Slash-and-char is an alternative to slash-and-burn that has a lesser effect on the environment. It is the practice of charring the biomass resulting from the slashing, instead of burning it as in the slash-and-burn practice. The resulting residue matter charcoal and biochar improves the soil.
In that context, charcoal can be made by numerous and varied methods, from the simplest (an earth cover on the pile of wood, with strategically placed vents) to the most sophisticated (a modern plant that recuperates and recycles strictly all exhaust gases). (See also: biomass, explaining some of these methods and advantages.)
Slash-and-char offers considerable benefits to the environment when compared to slash-and-burn.
It results in the creation of biochar, which can then be mixed with biomass such as crop residues, food waste, manure and / or other, and buried in the soil to bring about the formation of terra preta. Terra preta is one of the richest soils on the planet - and the only one known to regenerate itself, although precisely how this happens is hotly debated within the scientific community.
It moreover sequesters considerable quantities of carbon in the safest and most beneficial fashion, as opposite to the negative effects of the slash-and-burn. Switching to slash-and-char can sequester up to 50% of the carbon in a highly stable form. The nascent carbon trading market that sponsors CO2 sequestration projects, could therefore help supplement the farmers' income while supporting a decrease in the pace of deforestation and the development of a more sustainable agriculture.
- Lehmann – Biochar sequestration in terrestrial ecosystems, supra note 11 at 407 (“If this woody aboveground biomass were converted into biochar by means of simple kiln techniques and applied to soil, more than 50% of this C would be sequestered in a highly stable form.”)