Handbook for Irrigation of Wine Grapes in South Africa

13 October 14 October

15 October

16 October

17 October

0 0

-0 1

-0 2

-0 3

-0 4

ψ m (MPa)

-0 5

Drip irrigation Micro-sprinkler irrigation

-0 6

Irrigation

Irrigation

-0 7

FIGURE 2.28. Mean daily ET of grapevines that were irrigated with drippers and micro- sprinklers, respectively, near Augrabies in the Lower Orange River region (Myburgh, 2012a). 0 1 2 3 4 5 6 7 8 9 10 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul ET (mm/d) Drip irrigation Micro-sprinkler irrigation Figure 2.28 FIGURE 2.27. Effect of irrigation with drippers and micro-sprinklers, respectively, on the rate of soil water extraction in a vineyard as determined by measuring Ψ m hourly during the day by means of tensiometers (Myburgh, 2012a). -0 8

52 CHAPTER 2 – THE DYNAMICS OF WATER IN AND AROUND VINEYARDS