Details
| Original language | English |
|---|---|
| Journal | International Journal of Remote Sensing |
| Publication status | Accepted/In press - 2025 |
Abstract
The heavily strained water resources in Bengaluru, India, as a result of rapid urban expansion are increasingly at risk of overexploitation and pollution due to intensified agriculture practices, such as increased nitrogen (N) use and irrigation. In recent years, thermal cameras mounted on Unmanned Aerial Vehicles (UAVs) have proven useful in detecting crop water stress and managing irrigation. However, the use of these cameras in managing N fertilization in the subtropics has been understudied. We employed this technology in two agricultural field experiments in Bengaluru to study the effects of N fertilization on canopy temperatures of maize, finger millet, and lablab, and their correlations with Leaf Chlorophyll Content (LCC), and soil temperature. The results showed that the effect of N was more pronounced at the rainfed experimental site, where the soil is highly acidic and porosity is low. At this site, N significantly affected the canopy temperature of maize and finger millet, particularly under sunny conditions (p = 0.000245), resulting in plots receiving higher nitrogen dosages showing canopies with 2.1°C and 1.3°C cooler temperatures, respectively. Lower temperatures with higher N application were also observed in the irrigated experiment (p value = 0.118), albeit only under sunny conditions. Additionally, canopy temperatures and LCC significantly correlated for maize (R = -0.68, p = 0.015) in the rainfed experiment and millet (R = -0.7, p = 0.011) in the irrigated experiment. However, the correlation of LCC with NDVI was stronger on both sites. Canopy and soil temperatures correlated significantly only when analysed without considering crop species. The use of thermal cameras, equipped with uncooled microbolometers, is accompanied by the dilemma of temperature drift, which affect measurement accuracy. We introduced a drift correction process, which effectively reduced drift by up to 45%, and decreased the drift standard deviation to less than 1°C, that resulted in homogeneous thermal maps suitable for robust statistical analysis. In my submission i added keywords, are they going to be included in the publication ??.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- General Earth and Planetary Sciences
Sustainable Development Goals
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In: International Journal of Remote Sensing, 2025.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Assessing canopy temperature responses to nitrogen fertilisation in South Indian crops using UAV -based thermal sensing
AU - Almawazreh, Albara
AU - Buerkert, Andreas
AU - Vazhacharickal, Prem Jose
AU - Peth, Stephan
N1 - Publisher Copyright: © 2025 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
PY - 2025
Y1 - 2025
N2 - The heavily strained water resources in Bengaluru, India, as a result of rapid urban expansion are increasingly at risk of overexploitation and pollution due to intensified agriculture practices, such as increased nitrogen (N) use and irrigation. In recent years, thermal cameras mounted on Unmanned Aerial Vehicles (UAVs) have proven useful in detecting crop water stress and managing irrigation. However, the use of these cameras in managing N fertilization in the subtropics has been understudied. We employed this technology in two agricultural field experiments in Bengaluru to study the effects of N fertilization on canopy temperatures of maize, finger millet, and lablab, and their correlations with Leaf Chlorophyll Content (LCC), and soil temperature. The results showed that the effect of N was more pronounced at the rainfed experimental site, where the soil is highly acidic and porosity is low. At this site, N significantly affected the canopy temperature of maize and finger millet, particularly under sunny conditions (p = 0.000245), resulting in plots receiving higher nitrogen dosages showing canopies with 2.1°C and 1.3°C cooler temperatures, respectively. Lower temperatures with higher N application were also observed in the irrigated experiment (p value = 0.118), albeit only under sunny conditions. Additionally, canopy temperatures and LCC significantly correlated for maize (R = -0.68, p = 0.015) in the rainfed experiment and millet (R = -0.7, p = 0.011) in the irrigated experiment. However, the correlation of LCC with NDVI was stronger on both sites. Canopy and soil temperatures correlated significantly only when analysed without considering crop species. The use of thermal cameras, equipped with uncooled microbolometers, is accompanied by the dilemma of temperature drift, which affect measurement accuracy. We introduced a drift correction process, which effectively reduced drift by up to 45%, and decreased the drift standard deviation to less than 1°C, that resulted in homogeneous thermal maps suitable for robust statistical analysis. In my submission i added keywords, are they going to be included in the publication ??.
AB - The heavily strained water resources in Bengaluru, India, as a result of rapid urban expansion are increasingly at risk of overexploitation and pollution due to intensified agriculture practices, such as increased nitrogen (N) use and irrigation. In recent years, thermal cameras mounted on Unmanned Aerial Vehicles (UAVs) have proven useful in detecting crop water stress and managing irrigation. However, the use of these cameras in managing N fertilization in the subtropics has been understudied. We employed this technology in two agricultural field experiments in Bengaluru to study the effects of N fertilization on canopy temperatures of maize, finger millet, and lablab, and their correlations with Leaf Chlorophyll Content (LCC), and soil temperature. The results showed that the effect of N was more pronounced at the rainfed experimental site, where the soil is highly acidic and porosity is low. At this site, N significantly affected the canopy temperature of maize and finger millet, particularly under sunny conditions (p = 0.000245), resulting in plots receiving higher nitrogen dosages showing canopies with 2.1°C and 1.3°C cooler temperatures, respectively. Lower temperatures with higher N application were also observed in the irrigated experiment (p value = 0.118), albeit only under sunny conditions. Additionally, canopy temperatures and LCC significantly correlated for maize (R = -0.68, p = 0.015) in the rainfed experiment and millet (R = -0.7, p = 0.011) in the irrigated experiment. However, the correlation of LCC with NDVI was stronger on both sites. Canopy and soil temperatures correlated significantly only when analysed without considering crop species. The use of thermal cameras, equipped with uncooled microbolometers, is accompanied by the dilemma of temperature drift, which affect measurement accuracy. We introduced a drift correction process, which effectively reduced drift by up to 45%, and decreased the drift standard deviation to less than 1°C, that resulted in homogeneous thermal maps suitable for robust statistical analysis. In my submission i added keywords, are they going to be included in the publication ??.
UR - http://www.scopus.com/inward/record.url?scp=85216881262&partnerID=8YFLogxK
U2 - 10.1080/01431161.2025.2452312
DO - 10.1080/01431161.2025.2452312
M3 - Article
AN - SCOPUS:85216881262
JO - International Journal of Remote Sensing
JF - International Journal of Remote Sensing
SN - 0143-1161
ER -