Determination of crop and soil evaporation coefficients for estimating evapotranspiration in a paddy field

Accurate estimation of evapotranspiration is important in efficient water management for improving water use efficiency. In order to obtain evapotranspiration and evaporation beneath the canopy using the Food and Agriculture Organization (FAO) method, pan evaporation was used instead of reference ev...

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Bibliographic Details
Published inInternational journal of agricultural and biological engineering Vol. 10; no. 4; pp. 130 - 139
Main Authors Haofang, Yan, Chuan, Zhang, Oue,Peng Guangjie, Hiroki, Opoku Darko, Ransford
Format Journal Article
LanguageEnglish
Published Beijing International Journal of Agricultural and Biological Engineering (IJABE) 2017
Subjects
Agricultural practices
Bowen ratio
Coefficients
Crops
Daytime
Energy balance
Energy measurement
Evaporation
Evapotranspiration
Irrigation
Leaf area
Leaf area index
Leaves
Methods
Moisture content
Oryza
Oryza sativa
Pan evaporation
Rice
Rice fields
Sensors
Soil water
Studies
Water management
Water shortages
Water supply
Water use
Water use efficiency
Japan
India
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Summary:Accurate estimation of evapotranspiration is important in efficient water management for improving water use efficiency. In order to obtain evapotranspiration and evaporation beneath the canopy using the Food and Agriculture Organization (FAO) method, pan evaporation was used instead of reference evapotranspiration calculated by the Penman-Monteith equation with detailed meteorological data. The total crop coefficient and soil evaporation coefficient were determined using actual measured daytime evapotranspiration and evaporation by the Bowen ratio energy balance and lysimeter, respectively, in a rice paddy field in Japan. The average evapotranspiration was 5.3 mm/d, 4.4 mm/d, 7.4 mm/d and 6.3 mm/d and crop coefficient was 0.79, 1.18, 1.01 and 0.86 for the initial stage, development stage, middle-season stage and late-season stage, respectively. The evaporation was low and almost constant with an average value around 0.77 mm/d when the leaf area index (LAI) reached 3. The proposed average crop coefficients for different growing stages were applied to estimate daytime evapotranspiration and found suitable. A simple soil water evaporation coefficient model was developed using leaf area index for practical use and it was found that it could accurately estimate evaporation.
ISSN:1934-6344
1934-6352
DOI:10.25165/j.ijabe.20171004.2290