Publication Date:
2012-05-19
Description:
The partition of available energy into evapotranspiration affected by environmental and physiological factors is critical in understanding the water cycle and optimizing the water management in the field. Our study attempted to accurately quantify the environmental and physiological control on variability in evaporative fraction ( EF ) based on the Penman-Monteith model. Eddy covariance method was used to measure water flux over canopy and then to calculate EF above a maize field in northwest China in 2007. Results indicate that EF was lower in other growth stages than in the heading stage, so the EF value in the heading stage was taken as the standard value. The decreases in EF caused by canopy conductance and environmental factors were 0.176 and -0.026, accounting for 117% and -17% of total difference in EF , respectively. Such results were mainly due to that (1) the variation of maize canopy conductance was greater than that of environmental factor, such as air temperature, air humidity, wind speed and radiation; (2) the EF of the maize was more sensitive to variation in canopy conductance than the environmental factor. Our study revealed that crop physiological factor played important role in determining energy partition processes and reducing sensible heat flux in the maize field. Copyright © 2012 John Wiley & Sons, Ltd.
Print ISSN:
0885-6087
Electronic ISSN:
1099-1085
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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