viii PRjEFAOE 



A large share of farm practice has to do with modifying 

 the soil environment and protection of the crop. 



THE PHILOSOPHY OF CROP PRODUCTION 



The art of crop production is based on an application of 

 the sciences, (a) to producing a natural condition as per- 

 fectly adapted as possible to the needs of some particular 

 crop, or (&) the adaptation of the crop to certain natural con- 

 ditions. 



The study of crop production for any large region in- 

 volves a study of four general phases of the subject, as : 

 1. The plant, its structure, physiology, and normal require- 

 ments. 2. A general survey of the region where it is pro- 

 posed to cultivate the plant, to note how the natural conditions 

 found correspond to the needs of the plant. 3. The adapta- 

 tion of the plant on the one hand to natural conditions and 

 adaptation of soil on the other to the needs of the plant. 

 Maximum production is obtained when perfect adaptation is 

 secured. 4. Protection is necessary against other indige- 

 nous plants, fungous diseases, and insects. 



The treatment of subjects in the text follows practically 

 the above plan. The plan also allows a wider use of the 

 text for different classes of students. The first two divisions 

 are technical and should only be studied by students who 

 have training in the sciences involved. With less advanced 

 students the work may begin with Part III, Adaptation. 

 The third and fourth divisions deal with the more practical 

 phases of production and are written in a more popular style, 

 this double use of the book being in mind. 



Acknowledgments. — For furnishing photographs- used 

 in illustrating the text, the author is indebted to Mr. Carle- 

 ton R. Ball, Mr. C. W. Warburton, and Mr. C. P. Hartley, 

 all of the Bureau of Plant Industry. A large number of 



