Handbook for Irrigation of Wine Grapes in South Africa

probe is a less expensive option than the EnviroScan ® system. Since soil contact between the access tube is also critical, it is recommended that the suppliers or other experts carry out the installation of the access tubes for Diviner 2000 ® probes. Figure 8.24

Shaft

Sensor

FIGURE 8.24. A Diviner 2000 ® probe and the console for setting up the instrument and recording soil water content.

Figure 8.25

8.4.1.6 DFM® PROBES These probes also use capacitance technology and can measure over the full plant available water range. It consists of a single probe containing sensors at various depth increments (Fig. 8.25). The length of the probe can be selected according to the root depth. Sensor depths are determined before manufacturing. The probe also contains an on-board data logger which enables continuous soil water content monitoring. The data can be downloaded in the field, or transmitted to a computer. Due to the data logging facility, DFM ® probes also provide an almost complete picture of soil water changes over time and soil depth.

258 CHAPTER 8 – PRACTICAL IRRIGATION SCHEDULING