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Towards Net-Zero: Arable Farms

Updated: Apr 24


Measuring emissions to target improved practice?

Agriculture, more so than any other industry, is uniquely placed to be a part of the solution to climate change as it acts as both a source and a sink for greenhouse gases (GHGs). The UK’s agricultural sector is in the position to become a global leader in low-carbon farming technologies – provided the concept of net-zero is embraced early on. Activities on arable farms consist of a mix of activities with low and high emissions of GHGs. Hence the aim is for an overall balance of net-zero when assessed at the farm gate. If a farm is able assess its own emissions, then the business can focus on actions which have the most overall impact, whether boosting productivity to produce more food with lower inputs and reducing emissions; increasing farmland carbon storage in soil, hedges, and trees; or, displacing fossil fuels by boosting land-based renewables. It may even be possible for a farm to become a carbon sink (a constant negative balance) – and hence sell its capacity to store carbon to other businesses. Two of the most user-friendly GHG emission calculators are the Cool Farm Tool, and the Farm Carbon Cutting Toolkit. Watch out for future blogs that describe the use of such tools in practice. However, no calculator is accepted as ‘standard’ at present. There were attempts to develop an EU-wide programme involving an open-source software, but its success was limited because of the large amount of data entry required and the limited additional benefit found by farm businesses.

What is already underway on-farm?

Many schemes, which include measures to improve on-farm efficiency or reduce environmental impacts, e.g. through Countryside Stewardship schemes or Catchment Sensitive Farming, also double up as GHG mitigation measures. For example, increasing soil carbon stocks through incorporation of cover crops, agroforestry, integrating grass and herbal leys in rotation, switching to low input forage crops (e.g. triticale), and reducing soil compaction are measures that have been long proposed as a way to maintain good soil health, and are also effective methods of reducing and offsetting GHGs produced.

In general, on-farm reducing emissions and improving efficiency go hand in hand. Well-thought out deployment of many GHG mitigation measures results in limited disruption to management practices already in place. Countless farmers across England, Wales and Scotland are already developing their own ways to mitigate their farms’ impact on the climate. Helpful case studies can be found at www.farmingforabetterclimate.org and via the NFU Net Zero campaign.


What measures can reduce GHG emissions for arable farms: are they hard or easy to implement?

As part of work, to underpin the development of new payment mechanisms to farmers under the Agriculture Bill, Defra commissioned a short project to consider the feasibility of GHG mitigation measures on-farm. The project was carried out by SRUC (Scotland’s Rural College), the Centre for Ecology and Hydrology and NIAB. The project team at SRUC firstly collated all the proposed GHG emission reduction measures from farming and reviewed the technical evidence about their expected effectiveness. The second phase involved consultation with farmers in different sectors arable, field vegetables, dairy, lowland beef & sheep, upland etc. In the workshops farmers shared their current actions to reduce GHG on-farm and discussed GHG-reducing practices that are being considered for their sector as part of the Defra-funded project. Attendees ranked these from ‘easy’ to ‘hard’ and commented on what each one might mean in practice and the implications, if any, to the business. Barriers to adoption of mitigation measures included lack of knowledge and information, concerns about how any scheme would work in practice as well as technical issues and the un-planned interactions between different policies e.g. loss of glyphosate undermining adoption of conservation agriculture systems. The results from the arable farmers are as follows, starting with those that they felt were easier to implement:

  • Improved nitrogen use efficiency using targeted release fertilisers within a farm-specific N management plan

  • Reduced intensity of cultivation

  • Increasing tree cover on farm

  • Reduced area of cropping systems on peat and reversion to wetland

  • Soil/land suitability mapping to define management and cropping choices

  • Reduced use of diesel or increased renewable energy

  • No bare soil – continuous green-cover cropping systems

  • Improving soil health

  • Targeted steps to increase soil organic matter

Many of these practices are already in place on some farms.


The workshops felt that the introduction of a farm-wide carbon levy/rebate system would probably be unpopular. Nevertheless, the group felt that financial ‘teeth’ might be needed to move more of the industry further towards hitting any GHG reduction goals for agriculture. Similar to other sectors, perhaps farms that produce too many GHGs could incur financial penalties whilst farms performing well could be rebated/rewarded. In these workshops, over half of the farmers mostly admitted that GHG was not something that currently factors high in their day-to-day farming priorities. Nonetheless, they recognised that, like other sectors, they will have to play their part. Farmer A from mid-Norfolk, acknowledged the usefulness of the discussions and the value of looking at the sources of GHG emissions and how his farming can lessen its contribution to the problem. “In my domestic life, we have already been taking steps to be ‘greener’. But I have not really paid much attention to how my farming could be changed in order to produce fewer GHG” he admitted. “It’s been useful to talk with others and get me thinking”.


Since the Project completed, Innovation for Agriculture has developed a short summary guide for farmers.


As part of the project Karolina took some time out to try and answer participants questions: our favourite question and answer is:


Question:

How many atoms of carbon have we as species created? I await a response.


Answer:

None, of course. But we have made significant difference to the types of molecules that the C atoms are found in and where they are within the Earth’s system.

Annual carbon emissions to the atmosphere due to human activities are estimated at about 36 billion tonnes. Every mole of carbon weighs 12.0107g and each mole of any substance contains Avogadro’s number of atoms/ molecules (6.02214 x e23) -simple answer, too many zeros on the number for me to count!!

Then… 18.5% of human body is made up of C, there are 7.8 billion people in the world so that’s an additional one hundred forty-four billion three hundred million C atoms moving around, and if we add all the livestock reared for human consumption with the same C proportion… These answers just give a taste of the changes we make as a species.


This article first appreared in NIAB Landmark, issue 42 May 2020, written by Karolina Golicz, Cranfield University and Elizabeth Stockdale, NIAB



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