Following an abnormally wet June, much of Nebraska has been sunny, hot, and dry since the Independence Day weekend. While most people have sought relief in the air conditioning or by the pool, plants have kept cool by transpiring water from their leaves. Transpiration is so important to plants that over 98% of water used by a plant is used for cooling. Plant transpiration, like human perspiration, is an example of evaporative cooling which transfers heat energy from hot grass leaves to evaporating water.
Many [facilities] irrigate to replace some or all of the water lost during plant transpiration and soil evaporation (evapotranspiration). While most on-site weather stations calculate daily potential evapotranspiration (pET), there is also a free website that provides accurate pET data from the High Plains Regional Climate Center. That weather data is combined with satellite images to create pET maps. Daily or weekly pET maps can be found at www.hprcc.unl.edu/awdn/maps/ under the potential evapotranspiration tab.
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