Examining the effect of land use changes on soil organic carbon.

Abstract

Significant demographic and socioeconomic pressures are exerted on carbon storing land uses such as forests in the tropics yet distribution and rates of change in tropical smallholder landscapes remain very uncertain. It is projected that if the forest loss continues at this rate, there will be nearly no tropical rainforest remaining by 2035 (Otukei and Male, 2015). SOC sequestering is seen as one way to mitigate climate change by reducing atmospheric carbon dioxide. The argument is that increase of SOC over very large areas will significantly reduce atmospheric carbon dioxide, improve soil quality through increased retention of water and nutrients, resulting in greater productivity of plants in natural environments and agricultural settings. However, there is lack of knowledge of the potential amount of carbon sequestered under the different land-use types and thus the spatial distribution of SOC in the different land uses is not known. This study was conducted to assess the relationship between Land use land cover change and SOC loss, a change detection for LULC in Najjemebe Sub County between 2000 and 2020 was performed to investigate the changes in LULC over that period. The SOC stocks in the current LULC classes was estimated to determine the sequestration capacity of each LULC class. The SOC stocks in the base year were estimated at the quantity of that of the forest class since it covered the largest percentage of the study area then. Investigations from this study reveal that area previously covered by forest were converted in to land uses such as grassland, cropland and built-up which had different effects on the SOC stocks quantities. Grasslands sequestered more SOC of about 49.111Gg while settlements and cropland resulted in SOC loss of about 12.302Gg and 39.25Gg respectively between 2000 and 2020.