In order to conserve water in our garden, it is recommended to encourage mycorrhizal growth.
But, first off, what is mycorrhiza?
Mycorrhiza is a type of fungus that has developed a symbiotic relationship with plants, in which it increases the absorption of phosphorus and other nutrients. The plant allows the fungus to attach itself to its root system. Because the amount of water and nutrients a plant can absorb is directly dependent on the surface area of the root system, this relationship increases the ability of plants to absorb what they need. Mycorrhizal networks are able to absorb all 15 essential nutrients for plants, and absorb the nutrients through intricate webs. It also makes certain enzymes that can aid in breaking down hard to claim nutrients such as phosphorus in order to make them easier for a plant to uptake and digest.
This is what it looks like close up:
“Ericoid mycorrhizal fungus” by MidgleyDJ https://commons.wikimedia.org/wiki/File:Ericoid_mycorrhizal_fungus.jpg#/media/File:Ericoid_mycorrhizal_fungus.jpg
And this is what its symbiotic relationship looks like:
Mycorrhizal growth on roots- http://commons.wikimedia.org/wiki/File:Vicia_sepium9_ies.jpg
These organisms can help plants thrive naturally and without fertilizer. They are also great at increasing the ability of soil to hold water because the water holding capacity increases as the amount of organic matter does. This means that less water will be lost by evaporation or runoff so that more water is available to the plants and you do not have to irrigate as much. Loss of water to the environment is a major source of water waste. Mycorrhizae produce humus and other organic glues that can hold the soil together and therefore increase water holding capacity.
Conventional gardening, unfortunately, can make it difficult for plants to interact with mycorrhizae. Compaction, top soil loss, and less organic matter discourages mycorrhizae from growing. Often, the effects of conventional gardening on this relationship are dually terrible because it both isolates plants and discourages fungal growth as well as increasing the nutrient needs. This increases the needs for fertilizers and other water-consuming products in the garden.
So how is it possible to encourage mycorrhizal growth?
- Add compost, rather than fertilizer, to soil. While fertilizer gives plants nutrients, it is chemical-heavy and strips plants of the need to develop this relationship with mycorrhizae. The chemicals are detrimental to existing fungi and, although providing plants with nutrients, discourage the development of natural nutrition uptake strategies. Adding compost will increase the amount of organic matter in the soil, and develop a more fertile topsoil, thus making an ideal environment for mycorrhizal growth.
- Use minimal tillage. When you till the soil, it can disrupt and harm the fungal growth on the roots of plants. It takes a while for mychorrhizae to grow, so tilling every season can be detrimental to colonies.
- Plant cover crops. While establishing different kinds of environments for the mycorrhizae, cover crops increase the amount of organic matter in the soil, thus increasing microbial activity and encouraging mycorrhizae to grow.
Mycorrhizae can be a natural defense against what could devastate a garden: drought and nutrient deficiency. It is in many ways essential to healthy, natural garden that does not deplete nutrients in the soil. Who knew such a little organism could make such a big difference?