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Revised February 2022
Rapeseed, (Brassica napus var. napus), is a winter or spring annual oil crop in the Brassica family. It is also known as rape and oilseed rape. Rapeseed is related to mustard, cabbage, broccoli, cauliflower and turnip. Rapeseed plants grow from three to five feet tall and have yellow flowers with four petals. It has a deep taproot and a fibrous, near-surface root system.
There can be confusion between what is rapeseed and what is canola, since canola is the same species as rapeseed. Rapeseed is the traditional name for the group of oilseed crops in the Brassicaceae family but that group is now divided into two — industrial rapeseed and canola. Visually, the seeds of the two types are identical. The distinguishing difference between the two types is their fatty acid profiles and the presence of gluscosinolates. Currently the term rapeseed, or industrial rapessed refers to any rapeseed with a high content of erucic acid in the oil (typically at least 45 percent). The name ‘Canola’ was registered in 1979 in Canada and refers to the edible oil crop that is characterized by low erucic acid (less than 2 percent) and low levels of glucosinolates. Since the production techniques for the two types are similar, there are frequent references to canola in this profile. The focus of this profile, however, is on industrial rapeseed. Canola is featured elsewhere in this website.
Rapeseed is primarily grown for its oil. A big challenge to profitable rapeseed production is the limited use and market for the meal remaining after oil processing. In some areas, rapeseed, which contains more than 40 percent oil, becomes more profitable than soybeans, which contain 18 percent oil. Rapeseed is also beneficial as a cover crop and for annual forage. It provides good soil cover over winter to prevent soil erosion, produces large amounts of biomass, suppresses weeds, and can improve soil tilth with its root system.
Some cultivars of summer annual rape are used for grazing. They are especially useful for finishing lambs, flushing ewes, for dairy cows and pastured sows Forage rape is ready to graze 80 to 90 days after planting. Winter rapeseed types can also be grazed by livestock during the fall growth period.
In the United States, the harvested acreage of rapeseed decreased from 200,000 acres in 2008 to 10,100 acres in 2020. Total rapeseed production in 2020 was more than 19.9million pounds and had a vale of $4.4 million. In 2021 there was a slight increase in acreage to 15,500 acres. Rapeseed has been grown in the Pacific Northwest for more than 40 years. It was also produced in the Southern U.S. during the late 1980s and early 1990s. Most recently, the greatest production of rapeseed has been in the pacific northwest and in south east regions of the USA. The average yield of rapeseed in 2020 was 1,971 pounds per acre. Rapeseed grows well on a wide variety of well-drained soils, prefers soils with a pH between 5.5 and 8.3 and is moderately tolerant of saline soils.
To date, seed meal remaining after oil production has limited uses. The glucosinolates in the meal limit its use in livestock feed rations due to the antinutritional and negative physiological effects.
Management of rapeseed for industrial oilseed production is similar to that of for canola. There are both spring and winter types rapeseed and planting dates for spring and winter types should correspond to planting dates used for spring or winter wheat for a given environment, respectively. Equipment needed to produce rapeseed include a tractor, drill or broadcast seeder, sprayer, combine harvester and wagons for transportation, similar to the needs for other small-seeded grain or oilseed crops.
Fertilizer needs vary based on yield potential of a production site, including both soil and rainfall potential. Nitrogen requirements range from 100 to 150 lb per acre. Phosphorus (P2O5) and potassium (K2O,) fertility needs vary with soil test levels. P2O5 recommended rates range from 0 to 80 lb per acre. K2O recommended rates range from 0 to 140 lb per acre. Sulfur is also important for profitable rapeseed and canola seed production, Recommended fertility rates range from 10 to 30 lb per acre.
Seed shattering at harvest is a potential problem, so rapeseed is commonly swathed prior to combining when seed moisture is about 35%.
Rapeseed is primarily produced for birdseed and oil for industrial purposes such as lubricants, hydraulic fluids and plastics. Oil from rapeseed is often referred to as high-erucic-acid rapeseed (HEAR) oil and is especially useful where high heat stability is required. One of the primary markets for HEAR oils is erucamide. Erucamide has been used for decades by plastic film manufacturers for use in bread wrappers and garbage bags and is preferred over cheaper alternatives for its production properties. Oil from HEAR can also be used in biodiesel production. The market for industrial rapeseed is fairly mature. However, with increased emphasis on renewable resources and biodegradability, there is a possibility of an increased interest in raw materials such as high erucic oil rapeseed. Given the limited market at the moment, howevrer, it is recommended that rapeseed for the industrial oil market be grown under contract.
On-farm biodiesel production is possible from rapeseed or canola. Economists at the University of Tennessee found that production from canola was financially feasible, whereas production from rapeseed was not due to a lack of market for the byproduct seed meal. Oregon State University researchers found financial losses to produce biodiesel from canola/ rapeseed.
Meal from HEAR varieties usually has high levels of glucosinolates, making it unsuitable as an animal feed.
Rapeseed cost of production are basically the same as for those of canola though there are no transgenic traits in rapeseed varieties, so seed cost of rapeseed may be less than those of transgenic canola. Weed control cost may also very as there are no herbicide resistant rapeseed varieties.
Sources and Other Background Material
- Brassica Breeding and Research Group, University of Idaho.
- Rapeseed and Canola for Biodiesel Production, 2019, Farm Energy.
- Crop Production Annual Summary, 2021, National Ag Statistics Service (NASS), USDA.
- Crop Values Annual Summary, 2021, National Ag Statistics Service (NASS), USDA.
- Rapeseed and Products: World Supply and Distribution, Foreign Ag Service, USDA.
- Energy efficiency for rapeseed biodiesel production in different farming systems, 2013, Energy Efficiency.
- Canola or Rapeseed Production in Pennsylvania, 2015, PennState Extension.
- Canola in the Pacific Northwest: An Opportunity Crop, PNW Canola.
- Canola Production Field Guide (North Dakota), 2011, NDSU Extension.