Since the origin of agriculture, thousands of years ago, soil has been more than just the place where seeds were sown. In addition to supporting plants, the soil was the storage place for water and nutrients that crops needed to grow, although until recently the effect on crops of something invisible that was present in the soil – its microbiome – was overlooked.
The soil microbiome is nothing more than the community of microorganisms that cohabit and colonize the soil, interacting with plants and influencing their health. The composition and diversity of the microbiome depend on multiple factors that are influenced by agricultural practices: soil pH, texture, structure and carbon concentration are largely modified by the different types of agriculture carried out. Likewise, the soil microbiota is favored by the heterogeneity of crops over time, so that crop rotations, for example, are techniques that help to maintain the diversity of the microbiome, while techniques such as the abuse of monoculture are very detrimental to soil microorganisms.
Factors affecting soil fertility
It is, therefore, easy to deduce that soil fertility is closely related to the microorganisms present in the soil. If we have a monoculture regime, which is already negative for the soil (due to the continuous extraction of the same nutrients in the same proportions), the additional decrease in fertility due to the loss of microorganisms can result in an extremely important decrease in yields in the long term.
Likewise, organic matter is another element to highlight if we focus on fertility. Organic matter works as a sponge, improving water holding capacity and also acts as a nutrient reservoir. But that’s not all, it also provides a better soil structure, which has a positive effect on root growth. Its mineralization increases the levels of nitrogen, phosphorus and sulfur, which facilitates greater biodiversity of microorganisms and improves the buffering power of the soil to control acidity, as well as reducing the need for chemical fertilizer application.
Much remains to be studied
We have seen that a healthy soil (in all its variables) is one of the keys to the future for a healthy crop, and therefore for obtaining high value-added food.
It has been fully proven that it is key to crop nutrition, but it is also key to crop health, since there are studies that show that some soil microorganisms can produce antimicrobial compounds that kill plant pathogens.
There is even data indicating that the soil microbiome can affect variables such as the final taste of food…perhaps modern agriculture should look both to the sky for the need for water and to the soil to take care of its microbiome.