SPRING WHEAT IN TI1K GREAT PLAINS ABEA. 3 
Dealing as it does with only one crop, to which certain sections of 
the Plains are obviously not adapted, this report does not afford a 
measure of judging the agricultural value or possibilities for other 
crops of any section of the country. 
In 1906 the Ofliee of Dry-land Agriculture of the United States 
Department of Agriculture began field investigations of the problems 
in methods of crop production in the Great Plains. The work begun 
at that time has been constantly and steadily added to, until in 1914 
work was conducted at 20 stations. The results here presented are 
from 1 4 stations, records covering only one or two years having been 
excluded. 
The method of work adopted was that of raising the standard crops 
of each section both in rotation and by different methods of prepara- 
tion under systems of continuous cropping. In no case have rotations 
requiring more than 6 years been used. Those of even this length 
have been tried only when sod of tame grass crops are included. More 
of the work has been done with 3-year and 4-year rotations. 
Figure 2 shows a diagram of the plats in the experimental field laid 
out in 1908 at the Judith Basin Field Station. This station, being 
a representative one, will serve to illustrate the general scheme and 
plan of work. The plats here, as in all the work, are one-tenth acre in 
size. Their dimensions are 2 by 8 rods. Along their larger dimen- 
sion the plats are separated by bare alleys 4 feet in width. Along the 
ends of the plats they are separated by roads 20 feet wide. At this 
station six crops are represented in a series of continuously cropped 
plats lettered from A to F or G. In this group, plats C and D are 
alternately cropped and summer tilled, so that each year a crop is 
grown on land that was summer tilled the previous year and a plat is 
summer tilled for cropping the next year. 
The remainder of the field is in rotations in which each plat is known 
by a rotation number and letter. On the field diagram the separa- 
tion of rotations is indicated by heavy lines. 
The movement of the crops in the rotation is in the direction from 
Z to A and from A back to the letter that marks the other end of the 
rotation. . 
In figure 2 the diagram is filled out to show the cropping in 1914. 
The letters following the crop indicate the treatment given the ground 
in preparation for it, S. P. standing for spring plowed, F. P. for fall 
plowed, Fal., or S. F., for summer tilled, G. M. for green manured, and 
D. C. for disked corn land. The addition of the letter M indicates the 
use of manure. To illustrate: In 1914 plat A of the 4-year rotation 
No. 14 was in corn on spring-plowed land, plat B was in wheat on 
disked corn ground, and plat C was in winter rye on fall-plowed land. 
This would be plowed under for green manure. Plat D was in oats 
