Biochar

Biochar is a type of charcoal added to soil that acts as plant food, or fertilizer. Biochar is made by heating biomass like wood in an oven to very high temperatures. This removes all of the water and easy to burn material from the biomass leaving only carbon. The final result is fragile and dark black charcoal.

 Uses 

 Carbon sink 

Biochar is made from organic material known as biomass. Biomass is mostly made from carbon. Carbon in biomass is captured from carbon dioxide in the air by plants. This means that when biochar is made carbon that was once in the air is made into a solid material. Biochar can last a very long time in soil and even longer in containers.

Some people propose making biochar to remove carbon dioxide from the atmosphere.Balal Yousaf, Guijian Liu, Ruwei Wang, Qumber Abbas, Muhammad Imtiaz, Ruijia Liu: Investigating the biochar effects on C-mineralization and sequestration of carbon in soil compared with conventional amendments using stable isotope (δ13C) approach. GCB Bioenergy 2016;  Carbon dioxide is a greenhouse gas that traps heat in the atmosphere, causing climate change. If a lot of biochar were made then there would be less carbon dioxide in the air, meaning less heat would be trapped. This is known as a carbon sink, because the carbon is sunk or put into a long lasting material instead of floating in the air.

 Soil amendment 

When biochar is made the biomass it is made from has most of its material removed. This means that biochar is very light and filled with tiny holes. These holes can hold water and nutrients which act as food for plants growing in biochar. Biochar can be soaked in nutrients to "charge" it which makes it a very good soil additive or fertilizer.Ingham, Elaine Interview with Elaine Ingham, (2015) The holes in biochar can also trap toxins which make water unsafe.Supra note 6; Day, Danny, Robert J. Evans, James W. Lee, and Don Reicosky, Economical , , and  capture from fossil-fuel utilization with combined renewable hydrogen production and large-scale carbon sequestration, 30 Energy 2558, 2560

Biochar was used by people in the Amazon to make their poor quality soil better for growing food. This made the soil very dark and the dark soil can still be seen today.Solomon, Dawit, Johannes Lehmann, Janice Thies, Thorsten Schafer, Biqing Liang, James Kinyangi, Eduardo Neves, James Petersen, Flavio Luizao, and Jan Skjemstad, Molecular signature and sources of biochemical recalcitrance of organic carbon in Amazonian Dark Earths, 71 Geochemica et cosmochemica ACTA 2285, 2286 (2007) ("Amazonian Dark Earths (ADE) are a unique type of soils apparently developed between 500 and 9000 years B.P. through intense anthropogenic activities such as biomass-burning and high-intensity nutrient depositions on pre-Columbian Amerindian settlements that transformed the original soils into Fimic Anthrosols throughout the Brazilian Amazon Basin.") (internal citations omitted)

 Slash-and-char 

In some rainforest places the forests are cleared for farming. When the forests are cleared they are usually cut down and burned. This process is called slash-and-burn and doesn't leave very many nutrients in the soil. "The published data average at about 3% charcoal formation of the original biomass C." If the forests were cleared and turned into biochar rather than burned the soil would have more nutrients.Biochar Sequestration In Terrestrial Ecosystems – A Review, by Johannes Lehmann, John Gaunt, and Marco Rondon. Mitigation and Adaptation Strategies for Global change 403, 404 (2006). supra note 11 at 407 ("If this woody above ground biomass were converted into biochar by means of simple kiln techniques and applied to soil, more than 50% of this carbon would be sequestered in a highly stable form.") This is known as slash-and-char and would make the soil better for farming.

 Animal food 

Biochar can be mixed with molasses for use as animal food. The biochar helps digestion and reduces the amount of methane produced by cows. Feces from animals that eat biochar is a high quality fertilizer.

 Commercial sector 

Biochar is mainly sold by fertilizer companies to people who grow plants. This may change. There are many tons of carbon dioxide in the atmosphere which is causing climate change. Many countries have agreed that this is a problem. In the future it may cost money to release carbon dioxide. If people who remove carbon dioxide are paid then there could be businesses which remove carbon dioxide for money. One way a business like that could remove carbon dioxide is by growing plants and turning them into biochar. This removes a large amount of carbon dioxide and could be very profitable in the future.

 References 

Category:Materials