Articles by Author: Johannes Hendrik Van Rooyen

Search results for Johannes Hendrik Van Rooyen

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  1. The inflation-hedging ability of individual shares: Evidence from the Johannesburg Stock Exchange (JSE)

    The inflation-hedging ability of individual shares: Evidence from the Johannesburg Stock Exchange (JSE)

    Item type: Journal Article • Journal: Investment Analysts Journal
    The erosion of purchasing power due to inflation is a source of concern for investors who invest in stocks over long investment horizons.
  2. Maximum profitability as a criterion for optimisation of utilisation intensity

    Maximum profitability as a criterion for optimisation of utilisation intensity

    A technique is proposed for the formulation of a factor/product relationship between grazing days/hectare (ha) and liveweight gain/ha in order to relate maximum profitability to intensity of herbage utilisation in beef production systems in the False Thornveld of the Eastern...
  3. Herverspreiding van grondwater in drie subhabitatte van ‘n <em>burkea</em> ‐savanna <em>redistribution of groundwater in three sub habitats of a</em> burkea <em>sa vanna</em>

    Herverspreiding van grondwater in drie subhabitatte van ‘n <em>burkea</em> ‐savanna <em>redistribution of groundwater in three sub habitats of a</em> burkea <em>sa vanna</em>

    Grondwaterherverspreiding vind vinnig in die hele grondprofiel van drie subhabitatte nl. Eragrostis pallens, Ochna pulchra en Grewia flavescens van ‘n Burkea‐savanna plaas. Na ‘n reënbui van 50 mm herversprei water binne 12 uur tot op ‘n diepte van 90 cm...
  4. Veld condition assessments in sour bushveld<sup>1</sup>

    Veld condition assessments in sour bushveld<sup>1</sup>

    The vegetation of the farm “Groothoek” in the Waterberg district of the Transvaal, situated in the Sour Bushveld, was recently studied using the Braun‐Blanquet method. As nested quadrats were used for sampling the vegetation, the condition of the vegetation was...
  5. Die produksie en kwaliteit van verskillende voersorghum‐ en Babala kultivars in die wes‐Transvaal

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    The production and quality of different fodder sorghum and Babala cultivars in the western Transvaal. A number of sorghum cultivars are available commercially, and periodically some cultivars are added while others are withdrawn from the market. The potential yield figures...
  6. Determinants of herbaceous plant species composition on a number of ranches in the north‐western Transvaal

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    Herbaceous plant species composition was measured on ranches in the Thabazimbi district, Transvaal, to obtain veld composition scores and to quantify the relations between such scores and certain determinants considered important in influencing species composition. Determinants investigated were mean annual...
  7. Measurement of exchangeable aluminium in soils and clay minerals by isotopic exchange

    Measurement of exchangeable aluminium in soils and clay minerals by isotopic exchange

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Isotopically exchangeable Al was determined in soils and clay minerals by equilibration with 28Al. Best results were obtained with a weak extractant and an equilibration time of eight min. The calculated amount of isotopically exchangeable Al was independent of the...
  8. Pedogeomorphic aspects of the Roodepoort area, Transvaal: Soil depth-slope relationships

    Pedogeomorphic aspects of the Roodepoort area, Transvaal: Soil depth-slope relationships

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Fifty hillslope profiles with associated soils in the Roodepoort area, Transvaal, were examined to determine the relationships between soil depth and hillslope characteristics. A meso-scale approach was adopted which implied the relationship between three soil depth phases and the hillslope...
  9. Quantitative criteria for distinguishing melanic from vertic soil horizons in the central Kruger National Park

    Quantitative criteria for distinguishing melanic from vertic soil horizons in the central Kruger National Park

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Criteria based on shrink-swell potential, viz. linear shrinkage and COLErod, were used to distinguish between melanic and vertic soil horizons of the Mooiplaas region in central Kruger National Park. For linear shrinkage the proposed boundary value separating melanic and vertic...