Dairy farmers in the UK and Ireland are being encouraged to introduce a slurry inoculant ahead of the winter housing period, to reduce ammonia emissions and increase nitrogen use efficiency (NUE).

With 2030 government targets to reduce ammonia emissions from agriculture by 16%, the use of biological slurry treatments has been highlighted as an extremely viable option, explains Lientjie Colahan, technical sales support at Lallemand Animal Nutrition.

“When slurry is spread, a process called volatilisation can happen, which means that ammonium N (NH4+) is converted into ammonia (NH3) and is released into the atmosphere,” she says.

“However, treating slurry with a biological inoculant can reduce the ammonium in the slurry and increase the organic nitrogen content which results in less ammonia production.”

Mrs Colahan explains how this has been proven in a recent trial. “From November 2020 to February 2021, a trial was carried out in a slatted dairy housing system showed that slurry inoculated with SlurriN PRO reduced ammonia emissions on average by 36.5%, improving air quality within the shed.”

She adds that there were further benefits. “The organic nitrogen content of the slurry was also greatly improved. With more nitrogen being incorporated into the bacteria’s cells there is less opportunity for nitrogen leaching after the slurry is spread. This form of nitrogen is also rapidly available to the plant.”

With the correct application of SlurriN PRO, the specific blend of enzymes and bacteria can improve the consistency and handleability of slurry which will reduce the fuel and labour costs associated with slurry management.

Mrs Colahan notes that to maximise the benefits of the inoculant,it is crucial to start the treatment ahead of winter housing, prior to new slurry being added to the pit,

“The simplest and most convenient way of applying the inoculant, if the slurry store only has a small amount of residual, slurry is once a month. Mix a 1kg sachet of SlurriN PRO into ten litres of water and pour this directly into the slurry store. This process should be repeated every month, for the duration of the winter housing period.”

While the government's reduction targets are ambitious, the promising results from the recent trial indicate that these goals are potentially achievable. The trial is the first of many that Lallemand Animal Nutrition is set to undertake, with the hope to further encourage dairy farmers to take full advantage of the benefits that improved slurry management has to offer.