CEREALS ON THE BELLE FOURCHE EXPERIMENT FARM. 11 
frost was recorded in. 1919 on June 1, while the earliest autumn 
frost was observed in 1910 on August 25. The average frost-free 
period was 126 days, but this has varied from 93 days in 1910 to 
145 days in 1917. The frost- free period is long enough to permit 
full maturity of all adapted varieties of small grains at Newell. 
EXPERIMENTAL METHODS. 
PREPARATION OF THE LAND. 
Most of the cereals on dry land were sown on either summer fallow 
or corn ground. Stubble land was usually plowed 6 to 8 inches deep 
with a disk plow in the fall and left rough over winter. Corn 
ground was not disturbed until spring, when it usually was double 
disked and harrowed before seeding. The fall-plowed fallow was 
not cultivated in the spring until weeds and volunteer grains began 
to grow, but after this time was kept bare throughout the season 
by the use of the disk or spring-tooth harrow. Owing to the tend- 
ency toward soil blowing early in the spring, which seemed to in- 
crease each year after the virgin sod had decayed, it became neces- 
sary to conduct most of the experiments on cornland. Yields of 
grain on summer- fallowed land were more certain and somewhat 
higher than with other methods of preparation, but were less profit- 
able than on corn ground because of the larger expense for tillage. 
All of the experiments with winter wheat on the dry land were con- 
ducted on fallow. 
PLAT EXPERIMENTS. 
Nearly all experiments except those in the breeding nurseries and 
the preliminary varietal experiments were conducted in field plats. 
These plats in 1908, 1909, and most of them in 1910 were 2 by 8 rods 
in size, containing one-tenth of an acre. The plats were separated 
by 5- foot alleys, and the road between each series of plats and the 
next was either 16.5 or 20 feet wide. 
Most of the experiments in 1911 and all of those in 1912 and there- 
after were in plats made by sowing a single drill width across an 
8-rod series. As the drill was 6 feet wide, this gave a plat of one 
fifty-fifth of an acre in area. The alleys between these plats have 
been 19.2 inches in width. By the use of plats and alleys of these 
dimensions it was possible to sow five plats within the area formerly 
occupied by a tenth-acre plat. As the plants draw considerable mois- 
ture and plant food from the alleys, it has been thought fair to con- 
sider these ^-acre plats as fiftieth-acre plats in computing acre yields. 
REPLICATION OF PLATS. 
In 1908, 1909, and 1910, when the experiments were conducted on 
tenth-acre plats, there was only a single plat of each variety. Check 
