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| Titel |
Plant Water Stress Detection Using Radar: The Influence Of Water Stress On Leaf Dielectric Properties |
| VerfasserIn |
Tim van Emmerik, Susan Steele-Dunne, Jasmeet Judge, Nick van de Giesen |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250110848
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| Publikation (Nr.) |
 EGU/EGU2015-10888.pdf |
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| Zusammenfassung |
| Recent research on an agricultural maize canopy has demonstrated that leaf water content
can change considerably during the day and in response to water stress. Model
simulations suggest that these changes have a significant impact on radar backscatter,
particularly in times of water stress. Radar is already used for several vegetation and soil
monitoring applications, and might be used for water stress detection in agricultural
canopies. Radar observations of the land surface are sensitive because it results in
two-way attenuation of the reflected signal from the soil surface, and vegetation
contributes to total backscatter from the canopy itself. An important driver that
determines the impact of vegetation on backscatter is the dielectric constant of the
leaves, which is primarily a function of their moisture content. Understanding the
effects of water stress on the dynamics of leaf dielectric properties might shed light
on how radar can be used to detect vegetation water stress. Previous studies have
investigated the dielectric properties of vegetation. However, this has mainly been done
using destructive sampling or in-vivo measurements of tree trunks. Unfortunately,
few in-vivo measurements of leaf dielectric properties exist. This study presents
datasets of in-vivo dielectric measurements of maize leaves, taken during two field
experiments. One experiment was done using was done during a period of water stress, the
other during a period without. Field measurements revealed a different vertical
profile in dielectric properties for the period with and without water stress. During a
period of increased water stress, the diurnal dynamics of leaves at different heights
responded differently to a decrease in bulk moisture content. This study provides insight
in the effect of water stress on leaf dielectric properties and water content, and
highlights the potential use of radar for water stress detection in agricultural canopies. |
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