Soil compaction

Damage to soil structure largely arises due to compaction as a result of vehicle and livestock trafficking, particularly when soils are wet and can’t withstand the compressive pressures. Research has shown that compacted soils can reduce grass yields by up to 25% due to restricted water drainage, root growth and nutrient availability.

Avoiding soil compaction

Due to our typically wet climate, soils in Northern Ireland are at high risk of compaction; however, steps can be taken to manage our soils to avoid this which include:

Soil test regularly – maintaining soil nutrient levels (pH, P and K) at optimum will promote good structure development.
Avoid working in wet soil conditions – where possible, postpone vehicular access to fields for 48 hours after heavy rainfall. Damage can be greatly reduced if land is given time to soak and dry out.
Reduce total axle loads (ideally below 6t) – the higher the axel load the more potential for soil damage. Where possible, try and reduce the weight of the machinery needed, for example, the use of umbilical systems for the spreading of slurry.
Reduce tyre pressure -use the minimum tyre pressure recommended for the load, this will increase the tyre contact area with the soil distributing the load better. In good conditions inflation pressures of 1.0-1.5 bar (14-21psi) are acceptable, but on cultivated or moist soils this should be reduced to 0.5-0.8 bar (7-10psi).
Control livestock trampling- During wet conditions remove or reduce the stocking rate on susceptible fields.
Control field trafficking – if possible, try to plan field operations carefully to minimise the amount of travel within each field. With animals, especially dairy cattle, access to and from milking should be via hard standing laneways as much as possible.

Alleviating soil compaction

Lifting your spade and digging a test hole approximately 50 cm square and at least 40 cm deep to inspect soil structure is a good place to start. Examine the structure of soil removed and sides of the test hole carefully. This will allow you to determine if compaction is an issue and at what depth. This will determine the type of machine or management that should be used to rectify the problem. More information on the different types of machinery to alleviate soil compaction can be found on this document.