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.

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Video: From Students to Solutions | On The Brink: Season 2, Episode 14

Ask Canada’s most decorated soybean breeder his favourite part of the job and he doesn’t name a single variety. He names the students.

Istvan Rajcan is a professor of soybean breeding and genetics in the Department of Plant Agriculture at the University of Guelph, where he has run the soybean breeding program for 28 and a half years. In that time he has developed 87 soybean cultivars, published 140 refereed papers and trained 51 graduate students. In 2025 he received the Public Sector Impact Award from the National Association for Plant Breeding.

He is also worried. In this episode he says Canada is at a crossroads, pointing to recent government cuts to plant breeding programs and to the facilities that support them. His prescription is structural. "Plant breeding funding formula has to be a long-term one," he says.

The formula he is defending is the public-private matching arrangement his program runs on. Private seed companies fund the work, provincial or federal money matches it, and the combined pool stretches each dollar further than either source could alone. At the National Association for Plant Breeding annual meeting in June, he says American public breeders were often surprised at how well that collaboration works in Canada.

He also describes how the people entering plant breeding have changed. His early graduate students came mostly from farms. More recently they include, in his words, "city kids who just became excited about genetics."

Topics covered:

Why public-private plant breeding funding in Canada needs a long-term

commitment rather than a larger one

How matching private seed company investment with provincial and federal

dollars multiplies research capacity

How the graduate student pipeline into plant breeding has shifted from

farm kids to city kids