Many Welsh farms are missing out on grass yield potential because they fall short on pH and key macronutrients (P, K, Mg), a Farming Connect report of agricultural soils has shown.

More than 3,000 soil samples were collected by Farming Connect from grassland fields on livestock farms across Wales in the 12 months to March 2024.

Analysis of these has highlighted the opportunity for many farms to correct soil pH and indices needed for optimal grass production and environmental benefits.

Less than 50 per cent were at pH 6.0 – 7.0, the optimum range for grassland, with the majority (53 per cent) of soil samples below the optimum pH range.

Soil pH is integral to forage productivity as inadequate levels can negatively influence nutrient availability in soils and, as a consequence, forage performance.

Soils within an optimum pH range, will benefit livestock performance and farm economics as well as delivering environmental benefitsthrough maximising resource efficiency as a Sustainable Land Management Outcome.

Reviewing lime and fertiliser applications may therefore be needed as a first step to ensuring pH does not negatively affect fertiliser utilisation while also reducing the risk of nutrient losses via run-off which will improve water quality.

It was a similar picture for phosphorus (P) and potassium (K), again with fewer than half of soil samples at the optimum indexes for these nutrients. In fact, a large proportion of soil samples were categorised as being below the optimum P and K indexes.

For P and K, altering the indices is no quick fix as industry advice is to build up depleted levels, and to run down concentrations of nutrients that are higher than they should be.

A large percentage were higher than the optimum index for magnesium (Mg), which can cause soils to become difficult to work.

Mg concentrations at index 0 were also reported and circumstances in which livestock risk hypomagnesaemia (grass staggers) are principal reasons for correcting levels of this nutrient.

Siwan Howatson, head of technical at Farming Connect, said: “These results indicate the importance of regular soil testing and targeted nutrient management on farms.”