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Determining pasture evapotranspiration using active optical sensor derived normalized difference vegetation index


Alam, MS and Lamb, DW and Rahman, M and Bradbury, R and McCarthy, C, Determining pasture evapotranspiration using active optical sensor derived normalized difference vegetation index, Preparing the digital future of livestock farming, 16-18 October 2017, Claudelands Conference and Exhibition Centre, Hami, pp. 1-7. (2017) [Refereed Conference Paper]

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DOI: doi:10.5281/zenodo.897037


Actual evapotranspiration (ETc) is one of the important parameters that determines the daily and seasonal water requirement by the crop community. It varies with numerous factors including weather, soil moisture availability and other crop related factors such as growing stage, fraction of field coverage and crop vigour. In this study we investigated the relationship between normalized difference vegetation index (NDVI) that is closely related to photosynthetically-active biomass (PAB) and the evapotranspiration of pasture at different soil moisture condition. A portable enclosed chamber was used to measure ETc of a target pasture canopy and consequently the NDVI with a hand held active optical sensor. The portable chamber was calibrated in the laboratory and produced a calibration factor of C=1.02. Field experiments were conducted on the UNE SMART Farm in Tall Fescue pastures (Festuca arundinacea var. Dovey). Under limiting soil moisture condition the relationship between NDVI and ETc showed a negative correlation (R2=0.73) whereas a strong and positive correlation (R2=0.82) were observed in a non-limiting soil moisture condition.

Item Details

Item Type:Refereed Conference Paper
Keywords:Evapotranspiration, Crop coefficient, Optical Sensor
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Agriculture, land and farm management
Research Field:Agriculture, land and farm management not elsewhere classified
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the agricultural, food and veterinary sciences
UTAS Author:Alam, MS (Mr Muhammad Shahinur Alam)
ID Code:154544
Year Published:2017
Deposited By:TIA - Research Institute
Deposited On:2022-12-12
Last Modified:2022-12-12

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