基于冠层温度的冬小麦水分胁迫指数的实验研究

AN EXPERIMENTAL STUDY OF WINTER WHEAT WATER STRESS INDEX BASED ON THE CANOPY TEMPERATURE

在田间实验基础上对冬小麦田逐日１４时基于冠层温度的作物水分肋迫指数（ＣＷＳＩ）进行了计算和分析。同一时刻干旱处理ＣＷＳＩ高于湿润处理；麦田灌溉后ＣＷＳＩ４～６天降到极小值，表明了灌水后作物从水分胁迫状态恢复所需的时间；从本次灌溉后ＣＷＳＩ达到极小值至再次灌溉期间，ＣＷＳＩ呈持续增加趋势。这些表明ＣＷＳＩ较好的反映了因土壤供水不足导致的作物水分胁迫，ＣＷＳＩ与叶水势之间呈明显的负相关关系。ＣＩＶＳＩ等于０．４，相当于实际蒸散与可能蒸散的比率为６０％，是指示冬小麦发生严重水分胁迫的关键性指标。

The crop water stress index (CWSI)based on the daily canopy temperature at 14: 00 ,has been calculated on the basis of winter wheat field experiment. The resultsindicate that the CWSI with drying process is higher than that with wet process at thesame time;after 4～6 days of irrigation,CWSI drops to a minimum,it is a period of plantrecovering from a stressed condition. And, the steady increase trend of CWSI betweentwo times of irrigation shows that crop water stress increases with time in this period.The above inclusions show that the plant water stress is due to the lack of water, Thereis obvious negative correlation between CWSI and leaf water potential.When CWSIequals 0.4,it could be a critical index in indicating winter wheat water stress.