A novel system for remote sensing measurements of evapotranspiration and CWSI of agricultural crops

摘要

Remotely sensed plant canopy temperature has long been recognized as having potential as a tool for irrigation management. Changes of actual evapotranspiration (ET)as a function of water availability were measured with infrared temperature radiometers (IRT). A a novel deterministic algorithm was developed and solved numerically to compare ground-based remote sensing method to ET from a weighing lysimeter. The algorithm is based on a closed form of Penman Monteith (P-M) model and its thermal interpretation by Jackson et al. this algorithm can automatically provide timely valuable information on plant and soil water status (Crop Water Stress Index CWSI) , which can improve the management of irrigated crops. Four treatments with 3 replications each were trickle irrigating soilless culture. They were used to test response of Lettuce (Lactuca sativa var 936) to water applications amounts by yield weighing and IRT evapotranspiration monitoring. Results of comparison between lysimeter and IRT measurements were satisfactory for field measurements with a correlation slope close to a unit and r~2= 0.77. The t-test accepted the null hypothesis that there was no difference between populations of IRT measurements and lysimeter evapotranspiration.