Low Emission Slurry Spreading

Low-emission Slurry Spreading

Slurry spreading is a leading farm-emission source, responsible for roughly 25 % of ammonia losses.

Low-Emission Spreading protects nutrients and cuts losses without harming grass growth.

The Climate Issue

Modern dairy farms rely on slurry. Farmers spread it to return nutrients, fertilise grass, and recycle the manure that builds soil organic matter. This liquid fraction holds ammonium, a valuable nitrogen source that drives faster growth and boosts pasture yields. Yet the same slurry can pollute if applied in the wrong way.

When slurry is spread with a splash plate, it lands in a wide layer and meets air and sunlight. Within hours, some of its nitrogen escapes as ammonia and nitrous oxide, wasting nutrients and harming the climate.

The Solution: Low Emission Spreading

Low Emission Slurry Spreading (LESS) is a smarter spreading method. It uses hoses, shoes, or injectors that lay slurry close to soil instead of spraying.

Placing slurry low reduces time exposed to wind, sun, and air direct. Less exposure means more nitrogen stays available for grass, boosting growth while slashing ammonia losses into the atmosphere. Field trials show these tools cut ammonia by up to 60 % and retain fertiliser value.

Unlock Farm-Level Impact

Key Benefits when using LESS

Cut Emissions

LESS reduces ammonia loss by delivering slurry beneath the canopy, slashing volatilisation and lowering indirect nitrous oxide formation at field scale significantly.

Nutrient Efficiency

Saving nitrogen keeps more nutrient in your fields. LESS lets grass capture that fertiliser, boosting growth and yields while trimming chemical inputs across the overall season.

Reduce Smell

By placing slurry in narrow bands, LESS lowers smell and splashing, enabling compliant spreading even near homes or schools and sensitive watercourses.

Impact of Switching to LESS

Adopting Low Emission Slurry Spreading (LESS) offers clear environmental benefits, but it also comes with higher spreading costs. Hiring a contractor with LESS gear can add up to €29/hour compared to standard spreading. Farmers need to weigh the environmental gains against these extra costs.

Field studies show that switching to LESS (compared to conventional splash plate spreading) can:

Improved nitrogen use efficiency by retaining more of the slurry’s nitrogen value in the soil
Reduced reliance on synthetic fertiliser, saving up to €45/ha in fertiliser costs
Reduce ammonia emissions by 60% compared to splash plates.

Below, we outline the impact of LESS compared to the splash plate, drawing on data from Irish grass-based dairy farms today.

Scenario	Total slurry applied(m3)	Available N ( kg /m3)	Total N saved (kg)	Fertiliser savings/farm (€)
Splash plate	552	0.6	-	–
Trailing shoe (LESS)	552	1	221	358

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Considerations

Equipment requirements

LESS requires specialist dribble bars or trailing shoes, plus a tractor with 100+ hp. Buying adds upfront costs of €15,000–€30,000. Extra fuel and maintenance also apply. In wetter months, hoses or pumps may be needed to manage slurry flow efficiently.

Field conditions

Low-emission gear works best on firm, level fields. Steep slopes, waterlogged soils, or heavy ruts can limit effectiveness. Operators must time applications for cool, calm weather and comply with closed periods under nitrate rules across the EU.

Safety and grants

Spreading systems are heavier and need careful handling during transport. Many EU countries, including Ireland, offer grants covering up to 60 % of approved equipment costs. These reduce investment barriers and ensure that machinery meets safety standards.

Implementation

Switching to LESS is straightforward, but results depend on sound planning and careful operation. Below are practical tips to help you spread slurry efficiently with LESS. These steps protect nutrients and support day-to-day farm goals.

1. Choose a suitable kit. Work with suppliers to select a dribble bar or trailing shoe matched to your tanker size, tractor horsepower, and field conditions and slopes.

2. Train your team. Ensure operators understand hose height, flow control, and safe turn techniques always. Spread in cool, calm weather and avoid saturated soil to minimise compaction.

3. Plan nutrient rates. Subtract the extra retained nitrogen from your fertiliser plan, and allocate slurry to paddocks with the greatest spring nutrient demand first.

Behind the Research

ODOS Tech was founded by Cian White and Alejandro Vergara, two sustainability specialists with deep expertise in agricultural climate action.

Alejandro (left), a PhD in environmental engineering from University College Dublin, helps farmers measure their carbon footprint and implement mitigation strategies to reduce their impact. Cian (right), a researcher at Trinity College Dublin with a PhD in ecology, works on restoring nature to increase biodiversity on farms using satellite imagery to monitor habitats.

Together, they helped lead the carbon and nature-based work for the Farm Zero C project at Shinagh Farm, one of Europe’s first net-zero dairy pilots. In 2020, they launched ODOS, a platform that built smart, science-based tools to help agri-food businesses protect the environment and restore nature.

Research

Teagasc LESS Trials

Teagasc endorses LESS after multi-year trials showing trailing shoes and hoses match splash yields while halving ammonia losses and increasing nitrogen recovery across dairy, beef, and silage systems throughout Irish farms.

Nitrates Directive & DAFM Support

Ireland’s nitrates regulation and DAFM grant scheme champion LESS as practice, requiring or incentivising dribble bars on derogation holdings to cut ammonia, support water quality, and align with climate commitments.

IPCC Manure Guidance

The IPCC highlights low-emission manure application as a proven mitigation measure, citing band spreading and shallow injection for lowering ammonia volatilisation and nitrous oxide, offering a solution for livestock systems.