Chinese researchers have shown that adding biochar to compost makes the process 25 percent safer and reduces greenhouse gas emissions.
Composting transforms organic waste into fertile soil, but it also releases methane, ammonia, and nitrogen oxides, all of which contribute to global warming. In response, a recent study from Sichuan Agricultural University, conducted together with international researchers, suggests the use of biochar as a solution.
Biochar, similar to a fine black powder, is produced by heating plant residues without oxygen through pyrolysis. This process transforms agricultural waste into a carbon rich material. While biochar is not new, its impact on improving compost and reducing emissions now has scientific backing.
The analysis of 125 composting projects in multiple countries showed that biochar accelerates compost maturity and reduces the release of harmful gases. Results showed increases in germination index by 25 percent, nitrogen nitrate by 32 percent, and reductions in ammonium by 35 percent, producing a more stable and more nutritious compost.
Traditional composting emits methane and nitrous oxide, while compost with biochar showed significant reductions. Methane decreased by 51 percent, nitrogen oxides decreased by 43 percent, and ammonia decreased by 48 percent. Biochar works due to its porous structure, which improves airflow and limits the bacteria that generate methane.
However, not all biochar is the same. Straw is the recommended raw material, using pyrolysis above 400 degrees Celsius, with a biochar carbon to nitrogen ratio between 100 and 200. For the compost mixture, the optimal formula includes 12 percent biochar and 55 to 60 percent moisture. Under these conditions, biochar transforms the microbial ecosystem of the compost by hosting beneficial microorganisms that improve decomposition.
Biochar turns a problem agricultural waste into a solution soil improvement, striking a double blow against waste and climate change. It can be applied in small farms as well as municipal systems.
Source: ecoinventos.com
