Center-pivot-mounted sensing system for monitoring plant height and canopy temperature

Authors: Sui, Ruixiu; Baggard, Jonnie

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2018
Publication Date: 6/15/2018
Citation: Sui, R., Baggard, J.L. 2018. Center-pivot-mounted sensing system for monitoring plant height and canopy temperature. Transactions of the ASABE. 61(3):831-837.

Interpretive Summary: Variable rate irrigation (VRI) technologies allow the producers to site-specifically apply irrigation water at variable rates to adjust the temporal and spatial variability in soil and plant characteristics in the field. Adoption of VRI has the potential to improve water use efficiency. Researchers at USDA-ARS Crop Production Systems Research Unit in Stoneville, MS built and deployed a center-pivot-mounted wireless data acquisition (WDQ) system for site-specific measurement of plant characteristics. The WDQ system was capable of making non-contact real-time measurements of plant height and plant canopy temperature as the center pivot irrigation system moved around the field, and the data could be wirelessly downloaded to a computer. Plant height and canopy temperature are important parameters in determining the amount of water needed by the plants. The data collected using the WDQ system could be used for field VRI practices to save water.

Technical Abstract: Easy-to-use data acquisition methods are required for variable rate irrigation (VRI) decision support system. Plant canopy temperature is related with plant water stress. Plant height is useful as an indicator of plant health conditions and can be used to estimate yield potential. Therefore, measurements of plant canopy temperature and plant height coupled with spatial information in field can be used for determining VRI water depths. A wireless data acquisition (WDAQ) system was developed to collect plant canopy temperature and plant height data in the field. Each WDAQ unit consisted of a GPS receiver, programmable data logger, infrared temperature sensor, ultrasonic distance sensor, solar power supply, and wireless data transmitter/receiver. The system included two WDAQ units installed on a 4-span center pivot VRI system. One unit was mounted at the middle of the third span, and the other at the fourth span from the pivot. Infarred temperature sensors were used to detect the canopy temperature while the ultrasonic distance sensor to measure plant height. The WDAQ system was designed to continuously and simultaneously make measurements of plant canopy temperature and plant height, and record spatial coordinates at each measurement location as the center pivot moved around the field. Data collected were wirelessly transferred to a wireless receiver for data process. This WDAQ system has been tested in field. The results indicated the system had great potential to be used for automatic creation of VRI prescription maps and plant-based irrigation scheduling.