Drought and heat put stress on plants and reduce grain yield. For some farmers, irrigation is the answer. Many of us assume the practice boosts crop yields by delivering soil water, but it turns out irrigation’s cooling effect on crops is important in its own right.
In a recent U.S.-based study, a research team led by University of Illinois scientists discovered 16% of the yield increase from irrigation is attributable to cooling alone.
“This study highlights the non-negligible contribution of cooling to the yield benefits of irrigation. Such an effect may become more important in the future with continued warming and more frequent droughts,” says Yan Li, lead author on the Global Change Biology study and a former postdoctoral associate in the Department of Natural Resources and Environmental Sciences at Illinois. Yan is now an associate professor at Beijing Normal University.
Irrigation cools crops through the combined effects of transpiration – water loss through tiny holes in leaves called stomata – and evaporation from soil. Transpiration can only occur when there is a sufficient soil water supply; when roots sense dry soil, plants close their stomata to prevent water loss. When this happens for long enough, plants heat up and suffer drought stress, sometimes leading to yield reductions.
Read more at University of Illinois College of Agricultural, Consumer and Environmental Sciences
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