Water conservation and food production are ever-growing global concerns, and a researcher from Penn State's College of Agricultural Sciences has devised a method to efficiently irrigate crops without wasting water.

Scientist Amin Afzal says he hopes using leaf sensors to determine the water needs of crops becomes standard practice in the near future.

"Leaf thickness is like a balloon. It swells and shrinks by water stress or dehydration. One way to improve the efficiency of irrigation is accurate timing, needing an accurate estimation of plant water status to detect when the plant needs water," he explains. "[The leaf] sensor enables us to directly estimate plant water status and it offers accurate and reliable information for automation systems" in order to gather and distribute information more quickly.

Afzal, a native of Iran who earned his Ph.D. in Agronomy from Penn State, currently works as a Research Data Scientist for the Monsanto Company based in St. Louis, Mo. He says the leaf system, unlike other current methods used to determine plant moisture, is "highly advantageous" when it comes to automatic irrigation timing.

Afzal points out that evapotranspiration techniques for estimating water status, such as the use of climatic and soil-moisture sensors, is "associated with a significant uncertainty and uncertainty in irrigation timing means early or late irrigation, or losing water or yield." In other words, if crops are watered too early, not only will water be wasted, but money will be lost. If irrigation occurs too late, the crops will be damaged and the yield will decrease.

 Another approach to moisture testing, according to Afzal, involves the use of plant organs, but he points out this method is not suitable for automation, because it's a lab procedure.

Water preservation is a serious subject for Afzal, who has witnessed severe and permanently-damaging droughts in his home country, as well as irrigation problems in the United States and other parts of the world. He says conserving water is crucial for several reasons, not the least of which is maintaining a critical natural resource

"Seventy percent of global freshwater consumption is in agriculture. The [world] population is growing rapidly and needs more food," he says. "Freshwater resources are already under tension because of over-withdrawal and regions with a lack of distributed precipitation during the growing seasons are irrigated."

Climate change has been one of the root causes, says Afzal.

"It's caused long-term droughts. As an example, California's agriculture significantly suffered from drought in 2014-15," he recalls. "Many farmers could not plant and bore the economic loss. Many people lost their jobs."

At the end of the day, these impacts are what inspires Afzal’s ultimate goal, which is, according to him, as simple as "delivering a device that automatically monitors plant water status for accurate triggering of irrigation and improving reliability and water use efficiency."