Articles by Author: Tr Hill

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  1. The management of plant cover on mine wastes in Zimbabwe: Fertilizer trials on slimes dams

    The management of plant cover on mine wastes in Zimbabwe: Fertilizer trials on slimes dams

    Factors limiting plant growth on mining wastes containing total values of 1 980 ppm As, 1 180 ppm Cu and 2 130 ppm Ni were investigated. Responses to 80 kg N/ha were significant (p = 0,01) on all wastes and...
  2. A root growth study used to examine the suitability of two grasses for stabilizing toxic mine wastes<sup>1</sup>

    A root growth study used to examine the suitability of two grasses for stabilizing toxic mine wastes<sup>1</sup>

    The rooting ability of Dactyloctenium geminatum and Paspalum vaginatum was studied in a pot trial using mining wastes (slimes) containing a total 1 980 ppm arsenic and a specific conductivity of 16 050 micromhos. Under the conditions of the pot...
  3. Refinement of a model describing forage production, animal production and profitability as a function of bush density in the false thornveld of the eastern cape

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    An existing model describing the influence of Aeacia karroo density on forage production, animal production and profitability is reviewed and amended to introduce recent research results.
  4. Coevolution of African grasses and large herbivores

    Coevolution of African grasses and large herbivores

    African grasslands have developed under the impact of fire and grazing. There has been strong selection for grass plants to deter, escape and tolerate herbivory, and to escape and tolerate fire. It follows that the complete withdrawal of fire from...
  5. Towards a method of assessing the veld condition of the valley bushveld in the Eastern Cape

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    Currently, no technique is available for assessing the condition of Valley Bushveld in the Eastern Cape. The objective of this investigation was to develop a method of scoring bushveld according to its productive condition. It was established, through principal component...
  6. Adaptation of a decreaser and an increaser grass species to defoliation in semi‐arid grassveld

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    Grasses have developed through natural selection to deter, escape and tolerate herbivory, and to escape and tolerate fire. In the semi‐arid grassveld of the Eastern Cape, the species Themeda triandra and Sporobolus fimbriatus have been classified as Decreaser and Increaser...
  7. The influence of an <em>Acacia karroo</em> tree on grass production in its vicinity

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    The investigation was concerned with the impact of an Acacia karroo tree on the productivity of the surrounding herbaceous layer.
  8. Browse and herbage production in the eastern cape thornveld in response to tree size and defoliation frequency

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    Grass yields in this semi‐arid savanna declined as the size of Acacia karroo increased. Browse yields, however, did not increase as trees grew out beyond 1,8 m in height and it follows that if bush thinning is required, then the...
  9. The effect of severe drought and management after drought on the mortality and recovery of semi‐arid grassveld

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    The False Thornveld of the Eastern Cape experienced a particularly intense drought during the 1982/83 growing season. Extensive grass mortality took place during the drought. After the drought, recovery was particularly sensitive to the post‐drought management treatment applied. Veld that...
  10. Water utilization patterns around isolated <em>Acacia karroo</em> trees in the False Thornveld of the eastern Cape

    Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa
    The effect of various vegetation treatments on two soil moisture regimes (i.e. the proportion of the experimental period where the soil had sufficient water for: (a) growth, and (b) to keep the plants turgid in the vicinity of experimentally isolated...