During slurry application, greenhouse gases and ammonia losses occur in the atmosphere. It is important to reduce such losses by spreading slurry using Low Emission Slurry Spreading Equipment (LESS).
Overview
Slurry is an excellent organic fertiliser, which offers many benefits, including a reduction in the cost of chemical fertiliser, slurry is also a significant source of direct CH4 and indirect N20 emissions. Therefore, appropriate slurry spreading reduces emissions and chemical fertiliser required.
Why should I use Low Emission Slurry Spreading Equipment (LESS)?
While conventional equipment such as splash plates spread the slurry across the entire surface in a short period of time, they also result in more greenhouse gas losses to the atmosphere. Teagasc advises farmers to use Low Emission Slurry Spreading (LESS) equipment which places the slurry in bands or lines on the ground such as:
- mobile slurry tanks with trailing shoes
- dribble bars or band spreaders
- mobile slurry tanks with shallow injection systems
slurry umbilical systems. The use of LESS equipment to minimise nitrogen losses is explained in the following video.
What should be considered when spreading slurry?
It is important to:
- Know the grass nutrient requirements and soil fertility level.
- Know the approximate nitrogen content of your slurry and apply at the correct rate to reduce nitrogen losses.
- Consider the timing and equipment used for spreading slurry.
Environmental and Economic Benefits
The Teagasc economic analysis of using LESS equipment shows that one can offset the extra cost of using a trailing shoe instead of a slash plate and reduce ammonia emissions by 60%. The economic and environmental analysis in Table 7 below shows the net savings and reductions in emissions from using LESS.
Table 7 Net savings and emission reductions from the use of LESS in Spring
| Scenario 1 | Scenario 2 | |
| Cattle slurry spread @33m3 ha/hr | Splash plate | Trailing shoe (LESS) |
| Available N kg /m3 | 0.6 | 1 |
| Fertiliser savings/farm (€) | 481 | |
| Extra spreading cost/farm (€) | – | -318 |
| Net savings /farm | – | 163 |
| Environmental impact | ||
| Total emissions(kg CO2-eq / kg FPCM) | 0.95 | 0.944 |
| Reduction in emissions (%) | – | 0.63 |
84 cow herd, soil drainage is average
Net savings/ cost are the savings or cost per year for the farm Fertiliser costs 2€/kg nitrogen
Research
The Farm Zero C adopted previous research results eg. from Teagasc at Johnston Castle on the use of LESS equipment in reducing NO2 emissions, hence at FZC the Trailing Shoe is used for all the slurry spreading.
Previous research
The key findings from previous research undertaken in Ireland including:
- Switching from a splash plate application method to a trailing shoe or band spreader application process will increase the N value by approximately 3 units per 1000 gallons during Spring thus increasing the amount of nitrogen available to plants (Forrestal et al., 2021).
- Up to 60% less nitrogen (in the form of ammonia) is lost when LESS equipment is used.
- Using LESS equipment reduces herbage contamination thereby increasing the opportunity for Spring application when slurry nitrogen retention is high. Even when the grass is tall it ensures cattle are reintroduced to the paddock earlier after slurry spreading (Brennan et al., 2015).
Links to more research
Manure and its Management in cattle
Low Emission Slurry Spreading Systems help to reduce ammonia emissions
Regulations
The following regulations and action plans apply to the use of LESS equipment for slurry spreading.
The Nitrates and water directive Ireland– The nitrates directive states that the maximum stocking rate on a farm is 170kg/ha (1.9LU/ha) unless the farmer applies for and is approved for a nitrates derogation.
The Nitrates Derogation 2022, measure 2 -Applies to all slurry spread and 50% of slurry has to be spread by 1st June each year.
- The volume of Slurry spread by LESS must be recorded on annual records
- Applicants are required to have evidence of their own machinery or contractor receipts where hired in LESS machinery is being used.
Available Support- Financial assistance for farmers to purchase new LESS equipment for the spreading of slurry is available through The Low Emission Slurry Spreading (LESS) Equipment Scheme.
Suppliers
The following company can supply LESS equipment alternatively the farmers can use their usual contractor: