Spatial and temporal distribution of nitrogen in surface water and soil under scattering and fertigating ammonium-sulphate for border irrigation

Based on the field experiments for different fertilizing methods and inflow rates in the greening period of winter wheat, the spatial and temporal distribution of Nitrogen in soil and surface water were analyzed, and the factors affecting the distribution uniformity of Nitrogen in soil after irrigation were discussed. The results showed that the influence of inflow rate on the distribution of Nitrogen were not obvious, however the fertilizing methods had obvious effects on it. Under fertigation the spatial and temporal distribution difference of Nitrogen in surface water were not obvious, but it was very obvious for scattering fertilizer. The spatial distribution uniformity of Nitrogen in soil after irrigation can be well improved under fertigation，the coefficient of variation Cv was about 0.07 at 1m soil depth, which was far smaller than that under scattering fertilizer. Under fertigation the distribution uniformity of Nitrogen had strong relation with the distribution of irrigation water, however under scattering fertilizer it was mainly related with the distribution of Nitrogen in surface water and the distribution of irrigation water. Fertigation was better than the scattering fertilizer in improving the distribution uniformity of Nitrogen and decreasing the loss of fertilizer during the irrigation, and it was easier for the joint management of water and fertilizer.