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ARS Home » Plains Area » Lubbock, Texas » Cropping Systems Research Laboratory » Wind Erosion and Water Conservation Research » Research » Publications at this Location » Publication #226255

Title: Evapotranspiration: Measured with a lysimeter vs. calculated with a recursive method

item Lascano, Robert
item Evett, Steven - Steve

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2008
Publication Date: 10/9/2008
Citation: Lascano, R.J., Evett, S.R., Van Bavel, C. 2008. Evapotranspiration: Measured with a lysimeter vs. calculated with a recursive method[abstract]. American Society of Agronomy, Crop Science Society of America, Soil Science Society of America Joint Annual Meeting. October 5-9, 2008. Houston, Texas. Paper No. 703-2.

Interpretive Summary:

Technical Abstract: Recently, a recursive combination method (RCM) to calculate potential and crop evapotranspiration (ET) was given by Lascano and Van Bavel (Agron. J. 2007, 99:585-590) that differs from the Penman-Monteith (PM) method. The main difference between the two methods is that the assumptions made regarding the temperature and humidity of the evaporating surface in the PM are not necessary when using the RCM. Rather, the RCM solves ET by finding the temperature and the humidity by iteration and therefore satisfies the energy balance. We compared values of alfalfa-ET measured with a large lysimeter in Bushland, TX, for a range of environmental conditions, to those calculated with the RCM. The RCM is based on the same physical principles of the PM but uses iteration to find an accurate answer of ET and can be easily be implemented using commercially available mathematical software such as Excel® and Mathcad®.