'Living Sand' Could Help Turn Desert Wasteland Into Farmland

Researchers at Switzerland's Empa institute and Khalifa University in Abu Dhabi have developed a technique they call "living sand" to make desert sand more suitable for growing crops. The idea: since sand grains don't stick together and can't hold water, add something that does. The team introduced specific bacteria and fungi into sand, which produce networks of fibers and biopolymers that bind the grains together.

The work grew out of the challenges facing agriculture in the United Arab Emirates, where most of the land is desert, only about 5% is suitable for farming, and the country can produce just 10% to 15% of its own food supply. Similar challenges are spreading elsewhere as deforestation and global warming turn more land desert-like.

Tested on both laboratory sand and sand collected from dunes in Abu Dhabi, the bacteria-treated sand was significantly more stable than untreated sand and slowed the movement of water through it by six times. A second method, using bacteria that produce nanocellulose to form thin sheets called geotextiles layered with sand, performed even better, slowing water seepage 28 times — though it is more time-consuming.

Neither method yet turns sand into fully fertile soil, nor has the team shown that crops can actually grow in it; the microorganisms also need nutrients, which the researchers suggest could come from sugars in organic waste. "This approach allows us to introduce organic matter and water into the sand and stabilize it somewhat," said Gustav Nyström, head of Empa's Cellulose and Wood Materials laboratory. "Ideally, this will then enable the growth of further microorganisms and plants, thereby initiating the process of making the soil more resilient and fertile." The next step is testing whether treated sand can support plant growth in a greenhouse and in the field. The research was published in the journal Carbohydrate Polymers.