Handbook for Irrigation of Wine Grapes in South Africa

Chapter 4

Figure 4.32

A

B

21 mm

2.2 mm

FIGURE 4.32. An example of porous pipe used for subsurface irrigation showing (A) the rough outside of the wall and (B) a cross section through the wall.

4.4 MAINTENANCE OF IRRIGATION SYSTEMS Due to the narrow flow paths, compared to other irrigation systems, drippers are more likely to become clogged if the system is not properly maintained. Therefore, it is essential to follow the prescriptions as presented in the NETAFIM SA maintenance guide that is accessible at www.netafim.co.za. Although there are international guidelines, growers are advised to rather follow the ones adapted for local conditions. It must be noted that many of these maintenance aspects will also apply to other irrigation systems. Water quality is one of the most import aspects that affects reliable functioning of irrigation systems, particularly drippers and micro-sprinklers. The primary factors that cause clogging are physical, chemical and biological (Table 4.6). It must be noted that clogging may be caused by a combinations of these factors. Other water quality aspects that may affect functioning of irrigation systems are discussed in Chapter 5.

IRRIGATION OF WINE GRAPES 95