Nearly half of Northern Ireland’s fields have been tested as part of the groundbreaking Soil Nutrient Health Scheme, designed to help farmers optimise soil nutrient management.

Approximately 70% of farms have registered for the £37 million program, the first of its kind globally, run by the Agri-Food and Biosciences Institute.

The scheme aims to address nutrient imbalances, such as excess nitrogen and phosphorus, which can lead to water quality issues and algal blooms in bodies like Lough Neagh through agricultural runoff. By identifying the specific nutrient makeup of their soil, farmers can target fertiliser applications more precisely, reducing excess nutrients over time.

Now in its third year, the program is expanding into the northwest. Fields not previously sampled in zones one and two will also be tested. Soil samplers employ a meticulous method, walking fields in a W-pattern and collecting soil plugs at set intervals. These samples are then analysed to determine the field’s existing nutrient levels and guide future fertiliser application.

Farmers receive detailed soil maps and training to achieve optimal soil health for grass production. Project lead Alex Higgins highlighted that soil pH levels in the zones tested so far are below recommended levels. Variations in average pH between zones reflect differences in farm use and physical conditions, such as increased rainfall in western areas.

Higgins noted that neutralising soil acidity will enhance nutrient uptake efficiency and reduce runoff of nitrogen (N) and phosphorus (P) into water bodies like Lough Neagh.

The long-term challenge of phosphorus is significant. Scientists estimate that phosphorus already settled in Lough Neagh will take about 40 years to deplete naturally. Dr. Rachel Cassidy, the scheme’s scientific lead, reported that phosphorus levels in tested soils often exceed recommended thresholds.

“Considering ongoing concerns over Lough Neagh, farmers are encouraged to carefully consider their P applications and to use the results in conjunction with the online run-off risk maps, which indicate areas of fields most at risk of nutrient loss during rainfall.”

By the program’s conclusion in 2026, all 700,000 fields in Northern Ireland are expected to be sampled and mapped. This ambitious initiative aims to promote sustainable farming practices, improve water quality, and support the health of the region’s ecosystems for future generations.