Handbook for Irrigation of Wine Grapes in South Africa

Figure 8.15

Owner: D. Du Plooy

Farm: Soetmelksvlei Nearest weather station: Lutzville Proefplaas Irrigation Schedule-block: 4A Area (ha) Pruning mass (kg/vine) Plant spacing (m x m)

Cultivar: Merlot

Root depth (m)

PAW (mm/m)

Maximum leaf area index

1

2.75 x 1.5 Spacing (m x m) 2.75 x .6

1.5

.6

70

5.0

Wetted Soil volume (%)

Application rate (mm/h)

Bruto requirement (mm)

Irrigation system

Number of irrigations

Drip

30

1.9

791

89

Estimated schedule based on total area

Month

ET (mm/d)

Crop Coefficient

Irrigation cycle (d)

Irrigation requirement mm Hours Cub m

August September November October December January February March April May June July

As for July 1.5

4 3 2 2 2 2 2 4 7

0.21 0.36 0.29 0.41 0.47 0.53 0.49 0.27 0.13 0.14 0.16

66 82

6.6 7.8 8.2 8.6 8.9 7.2 9.5 9.8 8.0 8.2 11.1

3.4 4.0 4.2 4.4 4.6 4.2 5.7 3.7 4.9 5.1 8.0

3.5 2.5 3.9 4.0 3.7 2.5 0.9 0.3 0.3 0.5

86 78 89 82 111

72 95 98 80

28 28 14

FIGURE 8.15. Example of the “Additional info” output for seasonal irrigation requirement as calculated by means of the VINET model for a drip irrigated wine grape vineyard in a sandy soil near Lutzville in the Olifants River valley. “Additional info” outputs can be printed for filing purposes.

248 CHAPTER 8 – PRACTICAL IRRIGATION SCHEDULING