The Benefits of Using Low Emissions Slurry Spreading on Drystock Farms this Summer
Type Media Article
Bryan Donnelly, B&T Drystock Advisor, Teagasc Galway/Clare
Low Emissions Slurry Spreading technology or LESS for short, has become a more common sight across the fields of Galway in recent years. Machinery such as umbilical pipes, dribble bars, trailing shoes and injection systems have been replacing the traditional splash plate for many reasons. Greenhouse gas and ammonia emissions are very topical at present. As livestock farming in Ireland is responsible for 99% of ammonia emissions we as farmers have a major part to play in there reduction. The use of LESS technology is a key player in this respect due to its ability to reduce ammonia emissions by up to 60%.
Slurry is an extremely valuable fertiliser and its nutrients should be recycled as best as possible. As well as containing (N) nitrogen, slurry is also a source of phosphorus (P) and potassium (K) fertiliser. Through use of LESS farmers can utilise more nutrients, especially nitrogen from slurry and therefore grow more grass with less chemical fertiliser. Improved nutrient usage allows farms to reduce fertiliser usage right throughout the year but especially in summer.
Nitrogen in slurry is in the form of ammonia which is very similar to urea fertilisers. This form of nitrogen needs cool and damp conditions when spreading to provide best returns. Otherwise there can be losses of nitrogen up into the atmosphere and a loss of nutrient potential from our farm which is a hidden cost. This loss can be reduced using Low Emissions Slurry Spreading techniques. Hot and dry conditions from summer weather can causes evaporation like reactions on the ground and prevents the organic nitrogen working into the soil.
As a splash plate spread width covers more ground there is more slurry exposed to the air. LESS machinery reduces the spread width by minimising the surface area to which slurry is applied and puts the slurry directly on the ground or in lines onto the soil beneath the sward of grass. Drystock farms can tend to apply slurry in summer months when silage has been taken as ground conditions and weather allows. Ideally target to spread on damp cool days to minimise losses to the environment and using a Low Emission system to reduce the exposed area.
Moving towards the summer and silage cutting, the target to is to get slurry returned to the silage fields as the silage crop will have removed a large amount of N, P and K from the soil. Cattle slurry typically when spread with a splash plate contains 5 units of nitrogen, 5 units of phosphate and 30 units of potash per 1000 gallons (5-5-30 N-P-K). By using a dribble bar or trailing shoe we can boost Nitrogen value up to 9 units by reducing the loss of nitrogen to the atmosphere. This represents greater than 50% increase in Nitrogen values from the same slurry.
So if we can get 3000 gallons of slurry back to silage ground supplying 27-15-90 units of N, P and K we are a long way towards replacing offtakes from first cut silage. Farms can make up a huge part of silage fertiliser requirement through cattle slurry that is already in the tank. It can also help to have wetter slurry as it may move easier through machinery while also improving the nitrogen efficiency by improving nutrient availability. By using LESS to retain more nitrogen from slurry, the after grass will recover quicker and come back for grazing sooner.
Keeping grass ahead of cattle while grazing the best quality swards is essential to maximise animal performances. Another great benefit of LESS systems is the ability to place the slurry on the soil or into narrow lines that avoid contaminating the full sward. By doing this it can allow slurry to go on heavier grass covers than usual as the slurry can be placed under the grass. This will allow grazing sooner after spreading. This can gives that bit more choice when deciding what field to spread on and how quick grazing can return. This also gives more chances of getting slurry out on land which widening the window for farmers to spread slurry.
The TAMS II scheme currently provides grant aid of 40% up to €40,000 of investments to farmers purchasing Low Emissions Slurry Spreading equipment. Young trained farmers or Registered Farm Partnerships may also avail of a higher rates and ceilings of funding. If farmers are interested in further information they should contact their Teagasc advisor or the local Teagasc office.