Articles
Actual transpiration of almonds under different production systems and water status with two-source energy balance models using high resolution aerial imagery
Article number
1425_7
Pages
47 – 54
Language
English
Abstract
During the last decade, new irrigated almond area has increased in Spain, rising water demands.
In a context of water scarcity, the estimation of crop evapotranspiration (ET) is crucial to monitor irrigation.
The ET can be retrieved from the two-source energy balance (TSEB) using very high-resolution imagery.
However, few efforts have been made to validate the transpiration with sap flow measurements in woody row crops with different production systems and water status.
In this study, the TSEB Priestley-Taylor (TSEB-PT) and contextual approach (TSEB-2T) models were assessed to estimate canopy transpiration.
An unmanned aerial vehicle (UAV) equipped with thermal and multispectral cameras allowed us to obtain the main parameters required for both TSEB models.
The TSEB transpiration was validated with calibrated sap-flow sensors.
The leaf area index (LAI), stem water potential (Ψstem) and fractional intercepted photosynthetically active radiation (fIPAR) were also measured.
Our results showed significant differences in measured transpiration (Tsf) between production systems and irrigation treatments.
The combined use of the TSEB-2T with the C&N-R transmittance model gave the best transpiration estimations for all production systems and irrigation treatments.
The model error can be associated with the radiative transfer model used to estimate radiation interception.
Besides, further refinements on the radiation transfer modeling approaches are needed, especially for row woody crops.
In a context of water scarcity, the estimation of crop evapotranspiration (ET) is crucial to monitor irrigation.
The ET can be retrieved from the two-source energy balance (TSEB) using very high-resolution imagery.
However, few efforts have been made to validate the transpiration with sap flow measurements in woody row crops with different production systems and water status.
In this study, the TSEB Priestley-Taylor (TSEB-PT) and contextual approach (TSEB-2T) models were assessed to estimate canopy transpiration.
An unmanned aerial vehicle (UAV) equipped with thermal and multispectral cameras allowed us to obtain the main parameters required for both TSEB models.
The TSEB transpiration was validated with calibrated sap-flow sensors.
The leaf area index (LAI), stem water potential (Ψstem) and fractional intercepted photosynthetically active radiation (fIPAR) were also measured.
Our results showed significant differences in measured transpiration (Tsf) between production systems and irrigation treatments.
The combined use of the TSEB-2T with the C&N-R transmittance model gave the best transpiration estimations for all production systems and irrigation treatments.
The model error can be associated with the radiative transfer model used to estimate radiation interception.
Besides, further refinements on the radiation transfer modeling approaches are needed, especially for row woody crops.
Authors
M. Quintanilla-Albornoz, X. Miarnau, A. Pelechá, J. Casadesús, O. García-Tejera, J. Bellvert
Keywords
modeling, TSEB, remote sensing, leaf area index, sap-flow sensors
Groups involved
- Division Plant-Environment Interactions in Field Systems
- Division Precision Horticulture and Engineering
- Working Group Modelling in Fruit Research and Orchard Management
- Working Group Modelling Plant Growth, Environmental Control, Greenhouse Environment
- Division Greenhouse and Indoor Production Horticulture
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