Exploring the value of remotely sensed sun-induced chlorophyll fluorescence for transpiration monitoring : case study of winter wheat (Triticum aestivum) at the ICOS station in Lonzée (Belgium)
Files
Pirotte_07701600_2022.pdf
UCLouvain restricted access - Adobe PDF
- 36.84 MB
Details
- Supervisors
- Faculty
- Degree label
- Abstract
- Climate change increases and amplifies the intensity and incidence of dry periods in some parts of the world generating drought stress on vegetation. This stress is leading to a loss of yield in agriculture. In the context of food security and integrated water resource use, early drought detection is needed for proactive decision-making. Sun-induced chlorophyll fluorescence for vegetation stress detection can be a real game-changer as SIF emissions are governed by photosynthetic activity. This feature of the SIF allows for earlier detection of drought than current techniques based on vegetation reflectance properties. However, the potential of SIF emission for drought detection needs to be further developed. This thesis analyses how canopy-scale SIF can provide information on plant transpiration using continuous field spectrometer measurements. SIF emissions of winter wheat (Triticum aestivum) are compared with meteorological and fluxes data from the Integrated Carbon Observation System (ICOS) station in Lonzée (Belgium). It allowed us to determine periods where the wheat was in limited water status, and analyze the response of the chlorophyll fluorescence. The fluorescence emission efficiency shows a decrease when photosynthesis is limited by water stress. Moreover, results showed that fluorescence emission efficiency can be a good proxy of canopy conductance and therefore give information on transpiration. This thesis highlights the potential and the limits of using the fluorescence emission efficiency at 760 nm from the upcoming FLuorescence EXplorer (FLEX) satellite to provide a unique insight on plant transpiration.