The influence of changes in grazing intensity on soil properties in the southeastern alpine rangelands of Sabalan

To evaluate the effects of grazing on some physical and chemical properties of soil, in the summer rangelands of southern slopes of Sabalan, three regions with different grazing intensity were selected after field observation and 27 soil samples were randomly taken along three 200-m transects. Soil samples were taken from the depths of 15-0, 30-15 and 45-30 cm and transported to laboratory and soil properties such as texture, organic matter, organic carbon, phosphorus, potassium, EC and pH were measured. Analysis of variance and mean comparison were made using Duncan's test. Results showed that no significant difference was found for soil pH and phosphorus among the grazing intensity treatments and soil depths; however, significant differences were observed for other variables. The results showed that organic matter content decreased with increasing of grazing intensity and the lowest content was recorded for the 30-45 cm soil depth in the heavy grazing area. According to the results of this research it can be concluded that soil structure is degraded with increased grazing intensity; therefore, a balanced grazing need to be taken into account in summer rangelands to prevent soil degradation.