Draft Reduction without Increase in Power Requirement Using a Vertically Oscillating Model Subsoiler

Abstract

Draft and power ratios of a vertically oscillating model subsoiler was determined. The subsoiler was oscillated at varying amplitudes (5 mm, 10 mm, and 15 mm), frequencies (2 Hz, 3 Hz and 4 Hz) and forward speeds (0.05 m s^－1 and 0.20 m s^－1) resulting in velocity ratios ranging from 0.3 to 7.5. The mean draft and power ratios stood at 0.65 and 0.89, respectively. Draft ratio decreased with an increase in amplitude but increased with an increase in forward speed. Power ratio reduced with an increase in forward speed but was not significantly affected by frequency and amplitude. Velocity ratio of about 4 gave the optimum result. The main reason inducing draft and power reduction was observed to be soil pulverization and crack propagation caused by the lifting of the soil by the chisel ahead of the shank.