in my recent readings on biochar i was hoping a few books published in the past few years would have more actual science and evaluation. alas the books _the biochar debate_ and _the biochar solution_ both could have filled more of that gap.
not that there wasn't scientific ideas in either of them, but that they both lacked discussion of experiments, methodology, or what you might expect while talking about something as basic as biochar.
of the two the second book by Albert Bates _the biochar solution_ at least did have several ideas that i hadn't seen before in the climatology debate. that was that the Little Ice Age was partially caused by the reforestation of the Amazon jungle (as a result of 99+% population decline after the European diseases were introduced). i didn't think the carbon ratio in the record had declined during that period. i'll have to go find some studies on that and see if it shows or not...
in looking around on-line the topic of biochar and evaluating it is still rather thin with quite a few links to works of very questionable value.
if you are looking into getting biochar for a garden you can do some things to make it more likely it will turn out ok.
- check the pH (both the soil and the biochar) -- you don't want to make your garden more acidic or alkaline
- make sure it has been processed under low temperatures (300-600C)
- make sure it is from plant sources and not soot or made from burned random garbage (tires, plastics or even crushed coal)
- the resulting material varies by what is used and the temperature and process and might even vary from batch to batch if the system or inputs are not consistent
- if it isn't already charged (by running it through a compost heap) it's likely to be a nutrient drain until it gets colonized by soil organisms
- worms should thrive in it (once it is charged up)
my own additions would be to make sure it is handled carefully when damp and to bury it deep enough to prevent it from blowing around or washing away.
songbird