Influence of Land-Use Practices on Soil Organic Carbon and Microbial Biomass in Coffee and Orange Agroecosystems

The agroforestry and intercropping systems are recognized as important options for greenhouse gas mitigation. The primary objective of this study was to assess the impacts of land use change from Orange (O) monoculture to Coffee-Orange (CO) intercropping and Coffee-Forest (CF) agroforest systems, implemented 20 years ago, on soil properties at three different soil depth layers (0–10 cm, 10–20 cm, 20–30 cm), with a particular focus on microbial biomass carbon (MBC) and soil organic carbon (SOC) levels. Although there were no changes in most of the soil’s physical properties, the soil’s chemical properties varied significantly across different land use types. SOC was higher in CF and CO systems compared to the O system; however, only in the CO system was the SOC incorporated evenly across all depths. Regression analysis showed that, in the CO system, microbial biomass carbon increased significantly, suggesting that these systems are more promising for carbon sequestration. The low pH and phosphorus values in the agroforest system were identified as limiting factors for microbial biomass enhancement. Importantly, the integration of coffee into orange cultivation not only enhances economic benefits but also contributes to long-term carbon sequestration by increasing SOC in deeper soil layers.