But this is not an infomercial. This week’s topic is, again, dirt, with a little focus on one particularly important component: a soil protein called glomalin, which exists thanks to the relationships between plants and fungi. From Terra Cognita:
Carbon molecules, in the form a sugar called glucose, pass from plant roots into a mycorrhizal fungus where they eventually makes their way to one of its hyphae – hairlike projections that extend as much as 2 inches into the soil in a never-ending search for nutrients. Then, in a process that is not completely understood by scientists, the carbon molecule is extruded from the hyphae as a sticky protein called glomalin.
As a plant grows, hyphae break off and the now free-floating glomalin quickly binds itself to loose sand, silt, and clay particles. Soon, small clumps of glomalin-glued particles form larger and larger aggregates, kind of like a vast, intricate tinker toy construction. As the aggregates grow bigger they become stronger and more stable, making the soil increasingly resistant to wind and water erosion. This process also makes the soil more porous (fluffy), with lots of tiny pockets in between the tinker-toy aggregates, and this facilitates oxygen infiltration, water transport, micro-critter movement, and nutrient transfer.
Next stop: humus – carbon rich soil, dark, rich, and sweet-smelling.
You can feel glomalin, by the way. It’s what gives soil its tilth—the smooth texture that tells experienced farmers and gardeners that they are holding great soil in their hands. To create tilth, the soil engine needs both biology and chemistry working together, and glomalin is the glue that binds them.
Glomalin itself is a tough protein. It can exist up to fifty years without decaying or dissolving. When locked into the stable tinker-toy structure of humus, it can persistent for even longer periods of time. Healthy soils have a lot of glomalin, which means this: since glomalin is 30 to 40 percent carbon, it is the ideal safe–deposit box for the long-term sequestration of atmospheric carbon dioxide.
Digging up soil, especially, for example, through plowing, breaks up glomalin and releases carbon, while simultaneously cutting up the mycorrhizal fungi that produce it. Glomalin was only discovered as such in 1996, by a soil scientist named Sara Wright, working for the USDA. She also conducted research that demonstrated that glomalin levels could be maintained and raised through regenerative farming practices, which includes no-till planting. The content of carbon in soil can also be measured much more precisely now that the existence of glomalin is recognized.
The article – which also has a nifty photo of glomalin on fungus – also talks about how the USDA recently announced an intent to “pursue partnerships and leverage resources to conserve and enhance greenhouse gas sinks, reduce emissions, increase renewable energy and build resilience in agricultural and forest systems,” and lists some of the specific actions the organization supports to do so, including these two:
Soil Health: Improve soil resilience and increase productivity by promoting conservation tillage and no-till systems, planting cover crops, planting perennial forages, managing organic inputs and compost application, and alleviating compaction. For example, the effort aims to increase the use of no-till systems to cover more than 100 million acres by 2025.
Grazing and Pasture Lands: Support rotational grazing management on an additional 4 million acres, avoiding soil carbon loss through improved management of forage, soils and grazing livestock.
It is really nice to have something really interesting, from a nerdy perspective (I mean how cool is that stuff! IT HOLDS THE EARTH TOGETHER AND IT’S MADE BY FUNGI THAT ARE BEING FED BY PLANTS BEING FED BY THE SUN OH MY GODS), and positive to write here, for a change. It’s odd: out of all the various topics, it’s the soil-related articles I’ve read these last few months that have made me feel the most amped-up, like I was gently vibrating with excitement, or (*glances at CAPSLOCK*) maybe not so gently, so I guess this is not just important because ecology, but Important for as-yet-unrevealed Reasons.