Effect of Zero Tillage Practice on Physical Properties of Soil: A Review

Abstract

Zero tillage (ZT), a core principle of conservation agriculture, minimizes soil disturbance and retains crop residues on the surface, offering a sustainable alternative to conventional tillage (CT). This review synthesizes research on the impact of ZT on key soil physical properties: bulk density, penetration resistance, hydraulic conductivity, infiltration rate, and moisture retention. Bulk density, a critical indicator of soil compaction and porosity, tends to be higher under ZT in initial years but decreases over time due to biological activity and residue-induced aggregation. Penetration resistance, which reflects mechanical impedance to root growth, may be elevated at the surface under ZT but is generally lower in deeper layers due to the absence of tillage-induced hardpans. Hydraulic conductivity and infiltration rate benefit from stable macropores and biopores preserved under ZT, enhancing water movement and reducing runoff. Surface residue cover also protects against slaking and sealing, improving infiltration efficiency. Moisture retention improves under ZT through reduced evaporation, increased soil organic carbon, and enhanced pore structure, leading to higher plant-available water. Field studies across diverse agro-ecosystems confirm that ZT supports better soil moisture dynamics and structural resilience. This review highlights ZT as a viable strategy for improving soil physical health and sustaining crop productivity under varying climatic conditions.