中文摘要：

选择太湖上游为研究对象，采集了1-400km^2不同尺度小流域产出径流TN、TP浓度实测数据，结合前期开展的地表坡面流人工暴雨实验监测结果，开展不同尺度流域水质监测对水体面源污染产出浓度估算影响的比较研究，探讨流域尺度之间入渗、汇流以及伴随的流域生态系统营养盐调节机制的差异．结果表明，流域监测尺度对土地利用面源污染产出浓度估算有较大影响．地表坡面流由于未经过流域汇流过程伴随的下渗滤过与吸附等过程，产出径流TN、TP浓度一般高于小流域．小流域林地生态系统具有较强的入渗机制、接近自然的生态沟谷汇流网络，对面源污染TN、TP有较强的削减作用．农业生态系统较弱的人渗机制、人工沟渠汇流网络对面源污染TN、TP的削减作用较弱．现代农业造成流域面源污染增加不仅仅是因为人类农业活动对流域局部土体及养分的改变，农业生态系统改变流域自然生态系统整体水文过程及营养盐调节机制也是面源污染增加的重要因素之一，恢复小尺度的生态沟谷网络系统对削减流域面源污染具有重要的意义。

英文摘要：

Based on artificial rain experiments and field monitoring to sub-watersheds in different spatial scale （ from 1 to 400 km^2 in area） in Taihu upper-river basin, The runoff mean concentration of non-point source nitrogen and phosphorus are assessed according to different spatial scale field monitoring. The discrepancy of watershed nutrient decay function, due to different soil infiltration and runoff routing process in different watershed spatial scale, is analyzed, The results proved that runoff mean concentration of nitrogen and phosphorus in different watershed scale is with more discrepancy. The runoff mean concentration of nitrogen and phosphorus based on overland flow monitoring is higher than that of watershed outlet monitoring, because the overland flow monitoring does not represent the soil infiltration and runoff routing processes relating to nutrient decay, The forest land of watershed, with strong soil infiltration and more natural stream systems, have more nutrient decay function than that of the farm land of watershed with weak soil infiltration and artificial canal systems. It is important factor of increasing non-point source nitrogen and phosphorus to alter watershed hydrological system and ecological system by modern farm activities. Restoration and remediation of natural ecological stream system is helpful to non-point source pollutant abatement of watersheds.