THE NEW EARTH 



one of the elements of fertility, nitrogen, per 

 acre in a period of five years, while, under a 

 system of rotation, each year planting a differ- 

 ent crop, the fertility of the soil not only 

 maintained itself but actually increased by 

 sixty-one pounds per acre. When the wheat is 

 grown continuously, as in certain of the wes- 

 tern states, notably the state of Iowa a few 

 years since, the humus, which is the binding 

 material of the soil holding the particles to- 

 gether, rapidly decays and the liberated nitro- 

 gen is taken up by the wheat plants, ever 

 hungry for food; the water filters down be- 

 tween the loosened particles ; the soil becomes 

 lean ; the crop fails. Tens of thousands of acres 

 of land in Iowa, and other central-western 

 states, once yielding remarkable wheat crops 

 suddenly began to deterioriate, then failed 

 utterly, the soil had entered its unanswerable 

 protest. From a single farm of one hundred 

 and sixty acres where exclusive wheat farming 

 is followed, there is an annual waste of fertility 

 equivalent to twenty -eight thousand five hun- 

 dred pounds of nitrogen, five thousand pounds 

 of potash, three thousand pounds of phosphoric 

 acid. 



22 



