Mighty Mycorrhizae

One of the great things about gardening — in addition to creating beautiful landscapes and delicious, healthy food — is its educational opportunities. Your friendly Planet Natural blogger has gardened on and off since my childhood some (garbled) years ago and I learn something new almost every time I pick up a how-to book, talk to a companion gardener, or get my hands in the dirt. Best are the things that I once knew nothing about and, as I explore them further, result in deepening levels of understanding and wonder. Current example? Mycorrhizae.

Mycorrhizal fungi are beneficial soil organisms that attach themselves to the roots of plants — almost 95% of the world’s growing things have a symbiotic relationship with mycorrhiza  –  and help them facilitate the uptake of water and nutrients. I first came aware of mycorrhizal fungi when pursuing hydroponic gardening a few years back. Hydroponic gardeners add mycorrhizal fungi inoculants to their growing solutions to encourage quick and vibrant growth. Some soil boosters also contain them. That’s good as far as it goes.

What I didn’t know is that mycorrhizal fungi play an important role in the environment. They assist plants in taking up carbon dioxide, which helps the plants and the atmosphere. Regardless of what you believe is causing global warming, there’s one fact that all sides acknowledge; and that’s not necessarily believing the planet is getting warmer. It’s that the average parts per million of carbon dioxide is increasing. That’s the actual mechanism of all things popularly labeled as “global warming” of “climate change.” Anything that helps take CO2 from the atmosphere so as to return it to more normal levels is a good thing. And guess what? That’s exactly what mycorrhizae do. Here’s a summary of one study from the U.S. Department of Agriculture’s Research Service:

Arbuscular mycorrhizal fungi (AMF) form symbiotic associations with roots of most plants. The fungi receive organic sustenance from host plants while contributing mineral nutrients to them. AMF have a major role in global carbon cycling because they consume up to 20% of plant assimilates and deposit slowly decomposing organic compounds in the soil, thus promoting soil carbon sequestration. Atmospheric carbon dioxide (CO2) enrichment often stimulates AMF growth, suggesting that soil carbon storage via enhanced AMF activity will also be increased in the future.

What this means is that nature provides a sort of balancing mechanism when it comes to CO2, or carbon, levels. The more CO2 there is, the more mycorrhizal fungi develop. At least that’s the theory. In truth, mycorrhizal levels across the world are reduced because of excess tillage, land being left fallow and exposed to sunlight (think cover crops), forest burning, and the use of pesticides and herbicides. Of course, we all know the solution to that: organic farming and gardening practices. The more we encourage the growth of mycorrhizal fungi, the more CO2 in the atmosphere, added from human activity or otherwise, we sequester. The intriguing movie Carbon Nation, a film that doesn’t dwell on the causes of increased CO2 in the atmosphere, or the politics, but instead focuses on the solutions to the problem (which also translates into saving money), suggests that changing to a more natural land use policy — in other words encouraging, not killing off, the mycorrhizal fungi — could draw down 39% of current carbon emissions. That’s as much CO2 as produced by all the fossil-fueled electrical generating plants in the United States combined.

I’m always amazed at the growing list of benefits that can be attributed to the application of smart organic practices. In so many ways, it’s becoming obvious that organic farming and gardening just might save the world… literally.