Ensuring the correct soil pH can result in the release of 80kg of nitrogen per hectare per year, the Farming for Soil Health event at Johnstown Castle in Wexford heard last week.

Dr Patrick Forrestal of Teagasc outlined that correcting soil pH should be at the top of farmers’ lists in order to increase soil nutrient supply.

The field day, held in association with the third Global Soil Biodiversity Conference, showed different practices and technologies that can be adopted on farms to both assess and enhance soil health. It included demonstrations of visual assessment techniques showing the damage of compaction and the effect different species’ roots can have on the soil, soil functional assessment and different practices that improve health in soils.

These ranged from the benefits of diversifying grassland swards, the role of cover crops, the benefits of straw incorporation in tillage soils and the importance of organic manures for soil biology.

Research officer Dónal Kinsella also spoke about ongoing research surrounding bio-fertilisers such as activated dairy sludge and cattle slurry.

Increasing soil carbon was also discussed on the day, with farmers receiving the latest information on the baseline measurement of soil organic carbon stocks on Irish farms, as well as their sequestration potential.

Cover crops

There was lively discussion on cover crops from farmers, with the take-home message from Martin Bourke, organic tillage specialist, being that nitrogen accumulation in cover crops does not necessarily mean a reduction in the fertiliser requirement.

However, legume cover crops such as clover or vetch have the potential to reduce N in the following crop.

The damage that compaction by machinery can have on soils was also discussed at length. Here, it was stressed that prevention was better than cure, with farmers urged to avoid trafficking on wet soils, while controlling traffic by considering fixing tramlines.