AMERICAN FORESTRY'S ADVERTISERS 



The New Agriculture 



WRITE FOR 

 THIS 



FREE BOOK 



FOR 2,000 years most 

 farmers have cultivated 

 only 6 to 8 inches of soil. 

 They have spent millions of 

 dollars adding to these 6-inch 

 farms plant foods, such as 

 potash, phosphorous and lime, 

 that already lay in the subsoil 

 waiting to be made available. 



VERTICAL FARMING 



y^ 



makes available tons per acre of new plant food, ensures abundant 

 moisture, and largely increases crop yields. 



Dr. G. E. Bailey, Geologist at the University of Southern Cali- 

 fornia, has prepared a reading course of instruction in soils and 

 vertical farming. We have printed it in a well illustrated book. 

 It will be mailed 



FREE ON REQUEST 



to anyone owning a farm in the United States. Get this book 

 about soils. Work your farm to its full capacity. Know your 

 land. Learn its composition. Use the fertilizers nature is storing 

 beneath your 6-inch farms. Send a postal request today for 

 Vertical Farming Booklet 350-F. Be sure to state the acreage 

 of the farm you own, 



DU PONT POWDER COMPANY 



Pioneer Powder Makers of America 



Established 1802 Wilmington, Delaware 



In writing to advertisers kindly mention American Forestry If 



