Chandan Shilpakar

and 4 more

Grassland ecosystems, which cover over one-third of the Earth’s land area, store 10-30% of global soil carbon (C). However, these ecosystems face substantial impacts from human activities, including mining. This study investigates the spatial distribution of soil C and related environmental factors in reclaimed grasslands on former uranium mine sites in Wyoming. We hypothesized that grazing duration and environmental factors would influence soil C levels. Interactions between topography, vegetation diversity, soil properties, and soil C in the context of grazing management in both natural and reclaimed grasslands from of a wide range of periods from 1 year to 100 years were analyzed using Geographically Weighted Regression models. Data collected from 2022-23 showed that total carbon was consistently higher in natural grasslands (1.2-4.9%) than in reclaimed grasslands (0.8-1.3%). Additionally, soil C was significantly higher in natural grasslands grazed for 1 year compared to those grazed for 100 years. In contrast, reclaimed grasslands had lower soil C in areas grazed for 1 year compared to those grazed for 7 or 14 years. The absolute values of coefficients from environmental covariates indicated that areas grazed for a shorter duration (~1 year) were more influenced by biotic and abiotic factors than areas grazed for longer periods (>7 years). Our findings show moderate grazing increases the resiliency of grassland ecosystem when grazed 7 years or longer and acknowledge the roles of topographic, soil, and vegetative factors in enhancing soil C concentration and developing sustainable land management practice in rangeland conditions.