Winter canola water use response under dormant and growth stage based irrigation strategies

Authors: SINGH, PARAMVEER - University Of California; ANGADI, SANGAMESH - New Mexico State University; Begna, Sultan; STAMM, MICHAEL - Kansas State University; SCHUTTE, BRIAN - New Mexico State University; VANLEEUWEN, DAWN - New Mexico State University

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2025
Publication Date: 9/18/2025
Citation: Singh, P., Angadi, S., Begna, S.H., Stamm, M., Schutte, B., Vanleeuwen, D. 2025. Winter canola water use response under dormant and growth stage based irrigation strategies. Agricultural Water Management. 319 (2025) 109807. Available: https://doi.org/10.1016/j.agwat.2025.109807.
DOI: https://doi.org/10.1016/j.agwat.2025.109807

Interpretive Summary: The sustainability of irrigated crop production in the semi-arid Southern High Plains of USA is challenged by the declining Ogallala Aquifer. This condition may not allow growers to grow high water intensive crops all the time. Winter canola is a promising alternative crop with less water requirement. A two-year study was conducted in Clovis, NM to examine winter canola soil water extraction (SWE), and water use efficiency (WUE) under different irrigation strategies [dormant period irrigation (DPI) and growth stage-based irrigation]. Dormant period irrigation increased Canola's SWE by 5 to 68 mm depending on crop growth stage and seasons. However, DPI was not efficiently used in yield formation. Canola fully irrigated and irrigation during its vegetative stages resulted in higher WUEs. Growers facing water limitations can also save water by irrigating canola during its vegetative growth stage without loss in yield. This strategy allows irrigating canola without competing for water with other crops when irrigation water is in high demand.

Technical Abstract: The sustainability of irrigated crop production in the semi-arid Southern High Plains of the USA faces significant challenges due to the declining Ogallala Aquifer. In this context, winter canola (Brassica napus L.), which requires less water, emerges as a promising alternative. However, information about its water uses and efficiency is limited. Therefore, a study was conducted in Clovis, NM, examining the soil water extraction (SWE), water use (ET), and water use efficiency (WUE) of two winter canola cultivars, Hekip and Riley, under different irrigation settings. After ensuring establishment in the fall, a total of 152 and 125 mm of irrigation was applied to one half of the experiment during the winters of 2017-18 and 2018-19, while the other received none. In the subsequent spring season, four growth stage-based irrigation regimes; FI, irrigation throughout the spring season, VS: no irrigation before first blossom stage, RS: no irrigation after first blossom stage, and RD: no irrigation, were applied to both DI and NDI halves. The results showed that DI increased SWE by 30 and 19 during vegetative growth, 19 and 10 during flowering, and 5 and 11 mm and 68 mm during seed filling and maturation phase in 2017-18 and 20189-19, respectively. However, dormant irrigation was not efficiently used in yield formation. The RD treatment had highest SWE of 42 and 19 mm from the planting to harvest but suffered significant forage (FY) and seed yield (SY) loss. FI and VS treatment were consistently performed better and higher WUEs in both seasons than RS and RD treatment. There was marginal effect of cultivar-type on SWE, and WUEs. In summary, winter canola did not use dormant period irrigation efficiently, and that water can be rescheduled to later growing periods. Growers with limited irrigation can save adopt VS regime without suffering significant yield loss.