Effects of grazing exclusure on some soil physical and, its erodibility and carbon sequestration (Case study: Bozdaghin rangelands, North Khorasan, Iran)

In view of the increasing adoption of rangeland exclosure in order to rangeland improvement and carbon sequestration, investigation of its effects on the soil properties and calculation of the economic value of sequestered carbon is important. The aim of this study was to evaluate the changes in some soil physico-chemical properties, carbon sequestration rate and its economic value following grazing exclosure as compared with open grazing areas in Bozdaghi rangelands in North - Khorasan province, Iran. Therefore, in each area (exclosure and open grazing) three transects of 500 meter length and 200 meter intervals) were set up. Along each transect, five soil samples were taken at the depth of 0–15 cm in a random – systematic method (15 soil samples in each area) and transferred to the laboratory. In the laboratory, some soil physical and chemical properties such as soil texture, bulk density, porosity, saturation percentage, pH , EC , percentage of organic matter, total nitrogen, the amount of cation exchange capacity, exchangeable sodium, potassium, calcium, and magnesium were measured and erodibility index was calculated by using the modified clay ratio relation. Data analysis was performed by using independent t test in SPSS v.16 software. The results demonstrated that establishment of exclosure in Bozdaghi rangelands had significant positive effects on soil physico-chemical properties, and reduced the soil erodability index significantly (P