ARTIFICIALLY SIMULATED COUPLING CHARACTERISTICS OF DIFFERENT SEDIMENT NUTRIENT WITH SEDIMENT LOSSES IN SLOPELAND OF PURPLE SOIL,CHINA

This paper revealed clearly the different coupling characteristics of sediment nitrogen and phos- phorus with sediment losses in slopeland of purple soil,and also the influence of rainfall intensity(RI)and slope on the characteristics with simulated rainfall method.It is found that sediment nitrogen losses de- creased with the increase of slope and RI,but sediment phosphorus losses were lightly influenced by both RI and slope.Correlation analysis demonstrated that with the increase of sediment losses,sediment nitrogen losses decreased,but sediment phosphorus losses increased.Both sediment nitrogen and sediment temporal- ly showed peak values,while sediment phosphorus did not.The accumulated amount of sediment nutrient losses increased with the increase of the accumulated amount of sediment losses,but sediment phosphorus loss was obviously higher than sediment nitrogen loss.In addition,there were differences in sediment nutri- ent enrichment ratios(Er),that is,the higher the amount of sediment losses,the lower sediment nitrogen Er,and the higher sediment phosphorus Er.Further,since sediment phosphorus Er was higher than sedi- ment nitrogen Er,sediment phosphorus was more coupling stable than sediment nitrogen,so as more likely to exhibit latent effect of its influence on the water environment of the downsream.