Variability of soil nutrients in field and fertilizer recommendation

The variability of soil nutrients was studied by grid sampling using DGPS in the Wangqi village of Qingzhuo City, Shandong Province It indicated that the soil nutrients had variability in field Based on the sampling distribution, the nutrients were divided to two classes One was called declining nutrients, such as nitrogen, phosphorus and sulfur The other called non declining nutrients The reasons of declining were mainly caused by supplying of chemical fertilizer For the large amount and longer history applying nutrients, the recommendation must be based on the spatial variability of soil nutrients, the others can be based on the average testing values of the field