Herbage Yield of Fertilized Cool-Season Grass-Legume Mixtures in Western Nebraska

Abstract

Herbage yield from five cool-season grasses (meadow bromegrass [Bromus biebersteinii Toem and Schult.], smooth bromegrass [Bromus inermis Leyss.], intermediate wheatgrass [Agropyron intermedium (Host) Beauv.], Russian wildrye (Elymus junceus Fisch.], crested wheatgrass [Agropyron cristatum (L.) Gaertn.]) in mixtures with alfalfa [Medicago sativa L.] or cicer milkvetch [Astragalus cicer L.] and with the two legumes in pure stands at two dates of harvest (June 5, June 26) and with four rates of fertilizer (0 kg N/ha-0 kg P/ha, 0 kg/ha-22 kg P/ha, 45 kg N/ha-22 P/ha) was studied in western Nebraska in 1977 and 1978. Higher precipitation and more complete stand establishment during the second year caused dry matter production to be higher in 1978 than 1977. Herbage yields were greater for the alfalfa-grass mixtures than the cicer milkvetch-grass mixtures. Dry matter yields were greater for the June 26 harvest than the June 5 harvest during both years which was attributed to the extra 3 weeks for growth to occur. Plots fertilized with 45 kg N/ha-22 kg P/ha and 45 kg N/ha-0 kg P/ha produced more herbage than plots receiving the other treatments during both years. The highest yields were recorded for the intermediate wheatgrass- and crested wheatgrass-legume mixtures and the lowest yields for the Russian wildrye-legume mixtures during the 2 years of this study.