Growth of spring canola (Brassica napus) under deficit irrigation in Western Nebraska

•Growth of spring-planted canola in western Nebraska was studied under deficit irrigation.•Canopy growth peaked by 9 weeks after planting and required less 25 cm of total moisture.•Seed yield increased irrigation to a maximum of 2900 kg/ha with 43 cm of applied water.•Maximum seed oil content was 35% with 43 cm applied water.•The two major fatty acids, oleic and linoleic acids, were not affected by irrigation level.

Drought is a periodic occurrence in the High Plains of the U.S.A.; thereby low-water using crops are desired. Canola, a biofuel and food oil, has been studied in the region under rain-fed conditions for several years. The study's objective was to measure plant growth, seed yield, and oil characteristic of canola at four levels of applied water in western Nebraska. The cultivar Hyola 357 Magnum was exposed to rain-fed only (RF), and irrigated with 10 (LI), 20 (MI), and 30 (HI) cm water. Adding irrigation increased plant growth, i.e., canopy height, stem length, and canopy weight. Highest canopy height (>100 cm for MI and HI) was reached by 10 weeks after planting (WAP) with a total of 23 cm of applied water or 13 cm of irrigation. By 8 WAP, canopy fresh weight was increased by 37 to 58% by MI and HI irrigations. Pod fresh and dry weights at harvest (13 WAP) were increased >50% and >20%, respectively, by all irrigations. Seed yield were increased by each incremental increase in irrigation from 1220 kg/ha for RF to 2905 for HI, a 2.4-fold increase. Seed oil content was increased by MI and HI irrigations (4–8%). The fatty acid profile was not substantially altered by irrigation. There was a slight decrease of palmitic acid and increase in linolenic acid with HI. Canola showed that >20 cm of applied water is needed for good vine and pod growth but >40 cm was needed to achieve the highest yield. Canola could be grown successfully in western Nebraska, supplying oil for fuel and cooking.