PREFACE 



In preparing this manual of the field crops of the United 

 States, the needs of the secondary schools where agriculture 

 is taught have been kept particularly in mind. The develop- 

 ment of agricultural high schools and of agricultural courses 

 in the regular high schools has been so rapid in the past few 

 years that the demand for suitable text-books is as yet 

 largely unfilled. The instructors in these schools have been 

 compelled to adapt to their uses college texts on the leading 

 agricultural subjects, to supply the necessary matter in the 

 form of lectures, or to supplement the necessarily brief treat- 

 ment which is given these subjects within the limits of a 

 single volume covering the whole field of elementary agri- 

 culture. It is hoped that the present book will prove to be 

 a useful basis for instruction in the subject of field crops. 



It is manifestly impossible to discuss each individual crop 

 as fully as some instructors may desire and yet keep within 

 the limits of a usable volume. Consequently, the discussion 

 has been made as brief as is consistent with completeness, 

 and repetition has been avoided by numerous cross-refer- 

 ences. Suggestions have also been made for supplementary 

 reading in the way of Farmers' Bulletins, which may be 

 obtained free from the Department of Agriculture at Wash- 

 ington, D. C., and of standard volumes, most of which should 

 find a place in the school library. In addition, the local 

 experiment station should be drawn upon for such of its 

 publications as may prove useful. 



One other feature needs comment. The laboratory 

 exercises which appear at the end of each chapter are 

 merely suggestive; as in the class-room, special emphasis 



