Why Actinomycetes are your great allies on the ground

Although we are talking openly about the potential of many fungi and bacteria that we find naturally in the soil, today it is the turn to talk about actinomycetes , a middle ground between fungi and bacteria that are closely related to the production and defense against diseases of your crops. 

To this day, we are not going to find many studies that speak of the potential of actinomycetes, although I know for a fact . This is because to a greater or lesser extent, it is a gift that the soil already offers us.

However, enhancing its growth or at least not reducing it greatly influences the potential for production and protection against diseases (fungi and bacteria) of a crop, and at practically zero cost .


One particularity of these microorganisms is that people classify them as a middle ground between a bacterium and a fungus.

This is so because, although they are actually classified by the scientific community as bacteria, they have filamentous bodies or false hyphae, like fungi.

So, and making things clear from the beginning, actinomycetes or actinobacteria have nothing to do with the fungi kingdom , although they look very similar.

One of the most famous bacteria within this group are Streptomyces , which are capable of producing spores or conidia, although, and repeating it again, they are bacteria.

We do not want to reveal much more about the potential of actinomycetes, but we will leave you a detail to whet your appetite:

In 1940, Selman Waksman won the Nobel Prize for the discovery of actinomycin, from which a multitude of antibiotics have been developed that have saved thousands of lives.


The main function that actinomycetes have, although they develop many more abilities, is to decompose the organic matter in the soil .

Having a good level of organic matter in a soil (between 1% and 2%) has always been related to good fertility and a good ability to exchange nutrients between soil and plant.

Well, what actinomycetes or actinobacteria do is to manage to decompose, together with other groups of microorganisms, those nutrients that in principle are blocked at the expense of mineralization .

To do this, we will use the nitrogen cycle, understanding this that we explain graphically:

The great importance of nitrogen in plants

As can be seen in the image and in an article that we developed in Gardenprue, there are many ways to provide nitrogen, either organically (organic matter) or inorganically (in urea, ammonia or nitric form).

What we deal with in this article, related to actinomycetes, is the development and decomposition of organic matter (plant remains, decomposition of animals, excretions, compost, etc.) from a group of microorganisms.

The organic matter contributed to a soil can provide a good ratio of nitrogen, phosphorus, potassium, calcium, magnesium, micronutrients and a lot of carbon.

However, not all these elements are initially absorbable or assimilable by plants, so they must undergo a decomposition process.

This is the case of nitrogen, for example, which in the organic state is not assimilable by the roots  and has to undergo a decomposition process (known as mineralization ) to pass into ammonia form (NH4 +), already absorbed by the roots, and then to other simpler forms of nitrogen.

This is where actinomycetes come into play , since they are the main interveners in the process of transformation of organic matter and they are the ones that put the nutrients that we provide with manure, compost or other organic forms in highly available forms for plants.

Otherwise, the transformation process slows down, is uncontrolled, and we can have highly available nitrogen when the plant enters a maturation process or we really do not need to contribute as much of this element


Antibacterial activity of actinomycetes isolated in the laboratory

Not only is it responsible for speeding up the nutrition process of a plant, as we have seen before, it is also capable of doing other things:

Degradation of other compounds, such as cellulose, hemicellulose, and chitin.

Formation of organo-metallic complexes to reduce nutrient losses.

Microbiological balance from the generation of antibiotics that stabilize the environment and reduce the proliferation of microorganisms that are pathogenic for plants.

This last point is what is known as suppressive soil . The fact that in a living soil there are a large number of heterogeneous microorganisms generates a balance where everything is connected.

With this, we avoid the rapid appearance of diseases that attack plants. Simply because their colonization is much lower and competition for space and food is high.


The so-called suppressive soil is closely related to the organic matter content of a soil, the atinomycetes and the disinfections or solarizations that are done to reduce the pathogen population.

Solarization as soil disinfection

When we use disinfectant agents in a soil, such as metam-sodium, dichloropropene or other agents, the microbiological population is reduced to a minimum.

Be careful, we always say minimums, since it is impossible to reduce it to 0, no matter how many quantities are used and many repetitions.

From here, a struggle begins to stand out in an environment without competition and with an abundance of nutrients to develop.

This is the turn of actinomycetes and other organisms that help plants, such as mycorrhizae or trichodermas.


Not properly as such, but there are products that harbor an indefinite and unclassifiable number of this type of degrading bacteria.

In general, all compounds rich in organic matter and carbon are capable of harboring small, eager to expand colonies of actinomycetes.

As we always defend in Gardenprue, it is unjustifiable not to periodically add organic matter to a soil, or to produce our own through compost or vermicompost. The potential and not only nutritional that comes with having a soil rich in these elements is impressive.

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