Rapeseed, Brassica napus subspecies, napus, is a large winter or spring annual oil crop in the Brassica family and is also known as rape and oilseed rape, and for a specific group of cultivars, ‘canola’. 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. Rapeseed has a deep taproot and a fibrous, near-surface root system.
Rapeseed is primarily grown for its oil. A big challenge of profitable rapeseed production is the limited use and markets 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 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. Rapeseed can also be grazed by livestock during the fall growth period.
People are sometimes confused between the use of the terms “rapeseed” and “canola.” Rapeseed is the traditional name for the group of oilseed crops in the Brassicaceae family. It can be divided into two types — industrial rapeseed or canola. Visually, the seeds of the two types are identical. The distinguishing difference between the two types is their individual chemical or fatty acid profiles. Generally, “industrial rapeseed” refers to any rapeseed with a high content (at least 45 percent) of erucic acid in the oil. 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. This profile will focus on industrial rapeseed.
Forage rape (Brassica napus L.)
Some cultivars of summer annual rape (Brassica napus L.) 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.
Traditionally, industrial rapeseed is produced for birdseed and oil for industrial purposes. Industrial varieties of rapeseed are used for non-edible purposes such as lubricants, hydraulic fluids and plastics. High-erucic-acid rapeseed (HEAR) oil 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.
In the United States, the harvested acreage of rapeseed decreased from 200,000 acres in 2008 to 10,500 acres in 2016. The crop totaled more than 19.3 million pounds in 2016, with a value of $4.8 million. The average yield was 1,840 pounds per acre in 2016.
Field production of rapeseed is the same as that for winter canola. Rapeseed grows well on a wide variety of well-drained soils, prefers a pH between 5.5 and 8.3 and is moderately tolerant of saline soils. 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.
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.
On-farm Biodiesel Production
On-farm biodiesel production is possible from rapeseed or canola. Economists at the University of Tennessee found that production form 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.
Management of rapeseed for industrial for oilseed production is the same as that required for canola and similar to that for winter small grains. Equipment needed 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. Spraying for weed management may be done on farm or by commercial applicators.
Fertilizer needs vary based on yield potential of a production site, including both soil and rainfall potential. Nitrogen requirements range from 100 to 150 lbs/A. Phosphorus (P2O5) and potassium (K2O,) fertility needs vary with soil test levels. P2O5 recommended rates range from 0 to 80 lbs/A. K2O recommended rates range from 0 to 140 lb/A. Sulfer is also important for profitable rapeseed and canola seed production, Recommended fertility rates range from 10 to 30 lbs/A.
The industry 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 Industry experts recommend that rapeseed for the industrial oil market be grown under contract.
Seed shattering at harvest is a potential problem, so rapeseed is commonly swathed when seed moisture is about 35%.
Rapeseed cost of production are the same as those for canola.
Production budgets for canola and rapeseed are available online for North Dakota, Pennsylvania, North Carolina, Maine, and Georgia.
Links checked August 2018.