Kieran Coughlan: Numbers behind water quality plans need fleshing out

As farmers, we don’t need to start measuring N losses on our own individual farms, but at least if we knew what the difference is between approaches to farming, informed choices could be made, writes rural accountant Kieran Coughlan.

Nationally, annual average river nitrate concentrations were the same in 2023 as in 2022, and there is no sign of improvement.

The EPA report into water quality for 2023 was issued this past week. The report isn’t a full assessment of Ireland’s water quality but an indicator report - we’ll have to until next year for a more comprehensive report as the next full report cycle will cover the period 2022 to 2024.

Nonetheless, the report does give insight into the direction of travel for water quality. Nationally, annual average river nitrate concentrations were the same in 2023 as in 2022, and there is no sign of improvement.

There is a debate as to whether the metrics used by the EPA to assess water and river quality are too high a bar.

There is also an argument to say why should we as a nation be looking to have pristine waters, cleaner than those which prevail in other European countries when it comes as such a high cost to business and communities?

There is an argument that farmers are being asked to do the heavy lifting on water quality, yet there is very little enforcement of water quality when it comes to wastewater, be it domestic one-off houses or urban discharges, which is contributing to river and lake pollution.

We are all aware of villages and towns and even cities where wastewater is not treated, or at certain times is discharged directly due to inadequate capacity.

Each of these factors deserves to be fleshed out, but from a PR perspective, if we are looking to convince our European neighbours that they should approve a renewal of the nitrates derogation, there is really only one core metric that will carry weight—has water quality improved relative to last year or last decade?

The problem with water quality and nitrates is that it is virtually impossible to know what factors are leading to elevated nitrate levels at any one testing site.

Indeed, some factors that we think might help us reduce our nitrogen usage might not be the case.

Something perhaps overlooked is that high clover swards can in some instances cause leaching where grass is not capable of taking up the available nitrogen, nitrogen losses can occur from the breakdown of organic matter such as the ploughing of old swards when replacing with what would be perceived to be a progressive move to multispecies swards.

Much of the nitrate leaching from cows is a result of urine patches rather than from dung or even slurry, and virtually none of the changes which have come in over the past few years are influencing that.

The goalposts are moving for farmers, but is there justification for the moves, which are sufficiently supported by science, and will they ultimately affect nitrate levels in rivers?

When it comes to emissions, Teagasc, to their credit, have done good work on the Marginal Abatement Cost Curve, which is essentially their roadmap as to how farmers can reduce their greenhouse emissions.

We already know, for example, that low-emission slurry spreading and protected urea products are two relatively simple and cost-effective ways to reduce emissions on our farms and can equally improve nitrogen efficiency.

When it comes to water quality, I expect farmers would be much more willing to implement changes to their farming practices if real-life examples were spelled out and their impact on water quality was tangibly quantified.

For example, what is the impact of river nitrate levels of spreading slurry on a wet spring day versus a fine summer’s day? What is impact on river quality from a farm stocked at 250kg/ha or stocked at 170kg/ha? What is the impact of, say, one or two rogue operators within a river or lake catchment area, and if they were brought into line, what effect would it have on improving river quality?

What is the impact on river quality if a tillage farmer grows winter crops instead of spring crops, or plants a cover crop versus none? Does red clover or multispecies sward establishment cause additional nitrate leaching when taken over a medium-term versus the retention of existing pasture or the establishment of ryegrass? 

Does the replanting of trees in commercial forestry cause leaching, and would a replanting program completed on a phased approach affect water nitrate levels?

Establishing a fertiliser register, reducing fertiliser inputs, imposing buffer strips and greater controls over slurry storage will have some impact on water quality but don’t be surprised if the impacts are minor given the whole host of other factors which are contributing to water N.

As farmers, our own farmers' representative bodies need to take ownership of it and work with Teagasc, the EPA and the Department of Agriculture to develop a roadmap that can measure and track the changes at the farm level required to bring improvements to water quality. 

As farmers, we don’t need to start measuring N losses on our own individual farms, but at least if we knew what the difference is between approaches to farming, informed choices could be made.