{"id":2195,"date":"2024-04-02T15:56:37","date_gmt":"2024-04-02T22:56:37","guid":{"rendered":"https:\/\/blogs.cdfa.ca.gov\/FREP\/?p=2195"},"modified":"2024-04-03T11:42:50","modified_gmt":"2024-04-03T18:42:50","slug":"research-update-nitrogen-and-irrigation-managements-for-onions","status":"publish","type":"post","link":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/research-update-nitrogen-and-irrigation-managements-for-onions\/","title":{"rendered":"Research Update: Nitrogen and Irrigation Managements for Onions"},"content":{"rendered":"\n

Note: This is part of a Research Update series that highlights projects funded by the California Department of Food and Agriculture (CDFA) <\/em>Fertilizer Research and Education Program (FREP) annual grant program<\/a>.<\/em><\/p>\n\n\n\n

Project Title: <\/strong>Assessing Drip Irrigation and Nitrogen Management of Fresh Onions Produced in California Low Desert<\/p>\n\n\n\n

Project Leader:<\/strong> Jairo Diaz, Director, University of California – Desert Research and Extension Center<\/p>\n\n\n\n

Project Status:<\/strong> Complete<\/p>\n\n\n\n

Project location:<\/strong> Imperial County<\/p>\n\n\n\n

Overview:<\/strong> This FREP-funded project evaluated the response of onions to drip irrigation regimes and compared onion production under different nitrogen (N) fertilizer application rates. Project results indicated that a switch from furrow to drip irrigation technology and accounting for residual soil nitrate can lead to notable reductions in irrigation water use and N fertilizer application rates.<\/p>\n\n\n\n

Background:<\/strong> <\/p>\n\n\n\n

Imperial County is one of the major onion production regions in CA with over $82 million in onion production in 2022. Agriculture is the largest water user in the Imperial County, where the Colorado River Basin (CRB) is the main source of irrigation water. However, the two largest reservoirs in CRB are at historically low water levels due to persistent drought and overallocation. Another issue facing growers in this region is salinity; to prevent soil salinization and enhance agricultural production, growers apply excess irrigation water to leach salts from the root zone. Thus, it is important to explore best management practices to conserve water and minimize nutrient export. The main goal of this project was to evaluate the effects of irrigation management and N fertilization rates on yield and quality of fresh onion bulb production in arid regions using slightly saline water.<\/p>\n\n\n\n

Approach<\/strong><\/p>\n\n\n\n

The project team performed annual field trials at the University of California Desert Research and Extension Center in Holtville, CA. The experiment was carried out with drip irrigation treatments and four N-fertilization rates. Irrigation treatments were set up as: 40, 70, 100, and 130% of crop evapotranspiration (ETc) and N treatments were pre-plant; pre-plant plus 75 lbs. N per acre; pre-plant plus 150 lbs. N per acre; and pre-plant plus 225 lbs. N per acre. The research team sampled soil at different times (pre-plant, mid-season, postharvest), measured onion yield and quality at harvest, and analyzed soil and tissue samples for N concentration.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

(Left) The onion irrigation and N rate trial at the University of California Desert Research and Extension Center, Holtville, CA. (Right) Accumulation of salt can be seen in the high irrigation treatment plots.<\/em><\/em><\/p>\n\n\n\n

Findings<\/strong><\/p>\n\n\n\n

Onion yields and bulb size distribution responded to irrigation rates and maximum yields were obtained in the 130% ETc treatment. The highly stressed irrigation treatment (40% ETc) had the lowest yield (Table 1). Onion size distribution, total yield, and firmness did not respond to N rates when total N available in the top foot of the profile ranged from 104 to 353 pounds per acre; this shows the importance of pre-plant soil sampling and analysis and adjustment of in-season N application rate accordingly. Onion size distribution, total yield, firmness, and brix responded to N rates in a field with only 54 pounds per acre of total N available in the top foot (Table 2). In this study, leaf temperature differential measures detected early water stress responses; however, water deficit regimes did not significantly affect photosynthesis activity.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n

Impact<\/strong><\/p>\n\n\n\n

This project highlights thathigh onion yields and large high-value sizes can be produced with 24 to 26 in of water per acre using drip irrigation, which is less than half the amount of water (typically about 60 in) required to grow high yielding onions with furrow irrigation. If 80% of fresh market onion fields switched from furrow to drip irrigation there would be a potential savings of up to 8,000-acre foot of water per season. Additionally, results indicated that growers can reduce N fertilizer applications by adopting drip irrigation, split fertigation techniques, and by accounting for N available in the top foot of soil. <\/p>\n\n\n\n

