Kura Clover Establishment Methods

Kura clover (Trifolium ambiguum M.B.) is a rhizomatous legume that produces high quality forage and has exceptional persistence. However, slow establishment has limited its use. Our objective was to evaluate the effect of alternative establishment methods on Kura clover forage and seed production. At Rosemount, MN, we compared the effect of an oat (Avena sativa L.) companion crop harvested for forage; a birdsfoot trefoil (Lotus corniculatus L.) companion crop seeded with or without preplant herbicide application (trifluralin); and soloseeding with or without a preplant herbicide application (trifluralin) on Kura clover yield and plant populations. At Roseau, MN, we determined the effect of solo-seeding with or without preplant herbicide (trifluralin), or with a flax (Linum usitatissimum L.) or a wheat (Triticum aestivum L.) companion crop on Kura clover forage and seed yield in the year following seeding. Kura clover forage production in the seeding and post-seeding years was maximized when solo-seeded with a preplant herbicide; however, results were variable across years. Kura clover forage yields in the seeding year were very low (< 400 lb/acre) for all treatments. An oat companion crop increased total weed-free forage yields in the seeding year, but reduced by 46% Kura clover yields in the seeding and post seeding years compared with solo-seeding with herbicide. A birdsfoot trefoil companion crop produced similar or lower Kura clover yields in the seeding and post-seeding year as soloseeding with herbicide but similar or greater total forage yields. Seed production only occurred for solo-seeding with a preplant herbicide. Solo-seeding with herbicide is the most reliable establishment method for Kura clover forage and seed production; however, Kura clover establishment remains challenging. Research QuestionKura clover is a persistent rhizomatous legume producing high quality forage. However, slow establishment and poor seed production are hindering its use. Information on methods maximizing Kura clover establishment and forage and seed production in initial years is limited. Our objective was to evaluate alternative establishment methods for Kura clover forage and seed production. Literature SummaryBecause of poor seedling vigor and slow development, Kura clover establishment can be challenging. This may be because Kura clover partitions most of its energy resources to root growth. This results in poor above-ground development and problems with competition from surrounding vegetation. However, alternative Kura clover establishment methods have not been compared in the Midwest. Study DescriptionSeparate forage production and seed production studies were conducted. The forage production study was conducted at Rosemount, MN. Kura clover establishment methods included: an oat companion crop harvested for forage; a birdsfoot trefoil companion crop with or without preplant herbicide application (trifluralin); and solo-seeding with or without a preplant herbicide application (trifluralin). Forage yields and botanical composition in the seeding and postseeding year, and plant densities in the post-seeding year were measured. The seed production experiment was conducted at Roseau, MN. Treatments included: Kura clover solo-seeded with or without a preplant incorporated herbicide (trifluralin); or a flax or a wheat companion crop; and two Kura clover seeding rates: 1.25 and 2 lb/acre. Seed and forage yields in the post-seeding year were determined. Applied QuestionWhat is the optimal establishment method for both Kura clover forage and seed production? Our research suggests that solo-seeding with preplant herbicide application to reduce competition with weeds will maximize Kura clover forage and seed production in the seeding and post-seeding years. However, results were variable across years. This may be the result of a greater sensitivity of Kura clover to environmental conditions during establishment (e.g., drought and soil crusting), or to herbicide injury than other commonly used forage legumes. In all cases, Kura clover forage yields in the seeding year were small and producers should not expect any significant production in that year. An oat companion crop increased total forage yields in the establishment year, although it often reduced Kura clover yields in the seeding and post-seeding years. Seeding with birdsfoot trefoil reduced Kura clover establishment and yields in the seeding year, and produced variable results. A birdsfoot trefoil companion crop resulted in similar or lower post-seeding year Kura clover yields than solo-seeding with herbicide but increased total forage yields and reduced weed mass. Kura clover seed production in the year following seeding was only successful when Kura clover was solo-seeded using a herbicide. Use of companion crops, even those providing minimal competition (e.g., flax), resulted in biologically insignificant seed production. Solo-seeding with a preplant herbicide appears to be the most reliable establishment method for both Kura clover forage and seed production.