CROP ROTATION AND CULTURAL METHODS AT AKRON, COLO. 
SCOPE OF THE EXPERIMENTS 
The rotation block as laid out in 1907 contains 144 tenth-acre 
plats. The plats are 2 rods wide by 8 rods long, separated on 
the sides by alleys 4 feet wide and on the ends by roadways 20 feet 
wide. The alleys and roadways are kept free from weeds. 
Within this .rotation block of 144 plats there are under experi- 
mentation ten 3-year rotations; sixteen 4-year rotations; two 6-year 
rotations; two groups of 7 plats each devoted to continuous cropping 
to corn and to spring wheat, each under six different cultural treat- 
ments; three groups of 6 plats each devoted to continuous cropping 
to winter wheat, oats, and barley, each under five different cultural 
treatments; and two groups of 3 plats each devoted to continuous 
cropping to milo and 
kafir, each under three 
different cultural 
treatments. 
Each rotation is rep- 
resented by as many 
plats as there are crops, 
fallow in this case be- 
ing considered a crop, 
in that it fills space 
that otherwise would 
be occupied by a crop. 
The 3-year rotations, 
for example, occupy 
three plats each; thus 
every crop in the rota- 
tion is grown each 
year. The rotations 
are numbered, and 
each plat in each ro- 
tation is lettered in 
the order A, B, and C. 
The plat treatment 
throughout the contin- 
uous cropping series is 
coordinated. The A 
plats of these series are shallow-plowed immediately before 
seeding time and then given meager seed-bed preparation. 
The plowing is in the spring for spring-planted crops and in 
the fall for winter wheat. The B plats are deep plowed in 
the early fall and given good seed-bed preparation. The average 
date of plowing these plats is September 1. In the winter- wheat 
series plat B is early plowed and plat A is late plowed. Good seed- 
bed preparation is given in the spring just previous to seeding. 
Plats C and D are alternately cropped and fallowed; that is, one 
plat carries the crop one year while the other plat is being fallowed. 
The fallow plats in this pair were fall-plowed until 1918; since that 
time they have been spring-plowed. The average date of spring 
plowing these plats is June 3. 
The practice is to plow at the time weed growth starts actively. 
After plowing, these plats are given the cultivation necessary to keep 
Fig. 4. 
Average monthly evaporation at the Akron Field Station for 
the 16 years from 1908 to 1923, inclusive 
