Carbon Sequestration Through Groundcovers and Pruning Residues in Sustainable Olive Orchards Under Different Edaphoclimatic Conditions

Soil organic carbon (SOC) is a key parameter of soil quality, and its improvement reduces the risk of desertification and provides several ecosystem services. Groundcovers are efficient for reducing soil degradation through erosion control and the improvement of organic matter. This article shows the effect of groundcovers with the addition of pruning residues on the SOC in olive orchards compared to soil management based on tillage. Four olive fields located in several edaphoclimatic zones of the Andalusia Region (southern Spain) were monitored, and the SOC stock was assessed during four seasons. The spontaneous groundcovers with the addition of shredded pruning residues had significant effects on SOC in all fields. The tillage treatment also increased the SOC content due to the carbon input through spontaneous vegetation and pruning residues, but to a lesser extent than the non-disturbed soil with groundcovers. The climate and soil characteristics of each zone, especially the clay content, determined the magnitude of the SOC increase. Carbon sequestration rates ranged from 0.02 to 3.02 MgC ha −1 yr −1 up to 30 cm in depth, and the SOC stock measured at the end of the four-season study period was significantly higher in the groundcover treatment, making this system sustainable in olive orchards and recommendable for the entailed ecosystem services.