Protecting Our Water Habitats for Future Generations

By Joanne Masterson, ASSAP Adviser, Teagasc Galway/Clare

The Environmental Protection Agency (EPA) released a report recently on water quality in Ireland, which focused on years 2016-2021. The report looked at the ecological and chemical status of Ireland’s surface waters (rivers, lakes, canals and transitional and coastal waters) and ground waters. The report shows that unfortunately the quality of our waters and aquatic systems are being damaged by activities that cause water pollution and are having an impact on water habitats.

The main issues are from activities that release pollutants into the water environment and damage water habitats. The main causes are:

• Run off nutrients, sediment and pesticides from agricultural lands & farmyards
• Activities such as land drainage, dredging and presence of barriers such as dams, weirs, culverts in water courses
• Discharges of poorly treated sewage from urban waste water treatment plants, domestic systems
• Run-off of nutrients and sediment from forestry operations.

As a country, we are required to have all our waters achieving “good status” by 2027, which is a goal we must all work towards. Nitrogen (N) and Phosphorous (P) loss from agriculture are the main nutrients, which are prone to loss and contributing to the decline in this regard. 

Nitrogen (N) Loss

Most Nitrogen (N) losses are from free draining soils, N does not bind tightly to soils therefore leaching occurs when more N is applied than the grass plant needs, this excess N is leached by rain to waters. It is important to use nitrogen efficiency; this will help to reduce losses. It is important to remember the following: right time, right location, right rate & right product.

Right time:

Are soil temperatures suitable to get the most from your application? Slurry and fertiliser should only be applied when soil temperatures are above 6 degrees and ground conditions and weather forecast are suitable. It is important that the slurry applied gets down to the roots of plants such as grass in the growing season. Is there sufficient slurry storage on the farm? - Extra slurry storage allows more flexibility on spreading times, particularly in a very wet spring.

Right Location

If you have an up to date soil sample completed you will have a better idea of which areas need slurry/fertiliser first – target fields that have lower phosphorus (p) and potassium (k) indexes. When spreading, it is important to be mindful of buffer zones.

You must not spread organic manure within 5m of surface waters (extends to 10m for first 2 and last 2 weeks of the spreading season) and for chemical fertiliser you must not spread on land within 2m of surface waters

Right Rate

It is important to match the application rate to crop demand & growth rate and to be mindful of weather conditions when deciding to spread. Make sure to calibrate fertiliser spreaders before spreading, to ensure that the correct rate of fertiliser is going out. 

Right Product

Protected urea can lead to significant reduction in nitrogen losses, more nitrogen stays in the soil available for plant uptake. The use of Low Emission Slurry Spreading (LESS) equipment allows slurry to be spread on heavier grass covers, which improves nutrient uptake and helps reduce the risk of diffuse nutrient and ammonia losses

Phosphorus (P) Losses

Most P losses are from low permeability soils. Heavy rainfall leads to overland flow of water, which causes P and soil sediment to wash off into drains & streams. To help reduce or prevent P and sediment losses you will need to break the pathway. Below are some of the key ways to reduce P losses.

• Buffer strips – a buffer strip may be fenced or unfenced, planted with trees or just grass, but in all cases acts to intercept and take up excess nutrients before they negatively affect water. Ditches and drains are designed to remove water from fields but act as corridors and connecting pathways for nutrients and so buffer strips should be sited along these areas of potential losses.
• Riparian margins – The objective of a riparian margin is to protect the river by creating buffer zones alongside them where little or no agricultural activity takes place. Wider riparian margins are beneficial, particularly in more sloped, marginal land where there is a greater risk of surface water runoff carrying nutrient and sediment with it.
• Hedgerows & Woodland planting - A well-placed hedge acts as a barrier slowing the flow of water over land, reducing the force of overland flow. It filters sediment and mops up nutrients as it intercepts the flow.
• Managing out wintering of livestock – keep stock in suitable locations and avoid poaching and damage to ground, which will help to avoid sediment entering water.
• Reduced P applications - looking at your soil samples and doing a nutrient management plan for the farm will help to target areas rather than have blanket spreading, it will also help reduce costs of buying fertiliser.

All of these measures will help us on the road to improve water quality, it is also important to note that water quality is improving in some places. If the correct practices are implemented, these steps will help us to further improve our waters and to protect water habitats for future generations.