برآورد ارزش اقتصادی مستقیم کارکرد حفاظت خاک پوشش گیاهی مراتع (مطالعه موردی: مراتع ییلاقی حوزه آبخیز نوررود)

One of non-forage functions of rangelands vegetation is soil conservation and prevents it from erosion. Water soil erosion has economic, social and environmental implication due to both on-site and off-site effects. So, the objective of this study was to assess the on-site effect of water erosion on conservation function of summer rangelands vegetation, using a combination between economic value and various vegetation density of Baladein North of Iran. So, economic value of soil conservation estimated by "loss of forage productivity" method. The initial framework of the model was bio-economical. The model fitted by Cobb-Douglas production function by OLS method. This function is based on soil physic-chemical parameters and soil erosion ratio. Results showed that only soil erosion had significant effect on forage production. According to the marginal production (MP) and economic value of each kg of soil conservation, value of MP (VMP) estimated per ha by different plant vegetation density. The results showed that, economic value of loss of forage productivity estimated 230084 Rails/ha from 94978.6 ha of rangelands. The most soil conservation value wasbelongedto rangeland with high density by 10.86 milliard Rails and the least value was belonged to rangeland with low density by 1.31 milliard Rails. Results showed that similar research in natural resources filed by natural vegetation is required to consider other independent variables in the initial framework of the function.