Hi, I'm new to permaculture and biochar and have this question. So many people have shown the benefits to low soil disruption and layering organics beneath the planting soil. I see that biochar does show benefits, but is it enough to justify the extra work?
Also, even taking windfall or dying trees from your woodland has an impact. Is the impact negligible enough to ignore?
I'm not trying to stoke anyone here, just anticipating the types of questions I would have to answer if and when I was to do biochar....which is way cool in my mind.
P.S. On a different note, I would like to see this software: Input all the variables of your operation to determine your +/- footprint.
For example: made a kiln from several derelict steel tanks that otherwise would have been melted down, (+2); had the tank delivered 50 miles (-2); didn't use factory bought kiln which required fossil fuels to produce (+5); didn't have factory kiln delivered 1,200 miles (+4); used welder which ran on carbon neutral woodgas used in my generator (+2); dragged windfall timber from my lot with tractor, 2 hours (-5); cut up wood with chainsaw, 3 hours (-2); rerouted off-gasses from pyrolysis to initial fire in biocharing (+3); dug 15'x6' foot garden trench 6 feet deep with backhoe, 2 hours (-2), didn't use xyz method of implanting organic wealth into soil (+8 ). After you plug in lots of variables you can see how good or bad you are doing.
I think of biochar as a remediation technique for degraded soils, especially in hot humid climates where direct application of organic matter degrades very quickly back to CO2 otherwise. In a rainforest or other hot humid climate forest there is often very little mulch layer....most of the carbon is in the standing forest. Biochar is thus a way to keep much of this C in the soil, sequestered from the air and available as a nutrient sponge, while the landscape is put to food-productive uses or jumpstarted back towards forest. The human use of hot humid landscapes for food production often involves pulses of disturbance of the native vegetation and biochar is one way to minimize C and organic matter losses during the disturbances.
I like the footprint considerations......I've only ever used recycled and on-hand materials for biochar containers, and charred sticks and paper that didn't require anything but a wheelbarrow and some time to gather. Finding a way to use the gas and heat generated is also a huge benefit, even if it's just to cook something on top of the burning barrel. Such activities really become practical when done on a somewhat larger than homestead scale (which is what I'm most familiar with working on) I'd like to see a biochar-producing woodstove.....a lot of homesteaders out there heat with wood, and quite a few cook with it too. I've made it in small quantities in my existing woodstove by stuffing a metal coffee can with wood chips, covering it with another slightly larger can, and setting this in the back of the stove upon building the evening fire. Next day, I have a can 1/2 to 2/3 full of charcoal. Not much, but every night all winter adds up.....
Oh yes, biochar is definitely worth it. In fact, in this age of rising atmospheric CO2, it becomes imperative to start using it on a mass scale.
First off, it sequesters carbon. If that biomass was converted to mulch, or fed to termites, or landfilled, or a host of other possible fates, it would turn into methane and CO2 in a few years, staying up in the atmosphere where it is not needed.
Second, it improves soil fertility. But you shouldn't think of it as a fertilizer like manure or compost. Biochar is a catalyst. In the true sense that a chemist uses that word. Biochar doesn't participate in the chemical reactions of plant growth; it just holds onto the nitrogen, the phosphorous, the water, the micronutrients that are needed for plant growth.
Suppose that the discovery of biochar's effects on plant growth came along at the same time as the invention of the oil well. After the start of the oil age, industrial civilization pretty much gave up on making charcoal and left that to the Third World. Had we kept manufacturing charcoal, but using it for soil amendment, we may not have put ourselves in the same predicament vis-a-vis atmospheric CO2. Maybe desertification would be an unknown problem, maybe we would be a lot better off.
I think without such an effective tool as biochar, it would be much harder to build a permaculture.
Great question, informed answers.
The discussion thus far suggests that biochar has its place in the hot humid places of the world,and anywhere wood is used as fuel.
What about biochar vs. hugels? Hugels seem to sequester carbon for a long time, though no where as long as biochar.
How about volume? Are there upper limits on how much biochar can be added to soils? How about wood in hugels?
It's hard to get too much carbon in the soil. I think some research with charcoal and potted plants showed improved growth up to 25% by volume!! I think charcoal is so inert, microbes don't even try to eat it, so it doesn't lock up soil available N like, say, wood chips would. I think the point of hugel is that the wood is in large enough chunks that microbes only attack it from the surface working inward, minimizing the N-lockup effect. Personally, as a wood heater in a tree-shy climate, I'll never get to the point of true hugel, but I will bury brush, grass, etc. in new raised beds, well inoculated with urine. In a climate and landholding which is yielding wood to excess, hugelkultur is certainly better than just burning to be rid of it. So is piling it up into brush piles and just letting nature have it's way with it....(that is, in a climate with relatively little wildfire....that changes things!!) Truly excessively organic soils are those derived from old peat, such as are found on drained wetlands, and they can be mineral-deficient.......
25% is certainly a lot!
Does biochar wick water? Could be good in a S.I.P. if it does.
What about a hugel bed made of biochar? I suppose using 100% biochar would be too much.
Then again, the ancient pits of biochar that are often described seem to work just fine,though they seem to include more than just char.
Even a hugel seems to have other things in it aside from logs and soil.
I am still working on my first biochar retort and my first hugel, so things are great interest to me.
My current beds are basically sheet compost raised beds,and they have worked great, but I love to tinker, so...