D. J. Undersander1, A. R. Kaminski1, E. A. Oelke2,
J. D. Doll1, E. E. Schulte1, and E. S. Oplinger1
1Departments of Agronomy and Soil Science, College of Agricultural and
Life Sciences and Cooperative Extension Service, University of Wisconsin-Madison,
2Department of Agronomy and Plant Genetics, University of Minnesota, St.
Paul, MN 55108.
The rutabaga (Brassica napobrassica), or swede, is believed to have originated
from a hybrid between the turnip (Brassica rapa) and wild cabbage (Brassica
oleracea), probably in Bohemia and as recently as the 17th century. Rutabagas
are grown for human and animal consumption. Researchers in the United States determined
in the early 1900s that the fleshy roots of rutabagas are valuable energy sources
for young livestock. However, livestock farmers at that time were turning away from
the brassica crops (which also include rape, kale, and turnips) because much hand
labor was required for their production and utilization. One study showed that the
labor requirement for these crops was three times that needed for corn silage production.
In the late 1970s, however, researchers began to recognize the potential of the
root brassicas as forage crops, thereby eliminating the need for manual labor in
harvesting and storage. In general, the forage brassicas are high-quality, high
yielding forage crops that are well suited to seeding into existing pastures with
little or no tillage.
Rutabaga is a cool-weather crop and is grown primarily in the northern parts of
the United States and Europe, in Great Britain and in Canada.
Brassicas are high-quality forage if harvested before heading. Livestock readily
graze on the stems, leaves and roots of rutabaga plants. Above-ground parts normally
have 20 to 25% crude protein and 65 to 80% total digestible nutrients (TDN). The
roots have 10 to 14% crude protein and 80 to 85% digestibility.
Rutabaga and other brassicas can provide grazing during the late summer and fall
after other forage crops have played out. Rutabaga maintains its nutritional quality
and palatability, if not heading, well into freezing temperatures and may be grazed
in the Upper Midwest into November.
III. Growth Habits:
Rutabaga is a biennial, which can overwinter as a storage root. The `root' consists
of the hypocotyl -- the plant part that lies between the true root and the first
seedling leaves (cotyledons) -- and the base of the leafy stem. A rutabaga root
can be distinguished from a turnip by the presence of a swollen "neck" bearing a
number of ridges, the leaf-base scars. The storage root may be purple, white or
yellow, with yellowish flesh. Rutabaga leaves are bluish, thick like cabbage, and
smooth. They emerge from the crown in a broad, low-spreading growth habit that inhibits
growth of weeds. Rutabaga flowers are small and have light-yellow petals. They differ
from turnip flowers in that they are not raised above the unopened buds on the raceme.
IV. Environment Requirements:
Rutabaga plants are both cold hardy and drought tolerant. They can be grazed 150
to 180 days after planting and can provide forage late in the fall. Their most vigorous
root growth takes place during periods of low temperature. The leaves maintain their
feeding quality even after repeated exposure to frost.
Like other brassicas, rutabaga grows best in a moderately deep, fertile and slightly
acid soil. Rutabaga will not do well in soils that are heavy, wet or poorly drained.
V. Cultural Practices:
A. Seedbed Preparation:
Rutabaga, like other brassicas, can be seeded into a sod with minimum tillage. The
sod should be suppressed or killed, as the young rutabaga seedlings cannot compete
with grasses. Once established, the rutabaga plants will smother out most other
weeds. To kill sod, apply 2 qt/acre of Roundup at least three days prior to seeding.
A reduced rate of herbicide can be used in 3 to 10 gal/acre of water to suppress
sod or to prepare a field of wheat stubble for seeding with rutabaga.
Rutabaga can also be planted with a forage crop seeder on a conventional seedbed.
Plow the seedbed at least six weeks before sowing. The seedbed should be fine, firm
and free of weeds and clods.
The advantages of direct drilling brassicas into sod include fewer crop losses due
to insect pests and less soil erosion on sloping sites where pastures are often
located. A field of brassicas established in sod gives animals a firm footing in
all kinds of weather. It also allows the original sod species to grow again the
following spring if it has only been suppressed.
B. Seeding Date:
Rutabaga seeds do not germinate well in cold soil. Plant rutabaga when the soil
temperature is at least 50oF. This means at corn planting time or later.
Later plantings may not have sufficient time to produce good forage growth.
C. Method and Rate of Seeding:
Rutabaga seed can be planted in 6 to 8 in. rows at a rate of 1.5 lb/acre with a
minimum-till drill. Alternatively, the crop can be seeded with a forage crop seeder
on a conventional seedbed or broadcast followed by cultipacking. The seed should
not be covered with more than l/2 in. of soil.
