Comments
Incorporation, irrespective of machine, has sped the increase in sub-surface pH in some soils.
It is necessary to consider the speed of the operation and hectares covered, (ha/hr), along with implementation cost ($/ha) when incorporating lime.
A comparison of the TopDown with the small offset disc on area per day and the impact this has on the whole business, in terms of lime incorporation only, shows:
- TopDown 6m wide x 6km/hr = 3.6ha/hr. After 100hr, 360ha have been covered at a cost of $45 000, assuming $125/ha cost for the implement and process.
- Small offset 12m wide x 8km/hr = 9.75ha/hr. After 100hr, 975ha have been covered at a cost of $39 000, assuming $45/ha cost for the implement and process.
More than twice as much area is covered by the small offset, at a lower cost.
It may be that the cheaper option has smaller yield benefit though greater return given the larger area incorporated. This would allow for increased investment in lime for years following.
Acknowledgements
Thanks to Mark and John Flannagan for managing the trial; also to DAFWA technical services staff for their assistance and SoilTech for soil sampling.
This project is supported by the Northern Agricultural Catchments Council, through funding from the Australian Government’s National Landcare Programme.