Right under our feet, hidden from our eyes, is a ubiquitous, bustling and persistent market economy which operates at the interface between plants and soil and which dates back to the time of the dinosaurs. Taken from the Greek “mykes” (fungus) and “rhiza” (root), arbuscular mycorrhizal fungi form symbiotic associations with the roots of over 80% of plant species. Their underground network (a ‘wood-wide-web’ of sorts) enables connections and communications between plants about resources and threats, the plant receiving nutrients and water from the fungi and in return the fungi getting sugars and fat from the plant. The body of these fungi may be thinner than a thread of cotton, while the length can measure up to 1 km in just 1 gram of soil. Every year, 5 billion tonnes of carbon are exchanged through this system globally via sophisticated trade dealings. What is remarkable is that despite lacking a brain, these fungi can do trading calculations like complex computer algorithms.
Arbuscular mycorrhizal fungi provide important ecosystem services through their underground network, such as nutrient cycling, removing hazardous contaminants from soil, soil formation, prevention of soil erosion, pest and disease regulation, mitigation of greenhouse gas emissions and water regulation. In addition, they promote agroecosystem resistance and resilience by improving plant tolerance to stress factors, such as nutrient deficiencies, drought, salinity, and extreme temperatures - stresses that are expected to become more frequent and intense with climate change.
Given their many roles, it is little surprise that over the last decade, attention has turned to mycorrhizal fungi as a new and important area of research.
The challenge is that common farming practices, which aim to maximize yields through monocultures, use of agrochemicals, and mechanical tilling of soils, disrupt this complex underground wood wide web. That can be harmful for both productivity and sustainability of the agroecosystem.
