Poor soil structure could cost up to £220/ha…but can you avoid common pitfalls?

Healthy soils are said to be the engine driving production on any farm; but just how much could poor soil structure be costing your business?

Researchers say the cost of soil compaction in reduced forage production and utilisation could be as high as £220/ha.

Recent wet summers, mild winters and heavy modern machinery have not helped.

Around 450 people turned out to two Sustainable Soil Management events in Northern Ireland held earlier this month as part of the Farm Family Key Skills (FFKS) programme.

The events provided guided tours highlighting the importance of managing a healthy soil with the following key messages.

Advisors gave the following pieces of advice:

Soil structure

A healthy soil is well structured and porous with rounded crumbs and lumps that are friable and crumble easily.

The more porous the soil, the better the drainage and aeration; oxygen drives organic matter decomposition, nutrient uptake by plants and the whole biological activity associated with a healthy living soil.

To examine soil structure and identify drainage and compaction problems, dig inspection pits.

Avoiding compaction

Soil compaction reduces both forage production and utilisation and can cost up to £220/ha.

Compaction is more severe when working on cultivated or bare soils and in wetter conditions.

Try to avoid compaction by working with lower tyre pressures. In good conditions inflation pressures of 1.0-1.5 bar (14-21psi) are acceptable, but on cultivated or moist soils this needs to be reduced to 0.5-0.8 bar (7-10psi).

The recommendation is that axle loads should be 6t or less, yet slurry tankers with over 11t axle loads are being used on damp soils.

Advisors recommended checking tyre pressures, investing in lower pressure tyre options and considering alternatives to heavy machinery.

Alleviation of compaction

Alleviation work should only be carried out if it is really necessary as you may just create a bigger problem. If required then remember:

  • The right treatment – Depending on the depth of the issue and degree of compaction. Options include spiking, sward lifting, ploughing, subsoiling or mole draining;
  • The right depth – You must work 1-2in below the problem;
  • The right time – Soils must be dry enough to create cracks and fissures, ideally in the autumn. It is vital to allow the soil to rest as it will be unstable following treatment and should have no further machinery on it for several months.

Nutrient management

Soil pH is critical. Adequate lime both increases nutrient availability and improves soil structure.

Slurry is also a valuable resource – applying slurry to fields that need it most by trailing shoe will save money and the environment.

Sward improvement

Swards can be improved by management alone, stitching in, min-till or plough and reseed depending on conditions and desired outcome.

Reseeding is expensive but introduces higher performing varieties. Forage types and varieties should be tailored to match sward management. Ploughing is more expensive but may be needed to improve soil structure.