As farmers and gardeners we are always searching for ways to make our soils better, richer, and more productive. Biochar is an inexpensive, lightweight, and readily available product that is easy to incorporate into vegetable beds, landscape areas, and orchards. Besides an amazing capacity to sequester up to three times its own weight in carbon (possibly for millennia), biochar helps the soil's ability to retain water, improves the condition of hard setting soils, increases microbial activity, stimulates mycorrhizal fungi, and enhances the absorption of nitrogen fertilizers. All of which means you can expect to drastically augment plant growth in your backyard while doing your bit to save the planet!
What is biochar?
Biochar is created when organic matter has been burned slowly with a restricted flow of oxygen (pyrolysis). The result is a carbon rich product obtained when wood, leaves, grasses, or animal manure is heated until the biomass reaches the charcoal stage, and then halted before it turns to ash. Recent explorations have traced the origins of biochar to the Amazon rain forest of Brazil an estimated two thousand years ago. Cultures there thrived by growing corn, melons, and fruit trees in soil made rich by adding compost, smoldered plant material, and mulching. These "dark earths", also known as terra preta, still exist in that region today. The ‘rediscovery' of this knowledge provides an opportunity for a sustainable solution to help enrich our gardens and farmland and vastly improve plant growth.
What does biochar do?
By using biochar, you will see long term improvement of your soil's fertility. Having the capacity to retain water and nutrients as they pass through, then slowly mete them out, helps regulate the distribution of these essential resources and increase soil productivity. Because nutrients and moisture are stored in the biochar, the amount of these resources can be decreased with each passing year. This slow distribution of nutrients also decreases fertilizer runoff into our waterways. Biochar provides the perfect habitat for many beneficial microbes, fungi, and microorganisms. The pores or spaces in biochar provide oxygen and moisture to protect these microbes from drying out between watering cycles. Microbes have a symbiotic (mutually beneficial) relationship with the roots of the plants growing in the soil. They help breakdown and make available nutrients required for optimal growth. In addition, the microbes, fungi, and microorganisms that take up residence in the biochar leave behind carbon molecules, a self-propagating process that increase the biochar's volume over time.
How do I use biochar?
While suggested application rates vary widely, some general guidelines are beginning to be established. Many sources cite 10% as a minimum starting point, yet even proportions as high as 90% appear to have only positive effects. Several other sources offer 5kg/m2 or approximately 1 pound/sq. ft. as a rule of thumb. Here at DripWorks we're experimenting with volumes of 10 pounds/yard of soil in our demo garden and anticipate carrying a line of biochar in the coming year.
If you're ready to learn more about biochar, here are some informational sites to get you started. Happy planting!
Biochar International This organization promotes biochar education through its website and those of its members. Lots of great information and videos. http://www.biochar-international.org/
The Biochar Project This Australian association offers tons of hands-on and how-to information. http://biocharproject.org/
Biochar TED talk Lopa Brunjes is a biochar pioneer, passionate sustainability advocate, and visionary businesswoman. Very informative. https://www.youtube.com/watch?v=ZroDAyIqW74
U.S. Biochar News A general portal for all things biochar here in the USA. Plenty of good information and lots of video. http://biochar.us.com/