FERTILISATION GUIDELINES FOR THE TABLE GRAPE INDUSTRY

CHAPTER 5

FIGURE 22: Copper deficiencies are not very specific, but are comparable to simazine damage, with dead growing tips (Photos: D. Saayman).

The Cu content of soils is also determined through EDTA-extraction, and for soils with a pH KCl of between 5.0 and 6.5, the Cu content should be at least 0.5 mg kg –1 (see Table 5 in Chapter 3).In cases where supplementation is required, soil application of Cu-sulphate at 15 kg ha 1 can be made, as for Mn or Zn, or combined therewith. The norms for Cu content of leaves is indicated in Table 25. It appears as if a level of 6 mg kg –1 Cu, in leaf blades during pea berry stage, can serve as general guideline for adequate Cu nutrition.

TABLE 25: Norms for the Cu contents (mg kg –1 ) of leaf blades and petioles of grapevines.

Fruit set

Veraison

Leaf blades

Petioles

Leaf blades

Petioles

High

High

High

High

Minimum

Minimum

Minimum

Minimum

Sufficient

Sufficient

Sufficient

Sufficient

3

6 > 20 3 5 – 10 > 20 3

6 > 20 3 5 – 15 > 20

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