New solution to deep level ground compaction in orchards and vineyards

Compaction caused by vehicles is a common problem in orchards and vineyards – mainly because narrow-spaced plant rows mean that vehicle wheels must travel on the same ground during every pass. Shallow compaction can be removed by low-disturbance subsoiling, or during re-seeding. However, when the compacted layer is deeper, then the new Air Jet Ground Aerator can provide a practical solution.

PJM Agri managing directors Pete and James Matsell, with the machine’s inventor, Peter Knight.

The operating principle is simple. A hollow metal probe is pushed down into the ground by a pair of hydraulic rams, and air at high pressure is discharged through vents at the sides. The air is forced directly into the compacted layers causing separation and cracks which allow plant roots and water to penetrate.

“It’s relatively easy to remove compaction in the top 20cm of soil, but much harder to tackle when it’s further down,” explained Peter Knight, who designed the Airjet Ground Aerator. “Our development trials included various situations; including sports grounds, grassland and even loosening subsoil below compressed type-one aggregate making up a school car park, and in all situations it proved very successful.”

Peter says that an exclusive compaction targeting system is key to the machine’s success. The user identifies the depth at which compaction is present using a ground penetrometer. Then a simple pin adjustment matches the air discharge point(s) precisely to suit. The user positions, then activates the probe which descends to a pre-set depth (50cm max) – automatically discharging air into the compacted layers as the vent hole passes. Air is discharged again at the same points as the probe retracts.

Compaction caused by vehicles is a common problem in orchards and vineyards.

The loosening effect depends on the soil type and conditions, but Peter estimates that 122 activations are needed for areas up to 400m2, and this takes approximately one hour.

Peter stresses that large volumes of air are required, rather than particularly high pressures. “We recommend setting the integral air reservoir to about 100psi. Using higher pressures creates more subsoil disturbance than necessary which could leave the surface uneven.”

Air can be supplied by a mounted portable air compressor, or one nearby linked by an umbilical hose.

The Airjet Ground Aerator is being marketed by PJM Agri Ltd, also based in Suffolk. “Soil compaction is a major problem for many vineyards and orchards, and the effects are well-known in terms of reducing crop quality and yields,” said PJM Agri agricultural specialist, Pete Matsell. “This tractor-mounted implement is fast and convenient, and automatic operation reduces user fatigue and boosts workrates.”