alfalfa mixtures are needed for DM yields over several years in response to N fertilization in the Northern Cultivars used in grass-alfalfa (Medicago sativa L.) mixtures for Great Plains. hay production in the semiarid Northern Great Plains have often lacked long-term productivity. This study was conducted to compare Alfalfa germplasm with a high proportion of its pardry matter (DM) yields of grass monocultures and grass-alfalfa binary entage from yellow flowering alfalfa [M. sativa subsp. mixtures receiving annual applications of 0 and 50 kg N ha Ϫ1 over a falcata (L.) Arcang] and with the capacity to spread 5-yr period. 'Reliant' and 'Manska' intermediate wheatgrass [Thinofrom new shoots arising from horizontal roots has dempyrum intermedium (Host) Barkw. and Dewey], 'Lincoln' smooth onstrated long-term persistence in the semiarid Northbromegrass (Bromus inermis Leyss.), 'Nordan' crested wheatgrass ern Great Plains (Heinrichs, 1975;Berdahl et al., 1989). [Agropyron desertorum (Fisch.) Schult.], 'Lodorm' green needlegrass Other legumes, including cicer milkvetch (Astragalus (Stipa viridula Trin.), and 'Dacotah' switchgrass (Panicum virgatum cicer L.) (White and Wight, 1984) and sainfoin (Ono-L.) were seeded in monoculture and in binary mixtures with 'Rangebrychis viciaefolia Scop.) (Dubbs, 1971), had inferior lander' alfalfa [Medicago sativa subsp. ϫ varia (Martyn) Arcang.] persistence to hardy alfalfa germplasm at semiarid sites. on a Parshall fine sandy loam (coarse-loamy, mixed, superactive, frigid, Pachic Haplustolls) near Mandan, ND. Plant stands of green Results from earlier studies (Kilcher and Heinrichs, needlegrass and switchgrass were inadequate, and yields were not 1966; Kilcher et al., 1966) indicated that intermediate measured. Total seasonal DM yields from two cuttings averaged 8.74 wheatgrass had poor persistence in mixtures with alfalfa and 2.71 Mg ha Ϫ1 , respectively, for grass-alfalfa mixtures and grass relative to standard and fairway crested wheatgrass monocultures at 0 kg N ha Ϫ1 . At 50 kg N ha Ϫ1 , grass-alfalfa mixtures [Agropyron cristatum (L.) Gaertner] and smooth bromeand grass monocultures averaged 8.72 and 5.04 Mg ha Ϫ1 DM yield, grass. The intermediate wheatgrass used in these tests respectively. Yields of the grass component of first cut grass-alfalfa originated from common seed that had no cultivar desigmixtures averaged 35% of total yield for intermediate wheatgrass, Abbreviation: DM, dry matter. Published in Agron. J. 93:463-467 (2001).

No abstract

Improved perennial grasses provide ranchers with high-quality forage for grazing and hay. However, in the Northern Great Plains of the USA, nutritive quality information is limited on both established and new cultivars. This study compares the nutritive quality of established and more recently released cultivars of crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schultes] (CWG), intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth and Dewey] (IWG), western wheatgrass [Pascopyrum smithii (Rydb.) Love] (WWG), and smooth bromegrass (Bromus inermis Leyss.) (SBG); evaluates the effect of plant maturity on tissue quality; compares nutritive quality differences among species; and evaluates nutritive quality relationships. Smooth bromegrass leaf tissue had the highest (P , 0.05) in vitro dry matter digestibility (IVDMD) and lowest neutral detergent fiber (NDF), but IWG and WWG had higher stem IVDMD. Few quality differences were detected between cultivars within a species, but 'Rosana' WWG had higher (P , 0.10) stem and whole plant IVDMD than the more recently released 'Rodan'. Leaf percentage differed significantly (P , 0.05) among species, with WWG (49.8%) having the highest, and CWG (21.2%) the lowest. Correlation coefficients between quality measurements suggest that if grass leaf tissue were selected for higher IVDMD, leaves should also have higher crude protein (CP) and lower NDF. This relationship was best illustrated with WWG for all three tissue types. The apparent lower quality of Rodan WWG compared with the older cultivar, Rosana, should caution plant breeders to monitor forage quality to ensure that selection for improved agronomic traits does not compromise nutritive quality.

Current agricultural systems are the result of decoupling crop/livestock enterprises for short-term economic gain at the expense of long-term sustainability. Objectives of our research were to determine the influences of winter grazing dry gestating beef cows on no-till forage and grain production, water-use efficiency, and protein and phosphorus (P) production for an oat/pea-triticale/sweet clover-corn 3-year cropping system. Oat/pea and triticale crops were harvested for grain, with the straw and chaff left in swaths after harvest for winter grazing. Drilled corn for forage was swathed in late September. Cropping system treatments were: (1) straw and corn chopped and left in place (IP); (2) straw and corn baled and removed without livestock (R); and (3) straw and corn swath grazed by livestock (L). The first winter for grazing dry, bred cows was in 1999-2000; therefore, no treatment differences occurred for the 1999 crop. In 2000, oat/pea and triticale grain and straw production for the IP treatment was about half of the production for the R treatment, because of low oat/pea and triticale plant stands on the IP treatment. Averaged over all years, corn was about 1.5 times more efficient in using water for dry matter production when compared to oat/pea or triticale. Generally, protein and P production, on a unit area basis, were highest for corn and lowest for triticale. Averaged over 4 years, about half of the nitrogen used for protein production was derived from sources other than applied commercial fertilizer. Data suggest that more than 4 years of research are needed to understand cropping system and animal interactions on forage and grain production in integrated crop/livestock systems, with trends in year four suggesting that livestock may enhance forage and grain production.