Change Drivers and Spatial Distribution of Soil Organic Carbon Concentrations in Croplands of Morocco

Soil organic carbon (SOC), a vital component of soil organic matter, plays a critical role in soil productivity, stability, and mitigating CO2 emissions. Factors such as climate, mineralogy, and vegetation influence SOC cycling, but its distribution patterns in Mediterranean arid croplands remain unclear. Using a spatiotemporal modeling approach, researchers analyzed a multi-year dataset of topsoil organic carbon concentrations from over 31,000 cropland sites in Morocco. These data were linked with environmental variables, including climate, vegetation, topography, and soil characteristics, to identify the drivers of spatiotemporal SOC changes.

The analysis revealed a low median SOC concentration of 11.71 g C kg⁻¹, with significant variability (Q1 = 8.46, Q3 = 16.24 g C kg⁻¹). Bioclimatic factors, particularly temperature seasonality and annual mean temperature, accounted for 57% of the variation in SOC content, along with contributions from vegetation and precipitation. This national dataset provides new insights into the environmental drivers of SOC variability in Morocco's arid croplands, shedding light on the mechanisms of SOC gain and loss and informing discussions about carbon cycling in arid soils and their response to climate change.