Diffuse export of nutrients under different land uses in the irrigation area of lower Beiyunhe River (China)

摘要: Abstract Non-point source pollution is serious in the agriculture watershed of China. Understanding characteristics rainfall-runoff from can provide theoretical support for controlling non-point pollution. In this study, we investigated runoff eight indices (dissolved total N, NO3--N, NH4+-N, phosphorus, dissolved particulate organic carbon, COD) three types land uses, including farmland, forest and village downstream irrigation area Beiyunhe River basin. The results showed that event mean concentrations (EMCs) N village, farmland forestland were 17.81 mg/L, 12.68 mg/L 3.14 mg/L, respectively. EMC phosphorus order: (0.44 mg/L) > (0.22 mg/L) (0.17 mg/L). COD (45.07 mg/L) (27.06 mg/L) (18.03 mg/L). changes nutrients water over a rainfall indicated transports are similar among various use types. instantaneous TN, NO3--N high initial period runoff, tend to decreasing with continuing, increase later period. Phosphorus concentration time variation was not obvious species proportion particle P (accounting 75%) forestland, dissolve (79%) (48%) (52%) village. curves TOC had been shown as tending increasing decrease First-flush all rank farmland. pollutions have taken place phenomenon first flush, while tended uniformly distribute or dilution throughout storm event.