Biochar

I'm posting this here because I think all gardeners would find this of great interest. In my Soils class we have to do a weekly short paper. ( I've gone back to college at the age of 64 for a second dgreee, this time for my first love - horticulture science.) This is my paper on biochar.

Charcoal is a product familiar to most of us. It comes in forms such as charcoal briquettes for the grill or activated carbon for the fish aquarium. There is a new form of charcoal that has the potential to revolutionize farming, and mitigate both global warming and climate change. This charcoal is called biochar or agrichar. Biochar is made by a process called pyrolysis. Pyrolysis is the burning of biomass in a low oxygen environment. The biomass can be any kind of organic material. Woodchips are the most common material but it can also be manure. What makes biochar important is that it is extremely carbon stable. It does not break down or degrade as compost quickly does.
To get a grasp of why this is important requires an understanding of soil as a carbon sink. Plants take carbon dioxide, a greenhouse gas, out of the atmosphere through photosynthesis and respiration. The plant vegetation, called biomass, holds the carbon until it decomposes. When the biomass stays in the soil, the soil holds the carbon and keeps it out of the atmosphere. Biomass decomposition is carbon neutral in that the carbon, once held by the plants and then held in the soil, is eventually returned to the atmosphere and added back to the greenhouse gasses produced by other means. The benefit of biochar is that, because it is so extremely carbon stable, it keeps the carbon from returning to the atmosphere. An organization dedicated to the advancement of biochar, The International Biochar Initiative, reports that biochar, when added to soil, can keep the carbon in the soil "for hundreds to thousands of years." Biochar is carbon negative because it amounts to a net reduction of the return of carbon dioxide to the atmosphere.
Biochar was first discovered in a soil type in the Amazon Basin called Terra Preta. Terra Preta soil is rich, fertile and has a high carbon content. It is believed that the early indigenous people of the region added the carbon to the soil through slash and charring to clear land instead of slash and burning. Biochar does more than sequester carbon. It improves both the nutrient content of the soil and the tilth of the soil. Soil researchers in Australia reported that the "biomass of wheat was tripled and of soybeans was more than doubled." It reduces the need for
fertilizer and improves water holding capacity. It can also clean up contaminated soil. Research done on soil biochar and it effects on plant uptake of pesticides looked at two agricultural products, chlopyrifos and carbofuran used on farm crops. Biochar in the soil acts similar to activated carbon in the fish aquarium, it adsorbs chemicals. In the journal "Chemoshpere" Xiang-Yang Yu reported that plant uptake of the pesticides was reduced in soil with biochar added. Hence, biochar can be a useful addition to soil to "reduce the plant uptake of pesticides from contaminated soils", an important consideration for produce crops.
More research is being conducted on biochar across the globe. The U.S. Government in November , 2009 made funds available for both research and production. Small plant producers are coming on line across the U.S. One such plant is R&A Energy Solutions LLC, located in Ridgeville, Ohio, just north of Cincinnati.

I had read an article about biochar a few years back (actually, it may have been about the Aztecs or Mayans and their farming methods; how they were able to sustain large populations with smaller fields) and forgotten all about it until this post. It really is fascinating. I wonder why it isn't in the news more. One would think it would be a revolutionary application for gardeners world-wide. Very good writing.

Thanks HG. This has been known for quite some time. It does seem slow to get into practice in agriculture. Countries that are facing depleted soils coupled with a growing demand for food production are moving ahead much faster. There's no telling when a home gardener in the US will be able to walk into a garden center and pick up a bag of biochar. For now it seems confined to the very dedicated gardeners willing to go to the trouble of making their own kiln and produce their own. There's debate about using the cheapest barbecue charcoal in its place. Some charcoals have added binders and fillers that could be a problem . Other's say the cheap stuff is cheap because it doesn't contain any additives. Another very alert DG'r just pointed out this thread.

http://davesgarden.com/guides/articles/view/1669/

Excellent thread.

The other problem with charcoal is all the pollution given off during production

Resin

I saw a "how to" article on biochar last year in The Mother Earth News and found it intriguing. Haven't tried it yet--but here's a link:

http://www.motherearthnews.com/Organic-Gardening/Make-Biochar-To-Improve-Your-Soil.aspx

This message was edited Jan 28, 2010 12:42 PM