A Low-Cost Infrared Thermometry System for Use in Research and Production Agriculture.

Plant canopy temperature is used in many studies of plant/environment interactions. Non-contact measurement of plant canopy temperature is often accomplished through the use of radiometric surface thermometers commonly referred to as infrared thermometers. Industrial-quality infrared thermocouples are widely available and often used in agricultural research. While research on canopy temperature has resulted in management tools for production agriculture, the cost of industrial-quality infrared thermocouples has limited their use in production agriculture settings. In this paper we evaluate the use of a low-cost consumer-quality infrared thermocouple device as a component of a wireless thermal monitoring system designed for use in a production agriculture setting. The performance of industrial-quality and low-cost consumer quality devices were compared under controlled constant temperature conditions and under field conditions using both grass and cotton canopies. Under controlled-temperature conditions, the consumer-quality infrared thermocouple output was closer to the value of the thermocouple control than the industrial-quality infrared thermocouple. In the field, the comparison of the 15-minute means of 5 industrial-quality infrared thermocouples devices and 6 consumer-quality infrared thermocouples devices monitoring a grass canopy during June of 2007 and a cotton canopy during September 2007 indicated that the two types of devices are functionally equivalent over 13°C to 35°C range of the measurement period. Over a range of temperatures experienced by plants in temperate regions (10°C to 50°C), the two types of devices would not differ significantly. The results indicate that the consumer-quality infrared thermometer may be suitable for use in production agricultural applications.