282 THE FARMER OF TO-MORROW 



regards any crop proved exceedingly simple, 

 just as it has in actual field practice. 



Part of the test soil was baked in an oven. 

 Nature does the same thing by prolonged 

 periods of drought. After the artificial 

 "drought" the soil became productive again. 



Boiling had the same effect. Boiling means 

 sterilization. Treating it with charcoal, bone- 

 black, lime, ordinary "pyro," used in photog- 

 raphy, freezing it, any of these methods had 

 the same effect. Exposing it to sunlight and 

 air tillage and mixing it with organic 

 manures which are subject to rapid decay were 

 other methods adopted with equal success. 



What does the intelligent farmer do in 

 actual practice? 



He rotates his crops. We have seen that 

 rotating crops in the experiments seemed to 

 do away with the toxic substances or at least 

 with their effects. 



He applies stable manure. He plows under 

 green crops. He tells himself that in so do- 

 ing he is adding "plant food" to the soil and 

 he accepts the word of the expert as to how 

 many pounds of minerals he is adding thus, 

 and he usually overlooks the fact, which the 

 expert seeks to impress on him, that barn- 



