This is a journal of my vegetable gardens. Skippy was my first dog and he thought the garden was his, even though I did all the work. Now Suzie and Charley follow in his footsteps. We're located near Boston (USDA zone 6A). I have a community plot, a backyard vegetable garden, fruit trees, berry bushes, chickens, and bees. I use sustainable organic methods and do my best to grow all of my family's vegetables myself.

Tuesday, December 29, 2015

biochar? carbon gardening?

Daphne brought up biochar as the most stable way to sequester unwanted atmospheric carbon. As a nice side effect, it also improves the soil. And Tony explained that my tasty lettuce gardens don't hold onto much carbon very long, but if I added more wetlands, that would. Hmm, carbon gardening - that's new to me. I had to do more research.

The main focus of recent Climate Change Conferences is to reduce emissions, but then, there's a secondary discussion: what to do with the carbon that's already in the air? Biochar is one proposal.

Solutions for the "What to do with it" problem have been divided into biological and chemical approaches. NOFA recommends tying CO2 up in plant/compost cycles. This has the advantage of using a free energy source: the sun. The disadvantage is that we have only the earth's surface for this activity.

Biochar (pyrolyzed organic products that sequester CO2) production is also considered a "biological approach". (I'm not sure why as it doesn't use the sun to do the pyrolyzing, it uses fossil fuel. It just make use of organic products.) Biochar has the advantage of great potential capacity as it can be buried, However, the scale it's used on currently is relatively minuscule.

There are also spectacularly varied chemical methods of capturing CO2 that are being proposed — "from direct air capture using resins, to the use of crushed olivine (a mineral that absorbs CO2 as it weathers) to seed beaches, to new forms of carbon-negative cement-making."

But back to the biochar, it's currently having an impact agriculturally as a soil amendment that revitalizes tired soils. It's not effective everywhere (negative issues include price, affects on soil microbes, and the large volumes that are needed), but in many places it is improving crop production. Like Daphne's garden! (Is that how she grew those beautiful sweet potatoes?)

As far as expanding biochar production to the point where it can impact atmospheric CO2, critics are concerned that land used to grow plant material could displace food crops, they sorry and about socioeconomic effects, and they worry about what eventually happens to biochar in soils - when it does breakdown. They worry that sufficient research has not yet been done.

I like the rational view of Stephen Joseph, a biochar researcher from Univ of New South Wales in Australia, "Biochar probably won’t save the world from climate change, nor is it going to be the key to increasing agricultural productivity everywhere. But used wisely, it is a tool that may help in both situations.”

Personally, I this I'll to stick with NOFA's very biological approach and traditional methods: Cover everything I can with plants (more lettuce!! more clover!!), compost everything I can on site, and use my chickens to enhance my composting. I'm also growing locally - in my backyard - and reduce driving to the grocery store. I hope my little micro-farm is at least a transient a part of reducing atmospheric CO2.

NY Times (July 24, 2015) A Third Way To Fight Climate Change
BloombergBusiness (June 8, 2015) Scientists Are Coming Up With 'Last Ditch' Remedies for Climate Change
PBS (July 3, 2015) The Coal That’s Good for the Climate



Blogger Zippi Kit said...

I don't know about biochar either. I do know that if the ashes from fireplaces and other furnaces was collected, like it once was for soap making, it could be composted instead of sent to land fills.

This would be better than nothing. And it would be better than using trucked in char, or specially grown plants and their resultant char, to enhance garden soil. Or, the plan to "harvest" burnt out areas of char. That would entail too much fossil fuels,again, and disturb a fragile regrowth of the forest.

This reminds me a little of growing corn for creating biofuels.
sorry this got so long

December 29, 2015 7:05 PM

Blogger kathy said...

Hi Zippi Kit

Thanks for your comment. I love long comments!

I think the main thing to make clear is that biochar is made in a way that no smoke or ashes escape. Usually you put all the biological stuff to be burnt in a big metal container. Then you light it on fire and burn it inside the container. It doesn't get any air coming in as it burns. That's called pyrolysis.

I think corn, or a crop like it, would be used, not fragile forests. And yes it does remind one if using corn for biofuel. More mono growth. More damaging the soil with conventional fertilizer and tilling.

I hope I'm explaining things right. If someone has a better understanding , let us know.

I do put my fireplace ash in my compost. The small amount I generate (from my bee smoker). I don't know if it's good in the carbon cycle, but I've switched to gas fireplaces and grills for nearly all. Less soot and smoke. No ash. A lot easier for us and no smoke allergies in the house.

December 30, 2015 10:21 AM


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