PREFACE 



In planning a course of study, the author must needs lay 

 out a working plan. He should know the philosophy of his 

 subject and its relation to other sciences. Field crops like 

 other applied sciences has little pure science of its own, but 

 is rather based on other sciences. The subject is not erected 

 so much as a superstructure on other sciences, but rather 

 moves in a progressive way, between them, abstracting such 

 elements from each as contribute to the art of producing the 

 crop under consideration. 



The outline on page vi is an attempt to illustrate the log- 

 ical order of study and relation of other sciences to the 

 study of Crop Production. 



The outline below indicates that a knowledge of all the 

 " earth sciences " is fundamental to a study of crop produc- 

 tion, hence a student should have a general course in all 

 these sciences with special emphasis on botany (physiology 

 and ecology) and chemistry. 



In regard to a particular crop like maize, this knowledge 

 needs special interpretation and application, which is the 

 function of field crops instruction. 



The ability to yield with our ordinary crops is far above 

 the average yield. With maize 200 bushels per acre have 

 been produced under optimum conditions, while the average 

 yield is about 26 bushels. Therefore the study of maize 

 production is principally a study of those factors which 

 serve to hinder full development, and thus limit production, 



