Abstract:
A field study of the effects of the microshape of a disc plough on the draught
requirement and the final soil tilth was conducted on a tropical agricultural soil. Three
factor-factorial experiment with three replicates ,\\ere conducted with three levels of tilt
angle. Soil data were acquired to help support the findings of the study. The disc blades
used were of uniform radius of curvature (concavity) size (diameter) and edge sharpness
to eliminate their effects on the performance of the tools. The magnitude of the angle of
soil-metal friction (which was used as an index of surface roughness) of the three
different blade surfaces are 19°, 14° and 21.6° respectively. The disk surface with the
greatest surface roughness gave the highest draught and highest Mean Weight Diameter
(MWD). An advantage of the disk plough, with revolving discs revealed that it requires
less effort and is highly efficient while working on soils having adhesion.
A mathematical relationship was established between MWD and other tillage
parameters under study. From the analysis, speed is the most strongly linearly related
variable to MWD. Also, there are no significant differences in the interaction of the three
input factors of tillage study namely. (Tool's surface roughness, tilt angle and speed).
Hence these factors are independent.
