Investigating Soil Phosphorous in Agricultural Lands of Pars Abad-e- Moghan

Application of phosphorous (P) fertilizers to calcareous soils has some problems, because only 10-25% of P- fertilizers added to the soil are absorbed by the plant and the rest (75 to 90 %) is precipitated as calcium phosphate. Research has shown that P accumulates in soils where P-fertilizer has been used for a long time. Accumulation of P has caused a number of environmental problems including reduction of surface water quality. In some parts of Iran, such as Pars Abad-e- Moghan, which are considered as agricultural pole, study of total P by environmental indicators is necessary. For this purpose, this experiment was conducted in 2016. At first, sampling grid was drawn (at 3 * 3 km intervals) for agricultural lands, then soil sampling was done by GPS. Soil texture, organic carbon, pH, T. N. V, total P and available P were analyzed in all soil samples. Also, Environmental Performance Index (EPI) was estimated by Bolster (et al. 2014) method. SPSS (version 16) and GS+ software were used to determine the spatial correlation of total P, available P and Phosphorus Environmental Index [H1]  . The results revealed that the range of available P varied from 7 to 40 mg. kg-1 and total P ranged from 718 to 2315 mg. kg-1. The minimum, maximum and average environmental indicators were 40, 72, and 55, respectively, indicating that almost all of the farms in this area were at medium risk. Increasing the environmental index is more severe in soils in which total P exceeds 1200 mg kg-1 [H2]  .