68 SIMPLE OPERATIONS OP TILLAGE. 



after being ploughed, by making the ground more compact, 

 which will facilitate the decomposition of the sod, and render 

 it less liable to suffer from the effects of drought. In corn 

 ground, in addition to the above, it prevents the furrows from 

 being moved by the cultivator in the dressing of the corn, and 

 places the ground in much finer tilth than it would otherwise 

 be, with the same labour, without it. 



In rolling grass lands it is necessary to attend, in a particular 

 manner, to the condition of the surface to be rolled if too wet, 

 the ground will be poached by the cattle's hoofs; and if too dry, 

 little or no impression will be made by the roller in levelling 

 the inequalities. 



IV. DIGGING. 



THE plough, the harrow, and the roller, are the essential 

 implements of preparatory tillage. To these, however, and 

 the plough coulter, may be added the Spade; which, though 

 properly the instrument of culture in the garden, may be em- 

 ployed occasionally in the field. 



Cultivation by the spade, however, though more efficient, is 

 greatly more expensive than by the plough. It may be some- 

 times employed with advantage, though rarely on a great 

 scale, where the profit depends upon economy of labour. 



