Rangeland Ecology & Management, Volume 64, Number 5 (September 2011)

Rebuttal Response: ‘‘Disturbance to Surface Lithic Components of Archaeological Sites by Drill Seeding.’’ Rangeland Ecology & Management 64:171-177

2020-09-06T01:19:32Z

Rebuttal Response: ‘‘Disturbance to Surface Lithic Components of Archaeological Sites by Drill Seeding.’’ Rangeland Ecology & Management 64:171-177 Bryan, Neal M.; Anderson, Val Jo; Fugal, Rachel A.

Rebuttal: Disturbance to Surface Lithic Components of Archaeological Sites by Drill Seeding

2020-09-06T01:19:25Z

Rebuttal: Disturbance to Surface Lithic Components of Archaeological Sites by Drill Seeding Rust, Jeffrey A.; Earl, Dale

Condensed Tannin in Drinking Water Reduces Greenhouse Gas Precursor Urea in Sheep and Cattle Urine

2020-09-06T01:19:19Z

Condensed Tannin in Drinking Water Reduces Greenhouse Gas Precursor Urea in Sheep and Cattle Urine Kronberg, Scott L.; Leibig, Mark A. Ingestion of small amounts of condensed tannin (CT) by ruminants may provide benefits including reduction of ammonia and nitrous oxide emissions by reducing urine urea excretion. However, providing grazing ruminants with sufficient amounts of CT- containing forages is difficult, and an alternative may be to provide CT in their drinking water. We conducted three trials to determine if urine urea levels in sheep and cattle decrease after they drink water containing CT. In two initial trials, blood serum urea was measured as a surrogate for urine urea when lambs or steers drank tap water containing low to higher amounts of quebracho tannin (QT). Serum urea concentration was measured after lambs drank the treatments for 7 d or steers for 4-6 d. Lambs consumed pellets (16% crude protein [CP] as fed) at 3.5% of body weight, and steers were fed cubes (15% CP as fed) at 3% of body weight. Mean serum urea concentration in sheep was reduced when they consumed water with QT (P = 0.03) and was also reduced for cattle (P < 0.001). In a third trial with a Latin-square design, four wethers were fed pellets (22% CP, DM basis) and given tap water or tap water with low, medium, or high amounts of QT, and their urine urea excretion was measured. There was a linear effect of QT intake on daily urine urea excretion as a percentage of nitrogen intake (P = 0.03). Reductions in daily urea excretion as a percentage of nitrogen intake were 3.5%, 6.6%, and 12.6%, respectively, for the low, medium, and high QT intake. Small amounts of QT in the drinking water of grazing ruminants can reduce their urine urea excretion./La ingestión de pequen ̃as cantidades de taninos concentrados (TC) por los rumiantes podría traer beneficios incluyendo, la reducción de emisiones de amonia y oxido nitroso al reducir la excreción de urea por la orina. Sin embargo, proveer a los rumiantes en pastoreo con suficiente cantidad de TC en el forraje es difícil y una alternativa podría ser agregar el TC en los abrevaderos. Realizamos tres pruebas para determinar sí el nivel de urea en la orina en ovinos y bovinos disminuía después que estos animales bebieran agua con TC. En dos pruebas iniciales, se medio suero sanguino con urea como sustituto de orina de corderos y novillos que bebieron agua conteniendo baja y alta cantidad de tanino de quebracho (TQ). Se midió el suero de urea concentrado después de que los corderos bebieron del tratamiento por 7 días y los novillos de 4 a 6 días. Los corderos consumieron el 3.5% de su peso vivo de suplemento en forma de pellets (16% de PC) y los novillos suplemento en forma de cubos (15% de PC) en cantidad correspondiente al 3% de su peso vivo. La media de la concentración de suero de urea en borregas se redujo cuando consumieron agua con TQ (P = 0.03), y también se redujo en bovinos (P < 0.001). En una tercera prueba con diseño de Cuadro Latino, cuatro corderos se alimentaron con pellets (22% PC, en base a materia seca) y tuvieron acceso a agua sin TQ o agua con cantidades bajo, media y alto de TQ y se medio las excreciones de urea en la orina. Hubo un efecto linear en el consumo de TQ y las excreciones diarias de urea en la orina como un porcentaje del consumo de nitrógeno (P=0.03). La reducción de excreciones diarias de urea en la orina como porcentaje de consume de nitrógeno fueron 3.5%, 6.6%, y 12.6% respectivamente para el bajo, medio y alto consumo de TQ. Cantidades pequeñas de TQ en el agua de beber para ovinos en pastoreo puede reducir la excreción de urea en la orina.

Understory Vegetation and Ponderosa Pine Abundance in Eastern Oregon

2020-09-06T01:19:13Z

Understory Vegetation and Ponderosa Pine Abundance in Eastern Oregon Carr, Craig A.; Krueger, William C. Management prescriptions for contemporary ponderosa pine (Pinus ponderosa Dougl.) forests often incorporate the restoration to a structure that more closely resembles pre-European contact forests. Successful restoration programs should incorporate the herbaceous understory component; however, published research specifically addressing changes in understory species composition is minimal. Ponderosa pine influence on the undercanopy environment may be an important factor in understory vegetation distribution. In this study, we addressed the relationships among ponderosa pine abundance, undercanopy environment, and understory species composition and made inferences with respect to restoration potential. Data representing vegetation, soil, and environmental attributes were measured in 28 plots in an eastern Oregon ponderosa pine forest. Relationships among the parameters measured were evaluated using cluster analysis, indicator species analysis, and ordination. Ponderosa pine occupancy was inversely related to understory perennial bunchgrass abundance and species diversity and appeared to regulate the undercanopy habitat through alterations in light intensity, nitrogen availability, and soil temperature. Light availability was the most important ponderosa pine-influenced undercanopy environmental parameter associated with understory vegetation distribution. These data suggested that degradation in the undercanopy environment associated with higher levels of ponderosa pine abundance may be temporary and that restoration practices that reduce pine occupancy should promote undercanopy conditions favorable to perennial bunchgrass growth. However, understory vegetation recovery in stands with excessive pine ingrowth may be constrained by desired understory species loss or invasion by more competitive understory vegetation.