I have been using, and writing, about biochar for several years, and I think I am starting to see some improvements in my own garden. Recently I had the opportunity to attend the "Biochar Field Day" workshop in the next county south of me, and want to report what I found interesting.
Biochar has been around for 2500 years or more, but largely unnoticed until recently. Terra Preta de Indio (or Indian Black Earth) is a Pre-Columbian dark earth mass re-discovered in the Brazilian Amazon region and several other countries in South America a few years ago. The soil is incredibly fertile, and contains charcoal (biochar) that has been there almost forever. Even though Biochar has received a lot of interest in the last few years, there have been very few documented studies that I've seen.
I was suitably impressed with this event, not just by their demonstrated results after 2 years of trials (which I expected), but by the the overall project.
The Virginia Tech Biochar Trials, headed by Dr. Rory Maguire, has developed a working prototype pyrolysis unit that can convert 4,000 pounds of waste poultry litter a day into some useable products. 40% is captured as high-value pyloric oil suitable for many purposes, perhaps like a heating oil; 40% is converted to a powdery biochar useful to help increase soil fertility, and the remaining 20% is mostly bio-gas, used as part of the fuel for the machine.
The speakers included Dr. Maguire and a couple of his grad students, Dr. Julie Major of the International Biochar Initiative who came down from Montreal (Canada), and Dr. Allen Straw, our very knowledgeable area rep from the Virginia Extension Service. Half he trials were done on the farm of Anthony Flaccavento (Abingdon Organics) where the workshop was held, and the other trial on another field several miles away belonging to Dr. Richard Moyer, who is my favorite egg man at the Abingdon Farmers' Market.
I am really pleased to see someone is making something useful from commercial chicken house litter, rather than just a stinky dump pile. Since I know I personally wouldn't use chicken manure from a commercial operation on my garden, I asked about contaminates from the litter. Dr. Maguire said the temperatures of the pyrolysis unit are so high that it kills any organisms that are in the waste. I didn't ask about other contaminants like heavy metals that might be in the feed.
I crush the biochar I make to about pea-size to use in my garden; it is far less messy than the bucket of powdered biochar demonstrated at the workshop. When they transferred the biochar from one bucket to another, a large cloud of dense black particulates hovered, and a good bit was carried away with the wind. Applying that fine powder on a field would mean tilling it in immediately, and even then there would be considerable loss from the mechanical action and air movement.
Something else I do with my biochar that they did not, is to inoculate it. I started using some fresh urine, which has a urea content of about 3-4%, as an inoculate. (Commercial urea is about 40% and will burn plants.) It helps feed the soil microbes. Next year I plan to inoculate my biochar with some EM™ (living microbes) and probably some fish emulsion.
Some of the group were totally unfamiliar with biochar, and I described adding plain crushed biochar to my garden as 'salting the soil with condos for the microbes'... and when I add inoculated biochar, I'm adding 'condos fully furnished, and with food on the table'.
One lovely couple in attendance are hosting a 5-weekend Permaculture Certification Course next Spring (as part of their "Help Build Community Resilience" efforts) and have asked if I'd do a workshop on building an inexpensive backyard burner for making biochar. Of course I'm delighted!