Scientists use bacteria to increase crop yield in salty soil

A new study has shown that salt-tolerant bacteria can be used to enhance salt tolerance in various types of plants, increasing crop yield in areas dealing with increasing soil salinity.

Each year, about two to three million hectares of irrigated farmland go out of production worldwide due to salinity problems, according to the US Agency for International Development. 

Although salt levels in soil can increase naturally over time, especially in arid areas, farming practices also contribute. Irrigation water, especially recycled wastewater, contains salts that concentrate in the soil. Fertilisers also add salts to the soil.

“Agricultural soil loss continues to rise, posing a very real threat to many important crops,” said research team leader Brent Nielsen, PhD, Professor at Brigham Young University. “Our method for enhancing the salt tolerance of plants could be scaled up to allow farmers to use more of their land and improve yield. This would create a more stable income for farmers and a more reliable food supply for consumers.”

In previous work, the researchers isolated salt-tolerant bacteria from plants growing in salty soils. They then immersed young alfalfa seedlings in liquid containing the individual salt-tolerant bacterial strains, a process called inoculation. The alfalfa inoculated with some of these salt-tolerant strains exhibited improved growth in high-salt conditions compared to plants not inoculated with bacteria. In the new work, they explored whether this salt tolerance could be transferred to other plants.

“We’ve found that salt tolerance can be transferred to many plant types,” said Ashley Miller, a graduate student working in Nielsen’s lab. “Initial studies with Kentucky Bluegrass have been particularly successful.”

The researchers found that Kentucky Bluegrass grown in salty soil after inoculation with a Bacillus strain increased yield 8.4 times in dry weight compared with control plants grown in the same soil without the bacterial inoculation.

The researchers continue to test whether salt tolerance can be conferred to additional plant varieties, with promising initial results. They are also working to understand how the bacteria confer salt tolerance.