Effects of conservation and standard tillage on soil physico-chemical properties and overall quality in a semi-arid agrosystem

Context: Shifting agricultural operations to more sustainable management practices is needed in the face of a changing climate. Aims: In this study, the short-term effects of three tillage systems (no tillage, minimum tillage and conventional tillage) on a wide selection of soil properties in a semi-arid agrosystem of eastern Tunisia were assessed. Methods: The studied soil properties included saturation percentage, bulk density, penetration resistance, mean weight diameter, electric conductivity, soil reaction, soil organic matter, carbonates, available phosphorus and exchangeable potassium. The impacts of tillage systems on soil quality indices (SQI) developed based on the total set of properties (SQI-T), or a minimum set (SQI-M) selected through principal component analysis, were also investigated. Key results: Relative to conventional tillage, no tillage increased bulk density, penetration resistance and electrical conductivity, whereas minimum tillage affected only saturation percentage and pH. No tillage and minimum tillage did not enhance soil quality relative to conventional tillage. The SQI-T and SQI-M were highly correlated (r = 0.93) to each other suggesting that the outcomes of the two indices are comparable. Principal component analysis efficiently selected the most influential indicators of the effects of tillage systems on soil quality. Conclusions and implications: Farmers in the study region are encouraged to consider minimum tillage during the early years of transition from standard to no tillage systems to avoid rapid decline in soil quality and consequent yield loss.