In this Gardenprue article we have to talk about mycorrhizae , fungi that form a very interesting symbiosis with plant roots to obtain mutual benefit. They are great transporters of phosphorus and other nutrients in exchange for the carbohydrates that the plant exudes through its roots. This symbiosis will increase the production and resistance of your plants.
WHAT ARE MYCORRHIZAE?
The term mycorrhiza refers to the symbiosis that occurs between a fungus and a plant. It is a genus that includes many types of fungi, among which we can find some well-known ones.
For example, this is the case of the chanterelle ( Lactarius deliciosus ), which we have already discussed in Gardenprue. It is considered an ectomycorrhizal fungus.
This of ecto and endo is something that we have to explain, because that way we will better understand the associations that occur between mycorrhizae and plant roots, which is where we are going.
ECTOMYCORRHIZAE AND ENDOMYCORRHIZAE
These terms separate the types and classes of existing mycorrhizae.
- In ectomycorrhizae , the hyphae of the fungus do not penetrate into the cellular juice of the root, but either remain outside or between the cells (intercellular), weaving a “road circuit” known as the Hartig Network.
- In endomycorrhizae , hyphae pass through root cells, without adversely affecting the plant. This type of mycorrhizae are the most characteristic and common, where practically 80% of the total are of this type.
EFFECTS OF MYCORRHIZAE ON YOUR CROPS
When the installation of a mycorrhiza in the roots of a crop occurs, it is as if it enlarges the nutrient uptake surface.
Therefore, we increase the efficiency in the absorption of essential nutrients such as nitrogen, phosphorus, magnesium, manganese, zinc, etc.
In addition, the colonization of this fungus in the root reduces the ability of other fungi, in this case pathogens, to colonize and affect the plant.
These are, in summary, the functions of a mycorrhiza in your crops:
- Facilitate the absorption of water and nutrients.
- Physical protection against pathogenic fungi and nematodes.
- Limitation in the absorption of heavy metals (cadmium).
- Greater root development and exploratory capacity of the root.
- Formation of aggregates in the soil by adhesion of particles.
- Increased moisture retention capacity.
The fundamental role of mycorrhizae, when it comes to improving the absorption of nutrients, has special relevance with phosphorus.
In most soils, both acidic and alkaline, with a greater or lesser presence of calcium, magnesium or aluminum, phosphorus is almost always limited in its absorption or poorly soluble.
That is why we are used to seeing a multitude of soil analyzes where phosphorus is found in very high amounts (up to 10 times that of Olsen phosphorus) but the response of this element to absorption is very low because it is insolubilized.
The application of mycorrhizae in this type of soil can give us a productive advantage by facilitating the disposal of phosphorus to plants.
These fungi are responsible for facilitating phosphorus in forms assimilable to the plant and it returns exudates rich in sugars. It is a process related to rizodeposition , which we already talked about on this website.
Well-installed mycorrhizae in a crop reduce the effects of biotic stress (caused by living organisms) and abiotic stress (caused by excess or scarcity of water, inclement weather, etc.).
In summary, we can say that mycorrhizae act as follows:
- exponentially increasing the volume of the soil that the roots explore due to the increase in the mycelium network, which allows the transport of the main nutrients (N and P) and water for the plants, including the low mobility elements.
- By directly increasing the solubilization of the phosphorus mineral and the nitrogen capture of organic matter.
MYCORRHIZAE AND WATER STRESS
In areas where there is a real water supply problem , mycorrhizae can have a positive effect, since they facilitate the transport of this element into the root.
The effect caused by the lack of water is expressed with less intensity in plants that have symbiosis with this type of fungi.
By multiplying the area of reach of the roots , since as we have commented, these hyphae act as a branching or lengthening of said roots, their functionality is multiplied and they have a greater capacity to explore soil and absorb moisture.
TYPES OF MYCORRHIZAE AND SELECTED STRAINS
Although we have already discussed the difference between ectomycorrhizae (hyphae that do not penetrate the interior of the root cells) and endomycorrhizae (the most common on the market), we are going to comment on some interesting strains to apply in different cultures.
In general, the mycorrhizae selected are endomycorrhizae of the type glomus sp.
- Inoculation iranicum
- Rhizophagus irregularis, with applications of 1 L / ha after transplantation.
- Inoculation of aggregate
- Glomus mosseae
- Glomus etunicatum
- Glomus intraradices
We can find different products on the market where there is a mixture of different strains.
It is common to see tablets that are placed buried in the earth, in contact with the roots, before introducing the plant, and they gradually release and activate the fungi, so that they are inoculated in the first waterings.
It must be taken into account that the application of fungicides, fertilizers rich in phosphorus and disinfectants affect the inoculation of the fungus. Therefore, it is recommended not to apply any of these products during the first weeks.
HOW TO APPLY MYCORRHIZAE ON YOUR PLANTS
The application of the mycorrhizae is important to be done at the right time, very close to the post-transplant, to ensure maximum installation.
The level of organic matter in the soil is a determining factor that affects the installation of this fungus. The more the better.
- In horticultural crops (greenhouse, outdoors or hydroponics) apply 3 kg / ha, starting 7 days after transplanting.
- In strawberry and other berries apply 3 kg / ha, starting 20 days after transplanting.
- In woody crops such as citrus, stone and pip fruit trees, tropical and subtropical, olive groves, vineyards, etc., it is applied at the beginning of sprouting (deciduous crops) or winter season (perennial crops).
- 2 kg / ha in young plantations.
- 3 kg / ha in full production.
USE OF MYCORRHIZAE IN VEGETABLES
In horticultural plants, with a vertiginous growth in the hot months, the inoculation of the mycorrhizae is an effective system to allow a fast rooting and a vigorous development of the plant.
Both in outdoor horticultural crops and in high-tech greenhouses, mycorrhizae have been successfully implanted on the market and their effectiveness for all types of plants is more than proven.
USE OF MYCORRHIZAE IN OLIVE GROVES
The inoculation of specific types of mycorrhizae to reduce the spread of diseases is currently being successfully tested.
In this case, one of those that most affect the olive grove with a very bad solution is verticillium. Although it has been shown that mycorrhizae do not eliminate the disease , they do offer beneficial conditions to reduce its appearance or control the progress of the disease, if it is already installed.
This is also related to the effects of mycorrhizae to protect the plant from abiotic stress, which is a negative addition when this type of disease appears.