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COCOA-GROWING COUNTRIES 437 



trenches" (Fig. 130). The small trenches are not 

 allowed to be longer than about 150 metres; they end 

 into a common canal (draining canal of the second 

 order), generally 4 to 5 feet deep and about 5 feet broad, 

 called " trekker," which means "puller" this canal 

 pulling the water from the small trenches into the 

 main trench. 



Generally the arrangement is as indicated in Fig. 128, 



FIG. 129. Sluice of the main drainage canal (plantation " Vredeuburg "). 

 The sluice is opened (drawn up) and the water is running under the sluice-gate to the river. 



with a main trench running on each side of the planta- 

 tion ; the two main trenches meet behind the front 

 embankment and run together into the canal in which 

 the sluice is built. 



As mentioned, the sluice is opened in the rainy 

 season at every low-tide, therefore twice a day. When 

 the rains are no longer heavy it is only opened when it 

 seems necessary, and in the dry season the sluice remains 

 closed all the time, and is even calked in order to prevent 

 the inflow of river-water, which is very brackish at this 



