The Environmental Protection Agency (EPA) has released a map showing how many tonnes of excess fertiliser were found in river catchments up to 2019.

The Irish Farmers Journal understands that the analysis, which was released this week, will be used in the final consultation of the Nitrates Action Plan review, due to be released next week.

The EPA highlights key catchments of concern where elevated nitrogen concentrations were found. These are mainly in the south, southeast and east of the country and include the Maigue/Deel, Bandon, Lee, Blackwater, Suir, Nore, Barrow, Slaney, Tolka/Liffey and the Boyne river catchments.

The EPA attributes 85% of the nitrogen sources in rural river catchments to agriculture, while the majority of nitrogen in the Tolka/Liffey catchment is from urban waste water.

The EPA warned that nitrogen concentrations in waters have been on the rise from 2013 to 2019, leading to unhealthy ecosystems.

Figure 1. Average nitrate concentrations in rivers for the period 2017-2019, showing elevated

concentrations in the catchments in the south, southeast and east of the country. \ EPA

Reduction needed

The EPA report warns that in some catchments, a cut as high as 8,000t of nitrogen would have been been required to prevent polluting some rivers.

It should be noted that 2018 was a year of extreme drought and fodder shortages, so nitrogen applied at the optimum timing may not have been used efficiently, once drought hit in the weeks following application. In addition, some may have been lost when rain arrived.

Since 2018, numerous measures to reduce nitrogen inputs have been increasing in popularity.

The use of low emissions slurry spreading equipment (LESS), protected urea, an increased focus on clover and improved grassland management are all resulting in a reduction in artificial nitrogen application, as well as other infrastructural changes such as fencing of watercourses.

However, the critical source area map that was published in the report clearly displays elevated nitrogen concentrations in some of the more intensively farmed areas of the country.

Tackling the issue will be difficult, as some farms may require a dramatic cut in nitrogen, while others may already be working from a low base, so a blanket cut solution will not suffice.