In this week’s edition of Growing Possibilities, we ask: Can ag-biologicals combat drought? More specifically can plant growth promoting rhizobacteria (PGPR) play a role in mitigating the effects of drought on row crops? This year some of North America’s agricultural acres are feeling the effects of drought, particularly Alberta and the American Midwest (1).
With the climate changing and water use becoming restricted in some areas growers need to find technological solutions to mitigate the effects of dry periods. Can ag-biologicals really play a role? Sure, some ag-biological companies will tell you that their product can do it all. But is there any scientific basis to the claim that certain microbes can help plants to weather drought conditions?
The short answer is yes. There is reputable scientific evidence that this can happen. The long answer as with much in the field of biologicals is that it depends on your crop, your soil type, your climate, and your biology.
Certain PGPR’s can help plants to survive in drought conditions by either producing exogenous compounds or triggering the plant to produce their own (2). For example, some microbes produce exopolysaccharides which are sugar polymers that can form hydrophilic biofilms. These films protect the roots from dehydration and maintain the moisture content of the rhizosphere by forming sheaths around the roots. Another example is the production of phytohormones by certain PGPR’s. Phytohormones can promote root development and the growth of root hairs. Root hairs have been found to facilitate the uptake of water in plants that are facing rapid transpiration (3).
Bacillus are a large family of bacteria that are found naturally throughout soils in nature. Certain bacillus have been found to aid in water retention among different row crops. For example, A species of bacillus was seen to have mitigated the effects of drought stress in corn by effecting changes on the cellular walls of the leaves in a 2022 study (4).
At XiteBio our own PGPR technology is based on our patented Bacillus firmus bacteria. In checking our field trials our sales agronomists have noted that when they dig up plants treated with XiteBio® Yield+ they find a significant root ball that retains moisture much better than a plant from an untreated portion of the field. This has led to the hypothesis that our ag-biological could have drought mitigating effects. Since our product produces phytohormones this anecdotal evidence is bolstered by scientific fact.
We are not ready to officially claim that our product mitigates drought. But we continue to investigate and innovate in the hopes that ag-biologicals will soon be developed with the express purpose of mitigating drought stress in row crops to help farmers combat water scarcity and maintain profitability and productivity through natural technologies.