Estimation of wet canopy bulk stomatal resistance from energy flux measurements during sprinkler irrigation

Uddin, Jasim M. and Smith, Rod J. and Hancock, Nigel H. and Foley, Joseph P. (2016) Estimation of wet canopy bulk stomatal resistance from energy flux measurements during sprinkler irrigation. Biosystems Engineering, 143. pp. 61-67. ISSN 1537-5110


Bulk stomatal resistance, also known as surface resistance, is typically assumed to be zero during rainfall or other circumstances when a foliage canopy is wet, such as during sprinkler irrigation. However, some recent studies have suggested that resistance does not necessarily fall completely to zero. Although the assumption of zero bulk stomatal resistance for a wet canopy condition may be reasonable, estimation of actual evaporation as well as bulk stomatal resistance during wet conditions via the Penman-Montieth (P-M) equation is still problematic due to the difficulties in measuring the various energy fluxes in the energy balance. It has recently been demonstrated that eddy covariance (ECV) can be used to estimate the actual evapotranspiration during both irrigation and non-irrigation periods. It has also been shown that advection is important in sprinkler irrigation. . In Tthis paper it is demonstrateddemonstrates how the same technique can also provide an estimate of the bulk stomatal resistance for a wet crop canopy. It is shown that when all significant energy terms (including advected energy) are taken into account, the bulk stomatal resistance was effectively zero, in contrast to dry canopy values for the same crop of order 30 s m–1, both determined under midday, open sky conditions. The study also shows that ignoring advected energy can lead to an overestimation of bulk stomatal resistance and underestimation of ET when the canopy is wet.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version, in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Institute for Agriculture and the Environment
Date Deposited: 01 Mar 2016 01:01
Last Modified: 09 Feb 2017 06:45
Uncontrolled Keywords: bulk stomatal resistance, evapotranspiration, eddy covariance, advected energy, sprinkler irrigation, canopy evaporation
Fields of Research : 07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070199 Agriculture, Land and Farm Management not elsewhere classified
Identification Number or DOI: 10.1016/j.biosystemseng.2015.12.017

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