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Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency

In cocoa (Theobroma cacao), macronutrients of nitrogen (N), phosphorus (P) and potassium (K) are the essential elements that may drastically affect growth, appearance and most importantly, yield. However, detection of macronutrients can be slow while nutrient analysis can be time consuming. Adaptati...

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Main Authors: Tee, Yei Kheng, Balasundram, Siva Kumar, Phebe, Ding, Mohd Haniff, Ahmad Husni
Format: Article
Language:English
Published: Longdom Publishing 2018
Online Access:http://psasir.upm.edu.my/id/eprint/73947/1/Spectral%20reflectance%20and%20physiological%20studies%20of%20cocoa%20leaves%20in%20response%20to%20macronutrient%20deficiency.pdf
http://psasir.upm.edu.my/id/eprint/73947/
https://www.longdom.org/proceedings/spectral-reflectance-and-physiological-studies-of-cocoa-leaves-in-response-to-macronutrients-deficiency-11786.html
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spelling my.upm.eprints.739472020-04-29T17:25:15Z http://psasir.upm.edu.my/id/eprint/73947/ Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency Tee, Yei Kheng Balasundram, Siva Kumar Phebe, Ding Mohd Haniff, Ahmad Husni In cocoa (Theobroma cacao), macronutrients of nitrogen (N), phosphorus (P) and potassium (K) are the essential elements that may drastically affect growth, appearance and most importantly, yield. However, detection of macronutrients can be slow while nutrient analysis can be time consuming. Adaptation of hyperspectral analysis techniques along with physiological study for the determination of specific nutrient stress in cocoa could allow early detection and precision in fertilization. The objective of the study was to investigate the prediction possibility of N and K deficiency in cocoa seedlings using a spectroradiometer. Spectral reflectance of fully expanded cocoa leaves from 350 to 1000 nm; growth (height, girth, leaf area) and physiological studies (photosynthesis, transpiration rate, chlorophyll content) were measured at monthly intervals for 3 months after treatment. A total of 72 seedlings (3 treatments x 4 replication x 6 sampling = 72 seedlings) with treatments (T1: 15-N: 15-P: 15-K; T2: 0-N: 15-P: 15-K; T3: 15-N: 15-P: 0-K) were arranged in a factorial randomized complete block design replicated four times in a greenhouse. Multispectral reflectance showed that leaves with no N (T2) had the highest reflectance peak at about 550 nm as absorption of incident light by chlorophyll decreased. This was further supported by T2 cocoa seedlings with significantly lowest readings in growth, net photosynthesis, transpiration rate and chlorophyll content (P≤0.05). Next, cocoa seedlings with no N and K involved response to nutrient stress by showing a shift in the red edge with greater reflectance at 675-750 nm. This is because healthy cocoa seedlings with complete ratio of NPK absorbed light as energy for photosynthesis and reflect near infrared light by bouncing off from the mesophyll layer. Overall, reflectance measurements could be a powerful non-destructive technique to decide on fertilizer application and timely correction of nutrient deficiencies before irreversible stress or damage occurs. Longdom Publishing 2018 Article PeerReviewed text en http://psasir.upm.edu.my/id/eprint/73947/1/Spectral%20reflectance%20and%20physiological%20studies%20of%20cocoa%20leaves%20in%20response%20to%20macronutrient%20deficiency.pdf Tee, Yei Kheng and Balasundram, Siva Kumar and Phebe, Ding and Mohd Haniff, Ahmad Husni (2018) Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency. Journal of Plant Pathology & Microbiology, 9 (2018). p. 41. ISSN ESSN: 2157-7471 https://www.longdom.org/proceedings/spectral-reflectance-and-physiological-studies-of-cocoa-leaves-in-response-to-macronutrients-deficiency-11786.html 10.4172/2157-7471-C1-009
institution Universiti Putra Malaysia
building UPM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
url_provider http://psasir.upm.edu.my/
language English
description In cocoa (Theobroma cacao), macronutrients of nitrogen (N), phosphorus (P) and potassium (K) are the essential elements that may drastically affect growth, appearance and most importantly, yield. However, detection of macronutrients can be slow while nutrient analysis can be time consuming. Adaptation of hyperspectral analysis techniques along with physiological study for the determination of specific nutrient stress in cocoa could allow early detection and precision in fertilization. The objective of the study was to investigate the prediction possibility of N and K deficiency in cocoa seedlings using a spectroradiometer. Spectral reflectance of fully expanded cocoa leaves from 350 to 1000 nm; growth (height, girth, leaf area) and physiological studies (photosynthesis, transpiration rate, chlorophyll content) were measured at monthly intervals for 3 months after treatment. A total of 72 seedlings (3 treatments x 4 replication x 6 sampling = 72 seedlings) with treatments (T1: 15-N: 15-P: 15-K; T2: 0-N: 15-P: 15-K; T3: 15-N: 15-P: 0-K) were arranged in a factorial randomized complete block design replicated four times in a greenhouse. Multispectral reflectance showed that leaves with no N (T2) had the highest reflectance peak at about 550 nm as absorption of incident light by chlorophyll decreased. This was further supported by T2 cocoa seedlings with significantly lowest readings in growth, net photosynthesis, transpiration rate and chlorophyll content (P≤0.05). Next, cocoa seedlings with no N and K involved response to nutrient stress by showing a shift in the red edge with greater reflectance at 675-750 nm. This is because healthy cocoa seedlings with complete ratio of NPK absorbed light as energy for photosynthesis and reflect near infrared light by bouncing off from the mesophyll layer. Overall, reflectance measurements could be a powerful non-destructive technique to decide on fertilizer application and timely correction of nutrient deficiencies before irreversible stress or damage occurs.
format Article
author Tee, Yei Kheng
Balasundram, Siva Kumar
Phebe, Ding
Mohd Haniff, Ahmad Husni
spellingShingle Tee, Yei Kheng
Balasundram, Siva Kumar
Phebe, Ding
Mohd Haniff, Ahmad Husni
Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency
author_facet Tee, Yei Kheng
Balasundram, Siva Kumar
Phebe, Ding
Mohd Haniff, Ahmad Husni
author_sort Tee, Yei Kheng
title Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency
title_short Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency
title_full Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency
title_fullStr Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency
title_full_unstemmed Spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency
title_sort spectral reflectance and physiological studies of cocoa leaves in response to macronutrient deficiency
publisher Longdom Publishing
publishDate 2018
url http://psasir.upm.edu.my/id/eprint/73947/1/Spectral%20reflectance%20and%20physiological%20studies%20of%20cocoa%20leaves%20in%20response%20to%20macronutrient%20deficiency.pdf
http://psasir.upm.edu.my/id/eprint/73947/
https://www.longdom.org/proceedings/spectral-reflectance-and-physiological-studies-of-cocoa-leaves-in-response-to-macronutrients-deficiency-11786.html
_version_ 1665896001655799808
score 13.211869

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