6Arheimer B. Nitrogen and phosphorus concentrations from agricultural catchments influence of spatial and temporal variables[J]. Journal of Hydrology, 2000,227( 1 -4) : 140- 159.
7Mario T V,Mario T L,Jeffrey J S,et al. Tillage system effects on runoff and sediment yield in hill slope agriculture[J]. Field Crops Res,2001,69(2) :173-182.
8Xue Y, David M B, Gentry L E, et al. Kinetics and modeling of dissolved phosphorus expert of a tile- drained agricultural watershed[J]. Journal of Environmental Quality, 1998,27(6):917 -922.
9Smith K A, Jackson D R. Nutrient losses by surface runoff following the application of organic manures to arable land. 1. Nitrogen[J]. Environmental Pollution,2001,112(1) :41-45.
10Heekrath G, Brookes P C, Poulton P R, et al. Phosphorus leaching from soils containing different phosphorus concentrations in the Broad balk experiment [J]. Journal of Environmental quality, 1995,94(5) : 904-910.