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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Production and Genetic Improvement Research Unit » Research » Research Project #440216

Research Project: Taking Proof of Concept to Wide-scale Field Use: The OSU High-performance Dendrometer

Location: Horticultural Crops Production and Genetic Improvement Research Unit

Project Number: 2072-21000-055-024-G
Project Type: Grant

Start Date: Sep 1, 2021
End Date: Oct 31, 2023

1. Build and deploy 32 dendrometers (equipped with LoRa communication) in replicated vineyard field trial; 2. Delay irrigation initiation time in vineyard field trial to establish two levels of water status among plots; 3. Monitor vine water status (using traditional methods) and trunk diameter (using dendrometers) over various time scales; 4. Correlate dendrometer signal with traditional methods to validate dendrometer as accurate irrigation decision support tool.

The recently developed OPEnS Dendrometer ( will be hand water-jet cut, soldered, and assembled by undergraduate student researchers. For this study, we plan to add LoRa (long range radio) telemetry and internet data access portal to the system, enabling researchers to remotely monitor plant behavior and device diagnostics in real-time. The student researchers will spend one month assembling and testing the systems locally before deploying in the field. Possible pitfalls are production supply and lead times for the growing season. One commercial vineyard site that is part of an already-established, separately-funded, three-site irrigation trial (Oregon Wine Board project 2020-2447) will be utilized for this study. The existing irrigation treatments consist of varied irrigation initiation times defined by midday stem water potential ('stem) thresholds ranging from -0.6 (earliest initiation) to -1.4 MPa (latest initiation). Five-vine treatment plots are arranged in a randomized complete block design with eight replications. Upon irrigation initiation, all plots will be irrigated at 65% of estimated crop evapotranspiration (ETc). Beginning one month after budbreak (approximately mid to late-May), 'stem will be monitored weekly using a pressure chamber. In this study, only the earliest and the latest initiation irrigation treatments will be instrumented with dendrometers. Two vines in each of the eight plots in each of the two irrigation treatments will be instrumented (2 * 8 * 2 = 32 dendrometers). Devices will continuously monitor trunk fluctuations 15-min intervals from installation. Dendrometer signal over time will be analyzed using time-series analyses techniques to compute maximum daily shrinkage (MDS) and other parameters such as overall trunk growth rate (TGR). Weekly midday 'stem data will be analyzed using two-way ANOVA for a split-plot design, with irrigation treatment as the main plot factor, and sample date as the split plot factor. Linear regression will be used to analyze the relationship between MDS and 'stem.