CAMPBELL'S SOIL CULTURE MANUAL 



63 



ROLLING VS. SUB-SURFACE PACKING 



It is here seen that when samples of soil are taken at 

 a depth exceeding two feet, the rolled ground as a whole 

 is dryer than that not rolled, and that this difference is 

 greater when the samples are taken at a depth of from 

 three to four or more feet. The data presented also 

 shows that the two to eighteen surface inches of loose 

 ground recently firmed contains more water than that 

 which has not been so treated. It is a matter we have 



Cut No. 4. Showing Soil after Packing and Harrowing. 



carefully studied, and in all our experimental work we 

 have observed that the statements of Professor King 

 have been verified fully; thus affording conclusive proof 

 of the truth of all that we have said with reference to the 

 sub-surface packing of the soil. When the extreme sur- 

 face is packed the effect is to draw the moisture to the 

 surface where it is lost by evaporation. By the sub- 



