Too much salt isn’t only bad for our bodies , it’s bad for our crops, which don’t grow well in highly saline soil. As climate change, poor water quality, and the misuse of agrochemicals degrades our land, the world’s soil is becoming saltier, threatening the global food system. But MIT engineers may have found a way to save our crops. They’ve developed a protective coating made of silk, sugar, and bacteria that could help seeds grow in soil that is currently unsuitable for agriculture.

So far, tests have found that chickpea and common bean seeds with the coating had an increased germination rate and better overall plant health in highly saline soil than uncoated seeds, researchers detailed in a paper published today in the journal PNAS. They hope the coating could be applied to other crops, as well, and be an accessible and cheap option for all farmers to make use of more land.

“If you go to Morocco, you see land that was fertile 10 years ago is not fertile now due to the salinity of the soil.”

Research into this began years ago, says Benedetto Marelli, one of the paper’s authors and a professor of civil and environmental engineering at MIT, with his previous work on how silk coatings could extend the shelf life of food and crop seeds without the need for refrigeration. While studying that, he stumbled upon rhizobacteria, which are known as a “nitrogen-fixing bacteria,” meaning they transform nitrogen in the air into something usable by plants. These rhizobacteria act as a natural fertilizer and are known to improve plant growth when compared to synthetic fertilizers, insecticides, and pesticides, and Marelli incorporated it into the silk coating.

What this silk coating does for seeds is twofold: first, it acts as a barrier to protect the seeds from the harsh, salty topsoil, which is the uppermost layer of soil necessary for crop growth. Too much salt in this soil can be toxic to plants, cause nutrient imbalances, and affect how much water plants are able to take in. Second, the coating provides a built-in, natural fertilizer through the rhizobacteria, giving the essential nutrient of nitrogen to the seeds, enhancing their growth.

With those two benefits, it could be the answer to a current environmental conundrum: what to do with all that degraded, salty land that can’t grow crops anymore. “If you go to Morocco, you see land that was fertile 10 years ago is not fertile now due to the salinity of the soil, so our plan is to try to mitigate that,” says Marelli. And that’s only one example. Salinity is a major issue for soil around the world, and all over Earth our agricultural soil is getting more and more degraded and less and less fertile. Some experts say that if current rates of degradation continue, all the world’s fertile topsoil, which is used to grow our food, could be gone in 60 years.

While agricultural topsoil may already contain nutrients like nitrogen, farmers often need to add more through fertilizers to replace the nutrients crops take out of the soil and ensure the best growing conditions for their plants. Nitrogen fertilizer plays an important role in maintaining global food security, says Marelli, but it has a big environmental effect. Microbes in soil convert nitrogen to nitrous oxide, which is a greenhouse gas.

When farmers use too much of this synthetic fertilizer, which they often do, that means the greenhouse gas enters our waterways and atmosphere. Increased fertilizer use has been cited by researchers as the cause of a “dramatic rise in atmospheric nitrous oxide, which is a major greenhouse gas contributing to global climate change.” That’s where these rhizobacteria, which form a symbiotic relationship with many plants like legume crops, can come into play as a better, more eco-friendly alternative.