Much is made of the sustainability issues facing Irish dairy farmers. Environmental sustainability is at the core here, with concerns as to how measures to address these challenges could affect financial sustainability. Maintaining a sustainable workload for farmers and their employees is, and is likely to remain, a constant challenge.
In terms of the environment, there are four key challenges – water quality, air quality, greenhouse gas emissions and biodiversity. Each of these in its own right is a major challenge for the sector, but the fact that all four are coming to the policy table at the same time is a major concern.
Water quality
The Environmental Protection Agency (EPA) monitors water quality in Ireland. Speaking at a recent water quality webinar, Jenny Deakin of the EPA said that only about 50% of Ireland’s lakes and rivers have satisfactory water quality, while that figure is lower for estuaries at 38%. High-status waterbodies are in decline, while the number of waterbodies with poor to moderate status is also declining.
According to Deakin, the biggest challenge facing good water quality is nutrients entering the water. Phosphorus and nitrogen contribute most to the loss of water quality.
Geographically, the free-draining soils of the south and east are more prone to nitrogen leaching
The main contributor to phosphorus levels in water is urban waste water, followed by pasture land. Leaching from grasslands is by far the biggest contributor to nitrogen in waterbodies and the majority of this is associated with urine patches and leaching from chemical nitrogen.
Geographically, the free-draining soils of the south and east are more prone to nitrogen leaching and, as such, nitrogen levels in groundwater are the biggest risk in these areas. Elsewhere, the biggest risk of nutrient loss from agriculture is phosphorus from overland flow. Considering that most of the dairy cows are in the southern half of the country and that dairy farmers use more than 50% of chemical nitrogen while only farming 20% of the land, the focus on nitrogen is not surprising.
Air quality
In terms of air quality, ammonia is the big issue for Ireland and agriculture accounts for almost all of the emissions. Approximately 75% of Ireland’s ammonia emissions are related to animal housing, slurry storage and slurry spreading. These emissions relate to all animals that are housed, including pigs and poultry.
From a dairy perspective, there are a number of easy ways to mitigate ammonia emissions. Using a trailing shoe or dribble bar for spreading slurry and focusing on achieving a long grazing season at grass are two examples.
Using protected urea instead of ordinary urea has been found to reduce ammonia emissions. However, trials on the effect of protected urea on herbage production and soil microbes are ongoing.
Draft proposals from the Department state that by 2022, all new slurry stores should be covered and all slurry stores built in the last five years are to be covered by 2025
The Department of Agriculture has already suggested that changes will be made to the way slurry can be stored on farms. Draft proposals from the Department state that by 2022, all new slurry stores should be covered and all slurry stores built in the last five years are to be covered by 2025. This will reduce the amount of rainwater entering slurry, but the main purpose is to reduce the exposure of the stored slurry to weather – a key factor in ammonia losses.
In the main, ammonia is a problem for the entire livestock sector, but it is also one where dairy farmers can show leadership in tackling it without incurring a massive productivity burden.
Greenhouse gases
By far the biggest environmental challenge facing the dairy sector is greenhouse gases (GHG). As Teagasc researcher James Humphreys explained recently (Irish Farmers Journal edition of 18 July), 70% of GHG emissions from dairy farming are directly related to cow numbers.
Of this, 50% is methane and about 20% comprises nitrous oxide emissions from urine, faeces deposits and from the spreading of slurry. At this moment in time, the only proven way to reduce these GHG emissions is through a reduction in the national herd – something the industry does not want to see happening.
Switching from CAN-based fertiliser to urea will reduce nitrous oxide emissions
The other 30% of GHG emissions relates to carbon dioxide emissions from fuel, feed production and concentrates, but mostly from nitrous oxide emissions following application of chemical nitrogen. This is a big issue, as nitrous oxide (from both organic and chemical nitrogen) is a potent greenhouse gas and has a long life.
Switching from CAN-based fertiliser to urea will reduce nitrous oxide emissions, but many are calling for a reduction in overall chemical fertiliser use.
Clover is seen as a potential solution here, as the nitrogen fixed by clover in the soil does not contribute to nitrous oxide emissions to the atmosphere. However, the difficulties in managing clover on farms have been well-documented.
Biodiversity
Biodiversity loss is strongly linked to species decline and extinction. While Irish farmers can point to the richness of the country’s flora and fauna in comparison to other parts of the world, the fact remains that our countryside is becoming less diverse. It has to be accepted that dairy farming is a factor in this decline.
Yes, our predominately grass-based system of farming has many environmental benefits, but having large swathes of the countryside in perennial ryegrass is not diverse.
While some farming systems may support fewer species, in many cases those species exist because of that specific type of farming. So, diversity is not just about number of species supported by a habitat, but also the type of species.
Dairy farming is challenged by the four major environmental concerns – water quality, air quality, greenhouse gas emissions and biodiversity.A number of actions on farms can help to quickly address some of these concerns.Approaches to fertiliser choice and use can help both ammonia loss and nitrous oxide emissions.
