High-Density Temperature Measurements in Tree-Fruit Environments.
Francis J. Pierce1, Pedro Andrade-Sanchez1, Todd V. Elliot, and Matthew D. Whiting2. (1) Center for Precision Agricultural Systems, Washington State University, 24106 N. Bunn Rd, Prosser, WA 99350-8694, (2) Horticulture and Landscape Arquitechture, Washington State University, 24106 N. Bunn Rd, Prosser, WA 99350-8694
Frost protection strategies for tree-fruit crops depend heavily on the accuracy and timeliness of temperature information for real time control systems. The efficacy and efficiency of frost control systems can be improved by better understanding of the time and spatial distribution of temperature measurements, but still limited knowledge has been developed to understand the dynamics of temperature fluctuations with high-density deployments of temperature sensors. In this study we explored the dynamics of temperature fluctuations in cheery trees during the last days of freeze control season in the Lower Yakima Valley of Central Washington. Two different experimental settings were used: a) 3-D deployment of 48 temperature sensors inside the canopy of a single tree; and b) a 2-D deployment of 48 sensors in a 1 m2 square grid arranged in a plane perpendicular to the direction of the tree rows. The instrumentation to suit the needs of this study was developed by WSU-CPAS. The data logger used high precision thermistors of 2252 ohm resistance @ 25 oC. The distribution of temperature data showed significant gradients. Optimal positioning and data transmission frequencies under a variety of scenarios can be determined with the type of information generated with this study.