Errors in predicting furrow irrigation performance using single measures of infiltration

Langat, Philip K. and Raine, Steven R. and Smith, R. J. (2007) Errors in predicting furrow irrigation performance using single measures of infiltration. Irrigation Science, 25 (4). pp. 339-349. ISSN 0342-7188

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Abstract

Commercial performance evaluations of surface irrigation are commonly conducted using infiltration functions obtained at a single inflow rate. However, evaluations of alternative irrigation management (e.g. flow rate, cut-off strategy) and design (e.g. field length) options using simulation models often rely on this single measured infiltration function, raising concerns over the accuracy of the predicted performance improvements. Measured field data obtained from 12 combinations of inflow rate and slope over two irrigations were used to investigate the accuracy of simulated surface irrigation performance due to changes in the infiltration. Substantial errors in performance prediction were identified due to (a)infiltration differences at various inflow rates and slopes and (b) the method of specifying the irrigation cut-off. Where the irrigation cut-off at various inflow rates was specified as a fixed time identified from simulations using the infiltration measured at a single inflow rate, then the predicted application efficiency was generally well correlated with the application efficiency measured under field conditions at the various inflow rates. However, the predictions of distribution uniformity (DU) were poor. Conversely, specifying the irrigation cut-off as a function of water advance distance resulted in adequate predictions of DU but poor predictions of application efficiency. Adjusting the infiltration function for the change in wetted perimeter at different inflow rates improved the accuracy of the performance predictions and substantially reduced the error in performance prediction associated with the cut-off recommendation strategy.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Deposited in accordance with the copyright policy of the publisher.
Depositing User: Assoc Prof Steven Raine
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 03 Mar 2008 02:03
Last Modified: 02 Jul 2013 22:58
Uncontrolled Keywords: irrigation; furrow; errors; prediction; performance; computer simulation; flow rate; infiltration; mathematical models
Fields of Research (FOR2008): 07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070103 Agricultural Production Systems Simulation
07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070105 Agricultural Systems Analysis and Modelling
07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
Socio-Economic Objective (SEO2008): D Environment > 96 Environment > 9609 Land and Water Management > 960905 Farmland, Arable Cropland and Permanent Cropland Water Management
Identification Number or DOI: doi: 10.1007/s00271-006-0049-5
URI: http://eprints.usq.edu.au/id/eprint/3909

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