Blair L. Waldron

Fire Rehabilitation Using Native and Introduced Species: A Landscape Trial

Abstract Following the 1999 Railroad Fire in Tintic Valley, Utah, we initiated a large-scale fire rehabilitation study comparing a predominately introduced species seed mix used by the US Department of Interior–Bureau of Land Management (BLM), a mix of native and introduced species provided by the US Department of Agriculture–Agricultural Research Service (ARS), and 2 native seed mixes (high and low diversity). Mixes were seeded with a rangeland drill on the big sagebrush (Artemisia tridentata var. wyomingensis [Beetle & A. Young] Welsh) study area whereas the pinyon–juniper (Pinus edulis Engelm.–Juniperus osteosperma [Torr.] Little) woodland study area was aerially seeded followed by 1-way chaining. On drill-seeded plots and by the third year after seeding the native high-diversity mix (16.4 kg pure live seed [PLS]·ha−1) had the highest seeded species cover (11.5%) and density (14 plants·m−2). Both the BLM (9.3 kg PLS·ha−1) and ARS (9.1 kg PLS·ha−1) seed mixes had higher seeded species cover (BLM = 8.5%, ARS = 8.2%) and density (BLM = 8.4 and ARS = 7.2 plants·m−2) than plots seeded to the low-diversity native mix (8 kg PLS·ha−1, cover = 3.8%, density = 3.6 plants·m−2). Indian ricegrass (Achnatherum hymenoides [Roemer and J. A. Schultes] Barkworth ‘Nezpar’) in the native high-diversity mix was especially successful on the sandy soils of the drill site, whereas seeds of other species may have been buried too deep for optimum emergence. Aerially-seeded and chained plots had similar and successful seeded species frequency, cover, and density (third-year average = 10.6% cover, 17.2 plants·m−2) among all species mixes. All seeded plots had lower cover of annual species than unseeded plots, indicating that revegetation is necessary to reduce weed invasion following catastrophic wildfire in big sagebrush communities lacking residual perennial understory vegetation.

Forage nutritional characteristics of orchardgrass and perennial ryegrass at five irrigation levels

