Preliminary Study on Spatial Variability of Nutrients in Irrigation-silted Soil and Crop Yield in the Ningxia Plain

Abstract

In this study 157 topsoil samples were collected in a sampling site space of 100 m in the State Agricultural Scientific and Technological Demonstration Garden located in Litong District,Wuzhong City,Ningxia Hui Autonomous Region,China,the ASI extract method was used to measure soil nutrients,the crop yields at the corresponding spots were investigated,and the spatial variability of soil nutrients and yields in the study area were researched by Vesper developed by Australian Center of Precision Agriculture(ACPA).The results are as follows; (1)There is a semivariance structure in soil nutrients including N,P,K,Ca,Mg and S and crop yield,the variability coefficient varies in a range of 22.85%～70.22%,and the spatial variability is moderate;(2)Block Kriging interpolation can be used to reveal the spatial variability of all the variables,and the spatial variability can be visually and directly shown with the three-dimensional surface graph,for example,the ammoniacal nitrogen content is decreased from the south to the north,so nitrogenous fertilizer should be applied;(3)There are certain correlations among various soil nutrients,but there is a weak correlation between soil nutrients and crop yield,which reveals that the nutrients needed by crop growth are mainly supplied by fertilizer application.Therefore,it is suggested to rationally apply fertilizers and pay more attention to fertilizing soil fertility.