Research of soil testing and fertilizer recommendations at county level by GIS

Taking Guangrao County as research area, this paper studied soil testing and fertilizer recommendation technology facing management level at county level was studied. Based on data analysis and fertility evaluation, using “fertility distribution and target yield” method supported by GIS, fertilizer recommendations were determined. On the basis of recommendation units, which were divided according to fertilizer grade map of cultivated land and crop layout, and parameters obtained through field-testing nutrient demands and fertilizer recommendations were calculated, then using GIS, coupling fertilizer recommendation unit map and corresponding attributes, finally, recommendation map of fertilizer map in Guangrao County was formed. The results show that, the spatial distribution of nutrient contents is not uniform and there are 14 kinds of fertility recommendations, the proportion of N, P and K ranged in 1︰0.04～1.53︰0.05～0.82. This study probed the technical method of soil testing and fertilizer recommendations. It has a positive instruction on cultivated land utilization and fertilizing management.