the major contributors to NDF (Fisher et al., 1995). Laboratory measures of NDF are correlated with volunAs water resources become limiting, the need to produce stable tary intake (Casler and Vogel, 1999). Fisher et al. (1995) amounts of highly nutritional forage increases. An understanding of how levels of irrigation affect crude protein (CP), digestible neutral reported that energy is closely related to the digestibility detergent fiber (dNDF), in vitro true digestibility (IVTD), and neutral of NDF (dNDF) in forage grasses. Grant (2002) redetergent fiber (NDF) is critical in pasture forage management. Cultiported that NDF digestion can range from 2 to 20% vars of orchardgrass (Dactylis glomerata L.) and perennial ryegrass h 1 in dairy cows (Bos taurus). Oba and Allen (1999) (Lolium perenne L.) were established under a line-source irrigation reported that an increase in forage dNDF resulted in system to evaluate the effect of five water levels (WLs) and three increased dry matter intake and milk yield. They further harvest dates on concentrations of CP, dNDF, IVTD, and NDF. concluded that for every 1% unit increase in dNDF, Perennial ryegrass forage had higher CP, dNDF, and IVTD and lower NDF concentrations than orchardgrass at all harvest dates and within there was a 0.18-kg increase in dry matter intake and a WLs. The most notable trend in nutritional value across WLs was 0.03-kg increase in body weight in dairy cows. Selection the near linear increase in CP ranging from 175 g kg 1 at the wettest for increased CP and in vitro dry matter digestibility WL to 217 g kg 1 at the driest WL. Digestible NDF ranged from 709 in cool-season grasses has resulted in subsequent yield to 757 g kg 1 at corresponding WLs. These trends were particularly reductions in smooth bromegrass (Bromus inermis evident later in the growing season. Orchardgrass maturity (early vs. Leyss.) and reed canarygrass (Phalaris arundinacea L.) late) had little effect on forage nutritional characteristics across WLs. (Casler, 1998; Casler and Vogel, 1999). Combined over WLs, tetraploid perennial ryegrass cultivars averaged higher concentrations of CP, IVTD, and dNDF and lower NDF values Hall (1998) found that maximum forage nutrition was compared with diploid cultivars. In general, as water stress increased, achieved when orchardgrass, smooth bromegrass, and forage nutritional value (i.e., CP and dNDF) increased. reed canarygrass were harvested at 35to 45-d intervals. In another study (Turner et al., 1996), increased CP and lower NDF concentrations were observed under early I in maximizing productivity of irrigated pasand frequent defoliation compared with a hay managetures has escalated with the increased restrictions ment system for festulolium [Xfestulolium braunii (K. on grazing public lands in the western USA. Under Richt) A. Camus], orchardgrass, and prairie grass (Broadequate irrigation, cool-season grass pastures repremus catharticus M. Vahl). Similarly, CP in stockpiled sent some of the most productive grazing lands throughforage of 11 cool-season grasses declined by 55% from out the West (Bateman and Keller, 1956). Increasing June to September (Suleiman et al., 1999). Under the human population and droughty growing conditions same line source, orchardgrass cultivars had higher dry place additional demands on available irrigation water. matter yield and increased water use efficiency than As a result, producers are required to use less water perennial ryegrass cultivars (Jensen et al., 2001, 2002). while trying to maintain stable amounts of highly nutriA line-source irrigation system was developed to evaltious forage. Historically, germplasm improvement in uate plant growth under a gradient of WLs (Hanks et orchardgrass and forage-type perennial ryegrass has foal., 1976). This system has been used to study the recused on forage traits, disease resistance, and agronomic sponses of cool-season grasses to controlled irrigation adaptation to temperate areas (Balasko et al., 1995; levels (Johnson et al., 1982; Asay and Johnson, 1990; Christie and McElroy, 1995; Jung et al., 1996; Casler et Asay et al., 2001; Jensen et al., 2001; Waldron et al., al., 2000). 2002). Literature is limited regarding the effects of irriForage nutrition can be measured by the relative pergation on forage nutritional characteristics under reformance of animals when forage is fed to livestock. peated harvesting. Animal performance is highly influenced by nutrient Objectives of this study were to study the trends in concentration, intake, and digestibility (Buxton et al., CP, dNDF, IVTD, and NDF for nine cultivars of or1996). In the absence of feeding trials, forage nutritive value is often evaluated by measuring such characterischardgrass and seven of perennial ryegrass across an tics as CP, NDF, acid detergent fiber, IVTD, and hemiirrigation gradient. A secondary objective was to evalucellulose (Pavetti et al., 1994). Cell wall constituents are ate the effect of ploidy level in perennial ryegrass and maturity in orchardgrass on any observed differences USDA-ARS, Forage and Range Res. Lab., Utah State Univ., Logan, and trends in forage nutritive value across the irrigaUT 84322-6300. Joint contribution of the USDA-ARS and the Utah tion gradient. Agric. Exp. Stn. Journal Paper no. 7468. Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by the USDA or Utah State Univ. Received Abbreviations: CP, crude protein; dNDF, digestible neutral detergent 13 May 2002. *Corresponding author (kevin@cc.usu.edu). fiber; IVTD, in vitro true digestibility; NDF, neutral detergent fiber; NIRS, near infrared reflectance spectroscopy; WL, water level. Published in Agron. J. 95:668–675 (2003).

Breeding Improved Grasses for Semiarid Rangelands

Vast areas of semiarid rangelands in western USA are severely degraded and infested with troublesome weeds such as cheatgrass (Bromus tectorum) and medusahead rye (Taeniatherum asperum). Reseeding with appropriate plant materials that are adapted to the site and competitive enough to replace existing undesirable vegetation is often the most plausible way to reclaim such sites. Unfortunately, many of our native grasses are more difficult to establish and are not as competitive with these exotic weedy grasses as their introduced counterparts, including crested and Siberian wheatgrass (Agropyron cristatum, A. desertorum, and A. fragile). Most native grasses did not evolve under intense management or in association with species as competitive as cheatgrass. Genetically improved germplasms and cultivars of native and introduced (naturalized) grasses have been and are being developed by the Forage and Range Research Laboratory (FRRL) of the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) in cooperation with the Utah Agricultural Experiment Station (UAES) and other agencies. These plant materials have demonstrated the potential for increasing the genetic diversity, protecting watersheds and soil resources, and improving the habitat and grazing potential for livestock and wildlife on semiarid rangelands. Research is also in progress at FRRL to develop germplasm and methodology whereby introduced grasses may be used in combination with natives, and in some instances assist in the establishment of native stands. The proper choice of plant materials must be based on objective criteria if we are to protect our lands and natural resources from further degradation.

