Changes in Soil Carbon Stocks and Vegetative Indices in the Transitional Phases from Degraded Grassland to an Agroforestry System in the Cerrado Region, Brazil

Soil organic matter (SOM) is a key soil property used to predict the impacts of land-use changes as well as to indicate soil health status. The vegetative indices (VI) derived from remote-sensing data, such as soil adjusted vegetation index (SAVI), normalized difference vegetation index (NDVI) and normalized difference moisture index (NDMI) are important indices reflecting crop growth and biomass. They can be related to soil organic carbon changes in large-scale environments. However, there is little information in the literature about the relationship between VI and soil carbon changes over the transition of different farming practices from degraded grassland to an agroforestry system. This study aimed to determine the relationship between soil C stocks and VI over the transition of degraded grassland (DGL) to agroforestry (AgrfS) in the Brazilian Cerrado. Soil organic stocks, NDVI, SAVI and NDMI were measured from 2011 to 2015, when the area passed from a low-productivity grassland, followed by a crop-pasture intercropping system and an agroforestry system. The transitional phases from degraded grassland to agroforestry system promoted surprisingly large gains in soil carbon stocks, ranging from 41.7 Mg C ha⁻¹ in DGL to 68.4 Mg C ha⁻¹ in AgrfS. Similar to soil carbon stocks, the mean VI values increased over the years from DGL to AgrfS, indicating the importance of vegetation indices to predict soil carbon stocks changes over the restoration of degraded grasslands.