The Use of Open Communal Grazing Designs to Screen Options for Grazing Management

An open communal grazing design is described that enables a large number of grazing tactics to be concurrently evaluated in small plots under common grazing conditions. Pasture data indicated that the same level of utilisation occurred inside the experimental plots as in the surrounding field. However, differential grazing may occur where plots have divergent composition. The open communal design was economical using \u3c 5% of the land, livestock and fencing resources of alternative designs. The limitations of the open communal design as a research tool are also discussed

The Analysis of Results from Paired Paddock Comparisons

Paired-paddock comparisons are a common way of evaluating new grassland practices at a scale more relevant to farmers. They are also being used to replace or augment designed experiments and can be the only source of information available on a practice. However, it is often uncertain if the differences between paddocks are significant. Importantly, a current trend among funding organisations is to support paddock comparisons. The need for valid procedures to compare unreplicated treatments is increasingly urgent. It is suggested that a range of tools be used to infer statistical significance from using typical error values from related studies or subsampling, through to multivariate techniques to follow trends. Local ‘rules of thumb’ could be developed and data evaluated with calibrated models. A final judgement on treatment effects would need to be based upon the use of several criteria to achieve a ‘balance of probabilities’. Consideration of these problems suggests that paired-paddocks should only be used to evaluate contrasting treatments where large effects are expected and not small variations within a practice

Valuing the Pasture Resource - Importance of Perennials in Higher Rainfall Regions of South Eastern Australia

The premature decline of perennial grass based pastures in southern temperate Australia results in poor productivity and unstable pastures that allow invasion by less desirable weedy species and the potential for soil degradation. The loss of perennial species is attributed to overgrazing arising from an undervaluation of the pasture resource. Resowing pastures is largely uneconomic so maintenance of, or increasing the perennial, is dependent on improved grazing and pasture management practices. A key to changing perceptions is valuing the true worth of the perennial component. Results are presented from a model that takes into account the seasonality of production of pastures of different composition. The model uses specific metabolically energy values for the different functional groups that are typically within pastures (perennial grasses, annual grasses, legumes, broadleaf species) and livestock demand, to estimate animal performance and then gross margins for different pasture types. The results show that the value of perennial grasses is much greater than any other component and the more perennial grass, the greater the returns. The potential use of this approach to provide more useful information to landholders, permitting more appropriate management decisions to be made, is described

Grassland Rehabilitation through Re-Designing Livestock Management Systems

Grasslands are one of the most important land types supplying critical ecosystem services including feed for livestock grazing. They occupy ~54% of the world’s ice-free land surface. China contains the third largest area of grassland in the world, ~400 M ha, ~40% of China’s land surface. Chinese grasslands are severely degraded primarily due to overgrazing, which contributes to local poverty because of poor livestock production. To both recover the degraded grassland and to enhance the local herders’ income, a large farm-scale experiment was conducted in a desert steppe of Inner Mongolia, China from 2007 to 2012. We used a baseline survey, production models, and extension with government and private companies to test a redesigned grassland livestock management system. The new system employed summer grazing, winter greenhouse shed feeding, a reduction of overall stocking rate, lambing in summer (July), livestock infrastructure structure improvements, use of animal nutrient supplements, and incorporating crossbred Dorper and Mongolian sheep. This system showed positive advantages on animal production and household net income and transformed livestock production from a survival to a production enterprise. Of critical additional importance was that grassland rehabilitation occurred with the new management system, albeit slower than the more immediate positive changes to animal performance and herder net incomes. The integration of science, government and industry were key for this successful large-scale farm experiment

Coverage-dependent adsorption sites in the K/Ru(0001) system: a low-energy electron-diffraction analysis

The two ordered phases p(2 × 2) at a coverage θ = 0.25 and (√3 × √3)R30° at θ = 0.33 of potassium adsorbed on Ru(0001) were analyzed by use of low-energy electron-diffraction (LEED). In the (√3 × √3)R30° phase, the K atoms occupy threefold hcp sites, while in the p(2 × 2) phase the fcc site is favoured. In both phases, the K hard-sphere radii are nearly the same and close to the covalent Pauling radius

Evidence for geomagnetic excursions recorded in Brunhes and Matuyama Chron lavas from the trans‐Mexican volcanic belt

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99072/1/arar_methodology.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/99072/2/jgrb50214.pd

Oxygen adsorption on the Ru (10 bar 1 0) surface: Anomalous coverage dependence

Oxygen adsorption onto Ru (10 bar 1 0) results in the formation of two ordered overlayers, i.e. a c(2 times 4)-2O and a (2 times 1)pg-2O phase, which were analyzed by low-energy electron diffraction (LEED) and density functional theory (DFT) calculation. In addition, the vibrational properties of these overlayers were studied by high-resolution electron loss spectroscopy. In both phases, oxygen occupies the threefold coordinated hcp site along the densely packed rows on an otherwise unreconstructed surface, i.e. the O atoms are attached to two atoms in the first Ru layer Ru(1) and to one Ru atom in the second layer Ru(2), forming zigzag chains along the troughs. While in the low-coverage c(2 times 4)-O phase, the bond lengths of O to Ru(1) and Ru(2) are 2.08 A and 2.03 A, respectively, corresponding bond lengths in the high-coverage (2 times 1)-2O phase are 2.01 A and 2.04 A (LEED). Although the adsorption energy decreases by 220 meV with O coverage (DFT calculations), we observe experimentally a shortening of the Ru(1)-O bond length with O coverage. This effect could not be reconciled with the present DFT-GGA calculations. The nu(Ru-O) stretch mode is found at 67 meV [c(2 times 4)-2O] and 64 meV [(2 times 1)pg-2O].Comment: 10 pages, figures are available as hardcopies on request by mailing [email protected], submitted to Phys. Rev. B (8. Aug. 97), other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm

Evaluation of the multispecimen parallel differential pTRM method: a test on historical lavas from Iceland and Mexico

Accepted versio

Probing the crossover in CO desorption from single crystal to nanoparticulate Ru model catalysts

cited By 10International audienceUsing model catalysts, we demonstrate that CO desorption from Ru surfaces can be switched from that typical of single crystal surfaces to one more characteristic of supported nanoparticles. First, the CO desorption behaviour from Ru nanoparticles supported on highly oriented pyrolytic graphite was studied. Both mass-selected and thermally evaporated nanoparticles were deposited. TPD spectra from the mass-selected nanoparticles exhibit a desorption peak located around 410 K with a broad shoulder extending from around 480 K to 600 K, while spectra obtained from thermally evaporated nanoparticles exhibit a single broad feature from ∼350 K to ∼450 K. A room temperature deposited 50 Å thick Ru film displays a characteristic nanoparticle-like spectrum with a broad desorption feature at ∼420 K and a shoulder extending from ∼450 K to ∼600 K. Subsequent annealing of this film at 900 K produced a polycrystalline morphology of flat Ru(001) terraces separated by monatomic steps. The CO desorption spectrum from this surface resembles that obtained on single crystal Ru(001) with two large desorption features located at 390 K and 450 K due to molecular desorption from terrace sites, and a much smaller peak at ∼530 K due to desorption of dissociatively adsorbed CO at step sites. In a second experiment, ion sputtering was used to create surface defects on a Ru(0 1 54) single crystal surface. A gradual shift away from the desorption spectrum typical of a Ru(001) surface towards one resembling desorption from supported Ru nanoparticles was observed with increasing sputter time. © 2011 the Owner Societies