Post #9A What is Biochar?
Blog Description: An explanation of Biochar, with pros and cons.
Have you heard of biochar? From the basin of the Amazon Rainforest to a DIY set up in your own backyard, biochar is a centuries old soil treatment that is gaining traction in today’s modern landscape.
We find biochar to be an excellent addition to our gardens here in subtropical zone 10. Easy to make from yard waste, easy to apply, and easy to activate with some compost or compost tea, biochar is a free boon for your garden.
Biochar provides housing for beneficial microorganisms, soaks up and slowly releases water and nutrients, and stores carbon in the ground that would otherwise be released into the atmosphere and disappear.
Pretty cool, right? Read on to learn all about it!
What is Biochar?
Biochar is, in essence, pure carbon or charcoal. It can be purposefully produced through a process called pyrolysis – heating and transforming biomass in the absence of oxygen. Much as a kiln heats ceramics, pyrolysis systems heat biomass to a low and slow smolder, eventually rendering chunks of pure carbon. This form of carbon is very porous; just one gram of biochar has about 9000 square feet of surface area in it.
Terra Preta
To understand the value of biochar, one must understand how it works as a single component of a healthy soil system.
Terra Preta is a term used to describe deposits of exceptionally fertile soil found in the Amazon basin. It is dark in color and rich in nutrients, readily available to support plant life of any kind. This soil has been extensively analyzed and has been found to include such biomass as organic pottery shards, bones, decaying plants, feces, and pure charcoal or biochar.
These biomass and charcoal deposits are found almost exclusively near areas of past civilization sites, leading researchers to believe that the deposits were intentional. People native to the Amazon region still use this practice of farming, and it is catching on around the world as a viable way to add value to what would otherwise be considered a waste product, everything from brush and food waste to sewer sludge.
Why is Biochar Gaining Traction in the Modern Garden?
Biochar is a promising method of repurposing waste for the greater good, and any sustainable gardener can get on board with that, right? Not only is it upcycling (reusing) waste, it is an organic powerhouse for your plants.
Possibly the most notable reason to love biochar for the future of the planet is the fact that it fixes (stores) carbon in the ground. Why is this important?
The extensive surface area that biochar provides gives a home to billions of healthy soil microorganisms. The microorganisms and the carbon itself breaks down other biomass in the soil faster to create a dense, rich soil in a much shorter time than it would in the absence of biochar.
Biochar holds a slight electrical charge which draws in nutrients from surrounding soil. When water and rain come, the nutrients are kept firmly planted in the biochar as opposed to running off into the water table and away from your garden beds. And even better yet, the pores of the biochar fill with water and store it for slow release.
Potential Concerns of Manufacturing Biochar on a Global Scale
As visionaries of the biochar revolution want to figure out a way to use this as a potential energy source, they are looking for ways to continually fuel massive quantities of biochar. This requires feedstock, or biomass, and lots of it. Sure, we’ve got lots to burn, but do we have enough non-toxic organic matter to fuel biochar production on a global scale?
Residual biomass, or waste biomass seems like the obvious best option. Yet on a large scale this would require lots of transportation (which burns energy) and possibly some ill-fated decision making from money hungry agricultural industries.
The other obvious option would be to grow biomass with the specific intention of turning it into biochar for energy use. Primary biomass, or biomass grown specifically for creating biochar, would include perennial grasses, tree crops, and algae. Growing perennial grasses and trees specifically for this use would require land-use conversion on a planet already cramped for space. It would also require time and water to grow.
This brings us to some other options. Animal manure and sewer sludge. Two extremely intense, smelly, methane-producing banes of our existence? Or potential waste feedstock for biochar?
Well, there you have it. The pros, the cons, and everything in between when it comes to biochar. Have you experimented with it in your garden? Do you have a reliable source or do you make it yourself?
If you are interested in learning how to make it, check out our post, How to Make Biochar here. We’ve had some great successes and some major learning curves in our biochar adventures. Have you? Share with me, I love hearing from you!
Until next time,
Mary