Early-stage impacts of conservation agriculture on soil health in a French Mediterranean irrigated system

In Mediterranean regions, climate change has intensified droughts and extreme weather events, accelerating soil degradation through organic matter loss, erosion, and nutrient depletion. Conservation agriculture (CA), involving practices like zero or reduced tillage, crop diversification, and soil cover maintenance, offers a resilient strategy for mitigating these challenges. This study examines the short-term effects of irrigated CA on soil health in Mediterranean conditions over 3 years (2021–2023). Using the Biofunctool® field kit (assessing carbon transformation, nutrient cycling, and structure maintenance) alongside functional indicators from the laboratory, the study compares CA with conventional tillage (CT) under different water supply methods: sprinkler, subsurface drip, and rainfed conditions. Results reveal that CA enhances soil health indicators from the first year, improving soil aggregation and carbon transformation compared to CT. By 18 months, Soil Health Index (SHI) scores were 38% higher in CA than in CT. Minimal soil disturbance in CA addressed compaction and maintained SHI 23% higher than CT. Neither the water supply mode nor temporality post-CA adoption significantly affected soil functions in the short term. The complementary use of field-based and laboratory indicators provided a holistic view of soil functionality, confirming the potential of CA to improve soil health under irrigated Mediterranean conditions.