Last Wednesday we had jets of ground water blasting out from the turf on Seven Acres, outside the Terrace Cafeteria. What was going on? Aeration of the soil. Why? Because this area is heavily utilised for events and gets very compacted. The water table is quite high here too, so sometimes the turf is very soggy.
So why did we do it? We need our trees and turf to grow well in this heavily stressed area, and their health relies on healthy roots and soil. Wherever turf is failing due to heavy use, or wherever trees are dying back because of compaction and waterlogging, we need a method to restore a natural soil structure without destroying the trees and the surface of the turf.
The Terralift machines use air under pressure to restore the natural and vital circulation of air and water to the soil in the following ways:
• Extremely compacted ground is loosened
• Vital oxygen is injected into the ground to allow roots to breathe
• Long term gas exchange between soil and atmosphere is provided
Permeability of the soil is improved so that precipitation does not run off or stand around in stagnant puddles, but flows deep into the subsoil where it remains available at times of drought.
In came Terralift machinery, 'Airforce G'. It is a lightweight ride on machine with a hydraulically driven JCB hammer and rams that has one tonne of down force available to deliver the probe one metre down through compacted soil. It operates at up to 20 bar (280psi) on two-metre centre spacings repeated in a staggered grid pattern. Through the probe, dried nutrients are injected on the tail end of the main force of air, sticking to the fractures and fissures created by the main air blast. The air pressure can be adjusted so there is no surface damage. Backfilling the probe holes with aggregate aids in long-term aeration and drainage.
As a result of the high water table jets of ground water were forced back up out of some of the holes as the air was blasted in.
It looked quite bizarre, and caught the eye of a few of our visitors.