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 (20062016) 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 in- corporation in conventional (CV + R) and reduced tillage (RT + R) resulted in significantly higher system productiv- ity (13.01 t/ha and 12.48 t/ha respectively) than other treatments used in present study. Soil properties also im- proved with zero tillage and residue incorporation. The soil organic carbon (SOC) under tillage with residue treat- ments (CV+R, RT+R and ZT+R) increased from 14.81 to 39.47% at 015 cm soil depth over the control. The high- est carbon sequestration potential (0.67 t/ha/year) was obtained in zero tillage + residue (ZT+R) treatment at 015 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.