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Sanderson M.A.,Northern Great Plains Research Laboratory | Brink G.,University Park | Ruth L.,U.S. Department of Agriculture | Stout R.,U.S. Department of Agriculture
Agronomy Journal | Year: 2012

Maintaining a diversity of plant species in pastures may reduce weed invasion. Knowledge of how the proportion of species in a mixture (i.e., species evenness) affects weed invasion would be useful in formulating seed mixtures. We hypothesized that forage mixtures with greater species evenness would reduce weed invasion at establishment better than mixtures dominated by a few species (low species evenness) or monocultures. Fifteen mixtures and monocultures of orchardgrass (Dactylis glomerata L.), quackgrass (Elytrigia repens L.), alfalfa (Medicago sativa L.), and white clover (Trifolium repens L.) were sown in autumn 2008 at four locations in Pennsylvania and Wisconsin. There were four monocultures, four mixtures dominated by one species (evenness = 0.64), six mixtures dominated by pairs of species (evenness = 0.88), and one equal mixture (evenness = 1). We measured the amount of naturally occurring weeds in harvested herbage at each location in 2009. At two locations, we added seed of plumeless thistle (Carduus acanthoides L.) and canola (Brassica napus L.; a surrogate weed) to each treatment during autumn of 2008 and measured their establishment and dry mass during 2009. Grass-legume mixtures resisted weed invasion better than monocultures. Within mixtures, however, species evenness did not influence weed invasion. Species evenness did not affect resource use (light interception or soil inorganic N levels). Individual forage species had a strong effect because weed proportions decreased curvilinearly as orchardgrass proportion of the seed mixture increased. Selecting appropriate species to use in mixtures is more important than the evenness of the species in the mixture. © 2012 by the American Society of Agronomy. Source

Scholljegerdes E.J.,Northern Great Plains Research Laboratory | Scholljegerdes E.J.,New Mexico State University | Lekatz L.A.,Illinois State University | Vonnahme K.A.,North Dakota State University
Animal | Year: 2014

Twenty-four 3-year-old Angus cows (512.2±21.6 kg) and six ruminally cannulated beef heifers (523.1±16.9 kg) were used to determine the impact of feeding oilseeds starting at the beginning of estrous synchronization until maternal recognition of pregnancy on plasma fatty acid composition. Starting ∼60 days postpartum cows were synchronized with the Select Synch+controlled internal drug-release (CIDR) device and timed artificial insemination (AI) protocol. The day CIDR was inserted; cattle were randomly assigned to one of the three treatments being grazing only (CON) or a supplement containing whole soybeans (SOY); or whole flaxseed (FLX). Cattle continued to receive these diets for 28 days. Blood was collected every 3 days until 10 days after insemination and then every day until 18 days after insemination. All cattle grazed a common pasture and supplemented cattle were individually fed their respective supplements once daily. Ruminally cannulated heifers were used to evaluate the impact supplements had on forage intake, which was reduced (P=0.05) with oilseed supplementation. Feeding oilseeds increased total fatty acid intake (P<0.001) across treatments with SOY having greater (P<0.001) 18:2n-6 intake than either CON or FLX. Likewise, cattle fed FLX had greater (P<0.001) 18:3n-3 intake than either CON or SOY. There was a treatment×time interaction (P ≤0.05) for all fatty acids identified except for 20:5n-3 (P=0.99). Within 3 days after the start of supplementation, plasma concentrations of 18:2n-6 increased (P<0.001) for cattle fed SOY compared with CON or FLX, whereas flax-fed cattle did not exhibit an increase (P=0.02) until day 15 of supplementation over that of CON. Plasma concentrations for 18:3n-3 was greater (P<0.013) for FLX than both CON and SOY by day 12. Feeding flaxseed tended to (P=0.07) increase and increased (P=0.01) plasma concentrations of 20:4n-6 by day 18 over CON and SOY, respectively. Overall, treatment did not affect serum concentration of progesterone (P=0.18) or prostaglandin F metabolite (P=0.89). However, day after breeding had an effect on serum progesterone (P=0.01) with day 16 after timed AI being lower compared with other days. Feeding oilseeds during the time of estrous synchronization will not only increase the energy density of the diet but will provide key fatty acids around the time of maternal recognition of pregnancy. © The Animal Consortium 2014. Source

Foster J.G.,U.S. Department of Agriculture | Cassida K.A.,U.S. Department of Agriculture | Sanderson M.A.,University Park | Sanderson M.A.,Northern Great Plains Research Laboratory
Grass and Forage Science | Year: 2011

