Do management practices which enhance nature-based processes improve soil health in olive groves?

Abstract

Olive orchards in marginal Mediterranean regions are often cultivated on shallow soils over sloping terrain, with extensive bare ground between tree canopies, leading to severe soil degradation. Implementing management practices that enhance nature-based processes (NBS) is crucial for reversing this trend. Developing simple yet sensitive indicators to assess the impact of these practices on soil quality is essential for evaluating progress toward sustainability goals. In this study, 31 soil health indicators were assessed across 12 olive groves implementing NBS, 12 conventional groves without NBS, and two forest ecosystems. An agroecological sustainability index (ASI) was used to score management practices. Compared to conventional groves, NBS-managed soils exhibited 52–285 % higher levels of soil organic carbon, total nitrogen, and microbiological activity, all of which were significantly correlated with ASI scores. Soil functional α-diversity was also significantly higher in NBS groves and comparable to or exceeding that of forest soils. A minimum data set of eight indicators was identified to establish a soil health index, with effectively detected variations in NBS implementation intensity, showing a significant correlation with ASI (r = 0.76). Overall, NBS adoption led to a 72 % recovery of soil health in olive groves. Given that the ASI relies on qualitative, easily accessible information for farmers and strongly correlates with the soil health index, it could serve as a practical tool for predicting NBS impacts and supporting the European Uniońs sustainability objectives.