Chinese farmers could turn staple crop production into a carbon sink and improve crop yields by using biochar, a charcoal-like solid rich in carbon, on their soils, according to researchers from the University of Aberdeen in the UK. Biochar is created by heating raw biomass at a high temperature in an oxygen-free chamber. Studies have shown that applying it to soils not only locks carbon away, but also improves soil health and water retention. The process also produces bio-oil and syngas, which can be used to produce electricity.
The researchers designed a climate-friendly farming system that includes the use of biochar, along with reductions in fertiliser use and other pollution-reducing measures. They found that using biochar could turn crop production in China into a net carbon sink, absorbing the equivalent of 38 megatonnes of carbon dioxide every year, while also improving crop yields by 8% and air quality.
However, the rollout of this system would require the construction of thousands of pyrolysis plants and funding from the government. Subsidies for biochar purchases may also be necessary for farmers, at least in the early years. The carbon storage and crop yield benefits of using biochar may also depend on soil type and climate, which would require further testing.
Despite the challenges, the study suggests that China has the potential to become a leader in sustainable farming practices. “If the government of China threw its weight behind it, this could certainly make a significant contribution [to tackling climate change],” says Pete Smith, lead researcher of the study.
