IMPROVEMENT OF THE SOIL 43 



in the bottom of the ditch and covering it. The 

 only satisfactory underdrain, however, is made with 

 the regular cylindrical draintile manufactured from 

 brick clay. These tiles are made of any desired 

 diameter, in pieces one foot long. A narrow ditch 

 is dug, the bottom is carefully graded and shaped 

 with a special implement known as a tile hoe, and 

 the lengths of tile are laid in end to end and are 

 carefully covered. The water enters between the 

 joints, and when properly laid, the grade is such that 

 the water flows evenly without depositing sediment 

 to fill up the tile, and the work once well done is 

 good for an almost indefinite period. The whole field 

 may now be plowed and planted, and there are no 

 unsightly ditch banks to breed troublesome weeds. 

 The water, in working its way down through the 

 soil to the drains, leaves little passages by which the 

 air can enter so that underdrained soils are always 

 better aerated and mellower than those with open 

 drains. In consequence, they can also withstand 

 droughts much better. 



A competent drainage engineer should be consulted 

 in laying out a system of underdrains, and the work 

 of laying the tiles should not be undertaken by per- 

 sons without instruction or experience. Tile drainage 

 is as yet very little practiced in Southern countries. 

 The conditions on many of the sugar-cane lands are 

 such that it would unquestionably prove to be a 

 profitable investment, and the time will doubtless 

 come when it will be much more generally used. 



Terracing. — While the South is thus somewhat 

 backward in the matter of utilizing tile drainage, it 



