255-700 ETgage Evapotranspiration Simulator

The 255-700 ETgage has been successfully used in the turf and golf course industries, as well as in field crop and vegetable enterprises and tree and vineyard cropping systems. It has also been used by several private and extension projects involving ornamental horticulture. It is suitable for use in both outdoor environments and indoor growing environments, such as greenhouses and hotel terrariums.

The ETgage evaporates distilled water through a ceramic plate covered by green fabric. This physical model represents the reference evapotranspiration process from a well-irrigated plant canopy, such as turf grass or alfalfa. The fabric covering creates a diffusion barrier, controlling the evaporation rate in a manner similar to that found in healthy leaves in a well-watered plant community. Using the ETgage is simpler than using sophisticated electronic hardware to measure the various environmental variables necessary for determining ET. Evapotranspiration can be determined simply by visually reading the sight tube mounted on the side of the water reservoir cylinder. Cumbersome empirical equations and calculators are not required.

The 255-700E Electronic ETgage is an electronic version of the visual ETgage. It is a cost-effective alternative to a complete weather station for estimating evapotranspiration (ET). All weather variables (temperature, relative humidity, net radiation and wind speed) influence the evaporation of water through the ceramic/cloth cover interface. This produces an electronic signal (pulse) once 0.01 ET has been lost. The output can be counted and logged using the 260-2103 Rain Logger, the 110-WS-25 Weather Station, or converted to 4-20 mA by adding the 260-RGAI-70 Rain Gauge Analog Interface.