Potential storages and drivers of soil organic carbon and total nitrogen across river basin landscape: The case of Mo river basin (Togo) in West Africa

Abstract

tQuantification of carbon and nitrogen in soils in relation to ecological, landform and management factorsover river basins is essential to understand landscape ecosystem functions and efforts to manage landrestoration and the reduction of greenhouse gases emissions. Therefore, this research aimed at provid-ing distribution of the potential storage in soil organic carbon (SOC) and total nitrogen (TN) within themultifunctional landscapes of the Mo river basin in Togo. We (1) quantified the potential storages of SOCand TN under different land use/cover types, landscape positions, and land management regimes; and(2) highlighted the relationships among these soil chemical properties, in-situ ecological conditions, andother hypothesized controlling factors. We used soil data from 75 sample sites to determine the quan-tity of SOC and TN at two depths (0–10 cm and 10–30 cm). In-situ ecological variables were collectedsimultaneously during soil sampling. Spatial information on biophysical conditions of the study siteswere obtained from satellite images and most updated global topographic and soil databases. The resultsshowed that SOC and TN varied significantly according to land cover types, soil depths, topographicalpositions and land protection regime. Generally, forests and woodland contain highest SOC (4%) and TN(0.3%). Agricultural fields (fallowed and cultivating farms) exhibited the lowest values of SOC and TN,except in some selected farm sites where these chemicals are still high. Topsoil layer (0–10 cm) con-tribute up to 60% of the total nutrient contents in soils. The sequential multivariate statistical approachunpacked and quantified the effects of inter-dependent ecological, management and landform driverson the two important soil chemical properties (SOC and TN). The findings from this study could con-tribute to the improvement of national programme for assessing of greenhouse gases induced by land conversions. Based on this case-based finding in contextualization with related studies, we discussed onits implications for sustainable landscape restoration and climate change mitigation.