The Effect of Alternative Soil Amendments on the Botanical Composition, Basal Cover, Dry Matter Production and Chemical Properties of Re-Vegetated Mine Land

Coal mining impacts large grassland areas of the Mpumalanga Province of South Africa. To mitigate such impacts, it is imperative to restore the once productive soils to the best possible condition. The revegetation of mine land presents a particular challenge. Soils being rehabilitated are often acidic and nutrientdeficient, which are major limiting factors in re-vegetation programmes. Conventional methods of liming and inorganic fertilisation have been used to improve the productivity of impacted soils. In the past few years the use of a coal combustion by-product, class F fly ash, and an organic material, such as sewage sludge, have demonstrated the feasibility of using such materials to amend acidic and infertile substrates (Truter, 2002; Norton et al., 1998). The objective of this research was to determine if alternative amendments can create a more sustainable system where botanical composition, basal cover, dry matter production and soil chemical properties can be improved

Seed Production and Quality of Buffelgrass (\u3ci\u3eCenchrus ciliaris\u3c/i\u3e) Selections

As seed production and quality are critical considerations in the commercialization of new cultivars, an evaluation programme of promising Cenchrus ciliaris (Buffelgrass) accessions placed particular emphasis on these parameters. Accessions identified for registration proved to be superior in both respects, although storage of seed or cleaning of fresh seed reduced the differences in germination between accessions. The refinement of seed cleaning processes should receive greater emphasis by commercial concerns

Competition for Light in a \u3ci\u3eLeucaena leucocephala / Chloris gayana\u3c/i\u3e Silvopastoral System

The spatial variation in the vigour of Leucaena (Leucaena leucocephala cv. Cunningham) trees growing together with Rhodesgrass (Chloris gayana cv. Katambora) in an alley cropping system made it possible to assess the competitive effect for light. The height and especially lateral development of trees had a strong influence on light interception by the canopy, with radiation in the intercrop area being 49% lower where the trees were more vigorous. There was a corresponding (43%) decrease in grass production. These findings indicate that future studies should also include aspects such as espacement of trees, pruning of trees in the growing season, choice of shade tolerant grasses and the competitive effect for water

Influence of Grazing Frequency on Biomass Production Using Several Selected Tropical Grasses

To provide commercial growers with forage grasses that produce well throughout the year, there is a constant need for screening and testing new germplasm. Two rhodesgrasses (Chloris gayana cv. Rhods and Callide), four stargrasses (Cynodon nlemfuensis Vanderyst var. nlemfuensis cv. Florona, Zimbabwe, Okeechobee, and Rhodesian No. 2), one bermudagrass (C. dactylon var. dactylon cv. Jiggs), and one creeping signalgrass (Brachiaria humidicola CIAT 6369) were tested under a mob-grazing system. Dry biomass yield increased linearly as grazing frequency (GF) was delayed from 2 to 7 weeks. The cultivars, Florona, Zimbabwe and Okeechobee stargrasses and Jiggs bermudagrass, yielded best during the warm season regardless of GF. However, during the cool season Rhods rhodesgrass, Florona stargrass and Jiggs bermudagrass were generally most productive. These grasses were also the most persistent, averaging better than 97% ground cover after 3 years of grazing

Effect of Pre-Planting Seed Treatment Options on Dormancy Breaking and Germination of \u3cem\u3eZiziphus Mucronata\u3c/em\u3e

Ziziphus mucronata (Buffalo thorn) is a multipurpose tree, widely adapted to a range of ecological conditions and tolerant of extreme climatic conditions, including frost and drought (Venter & Venter, 1996). It is a valuable fodder tree for livestock and game animals, especially in the drier parts of Africa (Rothauge et al. 2003). Similar to many other leguminous species, establishment is constrained by low and erratic germination of the seed, which has been attributed mainly to the physical barrier of the stony endocarp and dormancy associated with seed coat impermeability . This experiment aimed to compare the suitability of various seed treatment options as practical methods to break seed dormancy and enhance germination

Effect of Pre-Planting Seed Treatment Options on Dormancy Breaking and Germination of \u3ci\u3eZiziphus Mucronata\u3c/i\u3e

