Persistence and spread of kura clover in cool-season grass pastures

Legumes can improve productivity and quality of cool-season grass pastures but often do not persist under grazing. In May of 1997 and 1998, field experiments were planted in cool-season grass pastures near Morris, MN, to evaluate establishment and persistence of kura clover (Trifolium ambiguum Bich.) compared with alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), and red clover (Trifolium pratense L.) under grazing pressure in the north-central USA. Each spring, from planting through 2002, stands of these legumes were evaluated for persistence. Pastures were grazed five or six times per growing season for 12-h grazing periods by lactating dairy cows (Bos taurus L.) over the duration of the study. Kura clover stand density was low relative to the other species in the growing season after establishment but increased and maintained denser stands in subsequent growing seasons. Alfalfa, birdsfoot trefoil, and red clover initially developed stands greater than 30% of the sward and remained constant or increased for two (1998 planting) or four (1997 planting) growing seasons before declining. In the spring of 2002, stands were greater (P > 0.001) for both planting years for kura clover (90%) compared with alfalfa, birdsfoot trefoil, and red clover (41, 28, and 9%) when averaged across planting years, respectively. Kura clover stands spread 60 (1998 planting) to 90% (1997 planting) over the length of the study. Stands of other species did not spread. In these studies, kura clover was able to compete, persist, and spread under intermittent grazing and has the potential to be an important and persistent component of cool-season grass pastures in the north-central USA.