The impact of dairy farming on the environment is of critical importance in gaining access to new markets, increasing market share in existing markets, while also maintaining access to premium dairy markets that will return a good milk price to the farmer.

Tom Curran, Teagasc regional manager for Cork West and Tim Hyde, environment specialist with Teagasc, explain further.

Environment and sustainability

To be sustainable, our dairy farming systems must operate in harmony with the surrounding environment, and we are obligated to contribute to reducing our carbon footprint.

At the same time, we must improve water quality and biodiversity on our farms. The storage and use of slurry is a key factor in this sustainability. We have to change our view on what slurry is.

Slurry is a valuable resource rather than a waste product. Put simply, just as grass is the cheapest feed for cows, slurry is the cheapest source of nutrients available to farmers to grow grass.

Every kg of grass you can produce from slurry reduces the chemical fertiliser that you have to buy to grow the grass.

For example, 3,000g/ac of good-quality slurry – 6% dry matter (DM) – applied to first-cut silage fields will supply approximately 30% of the crops nitrogen (N) requirements, and all phosphorus (P) and potassium (K) requirements.

Ag Climatise

The Ag Climatise roadmap mentions that chemical fertiliser usage needs to drop by 20% over the coming years.

It also sets a target to have 75% of slurry spread by Low Emissions Slurry Spreading (LESS) equipment by 2025.

The efficient use of slurry will increase your profit margin on every litre of milk. In an environment where chemical fertilisers are expensive and where their use is going to be subject to increased regulation, farmers must use slurry as the number one source
of nutrients on the farm.

Only then should you top up with chemical fertiliser to meet your crop requirements.

derogation report slurry best-practice guidelines for dairy farmers this month, ammonia

Why store slurry?

Over the winter period, when grass growth is low – at up to 5kg DM/ha/day – the uptake of nutrients is also very low.

Surplus nutrients are easily lost by runoff P or through leaching N. This is confirmed by research, which shows that the biggest loss of nutrients from farmland to watercourses occurs in late autumn, through the winter and early spring.

There has been, and continues to be, a lot of criticism of ‘farming by the calendar’, but this misses the point in relation to the impact of out of season spreading on the
quality of water in our nearby streams, lakes and estuaries.

Out of season spreading brings the amount of slurry storage available on the farm and the management of that storage very much into the limelight.

Slurry farmers

Why have extra storage?

  • More flexibility to match slurry application timings with grass growth;
  • Better use of nutrients when grass is growing;
  • To better manage increased rainfall events at the shoulders of the year;
  • Provide cover for miscellaneous issues where water enters tanks and reduces capacity;
  • Enough storage to meet the regulations and a buffer of 20% to cover miscellaneous occurrences;
  • Use slurry to replace one round of chemical fertiliser/year;
  • Apply slurry at the correct time to maximise the fertiliser replacement value (N, P and K) of slurry;
  • TAMS grants are available to farmers for additional slurry storage of 40-60%. The cost can also be written off against tax and the VAT is reclaimable.