Advancing Sustainable Jujube Cultivation: Field-based quantification of jujube water use in California’s San Joaquin Valley

Commodities

• Fruits: other
• Additional Plants: trees

Practices

• Crop Production: drought tolerance, irrigation, water management
• Education and Training: decision support system, extension, farmer to farmer, mentoring, networking, on-farm/ranch research, technical assistance, workshop, other

The San Joaquin Valley continues to experience periods of extreme drought and implementation of the Sustainable Groundwater Management Act will require growers to reduce groundwater use to bring the region into compliance. Drought-tolerant crops provide a potential solution to help reduce groundwater demand while maintaining land in agricultural production, especially if irrigation practices are efficient. Strategic irrigation scheduling is key to maximizing crop yields and quality.

Jujube is a small fruit native to Asia, It has many health benefits. Considered a “superfood”, jujube is gaining popularity in California, particularly due to its drought tolerance and adaptability to arid climates. Currently, jujube production is largely concentrated on small-scale farms in the SJV, but current trends point to its potential for expansion to regional . This expansion will require accurate estimates of irrigation requirements during the growing season as water remains the first limiting production factor in the SJV.  To date, such information is lacking; therefore, this research aims to determine the water use of Jujube and develop crop coefficient curves that can be used by growers to efficiently schedule their irrigations.

This research aims to characterize the irrigation practices of local Jujube growers and accurately measure the evapotranspiration and develop crop coefficients necessary for optimizing irrigation scheduling for Jujube.

This research will build on prior and ongoing research conducted by the University of California Cooperative Extension Small Farms Extension program to improve water use efficiency and assess irrigation needs of drought tolerant jujube grown on small-scale and diversified farms.

This project will assist California’s Jujube farmers who are currently growing this crop or interested in growing it in the future, by providing information that could improve their irrigation management practices, help them to adapt to regional water regulations and climate change, and contribute to statewide water sustainability efforts.

• Characterize irrigation practices of jujube growers in Fresno County in terms of their irrigation systems, scheduling practices, quantity of applied water, and frequency of irrigation.
• Estimate actual evapotranspiration (ETa) in three jujube orchards in Fresno County.
• Develop crop coefficient (Kc) curves for jujubes grown in Fresno County based on field-based ETa measurements and derive relationship between Kc and canopy cover.

          4): Compare actual Eta obtained from objective 2 with open ET.