Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang

Leaf chlorophyll content is an important indicator of the health status of pear trees. This study used Korla fragrant pears, a Xinjiang regional product, to investigate methods for estimating the relative chlorophyll content of pear leaves. Samples were collected from pear trees in the east, south,...

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Main Authors: Yufen Huang, Zhenqi Fan, Hongxin Wu, Ximeng Zhang, Yanlong Liu
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/25/11/3552
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author Yufen Huang
Zhenqi Fan
Hongxin Wu
Ximeng Zhang
Yanlong Liu
author_facet Yufen Huang
Zhenqi Fan
Hongxin Wu
Ximeng Zhang
Yanlong Liu
author_sort Yufen Huang
collection DOAJ
description Leaf chlorophyll content is an important indicator of the health status of pear trees. This study used Korla fragrant pears, a Xinjiang regional product, to investigate methods for estimating the relative chlorophyll content of pear leaves. Samples were collected from pear trees in the east, south, west, and north positions of peripheral canopy leaves. The leaf soil plant analysis development (SPAD) method was implemented using a SPAD-502 laser chlorophyll meter. The instrument measures the relative chlorophyll content as the SPAD value. Leaf spectra were acquired using a portable field spectrometer, ASD FieldSpec4. ViewSpecPro 6.2 software was employed to smooth the ground spectral data. Traditional mathematical transformations and the discrete wavelet transform were used to process the spectral data, then correlation analysis was employed to extract the sensitive bands, and partial least squares regression (PLS) was used to establish a model for estimating the chlorophyll content of pear tree leaves. The findings indicate that (1) the models developed using the discrete wavelet transform had coefficients of determination (<i>R</i><sup>2</sup>) exceeding 0.65, and their predictive performance surpassed that of other models employing various mathematical transformations, and (2) the model constructed using the L1 scale for the discrete wavelet transform had greater estimation accuracy and stability than models established through traditional mathematical transformations or the high-frequency scale for discrete wavelet transform, with an <i>R</i><sup>2</sup> value of 0.742 and a root mean square error (RMSE) of 0.936. The prediction model for relative chlorophyll content established in this study was more accurate for chlorophyll monitoring in pear trees, and thus, it provided a new method for rapid estimation. Moreover, the model provides an important theoretical basis for the efficient management of pear trees.
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spelling doaj-art-79ac6358d60a4d218be747bebb6c34922025-08-20T03:46:42ZengMDPI AGSensors1424-82202025-06-012511355210.3390/s25113552Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, XinjiangYufen Huang0Zhenqi Fan1Hongxin Wu2Ximeng Zhang3Yanlong Liu4College of Information Engineering, Tarim University, Alaer 843300, ChinaKey Laboratory of Tarim Oasis Agriculture, Ministry of Education, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Information Engineering, Tarim University, Alaer 843300, ChinaCollege of Agriculture, Tarim University, Alaer 843300, ChinaLeaf chlorophyll content is an important indicator of the health status of pear trees. This study used Korla fragrant pears, a Xinjiang regional product, to investigate methods for estimating the relative chlorophyll content of pear leaves. Samples were collected from pear trees in the east, south, west, and north positions of peripheral canopy leaves. The leaf soil plant analysis development (SPAD) method was implemented using a SPAD-502 laser chlorophyll meter. The instrument measures the relative chlorophyll content as the SPAD value. Leaf spectra were acquired using a portable field spectrometer, ASD FieldSpec4. ViewSpecPro 6.2 software was employed to smooth the ground spectral data. Traditional mathematical transformations and the discrete wavelet transform were used to process the spectral data, then correlation analysis was employed to extract the sensitive bands, and partial least squares regression (PLS) was used to establish a model for estimating the chlorophyll content of pear tree leaves. The findings indicate that (1) the models developed using the discrete wavelet transform had coefficients of determination (<i>R</i><sup>2</sup>) exceeding 0.65, and their predictive performance surpassed that of other models employing various mathematical transformations, and (2) the model constructed using the L1 scale for the discrete wavelet transform had greater estimation accuracy and stability than models established through traditional mathematical transformations or the high-frequency scale for discrete wavelet transform, with an <i>R</i><sup>2</sup> value of 0.742 and a root mean square error (RMSE) of 0.936. The prediction model for relative chlorophyll content established in this study was more accurate for chlorophyll monitoring in pear trees, and thus, it provided a new method for rapid estimation. Moreover, the model provides an important theoretical basis for the efficient management of pear trees.https://www.mdpi.com/1424-8220/25/11/3552discrete waveletrelative chlorophyll contentquantitative inversionpartial least squares
spellingShingle Yufen Huang
Zhenqi Fan
Hongxin Wu
Ximeng Zhang
Yanlong Liu
Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang
Sensors
discrete wavelet
relative chlorophyll content
quantitative inversion
partial least squares
title Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang
title_full Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang
title_fullStr Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang
title_full_unstemmed Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang
title_short Estimation of the Relative Chlorophyll Content of Pear Leaves Based on Field Spectrometry in Alaer, Xinjiang
title_sort estimation of the relative chlorophyll content of pear leaves based on field spectrometry in alaer xinjiang
topic discrete wavelet
relative chlorophyll content
quantitative inversion
partial least squares
url https://www.mdpi.com/1424-8220/25/11/3552
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