An economic evaluation of the effect of rangeland ecosystems degredation on the loss of soil nutrients (Case study: rangelands of Salman in Qom)

One of the functions of rangeland ecosystems is to prevent soil erosion and increase nutrient retention capacity. The present study was conducted to highlight the effect of Rangelands degradation on the preservation of Mg, Ca, N, P, and K elements in the soil and emphasize the role of rangeland plants in preventing the wastage of these elements in the rangelands of the Salman watershed in Qom. For this purpose, a sample was taken from the soil of the habitat in each work unit, in the classes of poor and good rangeland conditions, representing degraded and non-degraded rangeland, respectively. Then, the amount of eroded soil was determined from each unit using the modified PSIAC (MPSIAC) model. In the following, the amount of loss of nutrients using the results of soil analysis and related relationships, was calculated and based on the replacement cost method; by estimating the alternative fertilizer, the monetary value of maintaining nutrients by the ecosystem was calculated. The results showed that the destruction of the rangeland ecosystems of the region causes erosion equivalent to 35.68 tons per hectare per year, which damages the functional services of the ecosystem at an annual cost of 11.6 billion rials (11606427781 rials) by reducing the nutrients of the soil. Also, each hectare of good rangelands in the region can prevent the loss of nutrients with an approximate value of 335.6 thousand rials. The results indicate the effective role of the rangeland ecosystem in controlling erosion and preventing the loss of soil nutrients. What is certain to emphasize more the role of rangeland ecosystems in soil erosion control; it is recommended that are also estimated the amount of soil erosion by other common methods, such as the global model of soil erosion (USLE), EPM, etc., and the results are compared with each other in future research.