Sensing Water For Smarter Agriculture

Feb 14, 2023

By King Abdullah

Smart electronic soil sensors could enable farmers to deliver tailored doses of water to their crops, maximizing food production while saving water. KAUST researchers have developed a rapid and sensitive soil moisture sensor, at the heart of which sits a metal-organic framework (MOF) with a very high affinity for water.

Efficient water usage is a key challenge for farmers faced with feeding the growing global population in the face of climate change. "Irrigation management can help improve crop quality, decrease agricultural costs and preserve water," says Mohamed Eddaoudi, who led the research along with Khaled Salama. "Highly sensitive and selective soil-moisture sensors offer the potential to improve the water management process," Salama adds.

MOFs may be well suited to soil moisture sensing, Eddaoudi and his collaborators have shown. MOFs are highly porous synthetic materials with a cage-like internal structure that can be tailored to host specific small molecules, including water. "With their modular porous structure and easy functionalization, MOFs are excellent candidates for sensing applications," says Osama Shekhah, a research scientist in Eddaoudi's team. "MOF thin films have already been incorporated into electronic devices, paving the way for their translation to real-world use," he adds.

The MOFs in the study were selected based on their hydrolytic stability, water capacity and water uptake. "We explored several different MOFs, including the highly porous Cr-soc-MOF-1 developed by our group at KAUST that can capture twice its own weight in water," says Ph.D. student Norah Alsadun.

The team coated the MOFs onto an inexpensive interdigitated electrode microsensor that can be fabricated by inkjet printing or laser etching. When this sensor was inserted into moist soil, air in the MOF was displaced by water, altering its electrical capacitance, a process that can be detected and measured.

Each MOF device was tested in clayey and in loamy sand soil types, which can show significant differences in texture and water-holding capacity. "Notably, the Cr-soc-MOF-1-coated soil-moisture sensor showed the highest sensitivity, of about 450% in clayey soil, with a response time of around 500 seconds," Salama says. The sensor's response was highly selective for water even when various metal ions were present in the soil.

Click here to see more...

Video: Why Your Food Future Could be Trapped in a Seed Morgue

In a world of PowerPoint overload, Rex Bernardo stands out. No bullet points. No charts. No jargon. Just stories and photographs. At this year’s National Association for Plant Breeding conference on the Big Island of Hawaii, he stood before a room of peers — all experts in the science of seeds — and did something radical: he showed them images. He told them stories. And he asked them to remember not what they saw, but how they felt.

Bernardo, recipient of the 2025 Lifetime Achievement Award, has spent his career searching for the genetic treasures tucked inside what plant breeders call exotic germplasm — ancient, often wild genetic lines that hold secrets to resilience, taste, and traits we've forgotten to value.

But Bernardo didn’t always think this way.

“I worked in private industry for nearly a decade,” he recalls. “I remember one breeder saying, ‘We’re making new hybrids, but they’re basically the same genetics.’ That stuck with me. Where is the new diversity going to come from?”

For Bernardo, part of the answer lies in the world’s gene banks — vast vaults of seed samples collected from every corner of the globe. Yet, he says, many of these vaults have quietly become “seed morgues.” “Something goes in, but it never comes out,” he explains. “We need to start treating these collections like living investments, not museums of dead potential.”

That potential — and the barriers to unlocking it — are deeply personal for Bernardo. He’s wrestled with international policies that prevent access to valuable lines (like North Korean corn) and with the slow, painstaking science of transferring useful traits from wild relatives into elite lines that farmers can actually grow. Sometimes it works. Sometimes it doesn’t. But he’s convinced that success starts not in the lab, but in the way we communicate.

“The fact sheet model isn’t cutting it anymore,” he says. “We hand out a paper about a new variety and think that’s enough. But stories? Plants you can see and touch? That’s what stays with people.”

Bernardo practices what he preaches. At the University of Minnesota, he helped launch a student-led breeding program that’s working to adapt leafy African vegetables for the Twin Cities’ African diaspora. The goal? Culturally relevant crops that mature in Minnesota’s shorter growing season — and can be regrown year after year.

“That’s real impact,” he says. “Helping people grow food that’s meaningful to them, not just what's commercially viable.”

He’s also brewed plant breeding into something more relatable — literally. Coffee and beer have become unexpected tools in his mission to make science accessible. His undergraduate course on coffee, for instance, connects the dots between genetics, geography, and culture. “Everyone drinks coffee,” he says. “It’s a conversation starter. It’s a gateway into plant science.”