A Study on the Relationships of Wheat Canopy and Alfalfa Canopy Temperatures With Microclimatic, Soil and Plant Factors

Raul Alberto Diaz, Utah State University

Abstract

Canopy temperatures were measured on spring wheat and alfalfa in six differentially irrigated plots. Canopy temperatures were measured daily between 1530 and 1630 hours from 21 June to 15 August 1980 with an infrared thermometer. Air temperatures measured 150 cm above the ground, in a nearby weather station, were subtracted form the canopy temperatures to obtain the stress-degree-day (SDD).

The daily summation of the stress-degree-day (ΣSDD), throughout the development stages of spring wheat, was linearly and inversely related to wheat cumulative evapotranspiration (r2=0.90) and to the normalized grain yields (r2=0.76). The similar type of relationship was determined for alfalfa. These results were found to be in good agreement with previous researches done at Phoenix, Arizona and at Davis, California.

The SDD concept shows promise as an indicator for estimating the crop water requirements and the crop production at Logan, Utah.

This paper has been withdrawn.