A range of measures are needed to combat nitrogen and phosphorus leakage into watercourses, the Environmental Protection Agency (EPA) has said.

A map published by the EPA shows the areas of the country where nitrogen leakage is occurring in the south and south-east of the country.

Map showing nitrogen and phosphorus leakage \ EPA

Speaking to the Irish Farmers Journal, Dr Jenny Deakin, manager of the catchment science and management unit with the EPA, said the map shows where the problems are most acute.

“There are two different problems highlighted on the map – nitrogen leakage and phosphorus/sediment leakage.

“Nitrogen leakage is an issue. Nitrogen leaches down through the soil, through the groundwater, which then links up with a stream before reaching rivers and estuaries.

“Pathway interceptions are not as effective [as they would be for phosphorus leakage] at reducing leaching effectively. Some countries do them, but they would be less effective in the Irish landscape,” she said.

The EPA has said that using less nitrogen fertiliser and using it more effectively would be a solution to the leakage.

Phosphorus leakage

“Issues with phosphorus or sediment are on poorly draining soils, mostly in the west, northwest and northeast. The problem is that sediment and phosphorus are running off overland and into watercourses.

A tiny amount of phosphorus can cause a problem,” she said, adding that a couple of hundred grams per hectare can cause damage.

Phosphorus loss

To combat phosphorus (P) loss, the EPA has outlined a number of measures to block the movement of P into watercourses.

These include buffer zones, hedges, farm ponds and management of ditches.

“The best scenario is for farmers and advisers to look at the farm and see what needs to be achieved, and what the farm is risky for in terms of N or P loss, and what measures that farm falls into to improve those losses,” Dr Deakin said.