Annual Medics and Related Species as Reseeding Legumes for Northern Utah Pastures

Abstract

Legumes are beneficial in providing high quality forage and enhancing fertility levels in the soil by biological nitrogen fixation. Nonperennial Medicago species have a world-wide distribution and have been used successfully for grazing in Mediterranean-type environments. The feasibility of using nonperennial Medicago species as reseeding pasture legumes in the northern Utah area was evaluated at 2 locations in replicated plantings of 584 accessions representing 34 Medicago species. These nurseries were planted in the spring of 1981 and data were collected through the 1983 growing season. Most of the species were easily established at both test sites. Many grew more rapidly during the seeding year than did the perennial check, M. falcata L. However, no annual or biennial species was as well nodulated or reduced acetylene on a per plant basis as well as M. falcata. None of the populations matured, reproduced, and initiated soil seed bank at the droughtier of the 2 locations. M. laciniata (L.) Mill., M. lupulina L., M. murex Willd., and M. muricoleptis Tin. excelled in the numbers of seedlings per meter of area established by natural reseeding in the fall of the first year of test. However, only M. lupulina (black medic) produced abundant seedlings during the second year following seeding. Results indicated that M. lupulina could develop a soil seed bank more rapidly than the other species. Black medic also had superior ground cover characteristics during the second and third years after sowing. Adapted populations of M. lupulina appear to have long-term value for forage production in Utah rangeland pastures with suitable soils and adequate precipitation.