Department of Agronomy, Haryana Agricultural University, Hissar-125004, India
* Present address: Deputy Director General (Education), ICAR, Krishi Bhavan, New Delhi-110001, India
his study was undertaken to demonstrate that crop canopy temperature responds to changes in leaf water potential (ψL), and therefore can be used for monitoring irrigation. The canopy minus air temperature difference (ΔT) was related to ψL in field grown wheat under two differential water supplies at 50% pnd 65% depletion of available soil moisture in the root zone soil. ψL ranged from 14 bars when valumetric soil water content(QV) was 0.25 to ψL-33 bars at the wilting point(QV=0.14). At 1400 hours, ΔT, was - 3.7°C at ψL=-10 bars. Increasing water stress decreased ψL markdely and increased ΔT. At ψL=-17 bars, ΔT was zero; and at ψL=-45 bars, T increased to 5°C. These results support the validity of the temperatnre difference method for sensing plant response to water stress conditions.
