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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