COVER CROPS in South African Vineyards

COVER CROPS IN SOUTH AFRICAN VINEYARDS

Reference list Fourie JC. 2005. Cover crop management in the vineyards of the Lower Orange River region, South Africa: 1. Performance of grass and broadleaf species. South African Journal of Enology and Viticulture 26(2), pp140–146. Olifants River valley A study was conducted over a period of six years to assess the effect of different management practices on the ability of cover crops to re-establish. Trials in the Olifants River valley were conducted at the ARC Infruitec- Nietvoorbij research farm near Lutzville. Eight cover crops were evaluated: rye, triticale, Overberg oats, black oats, grazing vetch, Paraggio bur medic, and Parabinga bur medic. Dry-matter production of plants that were resown annually was compared to that of plants that were allowed to seed themselves. Where plants were resown annually, full-surface chemical weed control was applied in August, before grapevine bud-break. Where plants were allowed to complete their life cycles and produce seed, full-surface chemical control was only applied at the end of November. The results of the trial are summarised in Figure 4.3. Grazing vetch and Parabinga bur medic re-established successfully in 1995. Although triticale, black oats, and Paraggio bur medic also re-established, dry-matter production was only about a third of that obtained with annual sowing. 4,50

4,00

3,50

3,00

1995 Sown annually 1995 Self-sown 1997 Sown annually 1997 Self-sown 1999 Sown annually 1999 Self-sown

2,50

2,00

1,50

1,00

0,50

Dry matter production in tonnes per hectare

0,00

Black Parabinga bur Paraggio Pink serradella oats medic bur medic

Grazing vetch

Rye Triticale Overberg oats

FIGURE 4.3. Dry-matter production of cover crops sown annually compared to re-estab - lishment from self-sown seed in the Olifants River valley. Adapted from Fourie et al (2005).

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