Interseeding legumes into established semiarid smooth bromegrass pasture

Abstract

Seeding legumes into established cool‐season grass pasture helps to lower the long‐term costs of production and may improve total forage yield and quality, but seeding these legumes in the semiarid Central Great Plains region is often ignored. Eight legumes commonly seeded in the Midwest and eastern USA were no‐till seeded in late winter into upland and lowland west‐central Kansas smooth bromegrass (Bromus inermis Leyss.) pastures. Purple‐flowered alfalfa (Medicago sativa L. ssp. sativa) and yellow‐flowered alfalfa [Medicago sativa L. ssp. falcata (L.) Arcang.] established well at the lowland and upland sites and helped improve forage yield compared with nitrogen‐fertilized smooth bromegrass. Korean lespedeza [Kummerowia stipulacea (Maxim.) Makino] and yellow sweetclover [Melilotus officinalis (L.) Lam.] established well on both landscape sites, but these legumes declined significantly over time and did not increase forage yield compared with smooth bromegrass alone. Legume establishment was greater in unfertilized smooth bromegrass at each landscape, indicating that early competition from the grass limited legume establishment. Purple‐flowered and yellow‐flowered alfalfa increased the crude protein concentration compared with smooth bromegrass alone on the lowland site, and increased crude protein and total digestible nutrient concentration on the upland site. Birdsfoot trefoil (Lotus corniculatus L.), cicer milkvetch (Astragalus cicer L.), and hairy vetch (Vicia villosa Roth) failed to establish with competition from smooth bromegrass at the upland and lowland sites. Purple‐flowered and yellow‐flowered alfalfa may establish and persist when seeded into existing smooth bromegrass pastures in the drier regions of central Kansas while increasing forage yield and nutritive value.