Kura Clover for Kentucky
Norman L. Taylor, Don Henry, and John Vandevender
Kura clover (Trifolium ambiguum) is a recently
introduced true clover from the Caucasian
Region of the former USSR. It is an
extremely long-lived perennial species, probably best adapted
to pasture conditions. It closely resembles white clover
but spreads by rhizomes rather than by stolons. Heads
are white to pink and a little larger than white clover,
but seeds are about as large as those of red clover.
Kura clover blooms only once per season and only
after being induced by low temperatures encountered
in winter. Interest in the crop was stimulated by
persistent stands that gradually thicken and by its high
quality forage. It also is excellent for control of soil erosion.
The most serious disadvantages of kura clover
are low seedling vigor making stand establishment
difficult and low forage yields after the first growth has
been removed. Since the crop is relatively new, not as
much information is available as on the more widely
Sowing the Crop
Because of lack of seedling vigor, kura clover
does not establish well when sown with a nurse crop.
Establishment is best after preplanting incorporation
of herbicide, such as Banlan or Treflan, to control
weeds (see AGR 148, Weed Control in Alfalfa and
Other Forage Legume Crops). Seedings are more successful
in the spring, but later sowings have been successful
when irrigated. Fertility levels should be similar to those
for white clover. Sowing on well-drained soils, limed to
a pH of 6.1 to 6.7 is recommended. A drill or
culti-packer seeder has been satisfactory.
Seeds must be inoculated with the
appropriate Rhizobium inoculum that is specific only for this
crop. Other inoculum will not nodulate kura clover.
Inoculum is available from commercial inoculant
companies (Trifolium Spec. 3). Seed may be sown at 10-12
lb/acre without grasses. Rates of sowing probably may
be reduced by about one-fourth when sown with
bluegrass, orchard grass, tall fescue, or timothy.
The only variety released in the United States
is RHIZO, developed by the Natural Resource
Conservation Service (NRCS) (formerly the Soil
Conservation Service) in cooperation with the University of
Kentucky. Norfarm Seeds, Inc. and Peterson Seed Company,
Inc. have been granted exclusive rights for production
of RHIZO seed. Breeders seed is currently maintained
at the NRCS Plant Materials Center, Quicksand, KY,
and will be maintained by the Kentucky Foundation
Seed Project, Department of Agronomy, in
Lexington, Kentucky. Small quantities of seed for testing
(100 grams or less) may be obtained from the NRCS
Plant Materials Specialist at P.O. Box 400, Beaver, WV
Kura clover stands slowly thicken with age, and
not much production may be expected in the year of sowing. Only light grazing, if any, should be
permitted in the first year. In the second year the crop
should begin blooming somewhat earlier than red clover.
Cattle grazing kura clover are subject to bloat, and for
that reason mixtures with grasses are recommended, as
well as the usual bloat precautions. The first crop may
also be harvested for hay or silage but will be
lower-yielding than alfalfa. Kura clover is of high quality similar to
white clover, in part because of a high ratio of leaves to
stems. The aftermath growth may be harvested by
grazing because of low yields. Kura clover should not
be intensively grazed after September 15 to allow
replenishment of root reserves and maintenance of stands.
Since only one crop of blooms is produced
yearly, the first growth produces the seed crop. Data
are incomplete, but yields of 100 to 200 pounds of
seed may be expected. Paraquat sprayed at a rate of 1 to 2 pt/acre might be useful in reducing weed competition at
time of combining seed. The procedures used for harvesting seed of other clovers should be successful for kura clover.
Kura clover is pollinated by both honeybees and bumblebees and is an excellent crop for honey production.
A trial comparing perennial forage species was sown in 1983 and irrigated to aid establishment (Table 1). Seed
of all species were inoculated with their appropriate inoculum. All species were harvested three times for hay in
1984 and either two or three times in 1985. The species harvested twice did not produce enough growth for a third
harvest. Red clover, alfalfa, and crown vetch produced initial high yields; whereas, kura clover required a year or more to
reach its maximum production. Stands of red clover, birdsfoot trefoil, zigzag clover, milk vetch, and crown vetch declined
by 1986; whereas, alfalfa maintained stand and RHIZO kura clover thickened. Kura clover was still in thick stand when
the experiment was discontinued in 1987. These data indicate that kura clover, similar to white clover, probably should
be used for long-term pastures.
|Table 1. Forage production and stands, 1984-86, of perennial legume species sown April 19, 1983, at
||Dry Matter Yield (Tons/Acre)
|(1) 3 harvests in 1984; (2) 2 harvests in 1985; (3) 3 harvests in 1985|
Insects and Diseases
Kura clover has not been deleteriously affected by insects and diseases. However, experience shows that
over time, newly introduced species develop their own set of insects and diseases that might or might not become serious.
- Kura clover may be sown and managed similarly to white clover, except that only one flush of blooms occurs per year.
- Management practices should be similar to those for white clover.
- Fertility levels should be medium to high. Maintain pH levels at 6.1 to 6.7.
- Stands, if not overgrazed, should last many years.
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