Cherishing Biochar

The Biochar Handbook: A Practical Guide to Making and Using Bioactivated Charcoal, by Kelpie Wilson

Information is cheap these days — a fact that has made trustworthy, useful information hard to find. Biochar is one of many agronomic topics that illustrates this principle. There are millions of videos and posts about biochar on the internet — so many, most of which have so much hype, that it’s difficult to know what to believe.

To guarantee you’re actually getting solid information these days, you might have to pay just a bit for it. Such is the case with Kelpie Wilson’s The Biochar Handbook. It’s not a free resource. But it’s 250 pages of distilled knowledge from an expert in the field. Whether it convinces you to use biochar on your farm or to forego it, the ROI on what you’ll save by having access to Wilson’s expertise will almost certainly pencil out.

The book is very helpful in its detailed account of how fire “works” and the mechanisms of various designs of biochar-producing stoves. Most of the emphasis is on on-farm production, and Wilson discusses the differences between gasifiers, top-load-updraft (TLUD) stoves and flame-cap kilns (which she generally recommends). The several chapters on these topics could help a farmer decide whether producing biochar is worth the effort or if it would be better to simply purchase it.

If for no other reason, biochar should be considered for agricultural use because it helps retain water in the soil and because it has high cation and anion exchange capacities — i.e., it holds on to nutrients that could otherwise leach out of the soil. Wilson catalogs plenty of other benefits of biochar, from human health (used as a tooth powder, it might help with gum recession!) to animal health (when fed as an additive, it can reduce livestock’s need for other mineral amendments) to greatly improving compost quality and providing places for bacteria and fungi to live. 

Yet it is water and nutrient retention that should really get the attention of farmers. In the long term, this of course could mean the opportunity to reduce both irrigation and fertility inputs, at huge cost savings to the grower.

Wilson seems to rightly emphasize not using feedstocks for making biochar that could otherwise serve better ecological purposes. In some circumstances, simply leaving organic matter to decompose could serve plants better, providing nutrients and energy to the soil food web instead of just carbon. But for feedstocks that would otherwise just be wasted, turning that into pure carbon and either using it to improve compost production or straight onto perennial plants is a great option.

Mark Shepard says this is the best book he’s read on biochar. That’s an endorsement worth trusting.