Investigation of spatial distribution of soil fertility elements in the Miyaneh wheat farms

This research was conducted in Miyaneh city to study the spatial structure of the soil fertility factors in order to estimate the nutrient vigor of soils and optimizing fertilizer usage rate and plant nutrition. The research was carries out in several steps. First of all, soil samples were provided in 0-30 cm depth from Miyaneh wheat farms and each sample position was recorded by GPS. Soil fertility factors of each sample such as: EC, pH, OC, P, K, Zn, Fe, Cu, Mn and B were measured. ILWIS 3.21 software was applied for mapping of mentioned variables. For this reason, interpolation method was applied to make spatial distribution maps of these variables. Classification of spatial variety of each parameter produced based on Iranian Soil and Water Research Institute standards. The main parts of the study area lacked salinity limitation but contained little alkalinity limitation. In more than 95% of these farms, the organic carbon (OC) rate was less than 1% and in more than 75%, absorbent phosphorus was in its medium range (5-10 ppm). But potassium rate in main parts of these farms was more than 300 ppm. Derived spatial maps showed that these farms suffered from shortage of B, Fe, Zn, and Mn, but Cu was sufficient in the study area. Appling organic fertilizer is essential for balancing of pH and increasing of OC of soil. Based on prepared maps, it is recommended to avoid using of fertilizer in non-deficient lands.