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Short-Term Effect of Grazing Exclusion and Uncontrolled Grazing on Species Abundance, Dry Matter Yield and Nutritive Value in an Invaded Area by Euryops floribundus in the Eastern Cape, South Africa

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Open Journal of Ecology 2023年第6期13卷 321-333页

作者： Sive Tokozwayo Eric Cofie Timpong-Jones Keletso Mopipi Masibonge Gxasheka Unathi Gulwa Siza Mthi Mthunzi Mndela Mzwethu Dastile Azile Dumani Department of Rural Development & Agrarian Reform D&#246hne Agricultural Development Institute Stutterheim South Africa Livestock and Poultry Research Center School of Agriculture College of Basic and Applied Sciences University of Ghana Legon Ghana Department of Range and Forage Resources Botswana University of Agriculture & Natural Resources Gaborone Botswana Department of Plant Production Soil Science & Agricultural Engineering University of Limpopo Polokwane South Africa Department of Rural Development and Agrarian Reform Queenstown South Africa Department of Livestock & Pasture University of Fort Hare Alice South Africa Department of Rural Development and Agrarian Reform Cradock South Africa

Grazing exclusion (GE) is the most effective rangeland restoration technique which facilitates species diversity and forage quality. This study aimed at assessing short-term impact of GE and continuously grazed rangeland on relative frequency, dry matter yield and nutritive value of dominant grasses in an area invaded by Euryops floribundus. A plot of 2.5 ha was measured and the boundaries demarcated using tape measure and steal pins, the plot was further divided into two subplots of 1ha each which were 5 m apart. One subplot was fenced and protected from grazing livestock, while one subplot was grazed continuously and not fenced. Three parallel belt transects of 100 m × 2 m with 3 m apart were laid out in both subplots. Woody plants occurring within the transects were identified and recorded to determine density. In each subplot, a 0.25 m2 quadrant measuring was thrown randomly to take detailed records on plant species, relative frequency of species and herbage biomass. Four dominant species at the two sites were harvested to determine the nutritive value. Results indicate that grazing exclusion (GE) facilitates grass species diversity, subsequently sixteen and thirteen grasses species were recorded in the GE and uncontrolled grazed (UG) sites, respectively. Eragrostis chloromelas (21.7%), and Themeda triandra (13.2%) had high relative frequencies in the GE site. Highest biomass production was recorded in the GE site (1400 kg·ha-1) compared to UG site (1102 kg·ha-1). Crude protein content was relatively lower at UG site (5.4% - 5.8%) as compared to GE site (7.2% - 7.8%). It was concluded that, GE showed a positive impact on a relative frequency (%), dry matter yield and crude protein content. UG creates a conducive environment for Euryops recruitment. Further studies are required to examine the impact of GE in long-term trial setup.

关键词： Dry Matter Yield Crude Protein Nutritive Value relative frequency

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Mathematical Modelling and Analysis of Lamb Waves in Elasto-Thermodiffusive Plates

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Advances in Applied Mathematics and Mechanics 2010年第2期2卷 238-258页

作者： J.N.Sharma P.K.Sharma Department of Applied Sciences National Institute of TechnologyHamirpur 177005India Department of Mathematics SL Bawa Dayanand Anglo Vedic CollegeBatala 143505India

The propagation characteristics of elasto-thermodiffusive Lamb waves in a homogenous isotropic,thermodiffusive,elastic plate have been investigated in the context of linear theory of generalized *** developing the formal solution of the mathematical model consisting of partial differential equations,the secular equations have been derived by using relevant boundary conditions prevailing at the surfaces of the plate for symmetric and asymmetric wave modes in completely separate *** secular equations for long wavelength and short wavelength waves have also been deduced and *** amplitudes of displacement components,temperature change and mass concentration under the Lamb wave propagation conditions have also been *** complex transcendental secular equations have been solved by using a hybrid numerical technique consisting of irreducible Cardano method along with function iteration technique after splitting these in a system of real transcendental *** numerically simulated results in respect of phase velocity,attenuation coefficient,specific loss factor and relative frequency shift of thermoelastic diffusive waves have been presented graphically in the case of brass material.

关键词： Diffusion Cardano method relative frequency thermal relaxation iteration method

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