"Much discussion has focused on how to deal with greenhouse gas emissions and resulting weather extremes. Most analysts believe we must stop burning fossil fuels to prevent further increases in atmospheric carbon. [But we} must also find ways to remove carbon already in the air....So here's a list of things vegetable gardeners can do to put carbon back in the soil:
"...where can we put carbon once it is removed from the air? There is only one practical approach -- to put it back where it belongs, in the soil.
- Plant nitrogen fixing cover crops and living row paths
- Heavily mulch weeds instead of pulling
- Incorporate no-till or shallow till practices
- Replace pesticides and fungicides with diverse beneficial organisms
- Incorporate perennials in our garden
- Compost your garden and kitchen waste
- Recycle biomass with livestock (grazers, browsers, compost to poultry)
And things yard-owners can do:
- Plant lawns with diverse species: deep rooted grasses and nitrogen fixing species like clover
- Incorporate multi-layer, perennial, diverse plantings
- Compost, rather than burn, yard waste
- Minimize pavement and unproductive mulch
- Grow nitrogen fixing trees and perennials
- Maintain diverse forested buffers and perimeters
I think we've all heard about the importance of doing most of these things since we know good soil health is important for our crops. Soil health is also important for the earth. More info is at the NOFA site (NOFA Carbon Soil Restoration).
7 comments:
Most carbon comes and goes in the soil in organic gardening, but biochar is pretty permanent and improves the nutrient holding capacity of the soil too.
Biochar is something I'm going to have to look up. That's new to me. Soil biochemistry is so interesting.
Ok some quick reading. How can burning anything be good? So much ash, soot, and carbon goes into the air. Seems we should go with carbon maybe less stable but staying on the earth in a composting and growing cycle.
Great post!! I agree in general it's a good idea to promote composting/growing cycles that involve carbon as surely this must build carbon literacy, a goal we share!
But one trick with carbon is that some carbon is more equal than others. Especially in terms of how long it sticks around in soil--its residence time.
One quick example: Your awesome Christmas harvest might have weighed about a quarter-pound (~100 grams). Most edible produce is 90% water by weight, leaving 10% dry weight (~10 grams), probably half of which is carbon (~5 grams). For everything green aboveground, there's often that same weight of carbon or more belowground. But that 5 grams of belowground carbon you left behind after your harvest does not accumulate indefinitely in your garden--it's food for microbes, just as your harvest is food for the "macrobes" in your family.
Like us, microbes prefer their food in certain forms, and charcoal is relatively unappetizing. It's true charcoal requires conversion of some mass to gas as carbon monoxide and carbon dioxide (~75%?), but the ~25% left can be quite tricky to break down, so if added to soil, it greatly extends its residence time! I'm not sure on the "tastiest" or most appetizing form of carbon in your garden (something chock-a-block with fructose?), but that would lead to very short residence times as the microbes would essentially convert all of that sugar into carbon dioxide, which escapes back to the atmosphere, contributing to our 401.63 ppm of CO2 as of Dec. 27 (http://www.esrl.noaa.gov/gmd/ccgg/trends/weekly.html).
I think another key to backyard carbon sequestration is to increase soil moisture--essentially creating "constructed wetterlands" one raised bed, farm, and ranch at a time. This shift from aerobic conditions to slightly anaerobic conditions can also slow down decomposition, increasing residence times, but unfortunately can also lead to increasing stinkiness. Rotten egg odor or hydrogen sulfide gas, for example, is the byproduct of anaerobic respiration/breakdown of carbon in the presence of sulfate. Another possible downside is that most roots--like us--require aerobic conditions, so it might be interesting to explore wetter and drier parts of a garden for carbon sequestration.
But tradeoffs must be essential to all aspects of gardening, including carbon gardening, no? Happy New Year!
So, I did more research and I see its burned in a container so no ash or soot. All carbon is retained in the biochar.
Does anyone have experience with biochar? Does is help your soil? Do you make your own or buy it?
Thanks Tony!!
I still like my transient little lettuce - and when it's pulled I plant more, so it's not really all that transient.
Maybe my lawn needs some biochar. Or more wetland. (Yikes. 1/4 of our property is already underwater!)
We do all we can to preserve our existing wetlands. I'm glad to know that this is another way to keep carbon out of the atmosphere. But in our raised bed gardens we always conserve water. It's expensive. And my understanding is that it's better off staying underground. How can you make more wetland when there isn't enough rain to fill existing wetlands and groundwater levels are falling?
Carbon gardening is a new thing to me!
Happy New Year!
Kathy, I know you planned to move your blueberries. I need to do the same. Three years ago, I planted 14 blueberry plants - diff varieties - we haven't had one berry. The birds eat berries before they ripen.
I tried bird netting - it gets tangled up in the plants, pulls off leaves and berries - and doesn't deter the birds at all.
I think I need to create a protective structure that I can cover with netting or wire. Do you have a plan to protect your blueberries?
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