Forecast evapotranspiration: fundamental information for agricultural irrigation management.



Forecast evapotranspiration: fundamental information for agricultural irrigation management

CMCC Webinar | Tuesday 23 July - 12.00 pm - 1.00 pm CEST

Language: English


Climate change projections indicate that precipitation depths are likely to decrease in regions where agriculture needs irrigation, which will further exacerbate existing problems with limited water resources. Knowing evapotranspiration (ET) rates of agricultural crops is especially important in these semi-arid and arid climates where supplemental or full irrigation is often needed to produce a crop. Forty years ago, there was limited availability of ET information to help growers determine water requirements and there was little interest by growers, who mainly used surface irrigation methods, to access available information. Because water resources have decreased relative to the water demand due to climate and agricultural and urban expansion, there is a clear change from surface irrigation to micro-sprinkler and drip irrigation systems. With low-volume irrigation systems, a big problem is that farmers need forecast estimates of ET to order the needed water and plan for the timing and amount of water to apply during the next week. This led to development of a forecast ET product (FRET) by the USA National Weather Service Sacramento Office and the University of California at Davis. Initially, the standardized reference evapotranspiration for short canopies (ETo) equation from the ASCE-EWRI was slightly modified to use available daily forecast products to calculate and distribute ETo information within the Sacramento forecast area. Since then, the forecast service has expanded to include the entire USA (excluding Alaska and Hawaii). It is now possible to obtain a seven-day forecast of ETo at any location, and growers can estimate energy-limited crop ET (ETc) as the product of ETo and crop coefficient (Kc) values distributed by UC and other sources. Growers are now starting to use FRET to improve application efficiency, reduce water applications, and save energy. In this Webinar, we will discuss the forecast ET (FRET) product, why it is important for agriculture and urban landscapes, and how it works.

Fondazione Centro Euro-Mediterraneo sui Cambiamenti Climatici

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