Spatial variability of soil organic carbon density under different land covers and soil types in a sub-humid terrestrial ecosystem

T he main objectives of the current study are i) to estimate SOC in different soil depths and to generate their spatial distribution maps, ii) to assess relationship between variation of different soil types and SOC density, iii) to determine effects of land cover types on SOC in Inebolu Watershed located in sub-humid terrestrial ecosystem. In order to determine land cover types of the study area, aster satellite image was used and five main land cover types that are bare land, sparsely vegetated area, broadleaved forest area, mixed forest area and needleleaved forest area were classified. Results indicated that soil types and land cover were two crucial influencing factors for spatial variation of SOC density. It was determined that SOC density of soil types, Vertic Haplustept ( 12.93 kg.m -2 ) was significantly higher than other soil subgroups. In this case, it can be said that main reasons of this result are indicated as soil profile depth and pedological development. In addition, when comparing the two main factors, land cover explained more of the SOC density variability and was the main controlling factor in the surface; in the subsurface, not only land cover types but also some properties of soil types such as texture, genetic horizons, soil depth have an important role on SOC density. On the other hand, it can be conclude that the combination of the soil type and land cover was a dramatically better predictor of SOC density.