CULTIVATION IN DRY AREAS 159 



tuberances on the rim of the drum, which aid in crushing 

 lumps and in leaving the soil in a condition that will 

 cause it to lift and encrust less readily with the wind. 

 While each of these may have a place on the dry land 

 farm, the place for the corrugated roller is more im- 

 portant than for rollers of the other types. 



The mission of the roller in dry areas is virtually 

 twofold first, to aid in smoothing plowed land so that it 

 may subsequently be pulverized more readily, and, sec- 

 ond, to aid in crushing clods when these are present. Its 

 use is much more restricted than in humid areas, and 

 chiefly for the reason that it tends to draw moisture to 

 the surface, much of which will escape into the air unless 

 the disc or the harrow follows the roller. It will not effect 

 the end served by the subsurface packer, as it firms the 

 soil above, and to a less extent below, whereas, the sub- 

 surface packer firms it below and leaves it loose above. 



Rollers should be used in dry areas: (1) To flatten 

 down sod land newly plowed so that the disc or harrow 

 or both may do more effective work when securing the 

 requisite pulverization that should follow. The com- 

 pression of the sod also hastens decay. In some in- 

 stances the disc, in the absence of the roller, will do 

 this work sufficiently well. (2) To crush clods when 

 preparing cloddy land for the harrow. When clods and 

 pulverized earth are both present, it may be necessary 

 to follow the roller with a disc or spring tooth harrow 

 to bring up clods from the subsurface soil and to roll a 

 second time. When a good subsurface packer is at 

 hand, it may suffice to crush the clods below without 

 bringing them up, providing it may be safely and ad- 

 vantageously used on such soil. (3) To press the soil 

 around newly sown grain when the grain has not been 

 put into the same with a press drill. But when thus 

 used the harrow should follow to prevent the too rapid 

 escape of moisture that would otherwise occur. (4) To 