This project also strengthened collaboration between University of California Cooperative Extension and local and regional colleges by offering opportunities for student participation. College internship opportunities provided new knowledge and career pathways to borderlands, first generation, and underrepresented students in agriculture. College students developed skills in irrigation and nutrient management research methods and students gained better understanding of onion production, handled research equipment, and got exposed to research protocols.<\/p>\n\n\n\n

After completion of the first field trial, the research team donated about 750 pounds of onions to Imperial Valley Food Bank in May 2020. This donation helped the local communities in need during the midst of COVID 19 restrictions and challenges.<\/p>\n\n\n\n

To learn more about this project and other current and completed FREP projects please visit: <\/em>https:\/\/www.cdfa.ca.gov\/is\/ffldrs\/frep\/Research.html<\/em><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Note: This is part of a Research Update series that highlights projects funded by the California Department of Food and Agriculture (CDFA) Fertilizer Research and Education Program (FREP) annual grant program. Project Title: Assessing Drip Irrigation and Nitrogen Management of Fresh Onions Produced in California Low Desert Project Leader: Jairo Diaz, Director, University of California – Desert Research and Extension Center Project Status: Complete Project …<\/p>\n

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These grants will fund six projects that will improve the efficiency and reduce the environmental impact of fertilizer\u2026","rel":"","context":"In "FREP Grant Program"","block_context":{"text":"FREP Grant Program","link":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/category\/frep-grant-program\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":334,"url":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/grants-to-begin-funding-january-2018\/","url_meta":{"origin":2195,"position":1},"title":"Grants to Begin Funding January 2018","author":"Brooke Elliot","date":"January 2, 2018","format":false,"excerpt":"The Fertilizer Research and Education Program (FREP) of the California Department of Food and Agriculture (CDFA) is pleased to announce the award of almost $800,000 in grant funds to agricultural organizations and universities this year. These grants will fund four projects that will improve the efficiency and reduce the environmental\u2026","rel":"","context":"In "FREP Grant Program"","block_context":{"text":"FREP Grant Program","link":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/category\/frep-grant-program\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":260,"url":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/fertigation-short-course\/","url_meta":{"origin":2195,"position":2},"title":"Fertigation Short Course","author":"Brooke Elliot","date":"June 15, 2017","format":false,"excerpt":"What: A one-day short course on fertigation is being offered by the Cal Poly Irrigation Training and Research Center (ITRC) with funding from the Fertilizer Research and Education Program (FREP) of the California Department of Food and Agriculture. The course covers new techniques in the control and application of fertilizers\u2026","rel":"","context":"In "Nutrient Management Events"","block_context":{"text":"Nutrient Management Events","link":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/category\/nutrient-management-events\/"},"img":{"alt_text":"IRTC","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/FREP\/wp-content\/uploads\/2017\/06\/Irrigation-225x300.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":212,"url":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/events-for-march-2017\/","url_meta":{"origin":2195,"position":3},"title":"Events for March 2017","author":"Brooke Elliot","date":"February 27, 2017","format":false,"excerpt":"Efficient Irrigation and Nitrogen Use Workshop What: Hosted by the California Almond Sustainability Program, this workshop gives almond growers an opportunity to learn about tools and techniques to increase irrigation efficiency through Almond Board of California\u2019s (ABC\u2019s) Irrigation Continuum, and to improve the accuracy of nitrogen applications through the use\u2026","rel":"","context":"In "Nutrient Management Events"","block_context":{"text":"Nutrient Management Events","link":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/category\/nutrient-management-events\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":195,"url":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/now-accepting-concept-proposals-for-2017-fertilizer-research-and-education-grants\/","url_meta":{"origin":2195,"position":4},"title":"Now Accepting Concept Proposals for 2017 Fertilizer Research and Education Grants","author":"Brooke Elliot","date":"December 16, 2016","format":false,"excerpt":"The California Department of Food and Agriculture\u2019s Fertilizer Research and Education Program (FREP) is currently accepting concept proposals for the 2017 grant cycle. FREP\u2019s competitive grant program funds research that advances the agronomic and environmental performance of fertilizing materials. 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TASC serves as an expert scientific panel on matters concerning efficient use of fertilizing materials and irrigation water. 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