Impact of Tillage and Residue Management on Hydro-physical Properties of Clay Soil under Rice-wheat Cropping System in Indo-Gangetic Plains of India

A field experiment on the residual impact of tillage operations and organic residues incorporation on hydro-physical properties of clay soil under the rice-wheat cropping system in split-plot design with three replications was carried out at the experimental farm of BAU, Sabour. The treatments of tillage operations and application of organic residues, along with their interactions, significantly decreased the soil strength/compaction and consequently bulk density of the soils over control. It was confirmed by the positive and highly significant correlation of soil strength with the bulk density (r = 0.802**). The maximum decrease was noted under T3 (Mould board plough) and C6 (GM + rice husk) and their interactions. A significant decrease in clod size was observed under treatments T3 and C6 and their interactions over control. The maximum increase in stable water-stable aggregates was estimated under treatments T3 and C6 and their interactions (T3 x C6) due to an increase in porosity and decrease in compaction of the soils which led to increasing in hydraulic conductivity. This was further confirmed by a positive and highly significant correlation of hydraulic conductivity with MWD (r = 0.788**) and negatively and highly significant correlation with compaction (r = -0.646**) and BD (r = -0.846**). It was revealed that the soil moisture content showed a variable increase with variable depth and observed their maximum values in T4 (28%) and C6 (29%) treatments at 45-60 cm depth of the soils. The increase in yield of wheat grain was highest under the influence of treatments (MB) T3 and C6 (GM + rice husk) and their interaction. These observations were further confirmed by the positive and highly significant correlation of yield of wheat grain with MWD (r = 0.514*) and HC (r = 0.482*) and negative and highly significant correlation with soil strength (r = -0.649**). The most effective treatments were T3 and C6 and their interactions, while minimum improvements were noted under T1 (desi plough) and C3 (paddy straw) and their interactions.