12 BULLETIN 30, U. S. DEPARTMENT OF AGRICULTURE. 
a hoe was used to kill scattered weeds and other plant growth. 
Just previous to the time the plats were planted they were usually 
- harrowed again. 
Seeding was done with a 6-foot single-disk press drill with seed 
spouts 7 inches apart. The seed was planted uniformly at what 
was considered the best rate and was placed at a depth of 1.5 to 3 
inches. Jt had previously been treated for bunt (smut) with a 
solution containing 1 pound of formalin to 50 gallons of water, in 
which it had been soaked for 10 minutes and then dried. The 
sowing was done usually between October 1 and 15 and was com- 
pleted in two to three days. After seeding, the plats were not culti- 
vated until the following spring. 
When the plants were about 4 to 6 inches high the plats were 
harrowed with a spike-tooth harrow. The teeth of the harrow were 
slanted backward in order to lessen the injury to the plants, and the 
harrowing was crosswise of the drill rows. No further cultivation 
was given the plats. The plats were rogued each year in order to 
keep the varieties as pure as possible. 
The harvesting was done with a binder. The bundles were shocked 
and the plats later were raked. ‘This raking insured against loss and 
error due to fallen and scattered heads. Those gathered by the 
rake were added to the shock. The shocks stood in the field for 
two to four weeks before they were thrashed. 
Check Plats. 
Check plats were used in determining the comparative or com- 
puted yields of the varieties. Several plats located at various 
points on the farm were planted to one variety of winter wheat. 
These plats received identical treatment and were called check 
plats. It was believed that the average yield of these check plats 
would equal the average yield of the variety used on them had it 
been grown exclusively on all parts of the farm. Then, by knowing 
the plat yield of any one variety, its average yield per acre in terms 
of the check variety could be computed with reasonable accuracy. 
The difference between the yield of any one check plat and the 
average yield of all check plats was used to express the relative 
difference which would exist in case any other variety were occu- 
pying the place of the check variety. Thus, if the difference were 
+5 bushels per acre, that difference would be added to or sub- 
tracted from the actual yields secured from any given one of the 
varieties in the vicinity of the smgle check plat. This would give 
the average yield of the given variety if it were grown on the entire 
farm. In order to facilitate computations the following equation 
was constructed: 
