Wooden poles are generally used to erect trellis systems for vineyards. The availability of wood is limited, however, and may be exhausted or become very expensive in future (Avenant, 1997).

Research on steel as alternative trellis material started in 1993 and is aimed at reducing the cost component for the industry (table, dried and wine grapes).

Various experiments have been conducted, mainly on overhead trellis systems. During the 1998/1999 season trials were conducted on the farm Panorama in Riebeeck West to monitor the influence of steel trellis material on the mechanical harvesters.

The wooden poles (50-75 mm) of five rows were removed and replaced by steel poles (ISCOR 2 kg/m hedge pole). Specifications for the experimental block are as follows:

Photo 5 Photo 4 Photo 3 Photo 2 Photo 1
  • Type of trellis
3 Strand Perold (Hedge)
  • Spacing between line poles
7 m
  • Row length
273 m
  • Number of poles
195
  • Pole length
1.850 m
  • Type of pole (wood)
50-75 mm
  • Type of pole (steel)
ISCOR, 2 kg/m Y-hedge pole

CONCLUSION

Iscor as well as the producers in question consider the experiment to be very successful since no damage was noticed to either the trellis material (steel poles) or the mechanical harvester. The poles in question were not removed, however, and will be monitored on a continuous basis. Similar trials are planned in the Robertson and Lutzville regions. Dimensions to be monitored during these trials are i.a.:

Stability of the system: stability of the respective rows in wind conditions.
Corrosion resistance: resistance to corrosion in vineyard conditions above and below the soil
User friendly: during erection of the trellis and mechanical harvest.
Environment friendly: effect of steel, if any, on the wine (must) quality.

Acknowledgement: Thanks to Mr Van der Bijl Brink, Panorama, Riebeeck West for making his vineyard and equipment available.

The Author:

Christo J Maré (Iscor Long Steel Products, Marketing, Special Profiles)

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