At a recent farm walk in Laois, Teagasc dairy specialist Patrick Gowing highlighted the need for farmers to invest in soiled water and slurry storage beyond the current and planned requirements listed by the Department of Agriculture. The farm walk was organised by Roisin McManus, a Teagasc Walsh Fellowship student, whose thesis is focusing on organic manure storage and its effects on water quality.

“If we are to look at the cost of storage, as a rule of thumb for a slatted tank on a 14ft 6in slat, per linear foot it’s roughly €400. So, for a 100ft tank it’s roughly €40,000 ex VAT,” said Gowing. “In 2015/2016, these tanks were costing €180/linear foot, so it has more than doubled in that timeframe.

“If we are looking at overground slurry towers, they are running at around €95/m³, which is similar enough to a slatted tank, depending on the size of them, before you put a roof or agitation point on them. While the towers are very good, unless you go for large volumes they are quite dear because the price of steel has gone up so much. Slurry bags are working out at €45/m³ excluding any of the ground works, and obviously they are working out cheaper as they get bigger.

“So, for most people, as you start to go down through it, putting in a slatted tank to solve the problem is probably the easiest way to get out of a storage issue.”

Dairy washings

As part of the new nitrates programme, closed periods for the spreading of soiled water came in to effect last year, with the prohibited dates as follows:

  • 21-31 December 2022.
  • 10-31 December 2023.
  • 1-31 December 2024 with exception of winter/liquid milk producers.
  • 1-31 December 2025 onwards for winter/liquid milk producers.
  • All holdings producing soiled water must have a minimum of 31 days of storage from 1 December 2024 with the exception of winter milk producers, where storage must be in place by 1 December 2025.

    Gowing said: “If you don’t have a dairy washing tank, water that goes into a slurry tank adds to your slurry storage as it is now treated as slurry. If you don’t have your adequate slurry storage overall, you will be in breach of your derogation.

    “The old metric for dairy washings is 30l/cow/day. That spec is built off a six- or eight-unit REPS-spec parlour.”

    However, Gowing highlighted that current parlours with larger-diameter milk lines are using higher volumes of water than this, with flow meters installed in Teagasc Moorepark farms to help accurately calculate the volume of water produced in parlour washing.

    “It was also calculated on the number of cows milking at the time, so if you were milking 20 cows over the winter period, it was calculated as 20 cows at 30l/cow over so many days.

    “If you milk one row or 10 rows of cows, the parlour will use a similar amount of water to wash itself out. So, if you are sizing the dairy washing tank, we are suggesting using the full herd size by at least 30l by six weeks. If you know your parlour is using more, you should use that figure.”

    The Department of Agriculture is currently working with Teagasc, collecting data on water usage in parlours, to help update this figure.

    Accelerated capital allowance

    Gowing said: “When the accelerated capital allowance was announced in the budget, they said you could use it in the next three years, so you could write it off over two years, whereas the normal write-off period is eight years. They then changed it, so now works have to be completed by June of this year. If it’s slurry storage in a shed, it has to be covered. If it’s an overground slurry store, it has to be covered or roofed. If it’s a tank in a collection yard, it (legislation) doesn’t mention it having to be roofed. Geo-membrane lined lagoons also have to be roofed, with the other option being the slurry bags, which the FDC Group (Farm development co-op) are confident will qualify for the accelerated capital allowance.’’

    The Department of Agriculture has since confirmed with the Irish Farmers Journal that the extended Capital Allowance Scheme, which will allow farmers to depreciate costs of slurry stores over two years rather than the normal seven, is due to be extended past the June 30 deadline and will run throughout 2023, 2024 and 2025.