Articles by Author: A W Schumann

Search results for A W Schumann

We found 11 results for you
  1. The Impact of Weeds and Two Legume Crops on <em>Eucalyptus</em> Hybrid Clone Establishment

    Item type: Journal Article • Journal: South African Forestry Journal
    The relative competition imposed on Eucalyptus hybrid clone GC304 grown from establishment with either complete weed cover, intra-row weeds, inter-row weeds or legume cover crops of Mucuna pruriens and Vigna sinensis is under study in a field experiment on a...
  2. The Amelioration of <em>Pinus patula</em> Mortality on Former Agricultural Sites through Fertilisation: A Bioassay and Greenhouse Study

    Item type: Journal Article • Journal: South African Forestry Journal
    Recent expansion of the timber industry into areas previously used for agronomic production has, in many cases, resulted in poor growth of Pinus patula and P. elliottii seedlings and in certain instances complete stand failure. A bioassay study was initiated...
  3. Evidence of Induced Nutrient Deficiency in Pine Plantings on Previously Cropped Lands

    Item type: Journal Article • Journal: South African Forestry Journal
    Widespread establishment failures of Pinus species have recently occurred on agricultural land acquired for commercial forestry in South Africa. These include about 10 000 ha of previously tilled soils in the north-eastern Cape belonging to Mondi Forests. A lettuce (Lactuca...
  4. Suppression of seed germination and early seedling growth by plantation harvest residues

    Suppression of seed germination and early seedling growth by plantation harvest residues

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The role of forestry plantation residues (leaf and branch) in the suppression of establishment of four weed species (Conyza sumatrensis, Trifolium spp., Echinochloa utilis and Lactica sativa) was investigated. Of the three residue types used, Pinus patula residues were found...
  5. The bottom boundary layer inshore of the Agulhas Current off Natal in August 1975

    The bottom boundary layer inshore of the Agulhas Current off Natal in August 1975

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Previous work off Natal showed that current flows are generally fairly strong on the narrow shelf regions inshore of the Agulhas Current. During August 1975, approximately hourly profiles of temperature, salinity and currents measured from a ship in 49 m...
  6. Ocean current and temperature structures in Algoa Bay and beyond in November 1986

    Ocean current and temperature structures in Algoa Bay and beyond in November 1986

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Data on ocean temperature, currents, salinity and nutrients were obtained in an area off Algoa Bay on the south-east coast of South Africa during a ship's cruise in early November 1986. Satellite imagery provided information on the position of the...
  7. An Agulhas Current intrusion into Algoa Bay during August 1988

    An Agulhas Current intrusion into Algoa Bay during August 1988

    Item type: Journal Article • Journal: South African Journal of Marine Science
    During August 1988, warm water from a plume originating in an Agulhas Current meander, and cold water from an eddy nested in the offshore deflection of the meander, penetrated over the adjacent continental shelf and into Algoa Bay. The intrusion...
  8. Upwelling and the occurrence of cold water around Cape Recife, Algoa Bay, South Africa

    Upwelling and the occurrence of cold water around Cape Recife, Algoa Bay, South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Between February 1989 and March 1990 a study was undertaken to investigate sea temperature variability around Cape Recife, Algoa Bay, during and after upwelling events. Data were collected by moored thermistors and during a ship's cruise, and wind measurements were...
  9. Dissolved Oxygen Characteristics of the Gamtoos Estuary, South Africa

    Dissolved Oxygen Characteristics of the Gamtoos Estuary, South Africa

    Item type: Journal Article • Journal: African Journal of Marine Science
    The fall and recovery of dissolved oxygen (DO) is documented throughout the Gamtoos Estuary, South Africa during dry conditions and following light and heavy rainfall over a 13-month period from November 1992 to November 1993. Hypoxic conditions generally occurred in...
  10. Oceanic variability in the western sector of Algoa Bay, South Africa

    Oceanic variability in the western sector of Algoa Bay, South Africa

    Item type: Journal Article • Journal: African Journal of Marine Science
    The city of Port Elizabeth lies in the western sector of Algoa Bay, and a number of projects have investigated the oceanic temperature, salinity and current structures in the vicinity. This paper analyses past results, and then incorporates measurements of...