Extracting Pasture Evapotranspiration Parameters from Proximal Sensing and Mathematical Modelling

Author(s)
Alam, Muhammad Shahinur
Lamb, David
Mccarthy, Cheryl
Rahman, Muhammad
Warwick, Nigel William
Publication Date
2020-02-07
Abstract
<p>Please contact rune@une.edu.au if you require access to this thesis for the purpose of research or study.</p> <p>Awarded the Chancellor's Doctoral Research Medal</p>
Abstract
<p>Knowledge of crop evapotranspiration is crucial for irrigation decision making. An appropriate, user-friendly and time-efficient means of inferring such information is therefore essential. In this study, a closed hemispherical chamber was instrumented, calibrated and deployed in the field for measuring actual evapotranspiration of a vital pasture species, Tall Fescue (<i>Festuca arundinacea</i>). The pasture crop coefficient (K<sub>c</sub>) was calculated from the measured instantaneous evapotranspiration and reference crop evapotranspiration (ET<sub>o</sub>) for a range of growth stages. Also the relationship between K<sub>c</sub> and Normalized Difference Vegetation Index (NDVI) as measured using an active optical sensor was established. Using the FAO dual crop coefficient approach and the hemispherical chamber, a technique for partitioning evapotranspiration components was developed. The components of evapotranspiration in terms of basal crop coefficient (K<sub>cb</sub>) and soil evaporation coefficient (K<sub>e</sub>) were expressed relative to canopy NDVI and Leaf Area Index (LAI). A theoretical model for estimating transpiration was also developed by scaling up stomatal conductance to canopy level in a controlled glasshouse environment. The model was validated against the measured transpiration.</p>
Link
Publisher
University of New England
Title
Extracting Pasture Evapotranspiration Parameters from Proximal Sensing and Mathematical Modelling
Type of document
Thesis Doctoral
Entity Type
Publication

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