Long-term effect of crop residues incorporation on yield and soil physical properties under rice - wheat cropping system in calcareous soil

The crop residue and Zn addition impacts on above ground biomass yield, Zn uptake and physical properties, viz.mean weight diameter (MWD) of water stable aggregates, bulk density (BD) and water holding capacity (WHC) were measured under a rice-wheat system in the 17 th and 18 th crop cycles.Results indicate that the highest yield in both the crops was recorded in the treatment receiving 10 kg Zn/ha as starter dose + 100% straw produced by each crop.Long-term application of crop residues along with Zn increased grain yield.The MWD, BD and WHC of post-harvest soil measured after harvest of the wheat crop varied from 2.80-3.88mm, 1.27-1.42Mgm -3 and 33.32-47.53%,respectively.The treatment with 100% CR and 10 kg Zn/ha had the highest level of MWD and WHC, whereas it resulted into the lowest BD.Increasing levels of Zn also influenced the MWD of water stable aggregates, BD and WHC positively.The correlations of WHC and MWD of water stable aggregates with different plant parameters were positive and highly significant, thus, indicating their synergistic relationship, i.e. higher the WHC and MWD of water stable aggregates higher the crop yield and Zn utilization by crops.