Scientists at the University of Leeds conducted research on the carbon storage potential of different soil types, discovering that soil under hedges stored an average of 40t more carbon per hectare, than soil located under managed grassland.
The researchers analysed soil samples taken from nine farms located across five locations in Yorkshire, Cumbria and West Sussex, to find out how carbon storage under hedgerows compared to that of adjacent pastures.
The research, which was was published in the Journal of Agriculture, Ecosystems & Environment, was the first to identify that hedgerows’ increased soil carbon stocks were the same, irrespective of differences in soil type, rock formation and climate.
The five locations analysed in the study were chosen for their differences in climates, rainfall, temperatures and soil types, consisting of intensively managed, fertilised pastures, which were used for grazing livestock and silage, all of which had hedgerows around them.
The team used a corer to sample soil at 10cm intervals, taken up to 50cm under the grass and hedges observed, to compare differences in carbon storage, nitrogen, pH and moisture levels in a laboratory.
Carbon storage
Researchers discovered that hedges stored more carbon than grassland sites, due to the decomposition of foliage, roots and other organic matter, which had been incorporated into the soil beneath the hedges.
The study also found that older hedges stored greater amounts of carbon than younger hedges, but concluded that hedges had an upper body capacity limit for the amount stored.
Research fellow in agricultural ecosystems, Dr. Sofia Biffi said: “We are very happy to share the results of our work, because they show how planting hedgerows can have a positive impact on soil health and the soil carbon storage all around the country.
“In the past few years, we have witnessed how farmers are engaging with hedge planting. They can see the difference that hedges make to the biodiversity on their farms.
“They see more birds, bats, and pollinators, and they enjoy their flowers, wood, and shade. And now they can also know that they are playing their part in storing more carbon in the soil.”
Hedges
As the soil under older hedgerows was found to store the most carbon, which is also prone to decomposition, researchers concluded there is a greater priority to protect it in order to negate the release of carbon into the atmosphere.
In addition, scientists have also concluded it is just as important to plant new hedges to increase the carbon sequestration capacity of hedges across the country.
According to scientists, carbon sequestration works by capturing, removing and storing carbon dioxide (CO2) from the earth’s atmosphere, which in turn, helps negate global warming and mankind’s carbon footprint.
Co-author and chair in biogeochemistry at the University of Leeds, Prof. Pippa Chapman, said: “We have seen some important hedgerow planting commitments from the government, which we hope they will support farmers to achieve in the next few years.
“It is not only hedgerow planting that brings so many benefits to farmland but also maintaining the network of hedges and hedgerow trees that we already have.
“If a hedgerow is removed, the additional carbon stored in the soil quickly disappears into the atmosphere.
“So planting, gapping-up, and hedge laying are all important actions that farmers can take to help protect the carbon stored in soil beneath hedges and the environment.”
