The Environmental Protection Agency (EPA) has launched a new online map for targeted agricultural measures in waterbodies of concern.

The map shows the ecological status of all waterbodies in Ireland and gives farmers an insight into what area(s) they need to look at on their farm in terms of nutrient leaching.

These maps provide the following information:

  • Ecological status for all waterbodies in Ireland.
  • Actions which have the greatest potential to improve water quality.
  • Rivers where agriculture is a significant pressure.
  • Critical source areas for N and P – areas where land is susceptible to losses.
  • Delivery flow paths

    The map is available on the EPA website and is further explained there. Farmers should examine the map to see the critical source areas on their farm.

    Based on whether phosphorus or nitrogen losses are a risk, farmers can then take action in order to mitigate the risk of losses.

    Understanding nutrient loss

    At Teagasc’s recent Woodlands for Water event in Moorepark, Agricultural Sustainability Support and Advisory Programme (ASSAP) advisers Claire Mooney and Cathal Somers explained what nitrogen and phosphorus losses are and what farmers can do about it in terms of nutrient management.

    Nitrogen (N) losses

    Cathal explained that free-draining soils are very susceptible to nitrate losses as N doesn’t bind to soil.

    If there is a surplus of N in the soil, it will wash away when heavy rain falls, potentially into groundwater and end up in waterways.

    He said that Teagasc is seeing a surplus of N at the back end of the year due to excessive spreading throughout the year.

    “Overapplying N causes a buildup of N and with the whole winter ahead, a large amount of this gets washed away due to rainfall. Reducing excess spreading, causing a surplus, can reduce leaching.”

    Ways to reduce N losses

  • Closed period: research has proven that up to half of our N is lost over the winter period. The closed period should be adhered to.
  • Right conditions: just because the closed period opens doesn’t mean that it is OK to spread.
  • Soil: soil temperatures have to rise above 5.5°C and ground conditions must be correct – no saturated soils or no frozen ground. Looking at the weather forecast before spreading is vital. If rain is forecast, slurry or fertiliser should not be spread.
  • Likewise, in the case of a soil moisture deficit (a drought), water is needed, and spreading N will not make grass grow.

  • Grass measuring: match nutrient application rates to grass growth rates. It is crucial to spread the right amount to avoid a surplus. Measuring grass is key to this. Leaching occurs when more N is available than what the plant needs.
  • Optimum fertility is important for phosphorus and potassium because it makes nitrogen uptake more efficient and produces a higher yield.

    Spreading lime to increase pH will increase fertility. The ideal pH for a mineral soil is 6.5.

  • Sulphur: additional sulphur increases nitrogen use efficiency and uptake and reduces nitrate leaching.
  • Phosphorus losses

    P is different to N in that it binds to soil and most losses occur in poorly draining soils, Claire told attendees.

    “In heavy rain, poorly draining soils become waterlogged, and the only way water can leave those fields is through overland flow.

    “The P and sediment are washed off the surface of the soil and into drains and streams,” she said.

    Teagasc is seeing a surplus of N at the back end of the year due to excessive spreading throughout the year.

    “Breaking the pathway is key to preventing P losses.

    “For example, if there is a slope going into a stream, the measures should be targeted there.

    “In that case, targeted planting should be looked at.”

    Ways to reduce P losses

    Targeted tree planting can break the pathway of overland flow and stop the P coming off elevated ground and into a waterway.

    Buffer strips can be implemented on all farms. When spreading fertiliser, stay at least 3m from the bank of the waterway, and this distance is 5m for slurry.

    A buffer strip of 10m should be kept two weeks either side of the closed period.

    Riparian margins along streams are another way of absorbing nutrients.

    Fence off drains to prevent animals from entering streams and offer alternative drinking sources.


    The recently announced water European Innovation Project (EIP) has €60m in funding allocated to improving water quality on farms, with €50m expected to go to farmers.

    For advice on measures to take and funding eligibility, farmers can go to their local ASSAP or Teagasc adviser.

  • Free-draining soils are susceptible to nitrate losses.
  • Surplus N in soils will wash away with heavy rain.
  • Breaking the pathway to a waterbody is key to prevent P losses.