COVER CROPS in South African Vineyards

CHAPTER 8 EFFECT OF COVER CROPS ON GRAPEVINE NUTRITION AND PERFORMANCE trol rol

16,00 14,00 12,00 10,00

8,00 6,00 4,00 2,00 0,00

Shoot mass 1995/96 Shoot mass 2002/03 Grape yield 1995/96 Grape yield 2002/03

Mass in tonnes per hectare

Sown annually

Sown annually

Sown annually

Sown two-yearly

Sown two-yearly

Sown two-yearly

Chemical control

Mechanical control

Henog rye

Overberg oats

Saia black oats

No cover crop

FIGURE 8.24. Vegetative growth and grape yield in grass cover-crop treatments compared to a control in the Olifants River valley. Adapted from Fourie et al (2007). trol rol

18,00 16,00 14,00 12,00 10,00

8,00 6,00 4,00 2,00 0,00

Shoot mass 1995/96 Shoot mass 2002/03 Grape yield 1995/96 Grape yield 2002/03

Mass in tonnes per hectare

Sown annually

Sown annually

Sown annually

Sown annually

Sown two-yearly

Sown two-yearly

Sown two-yearly

Sown two-yearly

Chemical control

Mechanical control

Parabinga bur medic

Pink serradella Grazing vetch

No cover crop

Paraggio bur medic

FIGURE 8.25. Vegetative growth and grape yield in legume cover-crop treatments compared to a control in the Olifants River valley. Adapted from Fourie et al (2007).

The ratio of grape yield to shoot mass is shown in Figure 8.26. Ratios of less than four, as well as the relatively high shoot mass, indicates that an even bigger crop could have been loaded on these young grapevines at their third harvest.

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