A 3-year field study on the effects of conservation agriculture on crop growth, yield, and quality in sustainable farming systems

Strengthening the resilience of agroecosystems to climate-related stresses requires the implementation of sustainable soil and crop management practices that enhance resource-use efficiency and buffer the effects of unfavorable environmental conditions. This study evaluated over three consecutive growing seasons in southern Spain the combined effects of reduced tillage, biosolid compost application, and rainfall exclusion on a Mediterranean rainfed crop rotation system (faba bean and wheat). The main objective was to determine whether sustainable soil management can mitigate water and climatic stress in these agroecosystems. The results show that interannual climatic variability and crop type were the primary drivers of yield. Biomass and grain yields of wheat declined by more than 70% between the second and third years, largely due to differences in rainfall distribution. Nevertheless, reduced tillage progressively enhanced soil biological activity, significantly favoring arbuscular mycorrhizal fungal colonization and enabling plants to maintain higher stomatal conductance and photosynthetic capacity under moderate drought conditions. In contrast, biosolid compost application consistently improved crop nutritional status, increasing leaf concentrations of potassium, sulfur, and nitrogen, as well as grain protein, while while modifying nitrogen acquisition dynamics relative to mineral fertilization. In conclusion, although extreme climatic factors may limit short-term yield, conservation agricultural practices such as reduced tillage and organic amendment complementarily strengthen the physiological resilience and long-term fertility of Mediterranean agricultural systems.