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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #305440

Title: Partitioning evaporation and transpiration in a maize field with heat-pulse sensors used for evaporation

item XIAO, XINHUA - North Carolina State University
item Sauer, Thomas - Tom
item SINGER, JEREMY - Basf Plant Science Llc
item REN, TUSHENG - China Agricultural University
item HORTON, ROBERT - Iowa State University
item HEITMAN, JOSHUA - North Carolina State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/14/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Evaporation (E) and transpiration (T) occur simultaneously in many systems with varying levels of importance, yet terms are typically lumped as evapotranspiration (ET) due to difficulty with distinguishing component fluxes. Few studies have measured all three terms (ET, E, and T), and in the few cases where such measurements have been obtained, E is typically determined via destructive lysimetery. Our objectives were to 1) assess the feasibility of heat-pulse measurements for determining E, 2) compare patterns observed in E and T measured independently, and 3) compare ET estimates obtained by three independent approaches (E+T, ET from eddy covariance, ET0). Measurements were collected for 20 d for a field with a fully-developed maize canopy. Overall, results support the need for individual measurement of each term (E, T, and ET) when attempting to interpret ET partitioning, and suggest that heat-pulse sensors may provide a viable compliment to previously tested approaches for determining E for ET partitioning. Disparities in ET estimates were likely due to variations in measurement scale, which did not reflect the full range of field variability for individually measured E and T, and differences in response to declining soil moisture amongst the three approaches.