Handbook for Irrigation of Wine Grapes in South Africa

Figure 4.7

A

B

FIGURE 4.7. Grapevine root distribution under drip in (A) a red, sandy soil on Dorbank near Vredendal and (B) in a vineyard in sandy loam soil on a slope near Stellenbosch.

3 4 5 6 7 8 9 p+ (.&l)

0-30 cP 30-60 cP

-ul 06

May 07 Oct 07 Mar 08

FIGURE 4.8. Effect of applying 5 t/ha lime on the grapevine rows on the pH (KCl) in a sandy, drip irrigated vineyard soil in the Lower Olifants River region (unpublished data). Arrows indicate lime application, and the shaded zone is the lower pH (KCl) threshold for grapevines (Conradie, 1983; Conradie, 1994).

Figure 4.9

FIGURE 4.9. Lime being applied on the grapevine rows to ameliorate acidification in a sandy soil under drip irrigation in the Lower Olifants River region.

78 CHAPTER 4 – IRRIGATION SYSTEMS