Integrating a Novel Method to Estimate Grapevine Water Use & Stress into Multi-Tiered Precision Irrigation Management. AVF Project #2023-2796.
Proposal Objective(s) and Experiments Conducted – Summary of Progress:
- We will evaluate our new method in commercial and experimental vineyards, where research grade flux tower systems are already in place, and integrate output with remotely sensed approaches. We will leverage existing datasets and expand installations to new vineyards to determine appropriate sensor orientation to best represent varying canopy types and row orientation.
- We will initiate the development of a web-based platform displaying sensor output to grower cooperators in near real-time.
- We will initiate the development of instructional materials for a citizen-scientist model showing users how to implement this new method independently.
Our efforts during the 2024 field season focused on Objective #1 using a combination of existing datasets, continuation of data collection in various GRAPEX sites, and installation of new sensors in an experimental vineyard in Davis. In 2025, we will also utilize large, mature vines growing in harvest collecting bins that are sitting on load cells. This system will allow us to track water use continuously and compare ET measured with the IRT wavelet sensor. This arrangement will also allow us to modify the orientation of the vines relative to incoming solar radiation, and to target a sustained deficit irrigation that treatment that relies on the IRT sensor output to trigger irrigation of appropriate amounts to match water use. Data analysis and interpretation of results is ongoing, and we expect much progress in the next two months. We can provide further updates to the review panel as we proceed. We will start to tackle Objectives 2&3 in the coming year of the project.
We originally submitted this proposal in January 2023 with the intent of conducting the first year of field work that summer. We had a post doc lined up, but he bailed on us just before the start of the field season. Around the same time, PI McElrone was dealing with a significant family health issue but is elated to report that everyone is doing well now. Given delays in initiating the proposed work and need to recruit a new post doc, we decided it was best to focus efforts on the 2024 growing season. Therefore, we did not request a second year of funding in January 2024 because we had yet to spend the funds. We successfully recruited a post doc, Dr. Weiyun Hua, to work with us starting in the Spring 2024. She unexpectedly left for another position at the end of the field season in early Fall 2024. Luckily, we identified another excellent candidate from the post doc pool, and Dr. Saroj Dash was able to start one month after Dr. Hua’s departure. He dove immediately into our existing datasets and is applying his skills with both ground-based thermal sensing systems and remotely sensed data. He is an excellent fit for the project and very enthused to continue this work. In his previous research, he used infrared data from a series of flux towers within a water basin to spatially map the crop water stress index for agricultural systems in India. He is now working to do the same across our various vineyard sites and links the IRT wavelet sensible heat flux output with the Two Source Energy Balance approaches for modelling ET. He has quickly become proficient in running the IRT wavelet analysis and comparing output with other ground-based data from our experimental flux towers. He has also begun the analysis of data collected from the sensor orientation experiment described below. We also conducted an intensive experiment with both Chardonnay and Cabernet Sauvignon in an experimental vineyard with variable rate irrigation system, where we conducted a drought experiment with heavily instrumented and measured vines. Below we describe experiments conducted in the summer of 2024 to apply the wavelet method in an experimental vineyard subjected to deficit irrigation and to refine the optimal viewing angle relative to canopy orientation.
Research Success Statements:
We aim to develop a user-friendly tool with off-the-shelf components for growers to use in their fields and integrate into our analysis platform. We think it has the potential to replace existing traditional measurements of plant stress and provide a more rugged version of an ET sensor that can be integrated with remote sensing tools to measure both vine and cover crop water use simultaneously. These ground-based measures will provide an improved confidence in data generated by satellite products like those from the OpenET platform.
