Researchers at Cornell University have used a small silicon chip to develop a microfluidic water sensor with a higher degree of sensitivity compared to other water sensors on the market.
This sensor chip is installed with wires and a card that allows for wireless data transmission. The chip can also be placed in soil for precise measurements of moisture levels. The microchip is particularly important for measuring moisture levels in perennial fruit crops that have high resistance and deep roots.
Researcher Vinay Pagay demonstrates the micro "lab on chip" water sensor that measures moisture levels in soil. Image credit: Jason Koski/University Photography.
Leaf and stem water potentials are extremely dynamic making it difficult for current water sensors to accurately correlate the water content in different soil horizons to plant water potential.
Water sensor technology is particularly beneficial for vintners regulating irrigation on grapevines to create the right conditions for optimum grape composition. This micro-water sensor is also becoming a key component for the civil engineering sector where its use to measure moisture levels is becoming particularly important during the process of curing concrete.
The micro-sensor is a glass slide with a liquid cavity covered by a silicon layer. The diaphragm to the silicon layer encaplusates a pressure sensor, conductive leads and a poly-silicon resistor. This device is then inserted into the phloem section of a plant’s trunk. A nanoporous membrane allows for the moisture exchange to take place and can also equilibrate pressure.
Some of the main parameters to identify when measuring water potential include stem water potential and mid-day stem water potential. The key components of an ideal water stress sensor is to measure plant growth and gas exchange, measure water potential continuously over a range of stress conditions, and to report this feedback in real-time via a wireless port.
A competitive edge to the new micro sensor developed at Cornell University is its durability, it can be easily installed, it is efficient to manufacture, and can measure water potential continuously. An additional advantage to this sensor includes its high special and temporal resolution.
The potential impact of this technology is to optimize irrigation efficiency and this will also help to identify how crops recover from water stress. “One of our goals is to try and develop something that is not only a great improvement, but also much cheaper for growers and others to use,” - Alan Lakso, professor of horticulture, Cornell University.