Abstract
Eight multiple-tine shares, consisting of narrow tines designed in accordance with established principles of soil/implement mechanics and soil failure theory, were developed and fabricated. The suitability of these shares for loosening soil at depth was investigated using draught force requirement and degree of soil disturbance as assessment criteria. Draught forces were measured using strain-gauge dynamometers wired through a d.c. signal amplifier unit into a multi-channel u.v. oscillograph. Cross-sectional soil disturbance profiles were captured by means of a multi-legged profile meter, and the areas bounded by these profiles were determined by polar planimetry. It was demonstrated that interactions among individual tines of a multiple-tine arrangement can effect significant reductions in share draught requirement, while simultaneously increasing the degree of soil disturbance at depth. It was also shown that staggered multiple-tine share arrangements can be superior to in-line multiple-tine configurations as tools for loosening soil at depth.