Handbook for Irrigation of Wine Grapes in South Africa

Figure 7.45

Chapter 7

A

Figure 7.45

B

FIGURE 7.45. An example where (A) an existing irrigation dam is being enlarged and (B) a lining was installed in a dam to prevent seepage losses.

7.3 POSSIBLE WAYS TO USE IRRIGATION WATER MORE EFFICIENTLY When it comes to the implementation of irrigation strategies, the actual irrigation water use efficiency for vineyards becomes an important consideration, and needs to be optimised. The WUE is defined as unit of fresh grapes produced per unit of irrigation water applied. For grapes it is usually a kilogram grapes per cubic meter water (kg/m 3 ). This specific WUE must not be confused with other definitions, e.g. dried matter produced per unit water in the case of grain crops. Economists might define WUE as income (R) per unit irrigation water. Plant physiologists commonly refer to WUE as the ratio of photosynthesis to transpiration.

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