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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVING WATER PRODUCTIVITY AND NEW WATER MANAGEMENT TECHNOLOGIES TO SUSTAIN RURAL ECONOMIES

Location: Soil and Water Management Research

Title: Effect of row orientation on energy balance components

Authors
item Agam, Nurit -
item Evett, Steven
item Kustas, William
item Alfieri, Joseph
item Colaizzi, Paul

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2013
Publication Date: November 3, 2013
Citation: Agam, N., Evett, S.R., Kustas, W.P., Alfieri, J.G., Colaizzi, P.D. 2013. Effect of row orientation on energy balance components [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. Session 63-8, p. 76

Technical Abstract: Solar irradiance is the primary source of energy that is converted into sensible and latent heat fluxes in the soil-plant-atmosphere continuum. The orientation of agricultural crop rows relative to the sun’s zenith angle determines the amount of solar irradiance reaching the plant and soil surfaces and its partitioning via absorbtion and reflection from soil and vegetation. Row orientation also affects soil heat flux and evaporation. Soil evaporation may be considered as a non-productive water loss. Thus, minimizing soil evaporation improves water use efficiency. To assess the potential for water conservation, quantitative determination of soil evaporation relative to total evapotranspiration is required. As part of a large scale experiment conducted in a cotton row crop in the Texas Panhandle, USA, extensive state-of-the-art micrometeorological measurements were undertaken. Experimental setup included measurements across the interrow in two fields with different and perpendicular row orientations. Results showed that row orientation influenced the diurnal pattern of soil heat flux, and that wind direction relative to row orientation regulated the amount of soil evaporation. Therefore, the overall energy balance and water use efficiency of a row crop is influenced by complex interactions between row orientation and meteorological variables. Row orientation should be accounted for when modeling the soil-plant-atmosphere continuum and may be an important management strategy for maximizing crop water use efficiency.

Last Modified: 12/19/2014
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