High precision zero-friction magnetic dendrometer

• Published in: HardwareX 2021-10, Vol.10, p.e00248-e00248, Article e00248
• Main Authors: Clonch, Cameron, Huynh, Mark, Goto, Bryson, Levin, Alexander, Selker, John, Udell, Chet
• Format: Article
• Language: English
• Subjects: Arduino; Carbon fiber; Irrigation; Maximum daily shrinkage (MDS); Trunk growth rate; Vineyard; Water-stress indicator; Woody plants
• ISSN: 2468-0672; 2468-0672
• DOI: 10.1016/j.ohx.2021.e00248

[Display omitted] Increasing agricultural demand for freshwater in the face of a changing climate requires improved irrigation management to maximize resource efficiency. Soil water deficits can significantly reduce plant growth and development, directly impacting crop quantity and quality. Dendrometers are a plant-based tool that have shown potential to improve irrigation management in high-value woody perennial crops (e.g., trees and vines). A dendrometer continuously measures small fluctuations in stem diameter; this has been directly correlated to water stress measurements using traditional methods. While plant-based measures of water deficits are considered to be the best measures of water stress, current dendrometer methods are imprecise due to mechanical hysteresis and thermal expansion. The high-precision dendrometer created at the OPEnS Lab alleviates these key failure points using zero-thermal expansion carbon fiber, zero friction via a spring tensioning approach, and a linear magnetic encoder. In-lab tests and field deployments have validated device measurements and the execution of these pivotal qualities. Mass deployment of these automated dendrometers has the potential to provide a continuous record of water stress, providing valuable decision support for irrigation management.