THE HUSBANDRY OF THE CANE 



121 



sugar industry in forming the furrows in which the cane is planted, in opening 

 irrigation channels, in " bursting out " the middle of the cane rows, and in 

 turning over weeds between the rows in young canes. 



FIG. 31 



Disc Ploughs. The essential part of the disc plough (Fig. 29) is the 

 revolving discs ; these are of concave shape and revolve about their centre, 

 the slice of soil being turned over by the action of the concavity of the disc. 



FIG. 



The disc principle was originally devised to lessen the draft on the plough, 

 and these ploughs find use in tenacious soils, where the mould-board plough 

 will not scour properly, and in very hard lands where it is not possible to 



