Harvest Date Effect on Forage Yield, Botanical Composition, and Nutritive Value of Novel Legume-Grass Mixtures

The potential for novel forage mixtures to address reduced herbage for late season grazing was investigated. Forage legumes, sainfoin (Onobrychis viciifolia Scop.) (SF) cvs. AC Mountainview, Shoshone, and Nova (MountainSF, ShoshoneSF, and NovaSF), cicer milkvetch (Astragalus cicer L.) cv. AC Veldt (CMV), Canadian milkvetch (Astragalus canadensis L.) cv. Great Plains (CaMV), and alfalfa (Medicago sativa L.) cv. AC Yellowhead (ALF) were evaluated in binary mixtures with meadow bromegrass (Bromus riparius Rehm.) cv. Admiral (MBG), hybrid bromegrass (B. riparius x B. inermis Leyss.) cv. AC Success (HBG) and Russian wildrye [Psathyrostachys junceus (Fisch.) Nevski.] cv. Tom (RWR) for yield, botanical composition, and nutritive value on July and September harvest dates at Saskatoon and Swift Current, Saskatchewan, Canada from 2016 to 2018. Hybrid bromegrass-legume mixture produced 16-38% greater forage compared to RWR-legume (7.5 vs. 5.6 Mg ha(-1) in July and 6.1 vs. 5.1 Mg ha(-1) in September at Saskatoon, and 3.2 vs. 2.0 Mg ha(-1) in July at Swift Current). MountainSF and ALF had the greatest legume contribution to total yield at July harvest at Swift Current (67.7 & PLUSMN; 3.2%) and Saskatoon (62.1 & PLUSMN; 2.1%), respectively, while CaMV had lowest composition at Swift Current (20.2 & PLUSMN; 2.5%) and Saskatoon (12.6 & PLUSMN; 3.5%). The CMV and ALF-grass mixtures at Saskatoon and legume-RWR mixtures at both sites in July had greatest CP content. The July harvest had greatest yield, legume content and nutritive value compared to the September harvest at both sites. Study results suggest if yield is the objective, then either ALF or CMV with HBG may be considered. If nutritive value is the goal, any legume with RWR is an option. Finally, ALF or CMV in mixture with either HBG or RWR could be summer or fall stockpile forage in the Northern Great Plains of western Canada.