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

Abstract

The main objectives of the current study are i) to estimate SOC in different soil depths andto generate their spatial distribution maps, ii) to assess relationship between variation ofdifferent soil types and SOC density, iii) to determine effects of land cover types on SOC inInebolu Watershed located in sub-humid terrestrial ecosystem. In order to determine landcover types of the study area, aster satellite image was used and five main land covertypes that are bare land, sparsely vegetated area, broadleaved forest area, mixed forestarea and needleleaved forest area were classified. Results indicated that soil types andland cover were two crucial influencing factors for spatial variation of SOC density. It wasdetermined that SOC density of soil types, Vertic Haplustept (12.93 kg.m-2) wassignificantly higher than other soil subgroups. In this case, it can be said that main reasonsof 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 densityvariability and was the main controlling factor in the surface; in the subsurface, not onlyland 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 concludethat the combination of the soil type and land cover was a dramatically better predictor ofSOC density.