Stockpiled Forage Kochia to Maintain Beef Cows During Winter

Abstract Extending grazing into the winter, as opposed to feeding of harvested forages, can increase the sustainability of ranching in the western US. This study was conducted to determine the economic value of grazing stockpiled forage kochia (Kochia prostrata [L.] Scrad.) and crested wheatgrass (Agropyron desertorum [Fisch. Ex Link] Schultes) during the fall and winter. Changes in cow body weight, body condition score, and ultrasound backfat were compared for late-gestation cows grazing forage kochia–crested wheatgrass pastures vs. those fed alfalfa (Medicago sativa L.) hay in drylot. The study was conducted from early November to late January for 2 consecutive years near Promontory, Utah. Forage availability and nutritional quality were monitored throughout the experiment. Cows grazing stockpiled forages did not receive any protein or energy supplements. Forage kochia comprised approximately 70% of available forage, with November crude protein content of 116 and 76 g·kg−1 in years 1 and 2, respectively. Nutritional quality declined throughout the season, presumably mostly because of removal of higher-quality forage by preferential grazing as opposed to weathering. Averaged over years, cows grazing forage kochia–grass gained body weight (19 kg), increased in body condition (0.3 points), and maintained backfat thickness, finishing well within the range considered optimum for onset of calving and return to estrus. Pasture- vs. drylot-fed cows did not differ with regard to changes in body weight or body condition score. Both treatments increased backfat in year 1, when initial backfat was less than 0.5 cm, but both treatments resulted in loss of backfat in year 2, when initial backfat was greater than 1.0 cm. Grazing was more economical, costing

Forage kochia?Uzbekistan's desert alfalfa.

0.24·cow−1·d−1 less than feeding alfalfa hay in drylot. Forage kochia can be used on western rangelands to extend grazing into the fall and winter, thereby improving the profitability of beef production.

Stand Establishment and Persistence of Perennial Cool-Season Grasses in the Intermountain West and the Central and Northern Great Plains

Forage kochia germplasm from Uzbekistan may increase fall and winter grazing and habitat for livestock and wildlife on western rangelands. DOI:10.2458/azu_rangelands_v27i1_waldron

Potential of Kochia prostrata and Perennial Grasses for Rangeland Restoration in Jordan

Abstract The choice of plant materials is an important component of revegetation following disturbance. To determine the utility and effectiveness of various perennial grass species for revegetation on varied landscapes, a meta analysis was used to evaluate the stand establishment and persistence of 18 perennial cool-season grass species in 34 field studies in the Intermountain and Great Plains regions of the United States under monoculture conditions. Combined across the 34 studies, stand establishment values ranged from 79% to 43% and stand persistence values ranged from 70% to 0%. Intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth & D. R. Dewey), tall wheatgrass (Thinopyrum ponticum [Podp.] Z.-W. Liu & R.-C. Wang), crested wheatgrass (Agropyron spp.), Siberian wheatgrass (Agropyron fragile [Roth] P. Candargy), and meadow brome (Bromus riparius Rehmann) possessed the highest stand establishment (≥ 69%). There were no significant differences among the 12 species with the largest stand persistence values. Basin wildrye (Leymus cinereus (Scribn. & Merr.) Á. Löve), Altai wildrye (Leymus angustus [Trin.] Pilg.), slender wheatgrass (Elymus trachycaulus [Link] Gould ex Shinners), squirreltail (Elymus spp.), and Indian ricegrass (Achnatherum hymenoides [Roem. & Schult.] Barkworth) possessed lower stand persistence (≤ 32%) than the majority of the other species, and Indian ricegrass (0%) possessed the lowest stand persistence of any of the species. Correlations between environmental conditions and stand establishment and persistence showed mean annual study precipitation to have the most consistent, although moderate effect (r = ∼0.40) for establishment and persistence. This relationship was shown by the relatively poor stand establishment and persistence of most species at sites receiving less than 310 mm of annual precipitation. These results will be a tool for land managers to make decisions concerning the importance of stand establishment, stand persistence, and annual precipitation for revegetation projects on disturbed sites.

Genetic Improvement and Diversity in Snake River Wheatgrass (Elymus wawawaiensis) (Poaceae: Triticeae)

Abstract Six varieties of forage kochia (Kochia prostrata [L.] Schrad.), two Atriplex shrubs native to North America, and four drought-tolerant perennial grass varieties were seeded and evaluated under arid rangeland conditions in Jordan. Varieties were seeded in December 2007 and evaluated in 2008 and 2009 at two sites. Conditions were dry with Qurain receiving 110 mm and 73 mm and Tal Rimah receiving 58 mm and 43 mm of annual precipitation during the winters of 2007/2008 and 2008/2009, respectively. Plants were more abundant and taller (P < 0.001) at Qurain than Tal Rimah in 2008. Forage kochia frequency was 48% and 30% in 2008 at Qurain and Tal Rimah, respectively. However, no seeded plants were observed at Tal Rimah in 2009, suggesting that 58 mm and 43 mm of annual precipitation are insufficient to allow plants to persist over multiple years. At the wetter site, forage kochia abundance in 2009 was similar (P  =  0.90) to that observed in 2008 and plant height increased (P < 0.001) from 2008 (14.4 cm ± 1.1 SE) to 2009 (38.4 cm ± 1.1 SE). Sahro-select and Otavny-select were the most abundant forage kochia varieties (P < 0.05), suggesting that these experimental lines could be more adapted to the environmental conditions of Jordan than the commercially available cultivar Immigrant. Frequency of perennial grass varieties declined (P < 0.001) at Qurain from 82% ± 4 SE to 39% ± 4 SE between 2008 and 2009, respectively. Among grasses, Siberian wheatgrass had better stands than crested wheatgrass, with Russian wildrye being intermediate. Based on this study, forage kochia appears to have great potential for establishing palatable perennial shrubs in arid rangeland conditions in Jordan if annual precipitation is at least 70 mm. Arid-adapted perennial grass varieties might also be useful in rangeland restoration if annual precipitation is over 100 mm.

