عنوان مقاله [English]
Land use capability for a type of range utilization with considering the sustainable land use is called range suitability, nowadays which is a priority in the science of range management. The objective of this study is evaluation of range suitability for sheep grazing through FAO method (Condition limitation) in Sarayan- South Khorasan province in 1990. For the purpose of this study, at first, the map of vegetation types was determined in each region and in each vegetation type, the status and tendency of rangeland and the amount of plant species were determined by cutting and weighing method and the suitability map was produced. Then, using EPM method, soil erosion susceptibility map was prepared. Also, to study the watershed suitability of the area, the drinking water resources of livestock area and sampling of each water source was done, the quantification of water was determined and water samples were transferred to the laboratory and TDS, EC and Mg + 2 parameters were measured for each sample and by integrating layers of quantity, quality and equal distant points from water sources, the water resource suitability map was adjusted. Finally, by finalizing production suitability maps, soil susceptibility to erosion and water, the final model of range suitability classification was prepared. The results indicated that there was no class of suitability (no vegetation type) (S1) in the region and the suitability classes S2, S3 and N (no grazing suitability) were 12.1%, 50.7% and 37%, respectively. Based on the research results, overgrazing, early grazing, formation susceptible to erosion, slope, allowable use limits and available forage, poor condition, negative trend of ranges and inappropriate distribution of water sources for livestock are the most considerable limiting factors in area for sheep grazing. In general, with regard to the obtained results using the livestock grazing suitability model in the study area, it is suggested to use this model as the basis for preparing rangeland plans with emphasis on removing the limiting factors as far as possible to improve rangeland status and Shepherds' income.