206-7 Measurements and Analyses of Surface Energy Balance in Maize Under Limited- and Full-Irrigation.

See more from this Division: ASA Section: Climatology & Modeling
See more from this Session: Evapotranspiration: Monitoring, Modeling and Mapping At Point, Field, and Regional Scales: II
Tuesday, October 23, 2012: 2:30 PM
Duke Energy Convention Center, Room 234, Level 2
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Timothy R. Green1, Saseendran Anapalli2, Robert Erskine1, Walter Bausch3, Lajpat Ahuja1, Liwang Ma1 and Allan Andales4, (1)Agricultural Systems Research Unit, Fort Collins, CO
(2)USDA-ARS & CSU, Fort Collins, CO
(3)USDA-ARS, Water Management Research Unit, Fort Collins, CO
(4)Soil and Crop Sciences, Colorado State University, Fort Collins, CO
Estimation of land-surface/canopy evapotranspiration (ET) is essential for quantifying land-atmosphere interaction and crop water use. Latent heat flux can be estimated using the Bowen Ratio (BR) method or as a residual component of the surface energy balance (EB). Practical issues of instrumentation will be discussed, along with theoretical concepts of estimating sensible heat flux, ground heat flux, and net radiation. Field installations include experimental plots (9 m wide) and larger fields (1.7 and 2.2 ha) of full and deficit-irrigated corn (maize) at the Limited Irrigation Research Farm near Greeley, Colorado, USA during the growing season. The BR and EB methods are compared using one season of data from two towers on the larger fields before analyzing the differences between plot data over three seasons. Implications of variable sampling areas, flux planes and lateral advection of energy between treatment areas are recognized. Although an individual plot may not be fully representative of a large field under the same irrigation treatment, sensors measure the actual plot conditions. Thus, estimated differences in ET reflect actual conditions of the experiment. Differences in estimated fluxes between plots will be illustrated. These measurements, energy balances and resulting ET estimates support on-going systems research to address agricultural management effects on crop production with limited water.
See more from this Division: ASA Section: Climatology & Modeling
See more from this Session: Evapotranspiration: Monitoring, Modeling and Mapping At Point, Field, and Regional Scales: II