to mean biomass charcoal produced via pyrolysis.
Biochar is employed commonly as a soil amendment. Qualities making it suitable:
It is largely inert. Microbial composting action leaves charcoal largely unaffected.
It is highly porous, serving to retain water in the soil or improve drainage, and to provide a large surface area for microbes.
It is of neutral or alkaline pH, reducing the acidity of (or sweetening) the soil.
It has very high cation exchange capacity, increasing the uptake of minerals such as Ca, K, Mg and P.
It is a good insulator, reducing average soil temperatures in hot climates.
There is evidence that low-temperature biochar produces robust growth in plants when compared to high-temperature biochar. It is speculated that it retains organic matter desirable to beneficial microbes (like mycorrhizal fungi), resulting in higher nutrient availability to plants.
Biochar is the main (and likely key) ingredient in the formation of terra preta, or Amazonian dark earth. Efforts to create these soils are being undertaken by companies such as Eprida, Best Energies, and Dynamotive Energy Systems. Research efforts are underway at Cornell University, the University of Georgia, Iowa State University, and The University of Hawaii at Manoa. One focus of this research is the prospect that if biochar becomes widely used for soil improvement, it will involve globally significant amounts of carbon sequestration, remediating global warming.
Biochar has potential as an amendment for aquatic habitats such as rivers, lakes and oceans being able to absorb nitrate and phosphate which runs off the land and into waterways. Also, rising levels of carbon dioxide in the atmosphere are thought to be leading to increasing ocean acidity and potential harm to some forms of marine life. Biochar is able to absorb and neutralise acids and toxins in the water which would lead to an increased ocean pH.