Get your dirt working with microbes

Fighting the carbon battle one compost bin at a time

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My first composting experiment started in college with a cute, ceramic bin on the kitchen counter of the drafty house I shared with seven other people. We were being green and trying to find ways to actually keep the smell of eight people (hippies, no less) in check.

My second composting operation was here in Taos -- the most sensible way to use up the food scraps and help out the plants I'd grow the following season.

But what if compost could address issues other than wounds suffered by the ego for not having a greener thumb? What if compost could actually be part of the constellation of solutions to humanity's biggest challenge - climate change?

It can.

Rivers and Birds, an environmental education nonprofit based in Arroyo Seco, recently hosted a workshop by the New Mexico State University scientist and compost innovator, David C. Johnson.

Together with his wife, Hui-Chan Su Johnson, the pair created the Johnson-Su Composting Bioreactor.

Making compost that helps regenerate the natural processes in dirt doesn't take a specific recipe. As Johnson explained, he created a stationary composting bin, or bioreactor, that costs about $40 in materials and can turn leaves, manure or food scraps into a compost dense with a diversity of microbes and fungi.

And Johnson's research, undertaken in the dry, hot environment of southern New Mexico, has shown that soil treated with his compost can be more productive than even the rainforests of the Amazon.

"If we are to achieve long-term stability in our agricultural systems," Johnson wrote in a bioreactor manual, "it may be advantageous for us to start emulating the composting actives of nature and our ancestors."

Mighty microbes

Let's start with the amazing fact that there are microbes (tiny, invisible fungi, bacteria and single-cell organisms) are everywhere and life is utterly dependent on them.

The human body is a perfect example of this microbial dependence in action. Cell to cell, every human is outnumbered by the microbes that live in and on the body. Our shared space isn't neutral; fecal transplants (of gut microbes) and eating fermented foods (rich in beneficial bacteria) are among the ways of restoring a healthy microbiome.

And in the same way microbes are essential to the body, they're essential to the soil.

But agriculture disturbs the soil. Tilling quite literally turns well-established microbial communities upside down. And in the process, stores of carbon are released.

"Plowing actually damages the soil structure and exposes soil carbon -- the crumbling blackness that generations of farmers have recognized as a feature of the best, richest soil -- to the air, where it combines with oxygen and floats away as carbon dioxide," Kristin Ohlson wrote in her 2014 book, "The Soil Will Save Us."

And carbon dioxide is a big contributor to climate change, according to scientists.

Sequestering carbon - trapping the gas back in the ground - is a big step in mitigating climate change as best we can. But getting carbon back into the ground is going to take working with the soil as a whole ecosystem and not as an isolated input in agricultural production.

"We've bred plants to grow in poor soils," Johnson explained. "Let's flip that. Let's fix our soils and see what plants can do."

'See how it goes'

Making the bioreactor isn't as simple as throwing leaves and leftovers on a pile of dirt and forgetting about it, but it isn't much more complicated.

The bin is built using a standard shipping pallet, several pieces of landscaping fabric, plastic pipe, tire wire and rebar. Participants in the Rivers and Birds workshop, which was also sponsored by the Harwood Museum of Art and Rio Grande Ace Hardware, spent an October afternoon eating lunch at the Farmhouse Cafe in El Prado and assembling a Johnson-Su bioreactor on site.

Check out this instructional video about making a Johnson-Su bioreactor.

The bioreactor differs from a usual compost pile in that it's filled up once and then left for a year. Johnson suggests chopping and wetting the starter material like leaves before filling the bin to the top. The bin is watered for a minute a day.

Otherwise, the community of soil microbes is left to grow strong without disturbance, resulting in a fungi-heavy compost that holds water and hosts hundreds of genetically distinctive microbes.

Julie Shedko, co-founder of Lettuce Grow Farms in Taos, said she found the workshop inspirational and practical.

"We're going to have to start with the soil. We keep taking from it but we haven't put a lot back into it. It's one way of composting we haven't done," Shedko said.

Floyd Archuleta, a longtime farmer and rancher in Des Montes, said "it was pretty exciting to learn," especially because the compost is low-maintenance and can be made in big quantities even though it doesn't take a lot of the finished product to improve water and carbon retention in the soil (just less than a pound per acre).

"We'll see how it goes," Archuleta said.

The finished compost out of the Johnson-Su bioreactor can be used as a slurry to coat seeds, spread on a pasture or farmland as a soil amendment like normal compost - used as an inoculant for the soil -- essentially a booster shot of microbes.

And beyond helping plants grow better, the compost also helps increase the content of carbon in soil. As Ohlson writes, Johnson's methods resulted in the dirt's carbon storage "accelerating in a non-linear fashion."

Of course, there are limitations to what good compost can do for the world.

While carbon sequestration by natural and mechanical processes is touted as a valuable and necessary tool to stabilize atmospheric carbon and mitigate climate disruptions, uncertainties abound about its effectiveness and implementation beyond computer models.

And certainly, home gardeners and small-scale ranchers aren't going to make up for a lack of aggressive climate policy.

But with such a daunting challenge (and existential crisis) as climate change, fixing worn soils with good compost full of fungi and bacteria can be a small but necessary part of a forward-looking strategy.

"Our workshop participants … were greatly inspired," said Rivers and Birds director Roberta Salazar. "I think this is a step in a powerful, no-till soil conservation movement for our region."

Rivers and Birds will be hosting another soil workshop next spring. For more information, visit riversandbirds.org or call (575) 776-5200.

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Kumudini Sandesha

Compost is rich in nutrients. It is used in gardens, landscaping, horticulture, and agriculture. The compost itself is beneficial for the land in many ways, including as a soil conditioner, a fertilizer, addition of vital humus or humic acids, and as a natural pesticide for soil. In ecosystems, compost is useful for erosion control, land and stream reclamation, wetland construction, and as landfill cover. Organic ingredients intended for composting can alternatively be used to generate bio-gas through anaerobic digestion.

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