COVER CROPS in South African Vineyards

COVER CROPS IN SOUTH AFRICAN VINEYARDS

Other minerals Soil potassium levels were measured in three years (1997, 2000, and 2003). Although differences occurred during this time, there were no trends. Figure 7.13 shows the values obtained in 1997. Soil potassium levels were significantly higher in some treatments than in the control, suggesting that cover crops, especially legumes, can incorporate potassium applied during grapevine full bloom.This potassium is released into the soil when the cover- crop dry matter breaks down, and becomes available to grapevines. However, the potassium levels never exceeded the norms established for wine grapes. from August

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0 Henog rye Overberg Saia black Paraggio Parabinga Pink Grazing No cover oats oats bur medic bur medic serradella vetch crop Weed control from August Weed control from November Potassium levels in milligram per kilogram soil FIGURE 7.13. Soil potassium measured at harvest in the 0–300-millimetre soil layer in cover-crop treatments compared to a control in the Olifants River valley. Adapted from Fourie et al (2007). Reference list Fourie JC, Agenbag GA and Louw PJE. 2007. Cover crop management in a Sauvignon blanc/Ramsey vineyard in the semi-arid Olifants River valley, South Africa. 3. Effect of different cover crops and cover crop management practices on the organic matter and macro-nutrient contents of a sandy soil. South African Journal of Enology and Viticulture , 28(2), 92–100.

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