COVER CROPS in South African Vineyards

COVER CROPS IN SOUTH AFRICAN VINEYARDS

Grazing vetch was less effective than triticale, especially when chemical weed control was applied later, but was associated with significant weed suppression in most years when chemical weed control was applied in August. . er.

3,5

3,0

No cover crop Triticale. Weed control from August. Triticale. Weed control from November. Grazing vetch. Weed control from August. Grazing vetch. Weed control from November.

2,5

2,0

1,5

1,0

0,5

0,0

. 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 . Year Dry-matter production of weeds in tonnes per hectare FIGURE 5.23. Dry-matter production of summer-growing weeds in cover-crop treatments with two different weed-control strategies compared to a control without a cover crop in the Breede River valley. Adapted from Fourie (2010). The results for the other annual cover crops are shown in Figure 5.24. Also shown in Figure 5.24 are the results for dwarf fescue, which was grown as a perennial cover crop, without chemical weed control.

3,5

3,0

No cover crop Rye + faba bean mix Triticale + grazing vetch two-yearly rotation Triticale + grazing vetch annual rotation Dwarf fescue

2,5

2,0

1,5

1,0

0,5

0,0

. 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 . Year Dry-matter production of weeds in tonnes per hectare FIGURE 5.24. Dry-matter production of summer-growing weeds in cover-crop treatments compared to a control without a cover crop in the Breede River valley. Full-surface chemical weed control was applied from the end of August to harvest, except for dwarf fescue, which was slashed. Adapted from Fourie (2010).

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