Harvest management and N-fertilization effects on yield and regrowth of smooth bromegrass, crested wheatgrass, and meadow bromegrass in the eastern prairies

Abstract

Little information exists describing how pasture-type grasses such as meadow bromegrass (Bromus biebersteinii Roem & Schult.; MBR) may differ from hay-type grasses such as crested wheatgrass (Agropyron cristatum (L.) Gaertn.; CWG) and smooth bromegrass (Bromus inermis Leyss.; SBR) in terms of DMY response to harvest and fertilizer management. In a 3-yr field trial at Brandon, MB harvest management (two-cut hay management or three- to four-cut simulated pasture management) and nitrogen fertilizer (0, 40, 80, 120, 160 kg N ha−1) were examined for their interactive effects on DMY and percent regrowth of CWG, MBR, and SBR Grasses managed under a two-cut hay system generally had greater (P < 0.05) DMY and lower (P < 0.05) percent regrowth than grasses managed under a three- to four-cut simulated pasture system. There were few consistent differences in DMY between grass species with relative ranking and significance changing between site-years. However, percent regrowth of MBR was always greater (P < 0 05) than either CWG or SBR, indicating its value in rotational grazing systems. Generally, MBR responded to N-fertilizer in a similar manner to CWG and SBR. Nitrogen fertilization increased (P < 0.0001) total DMY linearly m all site-years with an apparent optimum of greater than 160 kg N ha−1 yr−1, but percent regrowth did not respond in a consistent manner. Environment, management, and grass species, respectively, accounted for 38.4, 33.2, and 0.6% of the total variation in DMY, emphasizing their relative impact on yield of dryland grasses. Key words: Grass, fertilization, hay, pasture, nitrogen