24 THE BOOK OF FORESTRY 



by means of fertilization and the use of proper rotations, 

 to build up the soil which they have long drawn upon, 

 the future of this nation will be extremely dark. 



Of the land now idle through lack of rain it is believed 

 that fully 400,000,000 acres can be made productive by 

 the use of irrigation, or dry farming methods but how 

 much more practical it would be to make land now 

 owned and tilled yield maximum crops by the appli- 

 cation of commonsense principles. That the population 

 of this country will double within the next seventy-five 

 years seems more than possible and to feed so many 

 hungry mouths will require the best use of every acre 

 of land suited to tillage. It is only necessary to stop the 

 constant drain upon the land and by practicing systems 

 of agriculture which will at least maintain the soil 

 fertility to keep this country the food warehouse of 

 the world. 



Not only is soil fertility lost through shiftless agricul- 

 ture but great waste is caused by permitting erosion 

 and beating rains to rob the land of its richness. Dr. 

 Shaler estimated that no less than two hundred square 

 miles of fertile farm land are laid waste each year as 

 result of the action of water and when it is realized 

 that the Mississippi River carries away 400,000,000 

 tons of sediment, representing the most fertile portion 

 of the fields, some conception of the total loss may be 

 gained. The remedy consists in maintaining a proper 

 balance between agricultural and forest land. Land 

 which is too steep should not be tilled but should be 

 kept under forest cover as the tree roots bind the soil 

 together and prevent it from being gullied by the rains 

 and melting snows. In some places where bench lands 

 are tilled it may be advisable to leave occasional strips 

 of forest land between the tilled fields as the trees and 



