COVER CROPS in South African Vineyards

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CHAPTER 8 EFFECT OF COVER CROPS ON GRAPEVINE NUTRITION AND PERFORMANCE

clover

rol

1200

1000

800

600

400

1994–1999 2000/01 2001/02

200

0

Nitrogen in milligram per litre

Sown annually

Sown annually

Sown annually

Sown annually

Sown annually

Sown two-yearly

Sown two-yearly

Sown two-yearly

Sown two-yearly

Sown two-yearly

Chemical control

Grazing vetch Faba bean Paraggio bur medic

Kelson snail medic

Woogenellup clover

No cover crop

FIGURE 8.13. Nitrogen measured in the grape juice from vines in legume cover-crop treatments compared to a control in the Coastal region. Adapted from Fourie et al (2006). Vegetative growth and grape yield Shoot mass and grape yield for the grass cover-crop treatments are shown in Figure 8.14, and for the legume treatments in Figure 8.15.

In 1995/96, shoot masses and grape yields in the annually sown cover-crop treatments tended to be higher than in those sown two-yearly. Note that full-surface chemical control was started at grapevine bud-break where cover crops were sown annually, and three months later where cover crops were sown two-yearly. This illustrates the importance of full-surface chemical control from bud-break in young grapevines.

FULL-SURFACE CHEMICAL CONTROL FROM BUD-BREAK IS VERY IMPORTANT IN YOUNG GRAPEVINES.

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