Dirt Earth Clay Sand Silt Loam Humus Compost . . . Topsoil

[kentauros]

The topsoil the world over is possibly the biggest carbon sink we have available. I don't know the statistics on this, only that it is indeed a large means to sequester carbon, while at the same time growing the food we need.

This fact alone is my primary reason for buying organic produce. I support those that buy for superior flavor, and other reasons. Those of us that support organic farming are well aware of the benefits to the soil. Plus, healthy soil promotes healthy plants.

Our topsoil has the added benefit of being able to take in carbon and keep it there. Yes, some of it goes into the plants we grow, or the animals that eat the plants. The majority of the carbon remains in the ground, so long as you're doing things by organic farming methods. "Conventional" farming draws that carbon out, and none of it goes back in later.

Now, I don't claim to be an expert on farming or even growing in your typical home garden. I only know those things I've read (both online and off, so no links for books or grizzled old farmers!) and so far I've seen a fair number of people and experts talking about how to use the topsoil as a means of sequestering the carbon in the air.

I know not everyone will care about this topic. I mean, "It's just dirt! Who cares?!" and you're right. It is "just dirt." However, when you treat it well, it returns so much more than food, or a cleaner atmosphere.

Healthy and rich topsoil is home to a huge number of beneficial bacteria and fungi. I know I've read Paul Stamets saying that our topsoil couldn't exist in its current state without those fungi. It's a massive community down there, and we can help it or break it.

Oh, here's another benefit to healthy topsoil: it soaks up water. That means you have to water less, and it's more drought-tolerant. There's less runoff, and if it's an organic farm or yard, then no or less toxic runoff, too. It seems like I've read that deep, rich soil is frost-resistant as well, at least for the roots, but I'm not sure of that fact. Y'all can look it up.

We can "artificially" sequester carbon in the topsoil through something called "terra preta" where charcoal or biochar is buried in the ground. I don't know the exact burying methods, but I think it can be enough to till it into the soil and the plants will either use it or pass it over for more readily available forms of carbon. I guess that would depend on the plant and how it breaks such things down. Bacteria and fungi love the stuff, too.

I've done a little bit of my own use of terra preta by re-purposing some charcoal bamboo sticks I had (they were originally for odor control, and worked fairly well.) I crushed them up and put the shards in the bottom of my potted plants. I haven't noticed the plants being any healthier than before, but I have successfully sequestered just a little extra carbon into the soil again.

Bamboo grows fast and could be a good source for making biochar (among others, “agricultural waste” being one source floated by some scientists.) Yes, I know, it takes energy to turn that bamboo into charcoal, but that can be done with alternative energy sources, such as wind, solar, solar chimneys, tidal-action, wave-action, geothermal, ocean-thermal, ocean current, hydro-electric, Polywell fusion, and whatever else I've left out. Just do the carbonizing during the day, and it'll remain almost fully carbon-neutral (harvesting and transporting most-likely won't be carbon-neutral.)

Having recently read that NYC was beginning to compost part of their waste-stream, it's nice to see this catching on. I don't know what they're going to do with the composted material, but so long as it's going onto the top of the ground somewhere, it's all good.

I consider this a rather important topic as you may have gathered up to now. It goes beyond "how should I plant my next crop of wheat" or "what do you think of my tomatoes this year?" and puts us squarely on things we can do right now to recover some of that carbon we've blasted into our atmosphere. It's not the only method by any means, just that it is a method that carries multiple benefits other than reducing the amount of carbon in the air now. And yes, reducing how that carbon gets there is important as well. Yet stopping how it gets there won't pull it back out of the air, either. We need to do both.

So, my hat's off to all of you organic farmers and backyard gardeners out there. When I live in a house again, I'll be joining the ranks of those wanting to help make our topsoil healthy again. In the meantime, I'll be talking to more people about this topic and see what's going on overall.

Thanks for reading!


one additional link: Rodale Institute

[bluestate10]

1. i have some issues with your interpretation of how carbon is captured.

But your general summary is right. Plant material return carbon to soil and this is a useful process. Charring plant matter isn't a good idea because that can drive or modify compounds in plant matter. Best practices rely on composting of plant matter, that process takes longer. The point you made on bamboo must be highlighted. Bambo is a plant that can be used for every use from animal feed, to clothing to building materials. Bambo grows almost anywhere from dry land to wetland. Bambo is an excellent replacement for agricultural water intensive cotton is infinitely better than synthetics. Bambo fabric has the sheen of silk, bit looks like cotton fabric.

To me organic based agriculture has value because it reduces the amount of resources required to product food and materials for clothing and building. I am a bit skeptical of the claim that manufactured fertilizers leave harmful residues in food. My problem with manufactured fertilizer is the amount of energy and raw materials that go into their manufacture.

[kentauros]

2. I don't claim to be an expert on any of this.

I leave that to the experts

What I've read so far with regards to terra preta is that it is a viable form of carbon capture, even more-so than planting trees in an equal amount of land.

I agree about bamboo being practically a "universal" plant in what it can be used for. The same is true for hemp, if we can ever push the DEA aside and allow it to be farmed. Both plants are also good at helping to stop soil erosion due to their broad root systems.

I haven't read about manufactured fertilizers leaving a residue in food, only that runoff high in fertilizer is a major concern for water bodies, due to algae bloom, and subsequent dead zones.


(sorry it took so long to reply; having connection issues at home...)

[Tumbulu]

3. My problem with synthetic fertilizers

Is that they pump the plants up much as drinking sodas plump us up. These over fertilized plants that are artificially large and water soaked are more attractive to pests and diseases, and a viscous circle of Ag chemicals begin. Yields are higher, taste and nutrition are reduced per harvested pound.

When cotton is grown organically it is just as wonderful as other organically grown fibre yielding plants. We do not have any equipment in the US to process textile hemp. Until we have industries capable of processing it, the market remains paper products, which are good, but not it's highest or best use. And unless it is grown organically, I am not so impressed with it. Just because something can be grown organically, that does not make it organic.

[Tumbulu]

4. This is what really excites me about farming

I consider it to be the main way that we can save ourselves from this seemingly impossible task of drawing this outrageous concentration of CO2 from the atmosphere down. I think it can work and hope we can motivate more and more farmers to sequester as much carbon as we can as we build up our soils.

[Skidmore]

5. Just been grappling with terra firma issues as I make a shift to

raised bed gardening to circumvent the flooding my garden plot has undergone for most of the past 4 years. Part of that planning for next year is where get the soil and its amendments.

[kentauros]

6. Raised beds are great!

I hope you're able to solve your drainage issues. Growing up, my father amended our lawn with sand to level it out and then we added compost to add depth to the topsoil. I don't think he ever had the soil tested, which you may consider. Just talk to your county extension agent about that. They may even do that kind of thing, or tell you a lab to send it to.

Even just improving the topsoil of a home lawn helps overall

Here's a good site on organic lawncare:

Organic Lawn Care For the Cheap and Lazy