Long term effect of crop residue and tillage on carbon sequestration, soil aggregation and crop productivity in rice (Oryza sativa)-wheat (Triticum aestivum) cropping system under partially reclaimed sodic soils

A long-term field experiment (2006–2016) was laid out at Karnal, Haryana, to evaluate long-term effect of crop residue and tillage management on carbon sequestration potential, soil aggregates and wheat (Triticum aestivum L.) productivity under rice (Oryza sativa L.)-wheat cropping sequence on partially reclaimed sodic soil. Residue incorporation in conventional (CV + R) and reduced tillage (RT + R) resulted in significantly higher system productivity (13.01 t/ha and 12.48 t/ha respectively) than other treatments used in present study. Soil properties also improved with zero tillage and residue incorporation. The soil organic carbon (SOC) under tillage with residue treatments (CV+R, RT+R and ZT+R) increased from 14.81 to 39.47% at 0–15 cm soil depth over the control. The highest carbon sequestration potential (0.67 t/ha/year) was obtained in zero tillage + residue (ZT+R) treatment at 0–15 cm soil depth. Crop residue in zero tillage favoured a higher amount of carbon to be preferentially stabilized in fine and coarse aggregates. Crop residue either incorporated in conventional and reduced tillage or anchors in zero tillage proved a useful indicator for assessing soil carbon and sustaining crop productivity in the partially reclaimed sodic soil.