CAMPBELL'S SOIL CULTURE MANUAL 117 



CHAPTER XV. 



PERCOLATION; OR GETTING WATER DOWN 

 INTO THE SUB-SOIL. 



During the past three years the question of getting 

 the water down into the subsoil has commanded much 

 attention and discussion. 



In the more arid sections there seems to be a prevail- 

 ing idea that the soil must be broken up or loosened deeply 

 by subsoiling or otherwise, or the rain waters will not 

 permeate the subsoils of our great prairies to any material 

 depth. Theoretically, this is true, and all general observ- 

 ations so far as the prairies in their natural state is con- 

 cerned, have backed up the theory as a fact or truth. 



A little broader and more careful observation shows 

 the theory to be a theory only. 



What we have found to be true in cultivated soils is 

 also largely true of the prairies. Several trips over por- 

 tions of Eastern Colorado in the autumn of 1906 gave 

 strong proof that, when the soil is moistened to a depth 

 of one foot or more, that a subsequent rain of any mag- 

 nitude soon disappears by percolation. This was proven 

 in one instance in November; a quite heavy rain disappeared 

 from the level prairies very quickly, although it remained 

 cool and cloudy, so that little was lost by evaporation. 

 Four days later showed the prairie soil to be moist nine 

 inches deeper than before the rain; proving the readiness 

 of moist soil to take in more water. 



There is no subject that is more vital to the scientific 