Palatability and anthelmintic activity of chicory (Cichorium intybus L.) forage are influenced by the sesquiterpene lactones lactucin (LAC), 8-deoxylactucin (DOL) and lactucopicrin. Therefore, the objective of this study was to determine how sesquiterpene lactone concentration and composition vary during the growing season. Three forage chicory cultivars (Puna, Forage Feast and Lacerta) grown in West Virginia and Pennsylvania (USA) were managed during two consecutive years to maintain plants in the vegetative stage, and sesquiterpene lactones in leaves were quantified after each growth interval. Cultivars differed in the total concentration of sesquiterpene lactones and in the proportions of LAC and DOL. Total sesquiterpene lactone concentration generally decreased or remained constant during the season, but the specific response depended on the cultivar. Differences in seasonal patterns between years corresponded with unusual climatic conditions. The three cultivars had similar concentrations of DOL in the spring. Forage Feast provided a dramatically lower concentration of DOL during the summer. Uniformly high concentrations of DOL across the growing season in Puna and Lacerta make these cultivars attractive for use in bioactive pastures for control of Haemonchus contortus. Changes in both sesquiterpene lactone concentration and composition during the season result in large variations in forage bitterness. © 2011 Blackwell Publishing Ltd. Source

Reinhart K.O.,Fort Keogh Livestock and Range Research Laboratory | Nichols K.A.,Northern Great Plains Research Laboratory | Nichols K.A.,Rodale Institute | Petersen M.,Fort Keogh Livestock and Range Research Laboratory | Vermeire L.T.,Fort Keogh Livestock and Range Research Laboratory
Ecosphere | Year: 2015

We estimate rangeland managers assessing ecosystem health have measured soil stability .800,000 times. Our aim was to use quantitative data from a site in the Northern Great Plains, USA and asemi-quantitative literature search to demonstrate the robustness of soil stability as an indicator of ecosystem functioning. Empirical data included measurements of plant and soil properties along a locallivestock grazing gradient to determine whether soil stability (e.g., % water-stable aggregates) explained primary productivity and soil water transport for a mixed-grass prairie site in the Northern Great Plains. We measured: annual net primary productivity (ANPP), elevation, % soil moisture, measures of soil stability, and soil water transport (field-saturated infiltrability and sorptivity) across points spanning a localgradient in livestock grazing intensity (none vs. light to moderate stocking rates; mean distance separating points=39.9 m [range=5.2-71.3 m]). Across the sampled gradient, variation in ANPP was best explainedby a model with field-saturated infiltrability and % soil moisture. Infiltrability explained slightly more of the variation. We then determined that moderate amounts of variation in infiltrability were explained byANPP, % soil moisture, and % water-stable aggregates. We determined that most of this variation was explained by ANPP and then soil moisture. Our empirical findings indicate that plant production wascorrelated with infiltration though we could not determine whether variation in plant production was caused by variation in infiltration or vice versa.We generally failed to show that soil stability (e.g., % waterstableaggregates) was a useful predictor of primary productivity and soil water transport. Our semiquantitative literature review also indicated that soil stability was not a consistent predictor of either plantproduction or infiltration. The varying evidence reported here on whether soil stability is a predictor of ecosystem function illustrates the difficulty in identifying an indicator of ecosystem health that (1) is apredictor of ecosystem function across grassland types, (2) is sensitive to rangeland management, and (3) can be easily implemented by non-experts. Copyright: © 2015 Reinhart et al. Source

Sanderson M.A.,Northern Great Plains Research Laboratory | Liebig M.A.,Northern Great Plains Research Laboratory | Hendrickson J.R.,Northern Great Plains Research Laboratory | Kronberg S.L.,Northern Great Plains Research Laboratory | And 3 more authors.
Journal of Soil and Water Conservation | Year: 2016

A century ago, Johnson Thatcher Sarvis and scientists at Mandan set out to determine the area needed to sustainably support a steer during the grazing sea-son. In addition to answering the original question, scientists gathered some of the first data on grazing resilience of native grasses, determined the critical role of soil moisture in maintaining rangeland productivity on the semiarid northern plains, and generated applied ecological insights on the persistence and resilience of native prairie during the worst drought of the last millennium. Because of the foresight of Sarvis and others, this long-term study continues to serve as a unique and valuable resource. Important long-term ecological and resource management questions, such as vegetation, soil, and cattle weight gain changes with respect to weather, management, etc., simply cannot be answered with short-term data. Leveraging existing long-term data with formation of the LTAR network and NEON can allow us to peer into the future of the northern Great Plains. The question in the twentyfirst century is a similar one: how do we sustainably intensify agroecosystems in an era of climatic and social changes? Our challenge is to exhibit the same foresight and develop research that is still relevant in 100 years. © 2016 Soil and Water Conservation Society. All rights reserved. Source

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