Conservation agriculture improves soil physical properties and crop productivity: a long-term study in middle Indo-Gangetic Plains of India
K. K. Rao, S. K. Samal, S.P. Poonia, Rakesh Kumar, J. S. Mishra, B. P. Bhatt, S. K. Dwivedi, Surajit Mondal, Anish Choubey, Santosh Kumar, Manoj Kumar, R. K. Malik, Ram C. Dalal
Abstract
Context Conservation agriculture (CA) can potentially arrest deteorating soil fertility and improve crop production in the middle Indo-Gangetic Plains of India. Methods A field experiment (ICAR RCER, Patna, India; 2009–2016) tested four common farming practices: S1, a wheat–rice fallow rotation with complete removal of crop residues; S2, best management practices (BMPs) with puddled transplanted rice, drill-seeded wheat in no-tillage (NT), and drill-seeded mungbean in conventional tillage (CT) in a wheat–mungbean–rice rotation where residues were retained on surface in rice and wheat, and residue incorporated in mungbean; S3, CA system in a wheat–cowpea–rice rotation; and S4, BMP intensified and diversified cropping system in a potato + maize–cowpea–rice rotation (unpuddled transplanted rice with dribbled maize + potato, intercropped) in CT and relayed dibbling of cowpea in NT. Full residues of potato and cowpea were incorporated and one-third portion of rice and maize residue were retained on soil. Key results After 7 years, S2, S3 and S4 systems lowered soil bulk density and penetration resistance compared to S1. S3 resulted in higher soil macro-aggregates (>0.125 mm) and lower soil micro-aggregates (<0.125 mm). Avoiding tillage in wheat and including a food legume in rotation in S2 increased annual rice equivalent yields by 30.5–34.4%. S4 had the highest water productivity (1.04 kg rice equivalent grain m−3) and S1 had the lowest (0.64 kg rice equivalent grain m−3). Conclusions and implications NT and retention of crop residues have potential to improve soil health and monetary gains.