Spatial Variability and Mapping of Some Physico-Chemical Properties in Surface Soils and Influence of Land Use Management on Them in Agricultural Lands South of Tehran

Development of residential, commercial, and industrial areas and agricultural land use in sSouth of Tehran has, have caused changes in some physical and chemical properties in the soil environment. In this research, 196 soil samples were collected at depth of 0-30 cm, at 1000×1000m grids in 20000 ha agricultural lands of Ssouthern of Tehran. Soil texture, pH, calcium carbonate, cation exchange capacity, and organic carbon were measured. Geostatical analysis and, interpolation of soil properties by kriging and mapping were carried out by GS and ArcGIS software. Results showed that 26.3% and, 54.6% of lands were containeding of less than 0.9% and 0.9- to 1.2% of organic carbon, respectively. A lLands containing less than 0.9% of organic carbon is are often cultivated crops, residential areas, and barren lands. The land containings of 0.9-2.2% organic carbon is often cultivated to vegetables crops. Except the 29.9% of which lands which were affected by industrial waste water with a pH greater than 8, the remaining of lands have had a pH of 7.5 to 8. About 81% of the lands have had 5% to 15% lime and 78.6% of the lands have had a CEC of 20-35 cmolc kg-1. In this study, spherical models were fitted for organic carbon, pH, CEC, and lime. Exponential models were fitted for clay and silt and Gaussian model for sand. Use ofing wastewater, intensive agriculture, and specific management, especially for cultivation of vegetable crops, were had significant effects on soil properties.