Effects of Land Use and Land Cover Changes on Soil Physicochemical Properties and Organic Carbon Stock in Shonkola Sub-Watershed, Soro District of Hadiya Zone, Southern Ethiopia

Abstract

Land use and land cover changes have effect on soil fertility, soil organic carbon stock and soil physicochemical properties. To determine the effects of LULC on selected physicochemical properties of soil and soil organic carbon stock (SOCS) a study was conducted in soro district of Hadiya Zone at Shonkola sub watershed under different land use types. Soil samples from 0 to 15 cm and 15 to 30 cm depth were collected from three major land use types; grassland, cultivated land and forestlands the soil samples were air dried, allowed to pass though 2mm sieve and transported to the laboratory for analysis. After analysis, the data were subjected to one away ANOVA to determine statistically significant differences and simple correlation analysis was used to observe relationships between selected soil parameters. The results of the study showed significant difference in some soil properties and soil organic carbon stock under the different land use types. Thus, soil under forest land had significantly higher values of SOC (3.00% and 2.69%) than grassland use type (2.05% and 1.54%) and cultivated land use type (1.36% and 0.98%); total nitrogen under forestland was 0.30% and 0.21% and under cultivated land was 0.16% and 0.06% in surface and subsurface layers, respectively. whereas SOC stock in forestland was 81.97 MgC/ha was significantly higher than those of cultivated land 50.74 MgC/ha use type. As results showed, most of the soil properties were decreased with soil depth in all the land use types and revealed positive and significant correlation (P≤ 0.05) with clay content while negatively and significantly correlated with bulk density. Hence, the forest covers had more potential contribution to enhance soil physicochemical properties compared with grazing and cultivate land. Detailed studies of soil organic carbon (SOC) dynamics are necessary in order to identify factors determining fluctuations and intensity of changes