18 BULLETIN 1287, U. S. DEPARTMENT OF AGRICULTURE 
EXPERIMENTAL METHODS 
PREPARATION OF THE SOIL 
Practically all the earlier cereal experiments were conducted on 
summer fallow. Beginning with the crop of 1917 the varietal, rate-of- 
seeding, and date-of-seeding experiments with cereals were seeded in 
quadruplicate, two plats on fallow and two on cornland. Data on 
each variety, rate, and date thus were obtained on two soil prepara- 
tions each season. No definite system of fallowing has been followed. - 
The general plan has been to allow the stubble of the previous season’s 
crop to remain undisturbed over winter. In the spring the soil 
usually was plowed to a depth of 5 to 7 inches, although in a few sea- 
sons the plowing was omitted and the soil simply double-disked. 
During the summer the fallow was kept free from weeds by the use 
of disk or spring-tooth harrows or a duck-foot cultivator. The usual 
system followed in preparing the fallow for seeding either fall or spring 
cereals has been to disk the soil just before seeding time and to smooth 
the surface with a spike-tooth harrow. 
The cornland has presented several problems. The soil prepara- 
tion has varied slightly; but usually the small-grain stubble of the 
previous season remains undisturbed until the following spring, when 
it is double-disked. About the middle of May the corn is listed on 
the entire area, the rows running across the cereal plats. During 
the summer the land is cultivated several times to keep down weed 
growth and prevent the soil from baking. The corn is cut from the 
plats to be sown to fall grains. On the plats to be sown to spring 
cereals it is husked and the stalks allowed to stand until early spring, 
when they are disked into the ground. The chief difference between 
the two methods is that the standing stalks may catch and hold 
more snow than the stubble. As arule, little is left of a stalk field in 
this section after the winter and early-spring windstorms, and prob- 
ably disking in the cornstalks does not influence the results obtained. 
The nursery experiments always have been conducted on summer 
fallow, as yields on summer-fallowed land are somewhat higher and 
more certain than on that prepared by other methods. This is an 
important consideration where the supply of seed is limited. 
No definite cropping system has been followed on land used for 
conducting experiments with corn, sorghum, buckwheat, flax, proso, 
and millet, as the experiments with these crops have not been on 
definitely allotted areas. 
PLAT EXPERIMENTS 
Practically all experiments except the genetic and breeding studies 
and the preliminary seedings of varieties and selections were con- 
ducted in field plats. Previous to 1917 the field plats were not of 
standard size. When the station was first established single tenth- 
acre plats of each variety were grown. With the need for additional 
plats these tenth-acre plats were subdivided into smaller ones. The 
tenth-acre plats were 8 rods long by 2 rods wide, separated by alleys 
4 or 5 feet in width. The plats now used are 8 rods long and 6 feet 
wide and are separated by alleys 16 inches in width. ‘These plats 
contain one fifty-fifth of an acre, but as the plants in them draw 
considerable moisture and plant food from the alleys it seems fair to 
consider them as fiftieth-acre plats in computing yields, although the 
actual area is slightly less. 
eee" 
