Articles
Comparison of Punica granatum L. leaf area index determined using in situ and remote sensing techniques
Article number
1464_42
Pages
303 – 308
Language
English
Abstract
Leaf area index (LAI) is a crucial parameter for assessing vegetation health and canopy structure in a mature pomegranate (Punica granatum L.) orchard.
This study related LAI using remote sensing data processed through the PySEBAL model, and LAI modelled from in situ fractional interception measurements using the AccuPAR LP-80 ceptometer in Wellington, Western Cape province of South Africa.
The data sets of AccuPAR LP-80 and PySEBAL estimations were categorized on canopy development stages (ranging between 1.1 to 1.8 m2 m‑2 in September 2022, 1.1 to 2.8 m2 m‑2 in November 2022, 0.8 to 1.1 m2 m‑2 in August 2023, and 1.4 to 1.7 m2 m‑2 in October 2023) and full canopy-leaf fall (ranging between 1.2 to 2.9 m2 m‑2 in December 2022 and 1.0 to 1.4 m2 m‑2 in May 2023). The seasonal trend in remote sensing-derived LAI and Accupar LP-80 modelled LA was compared to each other and validated during three different periods (September 2022 to March 2023, April to May 2023, and July to October 2023) to assess model accuracy and reliability.
Results indicated that during the September 2022 to March 2023 period, a nonlinear relationship with a weaker correlation (R2=0.4059, p=0.1133) was observed.
However, a linear trend during the same period was observed, indicating a stronger correlation (R2=0.7878, p=0.3048). In contrast, during April-May 2023, the relationship weakened (R2=0.3608, p=0.3993), suggesting reduced alignment between PySEBAL and in situ LAI measurements.
The study revealed that none of the models were significant (p-values >0.05) in determining the seasonal variability of LAI.
This study related LAI using remote sensing data processed through the PySEBAL model, and LAI modelled from in situ fractional interception measurements using the AccuPAR LP-80 ceptometer in Wellington, Western Cape province of South Africa.
The data sets of AccuPAR LP-80 and PySEBAL estimations were categorized on canopy development stages (ranging between 1.1 to 1.8 m2 m‑2 in September 2022, 1.1 to 2.8 m2 m‑2 in November 2022, 0.8 to 1.1 m2 m‑2 in August 2023, and 1.4 to 1.7 m2 m‑2 in October 2023) and full canopy-leaf fall (ranging between 1.2 to 2.9 m2 m‑2 in December 2022 and 1.0 to 1.4 m2 m‑2 in May 2023). The seasonal trend in remote sensing-derived LAI and Accupar LP-80 modelled LA was compared to each other and validated during three different periods (September 2022 to March 2023, April to May 2023, and July to October 2023) to assess model accuracy and reliability.
Results indicated that during the September 2022 to March 2023 period, a nonlinear relationship with a weaker correlation (R2=0.4059, p=0.1133) was observed.
However, a linear trend during the same period was observed, indicating a stronger correlation (R2=0.7878, p=0.3048). In contrast, during April-May 2023, the relationship weakened (R2=0.3608, p=0.3993), suggesting reduced alignment between PySEBAL and in situ LAI measurements.
The study revealed that none of the models were significant (p-values >0.05) in determining the seasonal variability of LAI.
Authors
R.L. Kgaphola, T. Volschenk, P.C. Tharaga, S. Dzikiti, M. Ravuluma
Keywords
AccuPAR LP-80, leaf area index, PySEBAL, remote sensing
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