عنوان مقاله [English]
Rangelands play an essential role in preserving environmental balance, providing means of livelihood, and continuing the possible living of people. The policies of government are to leave the rangelands in the form of 30 - year long term programs and to make husbandmen as the owners and real exploiters of range lands in these schemes. In this study, first, the rangeland projects carried out in Birjand by COMFAR III Expert software, have been economically evaluated, and then the minimum economical size has been estimated. In the part of economical evaluation, two methods of "benefit – cost ratio" and "internal rate of return" were used to estimate 5 sample projects, which had economical explanations. The results of estimating the minimum economical size show that, all of the projects (but Aliabad) have the minimum economical size.