Mycorrhiza helps plants reach, break up and mobilize otherwise unavailable soil nutrients.
Fungi and Plant Roots: A Love Story
There are many types of “good” fungi that form symbiotic (mutually beneficial) relationships with plants. These relationships are known as mycorrhizae, and the microorganisms are called mycorrhizal fungi. These specialized fungi effectively extend the plant root system with mycelium – a web of long microscopic filaments called hyphae. A mycelium’s surface area can be up to 100 times greater than that of the plant root itself. This “secondary root system” absorbs valuable nutrients (and water) that otherwise are simply unavailable to the plant.
How Do Crops Benefit?
Over 90% of the Earth’s vascular plants are mycotrophs – plants which form symbiotic relationships with mycorrhizae. These fungi have contributed to plants since long before humans invented agriculture. In fact, many plants are considered obligate mycotrophs, i.e. dependent on mycorrhiza for healthy growth (e.g. corn, carrot, olive, cannabis). However, modern agricultural methods, including fumigation, cut-and-fill leveling, sterilization of growing media and even tilling, exterminate mycorrhizae along with the target pathogens. Reintroduction of mycorrhizae in soil restores the plants’ ability to absorb precious nutrients. As a result of this improvement in nutrient uptake, mycorrhizal plants have been shown to demonstrate improved health, higher crop yields and resilience to stress.
How Does the Environment Benefit?
Mycorrhizae have a direct impact on six out of eight measurable planetary boundaries: phosphorus cycle, nitrogen cycle, climate change, freshwater use, land use and ocean acidification. Some of the mechanisms that are instrumental in these environmental benefits are described below:
- The impact of mycorrhizae on the potential reduction of phosphorus consumption is dramatic. Phosphorus (P) is a chemical element that is essential for plants and is non-renewable. Most plants are able to absorb about only 15% of the phosphorus fertilizer, leaving 85% for run-off and leading to massive excess fertilization, which causes contamination of water sources and soil and blue algae pollution, not to mention lost funds invested in wasted chemical fertilizer. Mycorrhizae are able to dissolve and actively absorb phosphorus, mobilizing it from wide soil surfaces into the plant. The end result is significant savings in phosphorus fertilizer consumption.
- Mycorrhizal fungi are the only known organisms to produce glycoproteins called glomalin (incidentally named after the glomus genus). Glomalin is a sticky substance that acts as “soil glue” that permeates organic matter and binds it to silt, sand and clay. It is what gives soil its tilth – that smooth granular texture of quality soil. Glomalin simultaneously invigorates the soil, adds to soil structure and sequesters atmospheric carbon that is passed through the symbiont plants. Studies have shown that glomalin accounts for 27% of carbon in soil, making it one of the most significant carbon sinks on earth.
Mycorrhizal hyphae form mycelium, a fungal network that effectively extends the plant root system. Nutrients are mobilized and stored in vesicles contained within the root.