forcing themselves off the face of the earth. By mishandling the soil and itr 

 living cover man has, in fact, made vast stretches of the earth's surface worth- 

 less. And every year, in various parts of the world, millions of acres are being 

 ruined. 



The good earth of our Great Plains, stretching from Montana and the 

 Dakotas to the middle of Texas, had for centuries yielded only grass to feed 

 the bison, and so maintained a sparse and scattered Indian population. Farm- 

 ers moving westward after the Civil War hoped that their hard work on this 

 land would furnish abundance for their families. The flat lands would be 

 easy to work. In the course of some sixty years large-crop farming developed 

 rapidly. There were good years and poor years, of course. But as years went 

 by, the earth came to yield less and less to man's efforts. By 1938 millions of 

 acres had become so changed that they could no longer support the population 

 that had been depending upon them (see illustration opposite). 



The Great Plains land and farms, as well as millions of acres in other parts 

 of the country, were destroyed in part by man's interfering with the natural 

 relationships between living things and the underlying soil and waters. They 

 were destroyed in part by a working of the soil which we have called mining — 

 carrying off as fast as possible whatever is of value. We could, of course, re- 

 place the essential food-making minerals of the soil with materials brought 

 from other regions. But we had also replaced the perennial grasses, which 

 had in the past bound together the particles of the soil, with cultivated an- 

 nuals. And in this way we exposed the surface of the earth to the destructive 

 action of wind and water (see illustration, p. 644). 



Fifteen million acres can no longer be plowed. On most of the range lands 

 production has declined from 25 to 50 per cent in some places and by as much 

 as 75 per cent in other parts. Moreover, these acres can be of value in the future 

 only if we change radically our ways of treating and using them. It is not 

 exacdy a case of killing the goose that laid the golden eggs, for the acres are 

 still there. That is, the goose is not quite dead. But if she is left to herself, 

 she will not revive fast enough to be of help to us for at least a generation 



or two. 



The Soil's Fertility From ancient times people traditionally saved 

 household and farm wastes for manuring their fields (see page 150). It was 

 only in the first half of the last century that the foundations of soil chemistry 

 were laid by the researches of a Frenchman, Nicholas de Saussure (1767-1845); 

 a German, Justus von Liebig (1803-1873); and an Englishman, John Lawes 

 (1814-1900). From their work we learned to restore to the soil the essential 

 chemical and physical conditions. 



Working the soil physically to get the best results also had to be learned, at 

 first through trial and error, and later through systematic research and ex- 

 perimenting. Throwing seeds on the ground would yield something. Scratch- 



642 



