Production and Persistence of Self-Regenerating Annual Clovers in the Pacific Northwest

Self-regenerating annual legumes are commonly included in dryland pastures to increase the production of high-quality forages to meet the nutritional demands of growing and lactating animals. Balansa clover (Trifolium michelianum Savi), not as widely evaluated as subterranean clover (Trifolium subterraneum L.), has shown promise in Western Oregon. However, there is a paucity of information on the productivity and persistence of annual clover cultivars that have various flowering times. This study investigates the biomass production and persistence of early, mid and late flowering subterranean clover and balansa clover cultivars in Corvallis, Oregon. Averaged across the cultivars, the total annual dry matter yield (DMY) of subterranean clover was greater than balansa clover by 15% (3085 vs. 3612 kg DM ha-1) in the 2021/2022 growing season. Mintaro was the highest yielding subterranean clover cultivar with over 4465 kg DM ha-1 annual DMY. The biomass production of Campeda, Antas and Denmark was comparable to Mintaro. In contrast, the early flowering cultivar, Dalkeith was the lowest producing subterranean clover cultivar with less than 1500 kg DM ha-1. Herbage yield of balansa clover cultivars Border, Taipan and Viper ranged from 3446 to 3866 kg DM ha-1 and was comparable to the highest yielding subterranean cultivars. However, DMY of balansa clover cultivars Paradana, Fixation and VNS was lower than the other three highest-producing balansa cultivars. In the following fall, mean seedling number of subterranean clover (991 seedling per m2) was substantially greater than balansa clover (78 seedling per m2). Our preliminary findings indicated that mid to late maturing subterranean and balansa clover cultivars are well-suited to the agroecological conditions of the Pacific Northwest but regeneration of balansa clover cultivars was poor possibly due to hardseededness