EFFECT OF TILLAGE TOOL GEOMETRY ON SOIL STRUCTURE: CASE STUDY OF DISC PLOUGH

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.