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 (0). 
