SINGAPORE — Researchers from the National University of Singapore (NUS) have created an automated farming device featuring a new hydrogel that absorbs moisture in the air at night and releases water in the day to irrigate plants.

The copper-based hydrogel can take in moisture up to three times its weight and could potentially be used to grow food in space, NUS said in a media release on Wednesday (April 14).

The solar-powered device — dubbed SmartFarm — uses the water collected by the hydrogel to irrigate plants daily without the need for manual intervention.

Assistant Professor Tan Swee Ching who led the project and who is from the Department of Materials Science and Engineering at NUS, said: “This is a significant step forward in alleviating water and food scarcity in the near future.” 

SmartFarm “greatly reduces the demand for freshwater for irritation and is suitable for urban farming techniques such as large-scale rooftop farming”, Asst Prof Tan added.

Using the device, the team was able to cultivate kangkong, or water spinach, NUS said.

The water collected by the hydrogel also meets the World Health Organization’s standards for drinking water, the university added. 

HOW IT WORKS

SmartFarm consists of a container much like a fish tank with a movable cover. The hydrogel is placed in a flat rectangular tray.

The cover opens at night when relative humidity is higher, allowing the hydrogel to acquire moisture.

During the day, the cover closes, confining the water vapour and allowing water droplets to form on the enclosure’s surface.

Once all the moisture stored in the hydrogel is released, the cover automatically opens. The water droplets on the cover then fall onto the soil to irrigate the plants.

Under natural sunlight, 1g of the hydrogel releases 2.24g of water an hour, NUS said. 

Last year, the NUS team collaborated with the Hawaii Space Exploration Analog and Simulation facility in the United States to test the hydrogel in space-based agriculture.

During a simulated Moon mission from November to December, the hydrogel was used to control the humidity in small experimental greenhouses to grow and sustain crops of edible microgreen sunflower plants and upland cress for astronauts.

“The hydrogel-cultivated plants provided a welcome fresh supplement to the freeze-dried food supplied for the bulk of the mission,” the university said. 

Asst Prof Tan said that the team hopes to explore other potential space applications. The researchers are also in discussions on other commercial uses for the device.