BULLETIN 214, U. S. DEPARTMENT OF AGRICULTURE. 



investigations consists of about 400,000 square miles of territory 

 (fig. 1). It is bounded on the east by the ninety-eighth meridian 

 of longitude, on the west by the foothills of the Rocky Mountains 

 (indicated by the 5,000-foot contour), on the north by the Canadian 

 boundary, and on the south by the thirty-second parallel. The 

 area covers parts of 10 States, and includes all of the stations herein 



considered except the 

 one at Archer, Wyo. 

 The study as here 

 presented deals only 

 with spring wheat and 

 is made in such a way 

 as to show the effect 

 of cropping and culti- 

 vation in only the year 

 preceding its growth. 

 Reference hereafter is 

 made to the crop only 

 as wheat, but it should 

 be borne in mind that 

 spring wheat is meant. 

 The yields of winter 

 wheat and its response 

 to cultural methods 

 are in many cases very 

 different from spring 

 wheat. There is also 

 given a study of the 

 comparative cost of 

 production of wheat 

 under each of the 

 methods studied and 

 the resulting profit or 

 loss. 



The work here re- 

 ported from 14 sta- 

 tions covers an ag- 

 gregate of 73 station 

 years and embodies 

 the data from a total of 1,683 plat years. By station year is meant 

 one year at one station; by plat year is meant one plat at one sta- 

 tion for one year. It is manifestly impossible in dealing with such a 

 mass of data to go into much detail; only some of the broader 

 phases of the evidence are here considered. 



Fig. 1.— Sketch map of the Great Plains area, which includes parts of 

 ten States and consists of about 400,000 square miles of territory. 

 Its -western boundary is indicated by the 5,000-foot contour. The 

 location of each field station within the area is shown by a dot 

 within a circle (©). 



