Crop Evapotranspiration Estimations of Red Pepper Using Field Level Remote Sensing Data and Energy Balance

Abstract

In this study, the energy balance approach was used to estimate evapotranspiration (ET) of red pepper plots managed with four different irrigation strategies (100, 70, and 40% of ET, and rainfed) with drip irrigation systems in the sub-humid Bafra Plains located in northern Turkey. In order to calculate components of energy balance, hyper-spectral reflectance, infrared surface temperature, and net radiation data were measured using nadir-looking hand-held proximal sensing devices over the experimental plots. Additionally, soil moisture levels were monitored frequently with a well-calibrated neutron moisture meter and a soil water budget approach was used to calculate actual ET values. Current findings revealed that the response of red pepper crops to water stress offered a significant opportunity to detect different levels of spectral reflectance, surface temperature, and net radiation. Furthermore, statistical comparisons revealed significant relationships between measured and estimated daily ET (r = 0.92 and RMSE = 0.83) and cumulative ET (r = 0.99 and RMSE = 43.98) values. Estimation errors for daily and cumulative ET using the energy balance algorithm were 27% and 14%, respectively. Overall, present results indicated that the energy balance algorithm with field level remotely sensed data had a great potential to estimate ET of red peppers at plot scale.