THE ROTATION OF FARM CROPS 67 
ADDITIONAL READING 
‘‘Decline in Kansas Acre Yields.’”’ By L. E. Call. The 
Orange Judd Farmer. Jan. 25, 1913. 
‘Soils and Fertilizers’? (a book). By Harry Snyder. 
“‘Crop Rotations for Illinois Soils.’’ By Cyril G. Hopkins. 
Cireular No. 141 Tl. Agri. Ex. Sta. 
‘‘Thirty Years of Crop Rotations.’? By Cyril G. Hopkins. 
Bulletin No. 125 Tl. Agri. Ex, Sta. 
‘‘Married Men Cheaper than Single Help.’’ By Ralph M. 
Ainsworth. Prairie Farmer. March 1, 1918. 
“The Fertility of the Land.’’ By Isaac Phillips Roberts. 
