Infrared Thermometry Studies for Estimation of Crop Water Stress Index

An IR thermometry enables non-contact temperature measurements of the crop canopy, capturing infrared radiation emitted by objects without physical contact, which is beneficial for accurate Crop Water Stress Index (CWSI) estimation as it minimizes interference and temperature reading alterations. In this study, handheld IRT was used to measure the canopy temperature of selected crops in 32 farms, 8 each in crop of Maize, chilly, groundnut and Black gram which were predominantly grown in Bapatla and Prakasm districts. Canopy temperature (Tc) and temperature of non-water stressed crop (Tnws) were measured 4 times during the Rabi season on clear sky days. The results concluded that at the initial stage, crops were grown with residual moisture of Kharif paddy hence at that stage CWSI values were low. The highest CWSI in the season was observed for the crop black gram about 0.524 and the lowest was observed for the crop chilly about 0.245. The seasonal average CWSI values for Maize, Chilly, Groundnut and Black gram were 0.382, 0.323, 0.358 and 0.399, respectively. CWSI determination helps to monitor the crop stress level, by knowing it, it is easy for irrigation scheduling by taking a threshold CWSI value to start irrigation. The average CWSI for each crop can be taken as a threshold value for irrigation scheduling.