بررسي رابطه بين پسرفت خاك با جابجايي زماني و مكاني دام در مرتع

Relationships between the spatial and temporal patterns of rangeland condition, flock movement and soil properties: A case study from the Namrood catchment, Tehran, Iran

The semi-arid regions of Iran are obviously characterized by animal grazing. The flock movement takes place according to the availability of forage and water following some traditional habits. On the other hand, due to the escalation of population, much of the marginal rangelands are brought under cultivation. This has led to disregard of grazing patterns, and has also led to upland areas to be degraded. In order to recognize relationship between rangeland condition, soil properties and flock movement in rangelands, a study was conducted in the rangelands of Namrood catchments locating in north-east of Tehran, Iran. Accordingly, in order to study soil properties, geopdological approach based on the interpretation of aerial photographs, landsat TM images, topographic maps and field surveys was applied. Vegetation cover and its status was assessed using NDVI index and range condition was studied based on the four-factor method (present by FAO) and soil degradation maps were modified from the GLASOD soil degradation map. Results of the study were shown that most of rangelands in mountains and hill land are in good to medium condition, while there are also some rangelands with poor condition (mostly in dominated by piedmont). The human disturbance in some of these units are so high that original plant communities have been completely destroyed and invader species have been substituted. Field observations were also showed that human impact (i.e. over grazing and over intensive wood refuel gathering and shnib cutting) has contributed significantly in the changes of range condition. Based on the results of the conducted research study, it can be concluded that there is significant relationship between rangeland condition, land form, soil properties and flock movement. It therefore is essential to plan to match stocking and destocking of rangelands on the basis of spatial and temporal conditions. This plan can lead to improve the grazing condition and to control soil degradation of rangelands by soil erosion.