Baxter County Master Gardener Program • University of Arkansas System • Division of Agriculture • © 2013 BCMG
I was reading an article in Arkansas Gardener by Victoria Ligenza, on what really is happening in the soil under our plants. Scientists have found that plants communicate with each other by sharing information using a type of fungus called mycorrhizae. Mycorrhizal fungi assist plants with the absorption of minerals and water from the soil and protect the roots from other harmful fungi and nematodes. The plants in return provide carbohydrates to the mycorrhizal fungi. As much as 80% of the carbohydrates made by plants may be used for below ground processes, some of this energy goes into the root system but a high proportion is used to feed the mycorrhizal fungi.
The plant and the fungi have a symbiotic relationship, the fungi receives the carbohydrates to live and the plant receives nitrogen, phosphorus and other nutrients it needs to grow. The fungi colonize the soil around the roots of the plants and send out fine filaments called hyphae that extend out into the soil acting like an extension of the plants roots. These hyphae pick up nutrients and water far from the plants roots, thereby greatly increasing the plants ability to absorb nutrients from the soil.
This relationship between plants and fungi goes beyond nutritional exchange. They actually allow the plants to communicate with each other. If a neighboring plant, is being attacked by aphids, the plant will begin to produce a chemical that attracts wasps which are a natural predator. This chemical change will alert the neighboring plants to begin to produce the same chemical.
More than 90 percent of plants species have these symbiotic relationships with mycorrhizal fungi. In order for the relationship to continue the soil must not be disturbed. Tilling the soil destroys the fungi and they are slow to recolonize. Before you start tilling your gardens in the spring or fall think twice, there are better options. Planting a cover crop in the fall or early spring over your gardens will keep weeds at bay.. Don't till the cover crop into the soil, just cut it down and let it decompose on the surface. Mulching is another great alternative to controlling weeds and improving your soil.
There is much more happening under the soil than we ever thought, and we are just beginning to understand the relationships.
Submitted by Tamara Carl
Sources Arkansas Gardener, Feb. 2015
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