Ziziphus mucronata (Buffalo thorn) is a multipurpose tree, widely adapted to a range of ecological conditions and tolerant of extreme climatic conditions, including frost and drought (Venter & Venter, 1996). It is a valuable fodder tree for livestock and game animals, especially in the drier parts of Africa (Rothauge et al. 2003). Similar to many other leguminous species, establishment is constrained by low and erratic germination of the seed, which has been attributed mainly to the physical barrier of the stony endocarp and dormancy associated with seed coat impermeability. This experiment aimed to compare the suitability of various seed treatment options as practical methods to break seed dormancy and enhance germination

The influence of climate and soils on the distribution of four African grasses

Around 1900 temperate and semidesert grassland productivity declined, soil erosion increased, and drought destabilized the livestock industry in the northern and southern hemispheres. As government leaders throughout the world began to recognize the importance of grassland productivity and soil conservation, a massive experiment began to evolve. Government and private individuals collected seed from every continent, and planted seed at experimental stations and ranches in their respective countries. Hundreds of individuals who conducted thousands of seeding trials observed that buffelgrass (Cenchrus ciliaris L.), weeping lovegrass [Eragrostis curvula (Schrad.) Nees], kleingrass (Panicum coloratum L.), and lovegrass (Eragrostis lehmanniana Nees) plants from seed collected in Africa were easier to establish and persisted longer than other grasses. Between 1930 and 1986 scientists in many countries evaluated the establishment and persistence of these grasses, but no attempt was made to synthesize the data base and determine the effects of climate and soil on plant establishment and persistence. Our objective was to: (1) determine the climatic and edaphic characteristics of areas where the seed of each grass was collected in Africa, and where each grass has been successfully established in both hemispheres, and (2) identify characteristics which influence long-term persistence. Where buffelgrass predominates and spreads, summer rainfall varies from 150 to 550 mm, winter rainfall is less than 400 mm, mean miminum winter temperatures rarely fall below 5 degrees C, and soil texture is loamy. Weeping lovegrass can be established and plants persist when spring, summer, and fall rainfall varies from 400 to 1,000 mm on deep sandy soil and mean minimum winter temperatures rarely fall below -5 degrees C. The invasion of adjacent nonplanted sites occurs only in Africa where growing season rainfall infrequently cycles between 750 and 1,000 mm and soils remain wet in mid-summer. Kleingrass can be established where mean maximum daily summer temperatures are above 30 degrees C, mean minimum daily winter temperatures rarely fall below 0 degrees C, summer growing season rainfall varies from 400 to 990 mm, and soils are clayey or silty. Kleingrass, like weeping lovegrass, spreads to nonplanted sites only in Africa where a mid-summer drought does not occur. Lehmann lovegrass predominates and spreads only in southern Africa, southeastern Arizona, and northern Mexico when summer rainfall in 30 to 40 days exceeds 150 mm, and soil textures are sandy or sandy loam.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Cosmos: An SDL Based Hardware/Software Codesign Environment

International audienceThe goal of this chapter is to introduce COSMOS, a methodology and an environment for the specification and synthesis of mixed systems composed of hardware (HW) and software (SW) starting from system level specifications. The application domain aimed at is communicating heterogeneous systems. The description model used permits an efficient manipulation of complex communication protocol. The resulting target is a mixed architecture that can be either a circuit, a card or a network of distributed processors. The current version of the COSMOS project provides a model for the representation of systems as well as basic primitives for synthesis at the system level. It allows a semi-automatic synthesis starting from system level specifications on an heterogeneous architecture. The ongoing work consists of a study and realisation of systematic partitioning strategies and efficient methods for the estimation and synthesis of communication. The principal choices of languages, representation models and architectures very much favour the design of telecommunication systems. COSMOS uses the SDL (ITU standard) language for the system specification. The result of partitioning and communication synthesis is an executable model of an heterogeneous architecture described in C (ANSI standard) and VHDL (IEEE standard) languages. The COSMOS environment is built around an intermediate format, called SOLAR, designed to facilitate the migration between systems specifications and hardware descriptions. SOLAR permits representation of high level concepts using the hardware semantics. The model is general containing an extended finite state machine and a powerful communication model