Effects of Climate, Soil Properties, and Cultivation on Soil Organic Carbon in Croplands of Chile.

The changes in soil organic carbon (SOC) stock are mainly explained by climate, land use management and soil type. The soils located in semiarid climate are more vulnerable to SOC loss and degradation. In Chile, these soils correspond to 13% of the national territory and enclosed the most important agricultural production systems in the country. Previous studies in the semiarid zones have shown that SOC stock has decreased up to 50% in the last 35 years, while in southern Chile (with a temperate rainy climate) SOC have increased over the time. These soils are rich in SOC, with levels up to 150 tC ha^-1 in cultivated areas. Because of the difficulties for measuring the spatial and temporal variations in SOC, using a simulation model is highly convenient to evaluate the effects of climate and agricultural management. In this context, the objective of this study was to evaluate the SOC changes between 1980 and 2015 as a function of the climate, soil properties and agricultural management. With this purpose, the RothC model was calibrated based on actual field data, and used to understand the soil carbon dynamics in the study area. This paper identifies the key factor controlling the SOC content, its resilience, and the opportunities to implement strategies for SOC restoration in agricultural ecosystems.