Modelling Land-Use and Land-Cover Impacts on Soil Organic Carbon, Soil Texture, and Bulk Density over a Global Range of Environments

Abstract:

Soils control the impacts of land-use and land-cover (LULC) changes on global water, energy, and biogeochemical cycles. However, Earth System Models often assume soil properties stay constant over time and that leaves uncertainties in model projections and impact assessments. This study models the impacts of agriculture, pasture, grazing, vegetation harvest, and secondary vegetation cover on soil organic carbon (SOC), texture, and bulk density based on meta-analyses of 737 paired observations from 140 publications and forward modelling. We quantify the impacts of LULC change globally and adjust for the effects of local climate, slope, and soil texture conditions. The models are able to explain about 45%, 36%, and 67% of the variance of observed SOC, texture, and bulk density changes reported in the literature, respectively. By simulating scenarios of high- and low- intensities of agriculture and grazing, we estimate low-intensity land uses could reduce SOC losses by 46 Pg globally. Our results can assist assessments of LULC impacts on soil conditions over a global range of environments and support studies of human impacts on water and climate in Earth systems models.