Soil degradation and climate change are threatening the sustainability of Mediterranean
olive orchards, typically grown under rainfed conditions and conventional soil tillage. Thus, implementing
sustainable soil management practices is crucial to preserve soil health and mitigate the
negative effects on plant performance. In this study, we assessed the effects of conventional tillage
(T), an early maturing and self-reseeding annual legume cover crop (LC) and its combination with
natural zeolites (ZL) on plant physiological performance, tree nutritional status, crop yield, and soil
physicochemical and microbiological properties. Although both LC and ZL enhanced the photosynthetic
activity, tree nutritional status, soil moisture and olive yield relative to T, ZL was clearly more
efficient at improving some soil health indicators, namely at the 0–10 cm soil layer, once soil acidity
decreased and Kjeldahl N, extractable P and B, cation exchange capacity and microbiological activity
increased, as evidenced by the higher concentrations of easily extractable and total glomalin-related
soil protein, microbial biomass carbon, microbial biomass quotient, and actinomycetes. Therefore,
using natural zeolite with leguminous cover crops appears to be a promising strategy of sustainable
soil management in rainfed olive orchards, as it is able to provide numerous ecosystem services.
This research was funded by a doctoral fellowship under the Doctoral Program “Agricultural
Production Chains—from fork to farm” (PD/00122/2012) provided by the FCT-Portuguese
Foundation for Science and Technology to S. Martins (PD/BD/135327/2017) and by the Operational
Group “Novas práticas em olivais de sequeiro: estratégias de mitigação e adaptação às alterações
climáticas”, funded by PT2020 and European Agricultural Fund for Rural Development (EAFRD). The
authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under
Program PT2020 for their financial support to CQ-VR (UIDB/00616/2020), CIMO (UIDB/00690/2020)
and CITAB (UIDB/04033/2020) and also to the AgriFood XXI Project, No. NORTE-01-0145-FEDER-
000041, co-financed by the European Regional Development Fund (ERDF) through the North Regional
Operational (NORTE) Program 2014–2020.
