COVER CROPS in South African Vineyards

CHAPTER 5 WEED CONTROL

Dry-matter production of summer-growing weeds in the control were reduced in the first year after the establishment of the vineyard, and peaked in the second year. It can be seen that, from 1995 onward, weed stands tended to be lower in the annual cover-crop treatments than in the control, and dry- matter production of weeds also tended to decline over time. In contrast, perennial dwarf fescue was associated with increased dry-matter production of weeds in most years.

These results indicate that annual cover crops have the potential to improve weed control in the warmer regions where grapevines are cultivated. Good results were obtained with monocultures of grasses and legumes, as well as with mixtures and rotational plantings. However, perennial cover crops not only failed to suppress weeds, but were in fact associated with increased weed stands. Reference list

ANNUAL COVER CROPS HAVE THE POTENTIAL TO IMPROVE WEED CONTROL IN THE WARMER REGIONS WHERE GRAPEVINES ARE CULTIVATED.

Fourie JC. 2010. Soil management in the Breede River valley wine grape region, South Africa. 1. Cover crop performance and weed control. South African Journal of Enology and Viticulture , 31(1), 14–21. Coastal region Most of the trials in the Coastal region were conducted at the ARC Infruitec- Nietvoorbij research farm in Stellenbosch in the Western Cape. Different cover crops were sown in vineyards as described inVineyard trials in Chapter 3 (p61). Dry-matter production was measured for the cover crops, and for both winter- and summer-growing weeds. Trials also took place at Plaisir de Merle farm, near Paarl, and Blaauwklip- pen farm, in the Stellenbosch district. Winter-growing weeds The effect of ten different cover crops on dry-matter production of winter- growing weeds was assessed at the ARC Infruitec-Nietvoorbij research farm over a period of ten years.The vineyards received full-surface micro-sprinkler irrigation. Cover crops were sown each autumn, and full-surface chemical weed control was started at bud-break.

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