban land on the TP concentration, the rural residential area on the ammonium concentration, and the high-fertilizer-using farmland on the TN and the NO₃^--N concentrations were obvious and prominent respectively. (3) In the riparian area at 500, 1000 and 2000 m buffer distances, the influence of land use patterns on surface runoff water quality decreased gradually with increasing of the buffer distance. According to the study, urban land and high-fertilizer-using farmland had the greatest effect on the nitrogen and phosphorus concentrations in surface runoff on the western side of the Erhai Lake basin during rainy season, and the effects of land use patterns on the water quality decreased gradually with increasing of riparian buffer distance.