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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Water Management Research » Research » Research Project #435221

Research Project: Develop Improved Irrigation Strategies for Alfalfa Production in California

Location: Water Management Research

Project Number: 2034-13210-001-01-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2018
End Date: Aug 31, 2021

Objective:
Develop and improve irrigation strategies to increase water use efficiency in alfalfa production in California across different soil and climatic conditions.

Approach:
Field trials will be conducted at multiple locations in California. The first trial will test subsurface drip irrigation (SDI) as compared to flood irrigation while meeting full crop evapotranspiration (ET) needs. The second trial will test deficit irrigation at 50% and 75% water application rates as compared to the 100% rate using SDI. The third trial will test new wireless automated flood irrigation control mechanisms as compared to the conventional flood irrigation. These field trials will be carried out primarily in south central San Joaquin Valley in the Fresno area and southern California with experimental plots located at the University of California Kearney Agricultural Research and Extension Center at Parlier, University of California Westside Research and Extension Center at Five Points, UC Desert Research and Extension Center, Holtville, and USDA Agricultural Research Service San Joaquin Valley Agricultural Sciences Center at Parlier. These research sites are located in Fresno, Imperial and Tulare counties; both Fresno and Tulare counties are the major dairy production counties with high demand for fresh alfalfa as dairy forage. Imperial County is the major alfalfa hay producing county in California. Additional field sites will be considered in the Sacramento Valley near Davis where the soil and climatic conditions are different from the San Joaquin Valley. Soil physical and chemical properties will be characterized for each site. Measured parameters will include bulk density, soil water retention function by determining the volumetric water content at 0.1, 0.3, 0.5, 1, 5, 15 and bars, particle size distribution, pH, CEC, and nitrogen, phosphorus, potassium contents. Because alfalfa is a deep-rooted crop, measurements will be made at 6, 12, 18, 24, 30, 36, 48, and 60 inch depths. Soil water content will be determined using moisture sensors buried at the selected depths and recorded at hourly intervals for the entire duration of the experiments. Because multiple irrigation treatments will be used, these soil and water content measurements will also need to be made individually for each treatment. These measurements will be used in soil physics modeling of water movement under the different irrigation methods to determine the optimal moisture conditions for alfalfa growth. The reference or 100% irrigation treatment will be based on the recently developed Alfalfa Crop Management guidelines from the UC Division of Agriculture and Natural Resources (UC-ANR). Response variables will include alfalfa yield and quality. All data will be statistically analyzed. Upon completion, this project will improve irrigation management for alfalfa production in California. The project findings will be presented at annual alfalfa conferences and professional meetings as well as distributed through extension activities.