The Effect of Different Land Use Age on Dynamic of Different forms of Soil Organic Carbon (Case Study: Chardangeh Area of Kiasar City)

The aim of this study was to investigate the effect of land use age on dynamic of different forms of soil organic carbon in Chahar Dangeh region of Kiasar, Mazandaran province. In this area, the studied habitats include pastures conversion to agricultural lands (barley) and orchards (apples and walnuts) in three different ages (more than 30 years, more than 20 years and less than 10 years) in Era, Erost and Vavsar villages. In each land use, soil sampling was performed systematic- randomly from 0-15 and 15-30 cm depths. In total, ten soil samples from land uses were transferred to the laboratory for analysis of soil organic carbon, particulate organic carbon, microbial biomass carbon, labile organic carbon. The variance analysis results indicated that the higher values of soil organic carbon, particulate organic carbon, microbial biomass carbon, labile organic carbon found in orchard use during 30 years old, which was located at a depth of 0-15 cm. Due to the conversion of rangeland to orchard use (age more than 30 years), soil organic carbon, particulate organic carbon, microbial biomass carbon, labile organic carbon increased in 86.18%, 68.42%, 61.13% and 66.94% respectively. Also, the highest amount of EC was found in orchard use older than 30 years. But pH in barley land use older than 30 years at a depth of 15-30 cm had the highest value. In general, the results of this study indicated that the effects of the studied factors on different forms of soil organic carbon depend on the time. Therefore, soil organic carbon management strategies should be adjusted according to the time period.