COVER CROPS in South African Vineyards

CHAPTER 8 EFFECT OF COVER CROPS ON GRAPEVINE NUTRITION AND PERFORMANCE

rol

1200

1000

800

600

1994–1999 2000/01 2001/02

400

200

Nitrogen in milligram per kilogram

0

Sown Sown two- Sown Sown two- Chemical annually yearly annually yearly annually yearly control Henog rye Overberg oats Saia black oats No cover crop Sown Sown two-

The nitrogen levels measured as nitrates in the leaf petioles of grapevines in the different legume cover-crop treatments are shown in Figure 8.11. Nitrate-nitrogen was never deficient, and in nearly all the legume treatments exceeded 1 000 milligram per kilogram at times. rol clove ic ic FIGURE 8.10. Nitrogen measured as nitrates in the leaf petioles of grapevines in grass cover-crop treatments compared to a control in the Coastal region. Box indicates acceptable range. Adapted from Fourie et al (2006).

1800 1600 1400 1200 1000

800 600 400 200 0

1994–1999 2000/01 2001/02

Nitrogen in milligram per kilogram

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 8.11. Nitrogen measured as nitrates in the leaf petioles of grapevines in legume cover-crop treatments compared to a control in the Coastal region. Box indicates acceptable range. Adapted from Fourie et al (2006).

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