Chemical vegetation management in Pinus radiata plantations in South Africa

[摘要] ENGLISH SUMMARY: Pinus radiata is the most important timber tree planted in the western, southern andeastern Cape of South Africa, covering approximately 60000 hectares. The naturalvegetation in these areas is mainly macchia, but exotic invaders like the Acacia andHakea spp. cause severe problems. Macchia vegetation cannot be controlledsuccessfully by means of slashing, hoeing or burning, because it resprouts rapidly inresponse to these treatments. Weed control in P. radiata plantations is mainlyperformed manually.In this study the objective was to search for an alternative, more effective, cheaper,vegetation management option to manual weeding. Trials were conducted where anumber of herbicides (acetochlor, glyphosate, hexazinone, imasapir, metsulfuronmethyl,tetrapion and thiazopyr) were tested under different vegetation managementtreatments. These included the effect of seasons on herbicide efficacy. Preemergentherbicides were added to knockdown herbicides to test if longer relieffrom weeds could be obtained. Different application methods were also tested.Intra-row weeding was compared to total chemical weeding.Glyphosate at 1500g active ingredient per hectare (a.i./ha) and hexazinone at 2000ga.i./ha produced the best results for total weed control. In the southern Cape, weedcontrol in summer was significantly better than weed control in any other season.No significant difference existed between intra-row weeding and total weeding.Chemical vegetation management was less expensive and more efficient thanmanual weed control.

[发布机构] Stellenbosch University