Growth performance, ruminal fermentation profiles, and carcass characteristics of beef steers grazing tall fescue without or with nitrogen fertilization1

Abstract With the increased emphasis on using native plant materials in range revegetation programs in the western United States it is critical to identify genetically similar groups and develop native grasses that are competitive with invasive weeds, easy to establish, and persistent, and that produce high seed yield. A grass that shows appreciable drought tolerance on arid rangelands is Snake River wheatgrass (Elymus wawawaiensis J. Carlson & Barkworth). This study was designed to estimate genetic relationships and underlying genetic components for seed and forage trait improvement between plant introductions (PIs) of Snake River wheatgrass, 28 half-sib Snake River wheatgrass families (HSFs), and cultivars Secar and Discovery at Nephi, Utah, between 2005 and 2006. Based on molecular genetic diversity data in Snake River wheatgrass, with the exception of the PIs originating from Enterprise, Oregon, all other collections and cultivars are not genetically different and represent a common gene pool from which to develop improved Snake River wheatgrass germplasm. Selection in Snake River wheatgrass for total seed yield (g · plot−1), 100-seed weight (g), and seedling emergence from a deep planting depth had a positive effect. Further increases through selection and genetic introgression from hybridization with PIs will likely increase seed yield and 100-seed weight, but will not increase seedling emergence. Increases in dry matter yield (DMY) were observed after two cycles of selection in the HSFs compared to the PIs. There remains considerable genetic and phenotypic variation to further increase DMY in Snake River wheatgrass through selection and hybridization. Trends in forage nutritional quality were not observed after two cycles of selection in the HSFs or the PIs and will not likely result in improvement. Through recurrent selection, populations of Snake River wheatgrass have been and can be developed to more effectively establish and compete on annual weed–infested rangelands.

Salinity Tolerance of Foxtail Barley (Hordeum jubatum) and Desirable Pasture Grasses

A 2-yr study was conducted to evaluate the effects of finishing beef cattle grazed on tall fescue (TF) pastures without or with N fertilization on growth performance, ruminal fermentation, and carcass characteristics. In each grazing season, 18 Angus crossbred steers were arranged in a completely randomized design with repeated measures on the following 2 treatments: TF without N fertilizer (TF–NF) and TF with N fertilizer (TF+NF). Three replicated pastures with 3 steers per replicate were assigned to each treatment. A total of 168 kg/ha N fertilizer was applied in 3 split applications at 56 kg/ha each to the TF+NF in each grazing season. Steers rotationally grazed on 0.47-ha pasture for 7 d with a 28-d rotation interval for a total of 16 wk. Body weight data and pasture forage samples were collected every 4 wk, whereas ruminal fluid was collected at wk 4, 10, and 16. After the completion of 16-wk grazing, ultrasound measurement was performed to assess carcass characteristics. In response to N fertilization, greater CP concentration was detected on TF+NF compared with TF–NF in 2011 (11.9 vs. 10.6% DM, respectively; P < 0.01). Overall ADG was greater in steers that grazed TF+NF pastures (P < 0.05) in the 2-yr grazing seasons, and tended to increase (P = 0.07) overall DMI and G:F in 2010. Regardless of N fertilization, ADG peaked between wk 4 and 8 (1.05 kg/d; P < 0.01), and then declined until wk 16. A gradual decline of G:F was noticed with progression in grazing seasons (P < 0.05). Greater total VFA concentrations were detected in ruminal fluid of steers that grazed TF+NF (P < 0.01), but a minor effect was shown on individual VFA (acetate, propionate, and butyrate) concentrations and acetate-to-propionate ratio. Ruminal ammonia-N (NH3-N) concentration increased (P < 0.01) with N fertilization, whereas NH3-N:total VFA increased (P < 0.01) with the progression of grazing seasons. Backfat thickness, ribeye area, and intramuscular fat concentration did not differ between treatments. Overall results of this study indicate that N fertilization on TF affected ruminal fermentation which positively influenced growth performances, but did not affect carcass characteristics of grazing beef steers. In addition, readily fermentable carbohydrate supplementation is needed to improve utilization of increased dietary CP due to N fertilization and consequently enhance growth performances of grazing steers.