Sustainable Irrigation Demonstration Project: Demonstrating Irrigation Efficiency in California Winegrapes through Advanced Practices and Technologies

Sustainable Irrigation Demonstration Project: Demonstrating Irrigation Efficiency in California Winegrapes through Advanced Practices and Technologies

Summary

Water management in vineyards is a major issue in California.

Limited water availability is predicted to be a serious problem if the current climate warming trends and drought continue.

The use of a vineyard specific crop model has the potential to reduce water use and become an effective irrigation management tool. Crop models incorporate climate, soil, vineyard, and irrigation data to accurately estimate vine water status and recommend irrigation to meet production objectives.

This project will compare the existing grower practice of ET based irrigation scheduling with the use of a vineyard specific irrigation model known as VINTEL, demonstrate the benefits of using a crop specific model in vineyard management and develop a blueprint for the implementation of such models.

During year one of this project (2016 growing season) we showed that the VINTEL model provided an acceptable estimation of water status under our growing conditions and that irrigating based on the model’s recommendation has the potential to save 10-30% compared to the grower’s current practice of ET based deficit irrigation.   

During year two (2017 growing season) we will irrigate using the model recommendations and monitor plant health and fruit quality. 

Objectives/Performance Targets

Year one objectives included: 

1. Selecting monitoring sites
2. Defining, characterizing and inputting site specific parameters into the model
3. Calibrating model
4. Comparing model to grower standard (ET model)

Accomplishments/Milestones

During the first year of the project we accomplished the following:

1. 21 monitoring sites selected. Site selection based on crop vigor and variety. Refer to WSARE-Annual-Report-Figure-1_WSARE-Monitoring-Sites.
2. Defined and characterized site specific parameters for each monitoring location and populated the model. Refer to WSARE-Annual-Report-Table-1_Model-Parameters-Worksheet.
3. Visually assessed each site throughout growing season to confirm correctness of annual variables and adjusted model parameters as required. Annual variables include canopy width, canopy height, cover crop width, and canopy porosity.
4. Assessed vine water status with pressure chamber to validate model for each monitoring location. Refer to WSARE-Annual-Report-Figure-2_Vine-water-status-SB07C.
5. Ran model in parallel to grower irrigations and compared predicted water usage from model to actual water used model to grower standard for each monitoring location. Refer to WSARE-Annual-Report-Figure-3_Gower-Applied-Water-vs-VINTEL-Model-Comparison.

Impacts and Contributions/Outcomes

The first year of this project resulted in the following outcomes:

1. The vineyard specific crop model can accurately estimate plant water status. WSARE-Annual-Report-Figure-2_Vine-water-status-SB07C shows the VINTEL model closely estimated actual vine water status as measured with a pressure chamber.  During the 2017 season we will work to better define site parameters to tighten this relationship for all monitoring sites.
2. Irrigating based on the vineyard specific crop model has the potential to save 10-30% when compared to the grower’s ET based irrigation management. WSARE-Annual-Report-Figure-3_Gower-Applied-Water-vs-VINTEL-Model-Comparison compares grower applied water with VINTEL recommendations. In all cases the model showed a potential for water savings.  We will irrigate using the model recommendations during the 2017 season. 
3. Clarified the need for real time irrigation data. Flow meters will be installed prior to 2017 growing season. Data from these meters will feed directly to the crop model providing more accurate and timely irrigation information.
4. Identified need for soil moisture probes. Due to soil conditions on this particular property manual soil moisture assessment very arduous. Plant available water measurements are required for model calibration.
5. Indicated that differences in vine vigor may be due to plant nutritional status rather than vine water status as was expected. We will continue to run model and monitor water and nutrient status in both high vigor and low vigor sites to confirm this finding.
6. Scheduled vineyard tailgate meeting for August 3, 2017 with The Vineyard Team (project outreach partner).

Collaborators: