SOIL SANITATION 275 



aeration, lets it sleep. Yet, if a soil be sub- 

 jected to single-cropping for a generation or 

 two, it will decline in productivity, although 

 an analysis shows that it still has sufficient 

 food for many crops. Maybe the soil needs a 

 change of occupation, just as man. It is pos- 

 sible that the season of rest, intervened by 

 Nature, is not sufficient to enable a soil to re- 

 cuperate, if it is speeded at a fast rate. We 

 know that fallow will restore the life of soil. 

 Fallow is merely extending the period of rest, 

 giving the soil more time to sleep. We also 

 know that rotating crops, giving the soil a 

 change of occupation, accomplishes somewhat 

 similar results. 



Is fatigue in the soil a poison, just as is 

 fatigue in man and animals ? 



If such a suggestion could be established 

 as an actual fact, it would explain at once 

 many of the most perplexing problems in fer- 

 tility. It would explain rotation of crops as 

 "change of occupation," it would explain fal- 

 low as "rest" or "sleep," and it would explain 

 the benefits due to cultivation, in addition to 

 conserving moisture, as bringing light and air 

 into the soil to rejuvenate it. 



There is a set of interesting experiments 



