Soil moisture sensors help farmers save water by letting them know when their crops are actually harvested need Water. An experimental new sensor could be particularly useful because it incorporates a special material that becomes extremely sensitive to moisture.
The prototype device, developed by Professors Mohammed Edaudi and Khaled Salama of the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, is designed to stick into the soil like a tent peg.
The moisture-sensing element at its bottom edge is covered with a thin film of synthetic material known as a metal-organic framework (MOF). Previously used in applications such as water purifiers, carbon capture media, and vaccines, MOFs have an open cage-like internal microstructure that allows them to entrap specific types of molecules.
KAUST’s team experimented with various MOFs, but one MOF in particular, called Cr-soc-MOF-1, had a special affinity for water and was able to trap twice its own weight in liquids. got it.
Scientists coated an inexpensive electrode microsensor with a thin film of the material and inserted the sensor into moist soil. As the film began to draw water from the soil, the water displaced some of the air within his MOF, proportionally changing the capacitance. That change is detected by microsensors, which can read the soil moisture level electronically.
This setup was found to work with both loamy and clayey soil samples, the latter showing a response time of approximately 8 minutes. Plans call for a more portable version of the device to be used for real-world field testing of the technology.
“We expect MOF-based soil moisture sensors to advance the next generation of soil moisture sensor technology and provide automated and accurate irrigation systems,” said Professor Salama.
A paper on this study was recently published in the journal ACS Applied Materials & Interfaces.
Source: KAUST
