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Saving Plants From Salty Soil

Alfalfa is a major cash crop and significant food source for cattle, horses, chickens, turkey, and sheep across the western United States. According to the United States Department of Agriculture, 40.8 million tons of alfalfa were harvested in 2022. But alfalfa, among other abundant crops, is extremely susceptible to the salty soil brought on by Utah’s dry climate and low precipitation.

Members of BYU professor Dr. Brent Nielsen’s lab have made recent discoveries that could be key in solving this problem affecting farmers on a global scale. Utah’s lack of rainfall means the excess salt in the soil is left to build upon itself. Though Utah’s natural climate plays a part in soil salinity, higher salt levels can also be caused by poor soil drainage, improper irrigation, excessive fertilizer use, or run-off from de-icing salts used on roads and sidewalks. Salty and dry soil puts stress on the alfalfa plant, forcing it to put all its effort into staying alive rather than growing. A decrease in alfalfa crop yield is detrimental to farmers trying to sell it and those buying it to feed their animals.

A sunset in the background lights up a plant box full of green, leafy vegetables in the foreground. The box is wooden and the soil is moist.
The Nielsen lab has made strides in developing a "cocktail" that could help plants thrive even in extremely salty soils.
Photo by Unsplash

Armed with this discovery, the Nielsen Lab prepared to learn how to increase alfalfa’s capability to grow in the salty soil. They conducted research in the Southern Utah deserts—an environment where the natural grown plants have to endure extreme levels of dryness and heat.

According to Nielsen, certain bacteria in these plants called Kushneria helps them grow despite high soil salinity. Nielsen said that although the bacteria doesn’t return plants to their normal growth rate when grown in healthy soil, it’s a better alternative to leaving the plants untreated. Nielsen’s lab is working to unlock how Kushneria survives in those conditions.

To find out how exactly the plant bacteria promotes growth, Nielsen collaborated with Dr. Jonathon Hills’s lab to screen thousands of genes from the most successful bacteria. The Kushneria genome was fragmented so each individual piece could be tested. Then, each piece was grown in four different salty environments. The screening would allow Jenkins, Nielsen, and Hill to see how many of the bacteria survived the salty conditions.

“Through this screen, a number of novel genes show promise as potential tools for salt tolerance,” Jenkins said. “Finding salt tolerance genes is just the first step, however, and further research is required to determine which of these is alfalfa growth stimulating.”

Now that they’ve found the bacteria and successfully determined its positive use for plants, the goal is to create a sort of probiotic “cocktail” that could be sold to farmers worldwide. “Such a soil probiotic would contain any number of these salt tolerant, growth stimulating bacterial species that could work together to protect plants from dangerous levels of soil salinity,” Jenkins said. “Not only would the mixture be effective for plant growth, it would be an eco-friendly way of doing it, as it’s completely natural.”

The solutions being drawn up in the Nielsen Lab and the Hill Lab could be crucial in increasing crop yields in dry environments, like Utah. With 12 million acres of land dedicated to agriculture across the state, it’s important to prioritize the quality of soil for the plants, livestock, and farmers. “A new ecologically friendly tool is about to be added to the agricultural toolbox, and it’s set to make waves throughout the world,” Jenkins said.