A new approach to estimate canopy evaporation and canopy interception capacity from evapotranspiration and sap flow measurements during and following wetting

Uddin, J. and Foley, J. P. and Smith, R. J. and Hancock, N. H. (2016) A new approach to estimate canopy evaporation and canopy interception capacity from evapotranspiration and sap flow measurements during and following wetting. Hydrological Processes, 30 (11). pp. 1757-1767. ISSN 0885-6087

Abstract

Canopy interception and its evaporation into the atmosphere during irrigation or a rainfall event are important in irrigation scheduling, but are challenging to estimate using conventional methods. This study introduces a new approach to estimate the canopy interception from measurements of actual total evapotranspiration (ET) using eddy covariance and estimation of the transpiration from measurements of sap flow. The measurements were conducted over a small-scale sprinkler-irrigated cotton
field before, during and after sprinkler irrigation. Evaporation and sap flow dynamics during irrigation show that the total ET during irrigation increased significantly because of the evaporation of free intercepted water while transpiration was suppressed almost completely. The difference between actual ET and transpiration (sap flow) during and immediately following irrigation
(post irrigation) represents the total canopy evaporation while the canopy interception capacity was calculated as the difference between actual ET and transpiration (sap flow) during drying (post irrigation) following cessation of the irrigation. The canopy evaporation of cotton canopy was calculated as 0.8 mm, and the interception capacity was estimated to be 0.31mm of water. The measurement uncertainty in both the non-dimensional ET and non-dimensional sap flow was shown to be very low.


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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 01:37
Last Modified: 20 Oct 2016 03:55
Uncontrolled Keywords: canopy interception capacity; canopy evaporation; eddy covariance; Bowen ratio; evapotranspiration; sprinkler irrigation
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: 10.1002/hyp.10739
URI: http://eprints.usq.edu.au/id/eprint/28927

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