Psychologists say there are five stages of grief: denial, anger, bargaining, depression and, finally, acceptance.

It’s almost 30 years since the then EEC first proposed regulating the use of nitrogen to protect water quality.

The outcome was the Nitrates Directive.

Over this 30-year period, farmers have gone through most of the stages of grief as outlined above. I am not sure what stage farmers are currently at, but acceptance of change is something I’m sensing a lot more of.

Future reductions in fertiliser usage is now looking inevitable. The EU Farm to Fork proposals and the current review of the Nitrates Derogation are all pointing towards a reduction in allowances for chemical nitrogen.

How much that reduction will be and when it will be implemented is yet to be decided, but a 10% reduction in fertiliser usage for 2022 has already been mooted as one possible outcome of the current Nitrates Review.

Soil fertility will increase in importance.

For intensive dairy farmers, a 10% reduction in chemical nitrogen usage will lower the maximum amount of fertiliser that can be applied from 250kgN/ha to 225kgN/ha. On a unit/acre basis, this is a reduction from a maximum of 200 units/acre to a maximum of 180 units/acre.

It is likely that a reduction in allowances will be initiated through the nitrogen tables in the Nitrates Directive, meaning that farmers at every stocking rate would get a lower allowance, not just those stocked above 170kg of organic N/ha.

The challenge for all farmers is to avoid a reduction in chemical nitrogen becoming a reduction in grass growth leading to a reduction in stock numbers, an increase in purchased feed costs or having to take on more land just to maintain current stock numbers.

A recently published study by Teagasc found that farm profit will fall if nitrogen fertiliser is reduced.

The analysis modelled the profitability of a 40ha dairy farm stocked at 2.5 cows/ha and applying 250kgN/ha. The impact of a 10% and 20% reduction in nitrogen usage was looked at under three different scenarios:

  • A reduction in cow numbers and variable and fixed costs.
  • A reduction in cow numbers with no change to fixed costs.
  • Similar cow numbers but higher feed costs.
  • A negative effect on profit was found under all scenarios. This ranged from a 3.75% drop in profit when nitrogen is cut by 10% and when cow numbers and costs can be adjusted to a 9.6% drop in profit when nitrogen is reduced by 20% and cow numbers remain the same but extra feed is purchased in.

    As explained in Table 1, the average reduction in profit from a 10% cut in nitrogen is 4.45%, while the average cut in profit from a 20% drop in nitrogen will be 8.4%.

    Mitigating risks

    The Teagasc report makes for sobering reading. However, the report correctly points out that clover has a role to play in replacing chemical nitrogen as a means of supplying nitrogen to the soil.

    It has delivered on the Moorepark and Clonakilty research farms but adoption on commercial dairy farms has been minimal, despite positive research results going back over 20 years.

    The crux of the issue is clover content. In order to get appropriate nitrogen fixation and improved cow performance, there needs to be between 20% and 25% of clover in the sward on average over the year.

    This will vary depending on the season, with clover content peaking in late summer/early autumn.

    It has proven difficult to replicate this level of clover in research stations on to commercial dairy farms.

    A Teagasc study examining over sowing clover on nine commercial farms in 2017 had mixed results. Three of the nine farms were considered successful, with clover contents of between 17% and 19% in 2018.

    The other six farms had clover contents of between 0% and 11% in 2018. An expanded on-farm clover study is currently under way, taking in more farms and differing soil types.

    The bottom line is that when it comes to clover, farmers have more questions than answers. Issues such as how best to establish it, how to manage weeds, what sprays to use, what cover to close at, when to graze in spring, how much nitrogen to spread, what soil fertility is required and how to manage bloat are all questions without answers.

    Considering a reduction in nitrogen use is set to cost farmers something between 5% and 10% in lost profit – there needs to be a sense of urgency in finding these answers.

    There is a war on nitrogen. Farmers are on the front line and will be the first to take the hit, but the whole industry will suffer unless solutions are found on clover fast.

    Other approaches

    While clover is the big-ticket item, some farmers will find ways to reduce nitrogen while avoiding a drop in output.

    Low-emission slurry spreading (LESS), while designed to reduce ammonia emissions, has the added benefits of transferring more nitrogen to the soil and the ability to apply slurry to grazing ground in the rotation.

    Low-emission slurry spreading will help to improve nitrogen use efficiency. \ Odhran Ducie

    Slurry spread with a splash plate has to be applied to low covers and typically it has to be left for six or seven weeks between spreading and grazing as the leaf of the grass can be contaminated. This is much less of an issue with slurry applied by LESS. It can be spread on higher covers and grazed again in three or four weeks and often in less time.

    This slurry can be used to replace nitrogen in spring, whereas previous advice was to apply slurry and to apply chemical nitrogen. Every 2,500 gallons/acre of slurry equates to about 18 units/acre of nitrogen.

    Another area where some farmers feel they can make savings on nitrogen is on silage ground. While the previous advice was to apply 100 units/acre of nitrogen at closing, some farmers have successfully reduced this while not having an apparent reduction in silage yields. They are achieving this by fully accounting for the nitrogen available in slurry.

    In other cases, they are splitting the nitrogen application in two smaller amounts.

    So rather than applying say 100 units/acre of nitrogen at closing in early April, they are spreading 40 units/acre then and another 40 units/acre in early May.

    The thinking is that while less nitrogen in total is being applied, there will be a better response per unit applied.

    The other big area that can mitigate against lower nitrogen rates is soil fertility, specifically soil pH.

    Appropriate soil fertility, particularly pH, will help to release more organic nitrogen.

    Soil acidity locks up other important nutrients and it also restricts important soil life such as earthworms and a whole plethora of soil microbes. These soil biota serve an important function in breaking down organic matter and releasing soil nitrogen.

    Clover – next steps

    It is unacceptable that farmers should be faced with a sharp cut in income due to changes in Government or EU environmental policy.

    Remember, it’s not that long ago when farmers were encouraged by State agencies to spread 300 to 400 units/acre of nitrogen to maximise grass growth.

    Clover is continually being advocated as the solution to reductions in chemical nitrogen, but as demonstrated there are massive gaps in research, practical on farm management and advice around clover.

    If this is a war on nitrogen, a wartime response is needed. A beefed-up Teagasc project dedicated to research and advice on clover across different soil types needs to be established. Resources should not be a limiting factor in order for this to happen.

    The State has failed to properly resource clover experimentation up to now, but it would be unforgivable to let this continue, while dairy farmers suffer the consequences.

    The irony of the debate is that if clover replaces chemical nitrogen, it’s unlikely there will be any improvement in water quality as nitrogen is nitrogen, whether it comes from a bag or fixed from the air. Maybe they don’t want clover to succeed after all?