D. Fertility and Lime Requirements:
Test the soil and lime to a pH of 6.0. Fertilizers should be applied at the time
of seeding to give the crop a competitive edge on weeds. Apply 100 lb/acre nitrogen
to soils containing 2 to 5% organic matter, 120 lb/acre if less than 2% organic
matter and 60 to 80 lb/acre if soils contain more than 5% organic matter. Requirements
for phosphorus and potassium are similar to those of a small grain. In Wisconsin
and Minnesota, when soil tests are in the medium range, about 20 to 30 lb/acre of
P2O5 and 120 lb/acre of K2O should be applied.
Fertilizer applications should be banded at least 2 in. to the side or below the
seed or broadcast. Boron and sulfur may also be needed. If the soil tests "low"
in boron, apply l lb boron/acre on sandy soils and twice this on other soils. Apply
10 to 15 lb sulfur/acre if a soil sulfur test indicates a need for this element.
E. Variety Selection:
Some promising rutabaga varieties for use in the Upper Midwest are Calder and Sensation.
F. Weed Control:
Weeds are generally not a problem once the rutabaga crop is established. However,
sod and annual weeds should be controlled chemically before planting. Sod can be
suppressed or killed with Roundup, as described under Seedbed Preparation. If annual
weeds are present at planting time, eliminate them with a burn-down herbicide such
G. Diseases and Their Control:
Rutabaga crops may suffer from clubroot, root knot, leaf spot, white rust, scab,
anthracnose, mosaic and rhizoctonia rot. In some cases, diseases can lead to crop
failure. To prevent problems with diseases, brassicas should not be grown on the
same site more than two years in a row.
H. Insects and Other Predators and Their Control:
Insects are generally not a problem on rutabaga crops seeded in sod. However, an
insecticide should be applied at the time of planting under conventional tillage.
Rutabaga plants are ready for grazing or green-chop when the forage is about 12
in. tall (150 to 180 days after planting). It is best not to wait too long, because
fungal diseases may begin to cut yields after the plants reach maturity. The pasture
should be grazed for a short period of time and the livestock removed to allow the
plants to regrow. If grazed to a 5 in. stubble, one to four grazing periods may
occur, depending on planting date and growing conditions.
The forage quality of rutabaga is so high that it should be considered similar to
concentrate feeds, and precautions should be taken to prevent animal health problems.
Livestock should not be hungry when put on pasture the first time so that they do
not gorge themselves. If the livestock are moving from a feed of low nutritional
quality, feed a high-quality diet for two to three weeks prior to grazing rutabaga,
or feed rutabaga for 30 min/day for one week prior to heavier grazing. This will
allow for the development of a rumen microbial population that is adequate to digest
the high levels of protein in forage rutabagas. A lower quality hay should be made
available (2 to 3 lb of dry roughage/head/day for sheep and 10 to 15 lb for cattle)
to provide fiber in the animals' diet. Livestock should not feed on rutabaga during
the breeding season or after the plants have begun to flower.
VI. Yield Potential and Performance Results:
Rutabaga produces 6 tons or more of dry matter/acre.
VII. Economics of Production and Markets:
Rutabaga is a highly nutritious forage crop that can provide grazing in the late
fall after other forage crops are finished for the year.
VIII. Information Sources:
* A New Look at an Old Forage Crop. 1979. Pennsylvania Grassland News, Vol. XIX,
* Brassica Notes. 1989. D. Undersander. University of Wisconsin-Extension. FC 15.4.1
* Brassica Notes. G. A. Jung. U.S. Regional Pasture Research Laboratory, USDA-SEA-AR.
University Park, Pennsylvania.
* Production of Turnips and Rutabagas. 1927. W. R. Beattie. USDA Leaflet 142.
* The Oxford Book of Food Plants. 1969. G. B. Masefield, M. Wallis, S. G. Harrison,
B. E. Nicholson. Oxford University Press, Ely House, London.
* Those Brassy Brassicas. 1989. K. Kessler. The Furrow, Spring 1989, Vol. 94, Issue
4. pp. 20 to 21.
* Utilizing Brassicas for Fall Forage in Michigan. 1989. R. Leep. Michigan State
University, Cooperative Extension Service.
References to pesticide products in this publication are for your convenience and
are not an endorsement of one product over other similar products. You are responsible
for using pesticides according to the manufacturer's current label directions. Follow
directions exactly to protect people and the environment from pesticide exposure.
Failure to do so violates the law.