MOTHER EARTH 95 



cultivator is enabled to produce from two to seven crops a 

 year on a given piece of land. This makes possible the support 

 of a larger population on the same territory. 



73. More soil. In this country nearly half the land area 

 (outside of mountain and rock, which cannot be cultivated) 

 consists either of swamp or of desert. Soil that is too wet is 

 just as useless for farming as soil that is too dry. Through the 

 cooperation of farmers and engineers and workers of all kinds 

 it has been possible to reclaim millions of acres of desert lands, 

 and to make it all usable for raising valuable crops. By drain- 

 ing the swamps and by bringing water to the arid regions, 

 through miles of canals and ditches and pipes, soil containing 

 vast quantities of food-making salts has been added to the 

 national wealth. There is, of course, a limit to what man may 

 be able to accomplish in the way of reclaiming land. In some 

 of the Western dry regions the bringing of water may not be 

 practicable if the distance is too great. At the present time 

 more than half of the great staple food crops of the world are 

 raised on artificially irrigated land (in China, India, Egypt, 

 Canada, and other countries) ; the possibilities in this direction 

 will probably not be exhausted for several generations. 



74. Soil waste. The fertility of the Nile valley seems to be 

 inexhaustible. This is not because the usable salts are more 

 concentrated in this soil than they are in other soils. The rich- 

 ness of this soil is due to the fact that the river is constantly 

 bringing down into the valley more and more material from 

 the rocks in the mountains where the river has its sources. In 

 our own country every river that empties into the sea carries 

 away tons of usable minerals, which thus go to waste. In con- 

 nection with some of the irrigation projects in the Southwest 

 much water is lost during the spring, and with the water a 

 great quantity of valuable mineral salts. Plans are being devel- 

 oped for saving this water in huge reservoirs, some of which are 

 already completed. In this way it will be possible not only to 

 irrigate larger areas but also to save from waste the soil mate- 

 rials out of which our food supply can eventually be increased. 



