Tine Design and Breakout Rating: Issues to consider for no-till seeding
Adopting no-till seeding means changing over to low disturbance narrow opener systems and tilling deeper furrows. Deeper tilling is often required to: 1. break-up existing hardpans, 2. reduce root disease pressure (Rhizoctonia Solani), 3. band fertiliser at depth, away from the seeds. With no prior cultivation and a deeper depth of furrow during seeding mean greater soil forces are applied onto the tine. Additionally, the soil forces are applied further away from the tine shank pivot point due to longer narrow openers used in no-till seeding, which artificially render the existing tine design weaker (Under Australian conditions, up to 20% weaker, depending upon tine design). The narrow opener tip should always remain behind the vertical axis of the tine shank pivot point for best performance. To dampen force impacts arising from large obstacles (stones, stumps), the no-till seeding tine must be allowed to break-away from the obstacle and return into work position without damage. The following tine characteristics should be assessed to decide whether existing tines are suitable for no-till seeding: 1. Breakout force rating; 2. Jump force cycle characteristics; 3. Tine frictional losses; 4. Jump height capacity; 5. Spring vs hydraulic release system.