What is biochar (2)
- 1. What is biochar? Biochar.org Biochar is the product of heating organic matter such as wood, manure or plant material to temperatures over 300oC in a low-oxygen environment (pyrolysis) and is similar to charcoal. Biochar contains a high proportion of hexagonal carbon rings, making it highly stable in the soil, and retains many of the nutrients and minerals present in the original feedstock. Interest in biochar as a soil amendment was stimulated by the discovery of Terra preta (Portuguese: Dark earth) in Amazonia. The typical rainforest soils in the region are poor, but large areas of fertile land had been created by the early indigenous peoples through the addition of organic matter and charcoal. Terra preta soils created many centuries ago retain significant levels of stable carbon and are still highly fertile. This has stimulated research to establish the role of charcoal (biochar) in producing these properties. Left-Crop yield with biochar and fertilizer. Right- Yield with fertilizer only. (www.mcgbiocharpod.webs.com) UK Biochar Research Centre Biochar has been envisaged as having four co-benefits: • Climate mitigation by the long-term sequestration of carbon in the soil. • Energy production from oils , gases and heat produced during pyrolysis. • Management of organic wastes. • Soil improvement. Biochar has a highly porous structure and a huge internal surface area. It has been shown to improve water retention and aggregation of the soil. Other benefits include immobilisation of contaminants (e.g. heavy metals ) and an increase in beneficial soil micro-organisms. Biochar removes carbon from the natural plant/atmosphere carbon cycle and stores it in the soil. Evidence suggests that this carbon will remain locked in the soil for centuries to millennia, making a significant contribution to the reduction of atmospheric CO2 Plants remove CO2 naturally from the atmosphere. Biochar locks some of this carbon into the soil. (International Biochar Initiative) Philip Harries, Biochar Research Team, Swansea University. E-mail 450433@swansea.ac.uk Left- typical Amazonian soil. Right- Terra preta soil. (Bruno Glaser) Scanning electron microscope image showing the highly porous structure of biochar