Restoring degraded peatlands could play a vital role in tackling climate change, according to a new study led by researchers from Bangor University and the UK Centre for Ecology and Hydrology. The study shows that combining rewetting with biochar and iron sulphate additions can significantly slow down carbon loss and reduce greenhouse gas emissions from drained agricultural peat soils.
Peatlands, though covering less than 3% of the Earth's surface, store more carbon than all the world's forests combined. However, decades of drainage for farming have turned many peatlands from carbon sinks into major carbon sources. Rewetting is known to help restore these systems, but scientists have been searching for additional strategies to enhance carbon storage while minimizing methane emissions.
The research team recreated agricultural peatland conditions in outdoor soil mesocosms over one year to test various soil treatments. They found that raising the water table, along with adding Miscanthus biochar and small amounts of iron sulphate, created the most favorable conditions for stabilizing carbon. This combination suppressed soil enzymes that drive decomposition, reduced methane-producing microbes, and promoted the formation of iron-bound carbon compounds that resist decay.
"Rewetting alone is a good start, but when we add biochar and iron together, we see a strong synergy that protects soil carbon and limits greenhouse gases," said lead author Dr. Peduruhewa Jeewani. "Our findings show that the microbial community becomes less active in breaking down organic matter, leading to greater carbon preservation."
Biochar, a stable form of carbon produced by heating plant materials under low oxygen, not only adds persistent carbon to the soil but also alters microbial activity and nutrient cycling. Iron sulphate further enhances carbon protection by promoting the so-called "iron gate" effect, which locks organic matter in place through mineral interactions.
The study suggests that integrating these amendments with water table management could be a practical, scalable solution for restoring the carbon storage capacity of agricultural peatlands.
"Healthy peatlands are critical for both farming and climate resilience," said co-author Professor Davey Jones. "This research points to new tools that could help restore their balance and turn them back into carbon sinks."
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Journal Reference: Jeewani, P.H., Brown, R.W., Rhymes, J.M. et al. Restoring degraded agricultural peatlands: how rewetting, biochar, and iron sulphate synergistically modify microbial hotspots and carbon storage. Biochar 7, 108 (2025). https://doi.org/10.1007/s42773-025-00501-y
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About Biochar
Biochar is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.
