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

conference contribution
posted on 2023-05-23, 15:33 authored by Muhammad Shahinur AlamMuhammad Shahinur Alam, Lamb, DW, Rahman, M, Bradbury, R, McCarthy, C
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.


Publication title

Preparing the digital future of livestock farming


Warrick Nelson




Tasmanian Institute of Agriculture (TIA)

Event title

1 st Asian-Australasian Conference on Precision Pastures and Livestock Farming

Event Venue

Claudelands Conference and Exhibition Centre, Hami

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the agricultural, food and veterinary sciences

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