Find out everything about mycorrhizae, the natural soil biofertilizers
On Earth life begins and ends to start over again. The main responsible are the microorganisms that inhabit it and give it life, with their relationships and interactions (association, depredation, competition, etc.) giving them a balance.
The working soil is not something inert, being formed, on average, by an 93% mineral and an 7% organic matter. The organic part is composed of an 85% humus, an 10% root and an 5% of living organisms, mainly fungi, bacteria, worms, arachnids and insects.
In conventional agricultural ecosystems the soil exerts an almost exclusive function of supporting the plants, it does not imitate Nature in its energy flows. Energy is often "extracted" and replaced by synthetic materials that are almost always polluting, contributing to the degradation of the ecosystem. The dynamic role of MO for living species in the soil is forgotten. In these conventional systems continuous care is required because the System is highly modified, unstable and unbalanced. The crops are so strong that they are irresistible to the phytophagous and that is where the trophic chain ends, since everything that is not a crop is weeds or "bugs".
Agroecology tries to imitate the natural cycles to the maximum by means of continuous contributions of MO of the own ecosystem, as well as restoring the extracted from the outside, conserving the microbial diversity of the soils that is source of balance, health and productivity for them.
Main types of fungi in the soil
Fungi are dependent beings that do not have chlorophyll, obtaining their energy in the decomposition of the OM of the substrate where they develop. They can be classified in:
1) Saprophytes: along with bacteria and other microorganisms are able to attack the lignin and cellulose of vegetables by making available to the plants the nutrients they need for their development.
2) Pathogens: are those that get their nutrients from a host that they weaken and can end up killing. Examples: the "White Evil" (Armilliaria melea) or the "Mildiu" (Phytophora sp), etc.
3) Symbiotics: they also obtain their nutrients from a host but, unlike the previous ones, receive a counterpart in return, so that both benefit.
Of all the symbiotic relationships of the soil, the mycorrhizal fungi maintain a strict dependence on the plant: they belong to the genus "Fungi" and establish a mutualistic association between the roots of a plant species and the mycelium of the fungus, constituting a new "functional organ" underground of which both species are served. They are mycorrhizal fungi.
Potential benefits of mycorrhizae to cultivated plants
1) Improvement in the absorption of nutrients, mainly phosphorus and nitrogen.
2) Improved water absorption and increased resistance to water stress conditions. Increased resistance to saline culture conditions.
3) Increase in resistance to soil pathogenic fungi due to their antagonistic effect. A root colonized by mycorrhizal fungi is difficult to be affected by pathogenic fungi.
4) Improvements in the structure of the soil by the aggregates that form the hyphae and filaments of the fungus.
5) Hormonal effects on the roots that increase their development and that of the whole plant.
Types of mycorrhizae
1) Ectomycorrhizas: in them the fungus forms a kind of mantle with its hyphae around the thinner roots of the plant, but they do not get to enter their cells, developing in the intercellular spaces of the root bark. They are frequent in forest species where their reproductive organs can protrude from the ground, what we know as mushrooms and truffles.
2) Endomycorrhizas: the hyphae of these fungi penetrate inside the cells of the roots. They do not form any observable structure with the naked eye. In the "arbuscules" there is the exchange of nutritive elements by carbon, between the root and the fungus.
Why are they interested in organic farming and in what crops?
In conventional agriculture with agrochemicals, the use of fertilizers, insecticides, herbicides and excessive tillage, causes the soil conditions to be profoundly altered, so the favorable conditions for the development of the fungus - root symbiosis disappears or it does so very weak.
In organic farming, since synthetic products are not used, soil conditions to mycorrhizal are more favorable. But for the mycorrhizal infection to occur in a natural way, sufficient inoculum of the fungus is needed in the soil, the roots of the plants to develop, the colonization of the fungus to occur, etc. and all that takes time.
If we grow horticultural species, usually of short cycle, it can happen that when the symbiosis is established, the crop is already finished and its benefits do not affect its production. Therefore, it is of interest that the seedling is already mycorrhized before the transplant. The most effective and simple way to apply the inoculum in horticulture is in the sowing: To the substrate that we use in the Seedbed we will add the inoculum, so that from the moment the roots emerge from the seeds, they come in contact with the propagules of the fungus and establish the symbiosis quickly. In this way when transplanted to the field, your root system is already perfectly mycorrhized and you can take advantage of all the advantages of the symbiosis.
The mycorrhizal inoculums, are they phytosanitary or are they fertilizers?
In principle they can be both phytosanitary -antagonists of other pathogenic fungi of plants- as fertilizers, or better, biofertilizers to help the absorption of essential nutrients for plants.
Source: Ecoagricultor.com
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