Immediate effects of reduced tillage on soil health in a rainfed vineyard under Mediterranean conditions
Study in northeast Spain by José M. Mirás-Avalos et al., (2026) in Applied Soil Ecology journal finds occasional tillage may support soil quality however has clear negative affects on soil fauna.
Headline Findings
Introducing cover crops in Mediterranean vineyards can increase competition for water and nutrients, making managers hesitant to replace tillage with permanent cover cropping. As a result, complete elimination of tillage is not currently recommended in these regions. Previous studies indicate that vineyard green cover provides short-term soil health benefits, mainly in the first year, primarily through improvements in biological, biochemical properties and reduced soil erosion. Physical improvements, such as aggregate stability and carbon sequestration, generally appear after four to five years. Consequently, occasional tillage (e.g., every other year) is recommended to balance benefits and drawbacks.
This study examines the immediate effects of reduced tillage on soil health in a vineyard in northeast Spain.
Methods
Six randomized soil samples (15 cm depth) were collected two weeks after tillage. Three composite samples were taken from inter-rows with spontaneous vegetation and under-vine rows with bare soil, across upper, middle, and lower slope positions. Samples were stored at −85 °C, air-dried, sieved (2 mm), and analyzed using standard protocols. Physical and chemical analyses included texture, field capacity, wilting point, pH, EC, organic matter and carbon, total nitrogen, available phosphorus and potassium, cation exchange capacity, active limestone, ammonium, and nitrate. Soil biological quality was assessed via microbial biomass, respiration, enzymatic activity, microarthropod diversity (QBS-ar index), and DNA-based microbial analysis.
Results
Most chemical properties showed no significant differences. However, organic matter and organic carbon were consistently lower in vine rows than in inter-rows, regardless of vegetation or tillage. Organic matter was on average 23% lower under tillage compared to spontaneous vegetation, with similar trends observed for nitrogen. Available potassium was 12% higher under tillage.
Biochemical indicators (soil respiration, microbial biomass, and enzymatic activity) were highest in inter-rows with spontaneous vegetation. Tillage reduced microarthropod biological forms by 60% and the QBS-ar index by 52% compared to vegetated inter-rows. Members of Planctomycetota were present under both bare and vegetated soils, indicating adaptability to different management practices. Bare soils showed higher abundance of Micrococcaceae (Actinobacteriota), Vicinamibacteraceae (Acidobacteriota), and Bacillaceae (Firmicutes).
Considerations and Limitations
Results may be influenced by the short interval between tillage and sampling (two to three weeks), shallow tillage depth (10–15 cm), and heavy rainfall prior to sampling. Further studies using similar methods over longer periods are recommended to better capture management effects.
Overall
Occasional tillage in Mediterranean vineyards may support soil quality and vineyard performance but has clear negative effects on soil fauna, likely due to physical disturbance and/or increased predation once exposed (Roger-Estrade et al., 2010).
Original study here.
