• Bluegrass billbug feeding response to perennial triticeae grasses

      Nielson, D. C.; Asay, K. H.; Jones, T. A. (Society for Range Management, 1993-05-01)
      In a 4-year field study, 25 perennial triticeae grasses, representing a wide range of genomes and genome combinations, were evaluated as potential hosts for the bluegrass billbug (Sphenophorus parvulus Gyllenhal [Coleoptera: Curculionidae]). Root-sample data suggested that Russian wildrye (Psathyrostachys juncea [Fischer] Nevski) was unsuitable for billbug reproduction. Numbers of immatures varied significantly among remaining entries. Rhizomatous entries were more tolerant of billbug injury than caespitose entries. Plant mortality rates were frequently 50% or higher for self-pollinated caespitose entries with the SH genome complement (Elymus spp.). Losses to billbugs among the remaining species, particularly those with the J, N, and P genomes, were insignificant. Billbugs did not discriminate between native and introduced grasses, as resistant and susceptible entries were identified in both groups. The results obtained here may aid in selecting triticeae grasses for reseeding in areas where billbugs have damaged stands in the past.
    • Comparison of seeded and native pastures grazed from mid-May through September

      Hofmann, L.; Ries, R. E.; Karn, J. F.; Frank, A. B. (Society for Range Management, 1993-05-01)
      Cool-season introduced grass species are not recommended for season-long grazing in the northern Great Plains. They mature earlier than native species, which leads to an earlier loss in forage quality and palatability. A study conducted at Mandan, N.D., compared liveweight gains of yearling steers grazing crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.], smooth bromegrass (Bromus inermis Leyss.), and western wheatgrass [(Pascopyrum smithii (Rydb.) Love] and level native prairie (Class II and III land) and hilly native prairie pastures (Class IV and VI land), season-long. A set stocking rate of 1.5 AUM ha-1 was used from mid-May through late September in 1988, 1989, and 1990. Caged standing crop was higher from the seeded pastures than from the native pastures but liveweight steer gain was highest from the level native. Three-year average gains were 124, 114, 108, 106, and 105 kg per steer for level native, smooth bromegrass, western wheatgrass, hilly native, and crested wheatgrass pastures, respectively. The seeded cool-season grass pastures, grazed season-long at a rate 25% higher than that recommended by the SCS for native range, produced acceptable liveweight steer gains without additional inputs. Season-long grazing may provide an alternative use for marginal cropland and other highly erodible land that has been reseeded to cool-season species.
    • Decomposition of blue grama and rough fescue roots in prairie soils

      Dormaar, J. F.; Willms, W. D. (Society for Range Management, 1993-05-01)
      The mass of grass roots of blue grama (Bouteloua gracilis (HBK.) Lag. ex Steud) and rough fescue (Festuca campestris Rydb.) to a depth of 13 cm is similar but the carbon contents of their respective soils are quite different. The objective of the present study was to determine some of the physical and chemical changes of blue grama and rough fescue root masses during decomposition under both Brown (Mixed Prairie) and Black Chernozemic (Fescue Prairie) soil-forming conditions. Roots of each species in fine-mesh nylon bags were buried in the Ah horizon of both a Brown and a Black Chernozemic soil. Sixteen collections were made between November 1987 and June 1989 to determine diminution, loss of dry matter and gross energy, and changes in the concentration of carbon, nitrogen, methoxyl groups, alkaline-soluble organic acids and phenols, structural and nonstructural carbohydrates, lignin, and monosaccharides. Differences in substrate quality were only partially responsible for the increased decomposition of root mass in the Brown Chernozemic soil-forming environment. Comminution of root mass was significantly greater under the Mixed Prairie than under the Fescue Prairie conditions for both species. The nitrogen content of blue grama roots increased (from 1.17 to 1.56%) while that of rough fescue decreased (from 1.53 to 1.26%) significantly over the duration of the experiments at both sites. Methoxyl group content and energy levels were not useful parameters. Organic acid, phenols, and nonstructural carbohydrate contents decreased with time. Lignin concentration displayed a significant upward trend for both species (from 232 to 280 for blue grama and for 205 to 247 mg/g for rough fescue) in the Black Chernozemic soil only.
    • Forage response to N, P, and S fertilization on clearcut lodgepole pine sites

      Wikeem, B. M.; Newman, R. F.; Va, A. L. (Society for Range Management, 1993-05-01)
      The response of selected plant species to a single application of factorial combinations of nitrogen (N), phosphorus (P), and sulfur (S) on 2 lodgepole pine (Pinus contorta Dougl.) clearcut-logged sites in British Columbia was evaluated over 3 years. Increasing N rates typically resulted in higher forage standing crop on both sites, in all years. but standing crop at Fly Creek was nearly double that at Beaverdam Lake. On both sites, forage yields peaked at 400 kg N/ha in 1982 and carry-over of the fertilizer effect lasted for 3 years although yields declined annually. Addition of P to N applications enhanced (P < 0.05) total standing crop, other grass standing crop, and pinegrass (Calamagrostis rubescens Buckl.) standing crop at Beaverdam Lake and grass standing crop at Fly Creek, but had no effect (P > 0.05) on other species and groups. Sulfur, added to N applications, enhanced total yields compared to control on both clearcuts although at Fly Creek this response nearly doubled that produced at Beaverdam Lake. Nitrogen fertilization increased (P < 0.05) pinegrass crude protein (CP) content, particularly in the first year after fertilization. Acid detergent fiber (ADF) generally increased in response to increasing N levels in 1982, but declined compared to control in 1983 and 1984. Elevated forage CP levels, litter N concentrations, and soil N levels in 1984 indicated that the carry-over response on these forest sites resulted directly from N remaining in the soil or again becoming available for plant growth.