determining rangeland suitability for sheep grazing using gis (case study: sadegh abad watershed, kermanshah province, iran)

abstract. rangelands are mainly used for grazing the livestock in iran, it is essential to specify grazing suitability of rangelands in each region of country, so that it may improve the management policies and approaches for planning and designing current and future plans. the aim of this research was to determine the rangeland suitability for sheep grazing in the watershed of sadegh abad, kermanshah province, iran. three sub-models namely forage production model, water siutablity model (quantity, quality and distance of water resources) and erosion sensibility which formed the components of the final studied model. epm procedure for erosion sensitivity and fao method for land capability evaluation were employed. furthermore, combining information layers was done by means of arcgis9.3 software. for forage production suitability, the effective factors as allowable limit of exploitation, having access to forage and physical conditions were considered. our findings indicated two separate classes including low suitability (s3) and non-suitability (n) with the contributions of 68.65 and 31.34% rangeland area, respectively. low suitability was due to soil erosion sensitivity and limited standard exploitation of forage. in some regions, distance to water resources and high slope of grazinig land caused the decrease of grazing suitability. considering the grazing capacity and applying the correction programs in rangelands can affect the increase of range suitability for grazing sheep. using gis may lead to the increase in accuracy and speed of implementing plans.