Articles by Author: Dave Joubert

Search results for Dave Joubert

We found 174 results for you
  1. Visual obstruction as a method to quantify herbaceous biomass in southern African semi-arid savannas

    Visual obstruction as a method to quantify herbaceous biomass in southern African semi-arid savannas

    Item type: Journal Article • Journal: African Journal of Range & Forage Science
    Biomass of aboveground vegetation is a useful descriptor for studies of grazing, fire and wildlife habitat use in grassland systems. The traditional method to estimate biomass, hand-clipping, is time intensive and other indices of biomass have been used successfully. In...
  2. The effect of fire history on soil nutrients and soil organic carbon in a semi-arid savanna woodland, central Namibia

    The effect of fire history on soil nutrients and soil organic carbon in a semi-arid savanna woodland, central Namibia

    Item type: Journal Article • Journal: African Journal of Range & Forage Science
    Fire is an integral part of savanna ecosystems that has shaped these systems since the Miocene. Substantial uncertainty about fire effects in semi-arid ecosystems exists. Fire may affect ecosystem productivity directly through nutrient volatilisation, increased mineralisation and altering organic matter...
  3. Commercial Forestry on Signal Hill and Lion's Head, Cape Town

    Item type: Journal Article • Journal: South African Forestry Journal
    The history of afforestation with alien tree species on Signal Hill and Lion's Head, which form part of the Table Mountain Nature Reserve, Cape Town, was reconstructed. The natural vegetation comprises mostly West Coast Renosterveld which is considered the most...
  4. Vestigingsmetodes vir <em>osteospermum sinuatum</em> in die veld van die Klein Karoo

    Vestigingsmetodes vir <em>osteospermum sinuatum</em> in die veld van die Klein Karoo

    Osteospermum sinuatum of bitou is ‘n smaaklike inheemse meerjarige karoobossie wat feitlik uitgeroei is, deur oorbeweiding in die veld, maar wat suksesvol hervestig kan word van saad. Die resultate van ‘n vestigingsproef op die Worcesterse Veldreservaat het getoon dat geen...
  5. Die invloed van verskillende veedigthede teen dieselfde veebeladings op die produksie van jong groeiende ossies op oshonagrasveld

    Die invloed van verskillende veedigthede teen dieselfde veebeladings op die produksie van jong groeiende ossies op oshonagrasveld

    ‘n Weidingsproef is uitgevoer in Oshonagrasveld in Ovambo om vas te stel wat die invloed van verskillende veedigt‐hede teen konstante veebeladings op die produksie van jong ossies is.
  6. Die invloed van snoei op koolsuurg asabsorpsie en koolhidraatinhoud van <em>ehrharta calysina</em> en <em>osteospermumsinuatum</em>

    Die invloed van snoei op koolsuurg asabsorpsie en koolhidraatinhoud van <em>ehrharta calysina</em> en <em>osteospermumsinuatum</em>

    Verwydering van 80% van die bogrondse massa (op ‘n varsmassa basis) van Ehrharta calycina (gras) en Osteospermum sinuatum (bossie) in onderskeidelik die vlagblaar en blomknopstadium het ‘n skerp daling in die totale netto CO2 absorpsie van die plante tot vegolg...
  7. Die invloed van snoei tydens antese op koolsuurgasabsorpsie en koolhidraatinhoud van <em>ehrharta calycina</em> en <em>osteospermum sinuatum</em>
               <sup>1</sup>

    Die invloed van snoei tydens antese op koolsuurgasabsorpsie en koolhidraatinhoud van <em>ehrharta calycina</em> en <em>osteospermum sinuatum</em> <sup>1</sup>

    Verwydering van onderskeidelik 40% en 80% van die bogrondse varsmassa van Ehrharta calycina (gras) en Osteospermum sinuatum (Karoobossie) tydens antese het ‘n afname in die totale netto CO2‐absorpsie, suikerkonsentrasie, styselkonsentrasie en totale beskikbare koolhidraatinhoud van die plante tot gevolg gehad,...