310 CAMPBELL'S SOIL CULTURE MANUAL 



nothing on mere hearsay or authority. Every principle 

 advocated by him, he has tested, not once, nor in one place, 

 but many times, in widely separated localities, in seasojis 

 of greatly differing rainfall and temperature, throughout 

 the plains region from the James river valley to the Texas 

 Panhandle. In addition, there are principles of soil cul- 

 ture and methods of procedure that unquestionably origin- 

 ated with him. One of these is that of "summer culture" 

 on newly broken prairie land, before any attempt is made 

 to grow a crop. Anyone who breaks prairie lands, and 

 plants them without first devoting a full season to careful 

 cultivation in order to get the soil in the proper physical 

 condition for the promotion of plant growth, and in order 

 to store a sufficient amount of moisture within reach of 

 the plant roots to carry the growing crop through a pro- 

 tracted drouth, is simply inviting failure should a season 

 of unusual drouth follow. 



Another feature that originated with Mr. Campbell, 

 which he regards of vital importance, is the sub-soil packer. 

 This is an absolutely new farming implement, the essential 

 feature consists of a series of sharp, wedge-shaped wheels, 

 that cut into the ground, and literally wedge the portions 

 between them together. 



These wheels exert both a lateral and a downward pres- 

 sure, accomplishing a number of desirable results. They 

 elimnate the air spaces left by overturning the furrow slice 

 along the bottom and the sides of preceding furrows ; press ' 

 the earth firmly around the weeds, clods and stubble; aid 

 in pulverizing the soil, thus increasing its capillary attrac- 

 tion and its water-holding capacity; and, at the same time, 

 they leave the surface soil loose and in condition to prevent 

 unnecessary loss of moisture through evaporation. 



