6 
BULLETIN 219, U. S. DEPARTMENT OF AGRICULTURE. 
oats, a 
a ± 
COAN, PP. 
8AAL£Y,SP 
WHEATSe 
CO A* S. WHEAT OATS 
BARLEY W. WHEAT 
production of mature corn has been so uncertain at some stations as 
to make the crop unprofitable if grown for grain alone. 
GENERAL PLAN OF THE INVESTIGATIONS. 
The method of work adopted in these investigations involved the 
raising of different crops in various combinations or systems of rota- 
tions and under differ- 
ent methods of culti- 
vation in systems of 
continuous cropping. 
Most of the work has 
been done with 3-year 
and 4-year rotations. 
No rotations of greater 
length than six years 
have been used. Those 
of this length have 
been tried with sod 
crops only. 
PLAT AND ROTATION OUT- 
LINES. 
Figure 3 shows a di- 
agram of the dry-land 
rotation field at the 
Akron Field Station. 
This is one of the old- 
est stations of the Of- 
fice of Dry-Land Agri- 
culture, and is a repre- 
sentative one that will 
serve to illustrate the 
general scheme and 
plan of work. The 
plats involved in the 
work at this station 
W 
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W- WHEAT,' 
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Fig. 3.— Diagram of the dry-land rotation field at the Akron Field an( J ^X all of the sta- 
Station. The lettering shows the cropping practiced in 1914. The . , „ 
explanation of abbreviations used is as follows: D.= Disked, Fal.= tions are One-tenm 01 
summer tilled, .FP.= fall plowed, GM.=green manured, L.= listed, g^ &Cre in size. Their 
M.= manured, S.= spring plowed, 55.= subsoiled. ,. . _, , _ 
dimensions are 2 by 8 
rods. Along their larger dimension the plats are separated by 
alleys 4 feet wide. Along the ends of the plats they are separated 
by roads 20 feet wide. At all of the stations five crops are repre- 
sented in a series of continuously cropped plats, lettered on the dia- 
gram from A to G. In this group C and D are alternately cropped 