Much is made of the sustainability issues facing Irish dairy farmers. Environmental sustainability is at the core here, with concerns as to how measures to address these challenges could affect financial sustainability. Maintaining a sustainable workload for farmers and their employees is, and is likely to remain, a constant challenge.
In terms of the environment, there are four key challenges – water quality, air quality, greenhouse gas emissions and biodiversity. Each of these in its own right is a major challenge for the sector, but the fact that all four are coming to the policy table at the same time is a major concern.
Water quality
The Environmental Protection Agency (EPA) monitors water quality in Ireland. Speaking at a recent water quality webinar, Jenny Deakin of the EPA said that only about 50% of Ireland’s lakes and rivers have satisfactory water quality, while that figure is lower for estuaries at 38%. High-status waterbodies are in decline, while the number of waterbodies with poor to moderate status is also declining.
According to Deakin, the biggest challenge facing good water quality is nutrients entering the water. Phosphorus and nitrogen contribute most to the loss of water quality.
Geographically, the free-draining soils of the south and east are more prone to nitrogen leaching
The main contributor to phosphorus levels in water is urban waste water, followed by pasture land. Leaching from grasslands is by far the biggest contributor to nitrogen in waterbodies and the majority of this is associated with urine patches and leaching from chemical nitrogen.
Geographically, the free-draining soils of the south and east are more prone to nitrogen leaching and, as such, nitrogen levels in groundwater are the biggest risk in these areas. Elsewhere, the biggest risk of nutrient loss from agriculture is phosphorus from overland flow. Considering that most of the dairy cows are in the southern half of the country and that dairy farmers use more than 50% of chemical nitrogen while only farming 20% of the land, the focus on nitrogen is not surprising.
Air quality
In terms of air quality, ammonia is the big issue for Ireland and agriculture accounts for almost all of the emissions. Approximately 75% of Ireland’s ammonia emissions are related to animal housing, slurry storage and slurry spreading. These emissions relate to all animals that are housed, including pigs and poultry.
From a dairy perspective, there are a number of easy ways to mitigate ammonia emissions. Using a trailing shoe or dribble bar for spreading slurry and focusing on achieving a long grazing season at grass are two examples.
Using protected urea instead of ordinary urea has been found to reduce ammonia emissions. However, trials on the effect of protected urea on herbage production and soil microbes are ongoing.
Draft proposals from the Department state that by 2022, all new slurry stores should be covered and all slurry stores built in the last five years are to be covered by 2025
The Department of Agriculture has already suggested that changes will be made to the way slurry can be stored on farms. Draft proposals from the Department state that by 2022, all new slurry stores should be covered and all slurry stores built in the last five years are to be covered by 2025. This will reduce the amount of rainwater entering slurry, but the main purpose is to reduce the exposure of the stored slurry to weather – a key factor in ammonia losses.
In the main, ammonia is a problem for the entire livestock sector, but it is also one where dairy farmers can show leadership in tackling it without incurring a massive productivity burden.
Greenhouse gases
By far the biggest environmental challenge facing the dairy sector is greenhouse gases (GHG). As Teagasc researcher James Humphreys explained recently (Irish Farmers Journal edition of 18 July), 70% of GHG emissions from dairy farming are directly related to cow numbers.
Of this, 50% is methane and about 20% comprises nitrous oxide emissions from urine, faeces deposits and from the spreading of slurry. At this moment in time, the only proven way to reduce these GHG emissions is through a reduction in the national herd – something the industry does not want to see happening.
Switching from CAN-based fertiliser to urea will reduce nitrous oxide emissions
The other 30% of GHG emissions relates to carbon dioxide emissions from fuel, feed production and concentrates, but mostly from nitrous oxide emissions following application of chemical nitrogen. This is a big issue, as nitrous oxide (from both organic and chemical nitrogen) is a potent greenhouse gas and has a long life.
Switching from CAN-based fertiliser to urea will reduce nitrous oxide emissions, but many are calling for a reduction in overall chemical fertiliser use.
Clover is seen as a potential solution here, as the nitrogen fixed by clover in the soil does not contribute to nitrous oxide emissions to the atmosphere. However, the difficulties in managing clover on farms have been well-documented.
Biodiversity
Biodiversity loss is strongly linked to species decline and extinction. While Irish farmers can point to the richness of the country’s flora and fauna in comparison to other parts of the world, the fact remains that our countryside is becoming less diverse. It has to be accepted that dairy farming is a factor in this decline.
Yes, our predominately grass-based system of farming has many environmental benefits, but having large swathes of the countryside in perennial ryegrass is not diverse.
While some farming systems may support fewer species, in many cases those species exist because of that specific type of farming. So, diversity is not just about number of species supported by a habitat, but also the type of species.
Dairy farming is challenged by the four major environmental concerns – water quality, air quality, greenhouse gas emissions and biodiversity.A number of actions on farms can help to quickly address some of these concerns.Approaches to fertiliser choice and use can help both ammonia loss and nitrous oxide emissions. 
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