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• Three times more carbon dioxide • Crop deserves our closer scrutiny • Call to consider soil carbon loss Maize crops grown on drained... Warning over renewable energy from peat maize

• Three times more carbon dioxide

• Crop deserves our closer scrutiny

• Call to consider soil carbon loss

Maize crops grown on drained peat soils emit three times more carbon dioxide than burning natural gas, suggests a study.

Researchers say the finding highlights the need to consider soil carbon losses relating to bioenergy crops grown on drained peat – so better decisions can be made when it comes to generating renewable energy.

Recent years have seen a rapid expansion in biomethane crops such as maize to help meet net zero targets. But the study suggests their status as a cleaner alternative to fossil fuels deserves closer scrutiny.

Some of this increased cultivation – on drained peat – emits three times more carbon dioxide than it avoids by not using natural gas, according to the study by the UK Centre for Ecology & Hydrology (UKCEH).

Rich wetlands

The researchers estimate the area of UK peatland used for cultivating maize for biomethane has tripled since 2015. But they say emissions from draining these carbon-rich wetlands for farming have been widely overlooked.

The Defra-funded analysis focuses on maize grown in the UK. But the study team points out that maize cultivation on deep drained peat anywhere will result in large amounts of greenhouse gas emissions.

The research findings were published in the peer reviewed journal Nature Climate Change. Research leader Chris Evans said significantly more carbon was emitted from drained peatlands than was avoided by not using natural gas.

“Biomethane is an important renewable energy source – but it seems unwise to use drained peatland primarily for generating bioenergy in areas where this leads to higher CO2 emissions than the fossil fuel it replaces,” he said.

Locked up

Wetland drainage to grow crops released carbon that has been locked up in their soils for hundreds of years. This released carbon was then exposed to atmospheric oxygen, forming CO2 and resulting in huge amounts of additional greenhouse gas.

The study estimates UK area of drained peat soils for all maize cultivation rose from around 6,000 ha in 2015 to over 11,000 ha in 2021. Meanwhile, the proportion of the crop grown for bioenergy rather than food increased from 20% to 34%.

Not all bioenergy production on drained peat leads to higher emissions, said the researchers. Crops grown on peatland managed with higher water levels – known as paludiculture – could mitigate climate change, they suggested.

It is also less damaging to use maize as a ‘break crop’ within crop rotation, said Prof Evans. This would have commercial value and offset some of the CO2 emissions associated with food production on peat.

Solar offers on-farm income potential

More farmers could benefit from generating income from renewable energy, says the trade association representing the solar power sector.

Revenue from solar power could be a useful source of farm income at a time when growers and livestock producers face the ongoing uncertainty of unpredictable commodity prices and changes in farm policy, said Solar Energy UK.

“Compounded by external factors such as the cost of energy, inflation, changing subsidies and economic volatility, a perfect storm of crises is pushing farm margins to the brink,” it warned.

Potential revenue

An online survey launched by Solar Energy UK aims to understand the pressures faced by farmers, landowners and those working in the agricultural sector – and the extent to which renewable energy could be a new income stream.

Chris Hewett, chief executive of Solar Energy UK, said: “We believe the perspectives of farmers have been largely missing from the national conversation on farm diversification and renewables.

“We want our survey to assess the acute challenges farmers have faced this year, from turbulent energy prices to the weather.”

Mr Hewett added: “With margins squeezed to near breaking-point, it explores solutions to mitigate uncertainty in fallow periods and asks farmers to what extent diversification could help them maintain their livelihoods.”

Solar Energy UK believes renewables – including solar, wind, battery energy storage or anaerobic digestion – present a significant opportunity for farmers to generate a more predictable and sustainable income stream.

The survey results will be compiled into a national report to inform discussions on the government’s farming and energy policy. Mr Hewett says this will ensure farmers’ voices are heard in the debate.

Taking less than 10 minutes to complete, survey participants will go into a draw for a £100 gift voucher.

To take part, please visit the website www.farmingsustainably.co.uk