Abstract
To investigate the alfalfa crop response to environmental factors, a Bowen ratio-energy balance method was used to evaluate short-term alfalfa canopy resistance. Continuous evapotranspiration (ET a ) and the aerodynamic resistance (r a ) for an alfalfa crop in each 20-min interval were calculated. Using the calculated ET a and r a and the Penman-Monteith approach, the bulk stomatal or actual canopy resistance (r c ) was evaluated. The continuous 20-min resistances were computed for clear and partially cloudy sky conditions, and different average crop heights. The results show that this technique can satisfactorily be used to study the manner in which the aerodynamic and canopy resistances respond to short-term variations in weather elements such as photosynthetically active radiation (PAR), wind speed and atmospheric saturation vapor deficit.
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References
Bingham, G. E., Tanner, B. D., Green, J., and Tanner, M.: 1987, ‘A Bowen-Ratio System for Long Term Remote Measurement of Evapotranspiration’, Preprint Vol., 18th Conf. Agric. For. Meteorol., pp. 63–66. Amer. Meteorol. Soc., Sept. 15–18, 1987, W. Lafayette, IN.
Bingham, G. E., Malek, E., McCurdy, G. D., and Hanks, R. J.: 1990, ‘Irrigation Season Water Balance on the Huntington and Castledale Research Farms’, 1898 Report (Part 2). Utah Agric. Exp. Sta. Res. Rpt. # 133. 65pp.
Brutsaert, W. H. and Stricker, H.: 1979, ‘An Advection-Aridity Approach to Estimate Actual Regional Evapotranspiration’, Water Resour. Res. 15, 443–450.
Dunin, F. X., Nulsen, R. A., and Greenwood, E. A. N.: 1898, ‘Evaporation from a Lupin Crop: a Comparison of Methods’, Agric. For. Meteorol. 46, 297–312.
Hill, R. W., Johns, E. L., and Frevert, D. K.: 1983, ‘Comparison of Equations Used for Estimating Agricultural Crop Evapotranspiration with Field Research’, Bur. Reclam. USDI.
Malek, E., Bingham, G. E., and McCurdy, G. D.: 1990, ‘Evapotranspiration from the Margin and Moist Playa of a Closed Desert Valley’, J. Hydrol. 120, 15–34.
Monteith, J. L.: 1965, ‘Evaporation and Environment’, Symp. Soc. Exp. Biot. 19, 205–234.
Monteith, J. L. and Unsworth, M. H.: 1990, Principles of Environmental Physics, Routledge Chapman and Hall Publ. Co., New York. 228 pp.
Penman, H. L.: 1948, ‘Natural Evaporation from Open Water, Bare Soil, and Grass’, Proc. R. Soc. London Ser. A 193, 120–145.
Wilson, L., Olsen, M. E., Hutchings, T. B., Southard, A. R., and Erickson, A. J.: 1975, The Soils of Utah, Agric Exper. Station, Utah State Univ., Logan. 94 pp.
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Research Assistant Professor and Assistant Utah State Climatologist, Research Associate Professor and Research Assistant, respectively.
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Malek, E., Bingham, G.E. & McCurdy, G.D. Continuous measurement of aerodynamic and alfalfa canopy resistances using the Bowen ratio-energy balance and Penman-Monteith methods. Boundary-Layer Meteorol 59, 187–194 (1992). https://doi.org/10.1007/BF00120694
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DOI: https://doi.org/10.1007/BF00120694