172 SOILS 



and expense. I have come to appreciate the disk harrow 

 most highly for this work. The labor and expense inci- 

 dental to disking before plowing is more than met by the 

 lessened amount of both at the time of preparation. And 

 then the work is better done. A corn crop has been 

 known to show its appreciation by yielding 8.6 bushels 

 more per acre in favor of this sort of treatment. 



Saving water by cultivation. The work of the farmer 

 is to induce water to enter the soil both in summer and 

 winter. But it is more than this. He must save it, once 

 it is secured. And now we come back to our original 

 proposition : cultivation checks the water loss. Until you 

 grasp this idea, until you come to a full realization of its 

 force and importance, you will never be able to compel 

 your soils to expend their fullest powers toward the pro- 

 duction of maximum crops. 



The principle of moisture-saving, briefly stated, is this : 

 Water is carried from the water storehouse of the lower 

 depths of the soil by capillarity. It rises in the soil from 

 soil particle to soil particle, just as oil creeps up in the 

 lamp-wick. It moves sidewise and diagonally and up- 

 ward; it goes in the direction of the hardest pull. 



But always, in the end, unless prevented by some ob- 

 stacle a dry mulch so acts it finds the surface of the 

 soil, at which point it passes into vapor and leaps into 

 the atmosphere. 



You have no reason to doubt this principle, for you 

 have seen its evidence a thousand times. You have 

 picked a board from the ground, or kicked a stone from 

 its snug pocket, or taken leaves or grass or straw from the 

 bed made, and you found that beneath either there 

 was wetness ; even a great deal, although on every side 

 the surrounding soil was dry and hot. 



There was but one way by which this could happen : by 



