Evaluation of prevailing irrigation practices and their relation to soil properties - A case study of Hamadan-Bahar Area of western Iran

A study was conducted in a semi-arid area of Iran to investigate the relation between irrigation methods and the soils, using remote sensing data and a geographic information system (GIS). Spatial distribution of soils, soil attributes and kind of land use/land cover were the main determinant factors investigated. Spatial distribution of the soils was determined at semi-detailed level. Soil attribute maps were derived from the soil map and the laboratory analyses of the samples for physical and physico-chemical characteristics such as infiltration rate, permeability, bulk density, available water content (AWC), sodicity and salinity, pH, and by using rule-based expert survey system. Digital and visual analysis of LANDSAT TM data, supported by field survey, was performed to extract the required information on land use/land cover, on the basis of which the extent of each irrigation method was estimated. Suitability of the soils for the application of various irrigation methods were mapped and compared with the soils of the area where they are practised. This was done on the basis of spatial distribution of the soils and a number of determinant soil attributes, using ILWIS (ITC, 1993) geographic information system.