Estimate of erosion and sediment by using Cs-137

As one of the fauna and flora reservation sites, hyrcanian forest ecosystems have experienced sever destruction during recent decades because of the improper land uses. Use of fallout radionuclide, particularly Cs137, is one of the trusty methods in soil erosion rate. The purpose of this research was to estimate soil erosion rate in Hyrcanian forest heights in Ziarat catchment using radioactive element Cs137. Therefore, first Cs137 inventory was calculated in three land uses including forest, rangeland, and cultivate lands. After that, the erosion and sedimentation rates for each land use were determined using mass balance II model for cultivate areas and intuition and diffusion model for uncultivated area. The impact of land use on the soil erosion and sedimentation rate and organic carbon storage were investigated using ANOVA. The research found that the annual Cs137 inventory estimated was 575, 286, and 258 Bq/m2 in the forest, rangeland, and cultivate lands respectively. The maximum and minimum erosion rate had occurred in cultivated land by 39.8 and forest land by 5.2 ton/ha/y respectively. In addition, there was a positive correlation between erosion and sediment rate and organic carbon storage. The findings of this research can be used for sustainable management of Ziarat Catchment.