Handbook for Irrigation of Wine Grapes in South Africa

Figure 4.28 Figure 4.28

A

B

FIGURE 4.28. Examples of vineyards being flood irrigated by means of (A) 1.5 m wide furrows and (B) 0.6 m wide furrows in the Lower Orange River region.

water status, vegetative growth or yield, compared to full surface border irrigation (Myburgh, 2003a). This suggested that the wetted soil fraction was large enough to prevent water constraints in the grapevines, irrespective of irrigation frequency under the prevailing conditions. Likewise, irrigation in alternate work rows had no negative effects on grapevine water status, vegetative growth or yield, compared to full surface border irrigation (Myburgh, 2003a). TABLE 4.2. The effect of three flood irrigation systems on irrigation volume, cane mass, yield and WUE of Sultanina grown for dried grape production near Upington. Irrigations were applied every 14 days. Data are means for three seasons (after Myburgh, 2003a). Irrigation system Irrigation applied (m 3 ) Cane mass (t/ha) Yield (t/ha) WUE (kg/m 3 )

Border (full surface)

12 718 a*

3.0 a

24.5 a

1.9 b

1.5 m Wide beds

7 932 b

2.2 b

26.6 a

3.3 a

Irrigation in alternating rows 3.3 a * Values designated by the same letter within each column do not differ significantly (p ≤ 0.05). 7 386 b 1.9 b 24.6 a

TABLE 4.3. The effect of two flood irrigation systems on yield and cane mass of Colombar near Oudtshoorn (after Van Zyl & Van Huyssteen, 1988). Period Method Frequency (days) Yield (t/ha) Cane mass (t/ha)

1978/79 to 1981/82

Furrow

21

17.7 b*

5.4 b

Border (full surface)

21

26.2 a

8.4 a

1983/84 to 1985/86

Furrow

14

30.3 a

3.8 a

Border (full surface) 4.2 a * For each period, values designated by the same letter within each column do not differ significantly (p ≤ 0.05). 21 27.7 a

90 CHAPTER 4 – IRRIGATION SYSTEMS