Kura Clover: A New Pasture Legume for Ontario?
Kura clover (Trifolium ambiguum M. Bieb.) is a forage legume that appears to be well-adapted for use in pastures. Kura clover is similar in growth habit to white clover, except that kura clover spreads underground by means of rhizomes while white clover spreads on the surface by means of stolons. Kura clover can cause bloat similar to other clovers. Kura clover has a reputation of being extremely winterhardy and quite competitive under intensive defoliation. In 1993, we began our initial evaluation of kura clover in small plot trials. Our findings to date are reported below. Our work on kura clover is conducted in cooperation with Speare Seeds of Harriston, ON.
We established kura clover evaluation tests in 1993, 1994, 1995 and 1997. The 1995 seeding was abandoned due to poor nodulation. The species of Rhizobium bacteria required for kura clover does not occur naturally in Ontario soils. Proper inoculation procedures are therefore very important in achieving successful stands. The 1993 and 1994 seedings were generally slow to establish, but the 1997 seeding was quite successful in the seeding year. As with other forage legumes, proper seedbed preparation, seeding depth, and soil firming are critical in establishing kura clover. It seems unlikely that this species will frost seed successfully, although it has not been tried to date.
Based on the 1993 seeding, kura clover mixtures produced yields equal to or greater than other common pasture mixtures (Table 1). In the 1994 seedings, kura clover mixtures have produced yields similar to orchard-white clover mixtures but less than trefoil-brome mixtures. Kura clover is a much smaller component of the 1994 plots than in the 1993 plots (see below). In 1997, three cuts were taken on all plots, while only 2 cuts per year were taken prior to 1997.
The legume content of the kura clover plots in the 1993 seeding was generally high and increased over time, while the trefoil declined (Table 2). Much of the grass present in the initial stand was killed out or damaged over the winter of 1993/1994. Kura survived quite well and has established almost complete ground cover in plots where the grass was killed.
In the 1994 seeding, kura clover formed only a small portion of the mixtures initially as the conditions were ideal for grass establishment that year (Table 3). Only trefoil formed a significant portion of the mixture during 1994. By cut 1 of 1996, kura had become more abundant in the brome mixtures but not in the orchard mixtures. By cut 2 of 1997, kura had increased in the orchard mixtures as well. It is likely that under more intensive defoliation the kura content would have increased even more.
Pure samples of kura clover, white clover, and trefoil were sampled following the 1994 seeding. There were only minor differences in forage quality of the pure species (Table 4).
Kura clover mixtures had forage quality that was equal to or superior to other mixtures (Table 5). The quality reported below for cut 1 in 1994 is heavily influenced by the grass content of the mixtures. Since kura clover mixtures were mostly grass in that test, the quality was relatively poor.
Kura clover appears to have potential as a pasture legume in Ontario. It survived the very severe winter of 1993/1994 when other pasture species were damaged. Kura clover seems slow to establish, but good stands can be achieved with proper seedbed preparation and seeding methods. Proper inoculation of kura clover seed before planting is critical to achieving well-nodulated plants. Kura clover generally thickens with time, although a good catch of grass seems to compete quite well in younger stands (<4 years old). Kura will completely take over stands where the companion grass is winter damaged. Forage yield and quality of kura clover mixtures is generally equal to or greater than other pasture mixtures, although yields will vary with mixture composition.
Currently studies are underway to determine the best grass mixtures and seeding rates for kura clover and tests have been established at sites where specific winter hazards are common (ie: flooding and heaving).
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