Comparison of Variations of Water Stress Index of Chika Bean Plant under Surface Irrigation and Drip Tape Irrigation using Infrared Thermometer

The Plant Water Resistance Index (CWSI) is a tool that can be used for the rapid monitoring of plant water status, which is a key requirement for the accurate product irrigation management.The purpose of this study was to calculate the CWSI index for bean hares in the Khorramabad region for two methods of surface irrigation and drip tape ‎irrigation. For this purpose, a design was implemented in the form of randomized complete block design and split plot experiment. The main factors included drip tape irrigation (T) and surface irrigation (F), and the cultivars of Chibi cultivars including COS16 (C), Sadri (S) and diluted (K) served as sub-plots. By using the field measurements, the position of the upper and lower base lines was estimated for each treatment in different months and used to calculate the CWSI index. The results showed that CWSI values calculated in the surface irrigation during plant growth period were always higher than those in the drip tape irrigation. The highest value of CWSI index was obtained for the Sadri variety, which was equal to 0.20 and 0.26, for the type and surface method, respectively. Statistical analysis showed that the effect of irrigation method on the amount of water stress index was significant at 5% level, but there was no significant difference between different cultivars. According to the results of this study, the threshold values for CWSI were considered to be 0.19 and 0.24 for surface and drip tape ‎irrigation respectively, and relationships were presented based on the differences in vegetation and air temperature to determine the irrigation time.