Establishing Kura Clover Stands
University of Wisconsin-Madison
Over the last 12 years we have demonstrated kura clover to be a persistent, winter-hardy, grazing tolerant and high quality forage legume. It mixes well with all grasses that are currently used for forage in Wisconsin. The only apparent limitation is that establishment of kura clover is more challenging than other forage legumes. The reason for this is that the pattern of development of kura clover seedlings is different from other legumes. Kura clover seedlings germinate, emerge and develop the first three true leaves at about the same rate as other legumes, but then leaf development slows and energy from photosynthesis is used for root and rhizome development. Also, kura clover produces few or no upright stems during the first year and its short stature makes it extremely susceptible to shading from weeds or existing grass in the field.
There are no “tricks” to establishing kura clover. The same steps recommended for establishment of other forage legumes apply, but kura clover is less forgiving than other legumes if these steps are not carefully followed. The basic goals are to insure good seed-soil contact, inoculation by appropriate Rhizobia and control of competition from weeds or other forage plants after emergence. Although stand density and forage production in the seeding year will by low, because kura clover produces rhizomes and individual plants can spread from six to 12 inches per year after successful establishment, initial thin stands have the potential to improve with time. Time and resources spent to maximize chances of successful establishment should be considered to be an investment that will provide returns for years to come.
Like other legumes, kura clover in association with a specific bacterium (Rhizobia) can fix atmospheric nitrogen into a form useful for plant growth. Biological nitrogen fixation is essential for successful establishment and long-term productivity of kura clover. Since strains of Rhizobia that work with kura clover are not naturally found in Wisconsin soils, they must be applied to the seed before sowing. Evidence exists that strains of Rhizobia specific for kura clover are not as robust as other Rhizobia and do not survive long after application to the seed. Therefore it is recommended to apply Rhizobia to the seed on the day of sowing. Also, the practice of feeding clover seed to livestock and allowing them to deposit it in a pasture with manure will not work because it is unlikely that many Rhizobia will survive. Failure to put live Rhizobia in contact with young kura clover seedlings will result in certain failure of the stand.
Field and Seedbed Preparation
The year before sowing, soil tests should be performed and pH and fertility should be adjusted to levels recommended by UWEX for red clover. Like red clover, kura clover tolerates lower pH and fertility than alfalfa. Perennial weeds should be controlled the year before sowing. In the spring, prepare a seedbed with appropriate tillage methods to provide a firm seedbed free of large clods and weeds.
Sowing Rate and Depth
Seed size of kura is about the same as alfalfa but, because the plant spreads by rhizomes, a lower sowing rate can be used. We have obtained excellent stands of kura clover with 8 pounds of seed per acre and researchers in Minnesota have been successful with as low as 5 pounds per acre. If seedbed conditions are not ideal the higher rate would likely result in more acceptable stands. Shallow sowing of kura clover is important and the ideal depth is 1/4 to 1/2 inch. Cultipacker seeders or drills with presswheels can be adjusted for proper sowing depth and packing to ensure good seed-soil contact.
Mixtures and Companion Crops
Whether used for pasture, hay or silage, there are advantages to establishing kura clover in mixture with grass. Kura clover has very high protein and very low fiber contents so bloat is a serious concern when grown in pure stands for grazing. Addition of grass will reduce the incidence of bloat. Kura clover contains high levels of moisture and does not stand very well so is difficult to cut and wilt or dry for silage or hay when grown in pure stands. Grass aids in keeping semi-prostrate legumes more upright and speeds wilting or drying.
We have successfully sown and maintained mixtures of kura clover with Kentucky bluegrass, smooth bromegrass, orchardgrass, reed canarygrass, and tall fescue. The appropriate grass will depend on soil conditions, the intended use of the mixture and the farmer’s skills in managing some of the more aggressive grasses. We have never observed a situation where perennial grasses sown with kura clover provided fatal levels of competition during establishment.
Use of companion crops with kura clover establishment can result in additional forage production during the establishment year and reduced soil erosion on hilly sites. If small grains are used they should be sown at 1 to 1.5 bu per acre and grazed when vegetative or harvested for silage in the boot stage. Careful monitoring of kura clover and small grain development and also soil moisture will help to ensure that vegetation control operations are made in a timely manner. Mixtures of birdsfoot trefoil (2 pounds) or red clover (1 pound) with kura clover (6 pounds) have resulted in higher forage production during the establishment year without significant negative effects on long term kura clover performance.
Time of Sowing
Spring and late summer are the best times for conventional kura clover sowing. Early spring (April 15 to June 1) takes advantage of usually abundant moisture, but annual weed pressure can be severe. Late summer (July 15 to August 15) sowing can be riskier because of unpredictable rainfall and impending freezing temperatures, but competition from annual grass and broadleaf weeds is avoided.
Because kura clover will most often be sown with a grass, options for use of herbicides are limited. Furthermore, herbicide labels must be read and interpreted carefully to ensure that a given herbicide can legally be used on kura clover. In most cases, control of annual weeds after emergence can be accomplished by strategic grazing or clipping several times during the summer. If grazing is used to control weeds, then it is best to put hungry animals onto the pasture and remove them immediately after they have grazed weeds to the desired level. Soil should be firm to avoid excessive damage to the kura clover seedlings.
No-till seeding into suppressed or killed grass sod is an alternative method to introduce kura clover into a pasture. It is especially useful on hilly, erosion prone sites. Soil testing (and correction of deficiencies) and control of biennial or perennial broadleaf weeds should be done one to two years before this operation. Gramoxone Extra (paraquat) can be used to temporarily burn down existing grass early in the spring. Clover should be sown with a no-till drill within 1 to 2 days after herbicide application. The grass will recover within 3 to 5 weeks and must then be controlled by grazing or clipping to minimize competition for the remainder of the summer. This system will work only if spring and summer rainfall is “normal” and if grass competition is adequately controlled throughout the summer.
If the existing sod is killed with glyphosate (Roundup) then kura clover and the desired grass will need to be sown. The existing sod should be treated with glyphosate the previous fall to allow early no-till sowing. Spring treatment after vegetation has reached 6 to 8 inches will also work, but will delay sowing. Use of a small grain companion crop in killed sod will reduce soil erosion on sloping sites. Competition from the small grain companion crop will have to be controlled by grazing or clipping.
This low cost seeding method relies on repeated freezing and thawing to incorporate broadcast seed into the soil. Hard grazing the previous autumn followed by late autumn or winter broadcasting of seed onto the pasture surface has resulted in successful establishment of most small seeded legumes. It has been observed that this procedure works with red clover about 50 to 70% of the time in Wisconsin (Undersander, personal communication). We have had limited experience with frost seeding kura clover in Wisconsin and feel that it is a high risk operation because kura clover seedlings are more sensitive to competition from existing vegetation than red clover and most other legumes.