using the ability of geographic information system in evaluation of environmental capability in arid area case study: birjand auriferous basin

land use management policy and method are two important factors in usage of land by human. in this regard, evaluation of environmental capability would serve as a valuable basis for the best use practice of soil and water resources in addition to the reduction in environment consequences of the projects. in the correct study, the environmental capability of birjand plain, located in the south khorasan province, has been evaluated using the delivery method. result show that and salinity and alkalinity, under loped soil profile, inappropriate soil texture, low and dispersed precipitations and lack of adequate plant coverage are the most remarkable limitation in agricultural usage of the land in birjand. by combining the maps of geographical dimensions land slop, altitude suitability and plant coverage, considering ecologic – climatic, population and hydrologic characteristics. result also show that a considerable portion of the plan, excluding the central parts, is not suitable agricultural use. aquatic agricultural is only possible in the area above the aquifer in the plain area. also rain seed agriculture may be practiced hen the area above the aquifer and its vicinity on the above terraces, piedmont plains and area, values and quant outputs located in the mountainous parts of the plain. results also show that only area having slopes of above 10 suitable for key words marginal farm, geographic information system environmental capability, birjand.