Handbook for Irrigation of Wine Grapes in South Africa

Figure 4.21

A

B

Overhead sprinkler irrigation systems can be fully moveable (Fig. 4.22A). In order to reduce labour inputs, the lateral system could be permanent, but with moveable sprinklers (Fig. 4.22B). The latter systems are commonly referred to as “hop-along” sprinkler irrigation. In the case of permanently installed overhead sprinklers, labour inputs are reduced to a minimum (Fig. 4.23). However, it must be noted that the cost of the systems will increase as the labour requirements decrease. Overhead sprinkler irrigation is sometimes used when a vineyard is being established before a permanent system such as drip or micro-sprinklers is installed (Fig. 4.24). This approach is useful if the establishing costs of a vineyard need to be distributed over more than one year. In regions where frost commonly occurs, overhead sprinkler irrigation is sometimes also applied to prevent damage to vineyards, as is discussed in Chapter 9. These irrigations are usually necessary during spring when the new growth is most vulnerable to frost damage. Figure 4.22 FIGURE 4.21. Examples of vineyards being irrigated by means of overhead sprinklers (A) near Stellenbosch and (B) near Hermanus. Figure 4.21 Figure 4.22

FIGURE 4.22. Examples of a (A) fixed overhead sprinkler on a moveable lateral and (B) moveable overhead sprinkler on a permanent lateral. A B

86 CHAPTER 4 – IRRIGATION SYSTEMS