I’ve seen mentioned several places that biochar will suck all of the nitrogen out of soil. No doubt, tilling in 10-50% raw char (as seen in some trials) will tie up quite a bit of nitrogen. Of course, big ag and universities looks to synthetic nitrogen to solve the issue. But, for years, people said the same thing about wood chips, then we found out that if you place them on top of the soil, much like nature does with dead wood, that soil nitrogen is largely unaffected, or even preserved.
I’ve also noticed that biochar and some degree of associated ash seems to have just what legumes need, higher pH, phosphorous and potassium. Did some googling and found this study which showed a higher legume performance in biochar amended soils. Makes good sense, the legumes are often on the front line of nature’s repair crew after a fire.
Thought provokng post, Gray. I crush it and inoculate the char for 2 weeks first. I dig it into the drip line of my fruittrees and berry bushes. I use a shovel to dig it in (to the depth of the shovel). It is not spread across the surface at my place. I have a food forest, so it is more like an orchard that a monocrop farm. I believe that in Terra Preta, they burned their garbage piles, or so anthropologists/archaeologists believe, so there would be some nutrition with the wood. As I imagine it works in nature, a big forest fire goes through and sets everything back for several years. Afterwards, nature has slowly inoculated the char into biochar. Then it's ready to go along with everything else.
At my old property, in deep black #1 soil, I added coarse raw char and it was a benefit. Our major problem was that plants would grow and grow before starting to set fruit -- the soil was heavy in nitrogen. Not ideal in a very short growing season.
In my current "soil," a powdery sand where truckloads of compost disappear without a trace, both raw char and wood chips are a major drag on plant growth. I have taken to soaking char, chips, and some municipal compost in barrels -- using the stinky liquor captured from composters along with my personal contribution of Vitamin X. Early results are promising, though there is definitely still something missing. But it's a multi-year experiment.
Still thinking about this one. Over the past several days we have been hammered by thunderstorms, another source of free nitrogen. In theory, any char exposed to rain from thunderstorms should eventually be “charged” with nitrogen.
From the reading I have done, plus a few years of observation and experience, the main thing that raw biochar pulls from fertile soils is the microbial life. Bacteria and fungi move in and populate the pore structure, and as they're in the process of doing this they are less interested in what's going on out in the bigger world. This is a temporary state and once they've set up shop, they now have a home base that they use to get more active in the surrounding soil while their base population is safe from being eaten by grazing nematodes.
Nitrate and other nutrient ion attraction depends on an excess of these in a soluble form in the soil profile. So all biochar is going to do in this regard is mop up what the soil itself is not holding onto and would otherwise leach away, and it has no special powers to "pull" the ions away from clay or organic matter that they're bound to.
I think Phil's take on this is basically correct. Let's remember, though, Albert Bates considers mineralizing the biochar to be an essential part of inoculating in his book "Burn". The mycorrizae are able to transport nutrients over long distances and exchange them for other nutrients, using plant roots of different species and the mycelium as the "road". There is a scientist up at the UBC named Suzanne simard who has shown those connections. The soil food web is dynamic, so when one nutrient is traded, there are always other adjustments going on. Many species, many kingdoms, lots of interactions. An animal dies, another one poops, a raccoon takes a fish into the forest, a mushroom pops up, a fruit falls, a limb falls, etc. There is always something going on.
Oh, absolutely. Lightning ionizes nitrogen, making it available to plants. And lordy do they respond.
As long as it comes as liquid from the sky. In my part of the world, hail is a thing. It can pulverize everything in its path. I desperately want the liquid inonized nitrogen, and the rain the comes with it, but the "big white combine" can just buzz the **** off. Welcome to the prairies.
It is certainly cleaner not to inoculate charcoal. I use bio char more as a cleaning solution then anything else. One thing that I certainly partake in, is burning inoculation. You can save up urine, while the fire is still hot throw it on, let it burn off. You could also make an inoculation syrup, throwing it on the fire, let it burn off, these options are obviously cleaner. Feces, your own and your animals, can also be burnt, along with hair and mucus. What you have been doing is certainly cleaner then trying to inoculate the char, is a far better environmental cleaning solution then anything else.