Handbook for Irrigation of Wine Grapes in South Africa

Stellenbosch 469 mm Rainfall 7 to 21% Clay

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Adequate leaching

Rawsonville 548 mm Rainfall 3.3% Clay

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Adequate leaching

35% Clay

0.4% Clay

Robertson - 135 mm - Inadequate leaching

Lutzville - 94 mm - Inadequate l

Robertson 135 mm Rainfall 35% Clay

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Inadequate leaching

Robertson - 135 mm - Inadequate leaching Lutzville - 94 mm - Inadequate leaching 0.4 Clay 35% Clay

0.4% Clay

Lutzville - 94 mm - Inadequate l

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Lutzville 94 mm Rainfall 0.4% Clay

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Inadequate leaching

Lutzville - 94 mm - Inadequate leaching 0.4% Clay FIGURE 5.21. Effect of winter rainfall (May to September) and clay content on the probability that K and Na applied via irrigation with diluted winery wastewater will be leached from the soil at four localities in the Western Cape (adapted from Mulidzi, 2016).

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134 CHAPTER 5 – IRRIGATION WATER QUALITY