36 MANUAL FOR SUGAR GROWERS. 



ture and suffer from the effects of the heat of the 

 sun. If, however, the permanent water-level be 

 lowered by subsoil drainage, the roots have room 

 for luxuriant growth, thus ranging over a greater 

 space to absorb moisture and plant-food, a state of 

 things which soon shows an abundant result in the 

 increased growth of the portion above ground, with 

 its consequent increase of the crop. Again, a deep- 

 rooted plant is much better protected against changes 

 of season than a shallow-rooted one : in a wet season 

 the porous upper soil absorbs a large amount of 

 moisture which the subsoil drain quickly removes, 

 leaving the soil in good condition for plant-growth ; 

 in a dry season the small amount of moisture from 

 passing showers, dew, etc., is much more effectively 

 retained, and the roots of the crop, having a deeper 

 range, find a greater amount of moisture and are 

 farther removed from the hurtful effects of the heat 

 of the sun. The deep porous soil also retains a use- 

 ful amount of moisture for a longer period than a 

 shallow one. It follows, then, that subsoil drainage 

 is beneficial, both in wet and in dry seasons. 



Various methods of subsoil draining have been 

 devised, all of which are carried out by opening a 

 trench to the required depth of the drain, and plac- 

 ing in the trench something to leave a channel or 

 waterway along the bottom when the earth is 

 thrown back again into the trench. Many kinds of 

 material have been used for this purpose, such as 

 brushwood, loose stones, stones or brick or tiles 

 roughly built to form a small culvert ; and finally 

 coarse unglazed earthenware pipes. This last ma- 



