A study led by researchers from the Department of Microbiology at the University of Malaga has revealed how organic farming –the one that uses natural substances and processes, avoiding the use of synthetic chemicals– can, in the long term, help crops become more resistant to drought in a natural way.

This research team, which also belongs to the Institute of Subtropical and Mediterranean Horticulture ‘La Mayora’ (IHSM), has demonstrated that this sustainable agricultural management system enriches specific groups of soil microorganisms, particularly bacteria, helping plants to stand up to climate change.

Specifically, this research confirms that soils treated organically for decades favor the increase of bacteria, especially the genus Bacillus, which are characterized by being highly resilient to survive in extreme conditions and act as a ‘protective shield’ of plants. The results of this research have been published in the journal ‘npj Biofilms and microbiomes’, of the Nature group.

Invisible allies of plants

For the development of this study, two avocado orchards were compared: one managed organically, without chemicals and with organic matter, and the other conventionally, using fertilizers and intensive management, both located in the area of the Axarquía in Malaga.

“By comparing the rhizosphere (the soil attached to plant roots) of crops under organic and conventional management over 20 years, we identified important differences in their physicochemical properties that play a key role in the composition of microbial communities, observing an abundance of bacteria of the genus Bacillus”, explains the researcher and first author of this paper Blanca Ruiz Muñoz.

In a second phase, in the laboratory, the researchers isolated bacteria of the genus Bacillus and evaluated their effect on plants. Through different trials, they observed that some of these microorganisms improved plant physiological state and growth under drought conditions. “Therefore, it is not only that these bacteria are better prepared to survive under stressful conditions such as scarcity of water, but also play a direct role in plant survival,” they say.

Towards a new form of agriculture

According to these experts, these findings are especially relevant in southern Spain, with very dry areas, where more resilient crops would mean fewer losses; moreover, they would also bring other important benefits such as reduction of the use of fertilizers and chemicals, in favor of ‘bioinoculants’, products formulated with microorganisms that are beneficial to soil.

“It’s not only about cultivating plants, but also about managing and ‘training’ soil microorganisms to move toward another form of agriculture,” concludes Professor José A. Gutiérrez Barranquero, another of the authors of this paper.
In short, the way crops are cultivated today could enhance the ability of future crops to withstand climate change, so the key to surviving drought could lie underground.

Together with the UMA-IHSM research team, composed of Blanca Ruiz Muñoz, Víctor Carrión, Francisco Cazorla and José A. Gutiérrez Barranquero, researcher Kevin M. Bretscher, from the Institute of Biology of the University of Leiden, is also part of this publication.