TEMPERATURE RESPONSE OF OATS TO WATER STRESS IN FIELD

The temperature of actively growing plants may serve as an index of the water, environmental, or pathogen stress which the crop is experiencing. Spring oats (Avena sativa L.) were grown in a field plot equipped with a moveable shelter to permit programming of applied water. Stress was imposed on the crop at different stages of growth by withholding water. Plant temperatures, relative leaf water contents (RLWC), and leaf diffusion resistances (LDR) were measured during the stress treatments. The leaf temperature of water stressed oats was generally 2.5 to 4.0°C warmer than the leaf temperature of adequately watered plants during the period of maximum solar radiation on cloudless days. Water stressed oats had a RLWC which was 23% less and a 22 sec/cm higher LDR than the control (nonstressed) treatment when the stress was imposed at the boot (growth) stage. Remotely sensed crop temperatures, properly calibrated for local conditions, appear promising as a tool for identifying water deficits and for use in scheduling irrigation. © 1978.