Journal of Bio-Environment Control ISSN:1229-4675(Print) 2765-3641(Online) 생물환경조절학회지

The study was performed to calculate canopy temperatures and crop water stress index (CWSI) of 2-year-old ‘Yumi’ peach trees using thermal infrared imaging under different soil water conditions, and to evaluate availability for water stress determination. Canopy temperatures showed similar daily variations to air temperatures and they were higher during the daytime than air temperatures. Canopy temperatures for 24 h were correlated highly to air temperatures (r² = 0.95), solar radiations (r² = 0.74), and relative humidity (r² = -0.88). In addition, soil water potential showed a highly negative correlation to canopy temperatures (r² = -0.57), temperature differences between leaf and air (TD) (r² = -0.71), and CWSI (r² = -0.72) during the daytime (11 to 16 h). CWSI for 24 h was highly related to canopy temperatures (r² = 0.90) and TD (r² = 0.92), whereas CWSI was not correlated to soil water potential (r² = -0.27) for 24 h but related highly to water potential (r² = -0.72) during the daytime (11 to 16 h). Correlation coefficients between CWSI (y) and soil water potential (x) were highest from 11 to 12 h and a regression equation was deduced as y = -0.0087x + 0.14. CWSI was calculated as 0.575 at -50 kPa, which soil water stress generally occurs. Thus our result suggests that this regression equation using thermal infrared imaging is useful to evaluate soil water stress of peach trees.