Background
The concept of net zero carbon aims to achieve the optimum balance between production of greenhouse gas (GHG) emissions and the amount removed from the atmosphere. As part of the Paris Agreement (2015), the UK committed to reaching net zero carbon by 2050. Achieving this goal will require extensive change across all industries including agriculture. Reducing emissions of GHG’s to net zero is a challenging objective within the farming sector, requiring major changes to livestock and land management practices to fulfil the target.
Reducing the carbon footprint of agriculture is highly complex, with reductions in one area often causing increases in another. For example, reduction in use of imported concentrate feeds contributes to reduced CO2 emissions, however, can result in fewer daily liveweight gains and therefore, increased emissions resulting from a longer period of time spent on the farm.
A balanced and holistic strategy is important for reducing carbon emissions on farms. Improving farm efficiency in a variety of areas would be beneficial in reducing GHG emissions while simultaneously increasing productivity and reducing costs. Some of these methods include increasing livestock health and performance, improved nutrient management and efficient energy and fuel use.
Methods to Reduce CO2 Emissions on Livestock Farms
Altering livestock management practices to promote carbon sequestration can be implemented immediately and play a key role in the future strategy for achieving net zero on farms.
Precision Livestock Technologies
The integration of modern technologies enables animal health to be constantly monitored, increasing performance and productivity while reducing inputs across the whole farm business. Livestock management can be improved through the use of Internet of Things (IoT) sensor deployment, which is capable of monitoring livestock environments in real-time, enabling conditions to be kept at optimum. Animals can be fitted with GPS collars, accelerometers or rumen boluses that continuously monitor animal health with data being ingested instantaneously into machine learning platforms for constant analysis. This enables pre-emptive treatment of health conditions such as lameness, before it becomes acute and compromises performance, ultimately reducing long-term costs and improving production.
The use of precision livestock technology reduces instances of ill health by identifying disease before it becomes problematic, ultimately reducing infection instances and improving welfare while reducing inputs and costs which contribute to reduced carbon emissions. Additionally, increasing overall livestock health and performance means that livestock achieve target weights in a shorter amount of time and spend less time on the farm, reducing overall inputs and emissions. Selective breeding programmes that focus on animal productivity, fertility and health traits could also contribute to improved performance and efficiency in this area.
Livestock Diet
Precision feeding of livestock utilises data from sensors on automated weighing scales and feeders to tailor feed to bodyweight conversion and improve performance. This method reduces inputs and eliminates waste by optimising feed amounts to the individual animal.
Additionally, optimising high quality forage grown on the farm reduces the carbon footprint and overhead costs of the business when compared to imported feeds. Supplying animals with homegrown forage can contribute to reduced carbon emissions through less reliance on imported concentrates. However, it is important to note that feeding of low-quality forage could potentially reduce liveweight gains for the animal and increase time spent on the farm, resulting in increased GHG emissions.
Some studies have suggested that incorporating seaweed into cattle diets can help to reduce methane production by as much as 80% (Roque et al., 2021). Use of seaweed has not yet been widely commercialised as a feed supplement for livestock, however, there is significant future potential here. Expanding knowledge in this area and exploring different supplements of animal diets could help contribute to reaching the target of net zero.
Grassland Management
Maximising above-ground diversity directly correlates to flourishing below-ground ecosystems that retain and sequester carbon. Incorporating mixed herbal leys into grazing or cutting fields improves the quality of forage while boosting livestock health and soil fertility. Liveweight gains and milk production can be improved through adding forage herbs such as ribgrass, chicory and burnet that offer vital nutrients to the animal. Crops that are deep rooted such as cocksfoot or chicory push root exudates deeper into the soil, improving nutrient availability, structure and drought tolerance.
The production process of artificial fertiliser has a high carbon emission output, therefore, methods to reduce the use of fertiliser are beneficial in achieving net zero. These include maintaining existing nutrient levels and reducing bare soil by retaining permanent pasture and limiting ploughing and reseeding. Incorporating legumes such as clover into crop and grass mixes helps fix nitrogen in the soil, reducing the input of artificial nitrogen fertilisers required. If artificial is needed, opting for slow-release fertilisers and minimising the use of fertiliser containing urea or ammonia in high doses will help to limit carbon emissions.
Rotationally grazing livestock ensures rest periods between grazing that allows time for plant regrowth and can help to improve root systems, enabling more carbon to be sequestered into the soil. This method of grazing proves more productive in terms of grass growth and reduces the amount of trampling from livestock.
Whole-farm Business Efficiency
Improving efficiency at a real-farm scale can contribute to promoting overall sustainability of the business and help achieve net zero carbon goals. Making effective management decisions that optimise performance across the farm promotes improved efficiency and production while saving costs and reducing carbon emissions.
Making effective use of machinery and fuel efficiency also contributes to reducing farm emissions while saving costs for the business. The use of renewable energy sources such as solar panels, wind turbines, biomass boilers or anaerobic digesters can all be viable options for farms to invest in. These renewable methods often cover on-farm energy needs while generating surplus energy that can be outsourced.
Improving Grazing Management to Sequester Carbon
Grasslands constitute around 40% of the earths land surface and play a vital role in the carbon cycle and consequently, grassland and grazing management practices have significant potential to influence soil carbon. Studies have shown that land use and grazing management practices directly correlate to levels of carbon sequestration into the soil, indicating that grazing regimes can be altered to improve sequestration further.
In one study, constant moderate levels of grazing were found to accumulate the most soil carbon by encouraging the highest root production and turnover when compared to high intensity grazing (Chen et al., 2015). Additionally, lowering stocking rates and grazing animals rotationally has been found to improve levels of soil carbon. Another study suggested that mixing sheep and cattle grazing on high diversity grasslands can have a greater positive impact on soil storage levels due to different herbivore grazing preferences (Chang et al., 2017).
Net Zero at Farm Scale
Reaching net zero carbon within agricultural requires a holistic effort across the whole industry and a vital part of this target involves ensuring that it is achievable at a real-farm scale. Increasing whole farm business efficiency with the use of advanced technology and improved management techniques can ensure a viable, sustainable business that can be both carbon neutral, profitable and productive.
It is important to emphasise that this is only achievable if incorporating technology and altering management practices are effective for the business in terms of cost, viability and impact on production. For example, some techniques to increase carbon sequestration such as lowering stocking rates on land may not be possible for smaller farms with limited land areas. Consequently, it is vital to tailor management decisions to the individual farm taking into account factors such as land availability, farm type, budget constraints, farm labour, profit margins and productivity targets.
By Katie Parkinson, Bioscientist at Agxio
Acknowledgements
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