the effect of land use change on some of carbon components in bulk soil and aggregates in safashahr area, fars province

this study was conducted to investigate the impact of land use change on some of carbon components in safashahr area, fars province. four land uses (destroyed rangeland, agricultural land, new and old apple orchard) were selected. sampling was done randomly from two depths (0-20 and 20-50 cm) of each land use. particulate organic matter (pom) and extractable carbohydrate by hot water were measured in both bulk soil and aggregate particles and mineral-associated organic matter and carbon pool were measured in bulk soil. results showed that particulate organic matter, carbohydrate, and carbon pool in old apple orchard increased significantly. results also showed that the particulate organic matter in old apple orchard, agricultural land and new apple orchard increased 333, 120 and 113%, respectively. as components of organic matter have been accumulated in the macro-aggregates and these aggregates have high sensitivity to soil degradation, it is expected that the factors which control the stability or degradation of these aggregates may control organic carbon pool of soils as well.