Abstract
Straw cover protects soil from erosion caused by wind and water. For this purpose, small amount of straw is needed be
incorporation into soil. Tillage was done by disc in a soil-bin filled with paddy field soil with straw cover (100 g.m-2) at three
speeds and depths to study forces acting on disc, burial straw rate of different lengths of straw (7,13, and 19 cm), soil
disturbance and change in bulk density. Results showed draft, vertical and side forces of the disc increased from 533 to 1236,
243 to 632, and 418 to 1063 N. Disc tillage tool brought 47 to 86% of the straw buried in the 0-15 cm layer having smallest
straw length (7cm) share of 39 % as maximum. Further soil bulk density was improved from 8.5 to 26.9 % as depth and
speed was increased. Moreover, soil disturbance area was highest at 15 cm while lowest at 5 cm. Forces of disc, burial straw,
soil disturbance area and bulk density were highly significantly (p<0.05) at higher speed and depth. Present research
indicated that powered disc has provided constant and horizontal flow of furrow wedge to the side with more soil disturbed
area.
