Corn Canopy Temperatures Measured With a Moving Infrared Thermometer Array

Measurement of water stress and scheduling of irrigation are both enabled by noncontact infrared thermometers(IRTs). Technological advances have miniaturized IRTs and reduced power requirements so that inexpensive selfpoweredunits are now commercially available. The objective of this work was to test a linear array of IRT sensors mounted on acenterpivot irrigation machine, and to use this IRT array to examine spatial variation in water stress of corn under fourirrigation treatments imposed on a highly variable field with a center pivot equipped for sitespecific irrigation andagrochemical application. An array of 26 IRTs was mounted on the pivot, which was run dry for a full circle on 7 days duringthe 1999 corn growing season. Procedures were developed to adjust for time lag during the 3.5hr measurement period.Significant differences were obtained among the varying water treatments, as expected, but also among plots within the samesoil map unit and among soil map unit means. Distinct spatial patterns, not necessarily related to the 1:1200scale soil map,were observed. These results emphasize the necessity to consider soil water relations during the development of managementrecommendations for sitespecific agriculture.