The overarching goal of the LIFE Beef Carbon project – a joint European initiative – is to reduce climate polluting carbon emissions by 119,000 metric tonnes of carbon dioxide (CO2) equivalent in beef systems over a 10-year period. In other words, it aims to cut beef’s carbon footprint by 15% relative to 2016.

At the same time, the project aims to maintain beef production and actually improve performance and cost efficiencies on farms in the process.

Teagasc, through researcher Donal O’Brien and Walsh fellow Jonathan Herron, is coordinating the efforts of this project in Ireland and, to date, has identified a range of measures to reduce carbon emissions on beef farms while at the same time improve on-farm performance.

1 Age at first calving

Replacement beef heifers are a major variable cost on suckler beef farms and are a key source of carbon emissions, especially methane. Calving heifers as early as possible – ideally at 22 to 24 months – minimises the cow’s unproductive period. It also spreads her lifetime carbon emissions over the beef output of a greater number of calves, thereby reducing carbon emission per unit of output by 0.35% per month or 4.2% if compared to calving at 36 months.

2 Calving rate

Improving the number of calves reared per suckler cow spreads a herd’s emissions across a greater level of annual beef production. Carrying empty suckler cows on a farm adds financial cost to the system, which in the future could be compounded by a charge on her emissions. The calving rate of a suckler herd can be improved by getting a greater proportion of cows pregnant and by reducing calf mortality. The combined impact of these changes is substantial, reducing carbon footprint by 5% to 8%.

3 Earlier slaughter

The age of slaughtering is an important determinant of cattle lifetime carbon emissions. Shortening the time it takes to bring cattle to beef reduces feed requirements and animal methane emissions.

It also contributes to reducing carbon and nitrogen emissions associated with the production of forage. Combining these reductions in emissions with a 0.1kg increase in daily liveweight gain from forage, reduces the carbon footprint of beef by 0.5% to 1%.

4 Extended grazing

Well-managed grazed pastures are an excellent source of cheap feed that require less inputs and machinery to produce than ensiled or concentrated feeds.

Increasing the number of days cattle spend grazing displaces silage and reduces carbon emissions from forage production.

In addition, the measure reduces the proportion of forage an animal belches as methane, mainly because pasture is more digestible and less conducive for methane production than ensiled forage.

The longer grazing season also cuts methane emissions from slurry storage and reduces carbon and ammonia emissions from slurry spreading and silage harvesting.

On the flip side, there is a slight increase in nitrous oxide emissions from cattle manure at pasture, but this is more than offset by reductions in carbon emissions from fossil fuel use, feed digestion and manure storage. The practice should not lead to trade-offs with animal performance and instead it can actually improve production and profitability. Overall, it can reduce the carbon footprint of beef by 2% to 3%.

5 Soil fertility

The health and fertility of soil is strongly influenced by the pH level and concentration of nutrients – phosphorous (P), potassium (K) and sulphur (S). These should be regularly monitored by taking soil samples and acted upon. Unfortunately, less than 15% of soils in the country are at optimum fertility. By improving soil fertility, swards respond better to fertiliser application and grass production increases. The strategy also improves nutrient efficiency and profitability.

While it can increase carbon emissions through extra lime and fertiliser application, this is more than outweighed and culminates in a beef carbon footprint reduction of 2% to 3%. The measure is also likely to increase soil organic matter content, which removes carbon dioxide from the air through carbon sequestration. However, this is not factored into the analysis at present.

6 Spring slurry spreading

Slurry is a valuable source of organic matter nitrogen (N), P and K when applied under the right conditions. Ideally, most farm slurry (70%) should be spread on lower index soils in spring. This is when the sward’s uptake of slurry nutrients is at its greatest and it saves chemical nitrogen and cuts nitrous oxide and ammonia emissions.

Ammonia is not a climate pollutant but it is an air pollutant and it comes mostly from livestock – 98% of national emissions. It also indirectly contributes to climate change as some ammonia is converted in aquatic environments to nitrous oxide.

Cutting ammonia losses by spreading at the right time of the year indirectly reduces beef’s carbon footprint by as much as 1% to 2%.

7 LESS

As well as timing, the method of slurry application has an important influence on the nutrient value of slurry and its emissions. The most commonly used method to spread slurry is broadcasting with a splash plate. It is also the cheapest. However, the splash plate’s slurry N values are poor relative to low-emission slurry spreaders (LESS) like the trailing shoe and dribble bar.

For example, spreading 1,000gal/ac of slurry in spring with LESS provides 33% more N than the same amount spread with a splash plate.

The reason for this is the new techniques reduce the surface area of slurry exposed to air, resulting in less ammonia loss and more valuable slurry.

The greater nitrogen value of slurry tends to increase grass growth and displace chemical N, which positively influences carbon footprint.

8 Protected urea

Chemical N fertiliser is essential to support grass production and avoid forage deficits on livestock farms. The input works best when applied in moderate amounts under suitable conditions.

The majority is utilised by plants, but some chemical fertiliser is lost as ammonia and nitrous oxide. These gases, directly or indirectly, contribute to carbon emissions but this can be reduced by using protected urea.

Protected urea contains a urease inhibitor, coated on the granule or smelted into the product. That moderates the rate at which urea is converted to a usable form. This new urea product cuts carbon emissions by up to 73% compared to conventional nitrate fertiliser and grows the same amount of grass at a lower cost per unit of nitrogen. Using protected urea can cut a beef farm’s fertiliser bill and carbon footprint by 5%.

9 Adding white clover to the sward

White clover is an alternative to chemical N fertiliser and can support high levels of grassland production under appropriate conditions. The plant can fix 100kg to 200kg/ha of N and supply it to the sward when nitrogen fertiliser application is minimised (<80kg to 90kg/ha).

The measure directly reduces emissions from fertiliser application and avoids carbon emissions generated during fertiliser manufacture, which also consumes significant quantities of natural gas and oil.

In addition, white clover tends to increase carbon sequestration and enhances farm biodiversity – providing nectar for pollinators in summer, for example.

White clover’s impact on beef’s carbon footprint can be substantial, cutting it by up to 7%.

10 Preserving and planting hedgerows

Irish beef farms’ extensive networks of hedgerows are a unique European landscape feature that store and sequester significant amounts of carbon. Protecting these features and adding to them in suitable areas of the farm can cut emissions without affecting beef production.

Where the measure is deployed, the model estimates it can cut carbon footprints by 1% to 2%, in some cases. The project’s French partners have modelled similar reductions and are also finding hedgerows can be used to produce fuel or wood products. This further reduces emissions and conserves fossil fuels.