COVER CROPS in South African Vineyards

COVER CROPS IN SOUTH AFRICAN VINEYARDS

TABLE 3.5. The seeding dates and performance for grasses and legumes evaluated in open-land trials in the Olifants River valley. Cover-crops are ranked by dry-matter production. Adapted from Fourie et al (2001).

Dry-matter production in tonnes per hectare Cover crop 1 Weeds 2

Seeding date

Common name

Grasses Rye*

13–18 April 13–18 April 13–18 April 13–18 April 13–18 April

5.92 5.85 5.08 5.00 4.22

0.33 0.24 0.34 0.42 0.86 1.68 0.10 0.69 0.37 0.72 1.26 0.87 1.28 0.58 0.72 0.44 0.72 1.57 1.21 1.68 1.58 0.97 1.88 1.75 2.01 1.80

Black oats*

Overberg oats*

Triticale*

Barley

Perennial phalaris or bulbous canary-grass 25–31 March 1.78

Legumes Grazing vetch*

13–18 April

6.73

Paraggio bur or barrel medic*

25–31 March 6.58

Pink serradella*

13–18 April

6.40

Parabinga bur or barrel medic* Mount Barker subterranean clover Woogenellup subterranean clover

25–31 March 5.94 25–31 March 5.54 25–31 March 5.19 25–31 March 5.02 25–31 March 4.82

Clare subterranean clover

Broadleaf purple or common vetch

Trikkala subterranean clover

13–18 April 13–18 April 13–18 April

4.67 4.58 4.50

Harbinger medic

Rose clover

Kelson snail medic

25–31 March 4.47

Faba bean

13–18 April

4.45

Assegaai clover Balansae clover Persian clover

25–31 March 3.91 25–31 March 3.49 25–31 March 3.46 25–31 March 1.48 25–31 March 1.25

White clover

Palestine clover

Gabriel perennial lotus Campbell annual lotus

13–18 April 13–18 April

0.95 0.76

* plants that were included in long-term vineyard trials. 1 cover-crop dry-matter production below 2.5 tonnes per hectare is considered too low for weed suppression. 2 weed dry-matter production above 1.0 tonne per hectare indicates insufficient suppression.

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