480 



THE PRINCIPLES OF SOIL MANAGEMENT 



the bottom of the cultivated portion is left in hard 

 ridges. Such implements are now much less used than 

 formerly, and may be considered to supplant in a meas- 

 ure the use of the plow, where deep working without 

 turning is desired. Some of the wheel-hoes used in or- 

 chard tillage belong to this type. The old single and 

 double shovel -plows are earlier types of the same 

 implement. 



The small shovel-cultivators have very generally 

 supplanted the large shovel type in most cultural work. 



Fig. 138. Broadcast seeder, which also cultivates the soil. 



The decrease in size of shovels is made up by the great 

 increase in number. Ordinarily they operate shallow, 

 but very thoroughly and uniformly. They are now much 

 preferred in all inter-tillage work for eradication of 

 small weeds and the formation of a loose surface mulch. 

 A modification from these in shape of shovel is the 

 sweep, much used in the southern states, especially 

 in cotton-growing. It consists of broad blunt knife- 

 like blades, which pass along a few inches beneath the 

 surface of the soil and raise it an inch or two, then 

 permit it to drop back in place in a much broken con- 

 dition. It works best on soil relatively free from stone. 



