EFFECT OF COMPACTION AND TILLAGE ON THE YIELD AND PERCOLATION LOSS OF RICE IN LATERITIC SANDY LOAM SOIL

There is a large area of acid lateritic soils (Acrorthox) around Kharagpur in the state of West Bengal, India, where the top thin layer of soil mostly of detrital material, is underlain by a deep and highly porous lateritic crust (buried). Management of these soils poses a problem for their exceedingly high permeable nature. With the objective of increasing the production of rice in lateritic tract by way of reducing deep percolation, artificially compaction with the help of roller (800 kg) at the surface and subsurface levels were introduced under field conditions. Results indicate that the 6 passes of roller reduced the percolation by more than 3 folds over control. The increase in percolation rate with tillage depth was associated with the change in pore geometry obtained by tillage. The percentage increase in grain yield over the control was about 37 percent at 4 passes of compaction, the increase was attributed to the reduction of deep percolation losses. The decrease in yield at high level (6 passes) compaction may be attributed to increased mechanical impedance and reduced condition (low Eh [redox potential]) in the compacted soil. Yield of rice has increased significantly with tillage depths at high level (6 passes) compaction probably due to increased root penetration.