10 BULLETIN 1172, U. S. DEPARTMENT OF AGRICULTURE. 
season. In the fall the land ordinarily is double-disked and har- 
rowed a short time before seeding. 
At the Plant Introduction Station most of the plat experiments 
have been conducted on fall-plowed land. Owing to the limited 
area it has not been possible to follow a systematic rotation. In 7 
of the 12 years the cereal experiments followed corn. The summer 
irrigation of this crop did not greatly affect soil-moisture conditions 
in the fall, as the moisture was fairly well exhausted by the growing 
crop and by rapid evaporation. Where the cereals followed corn, 
the land was plowed in the fall, usually in October or November. 
For the 1920 crop the corn stubble was dry-worked in October and 
November. In 1910 the cereals were grown on land fall-sown to 
wheat, which was plowed under in December; in 1911 and 1917 they 
followed alfalfa and in 1913 chick-peas. In 1921 they were sown on 
summer-fallowed land which was double-disked and harrowed before 
seeding. Most of the cereal nurseries have been grown on summer 
fallow or on cultivated areas previously used for tree nurseries. 
PLAT EXPERIMENTS. 
Two general methods of conducting experiments with cereals have 
been used. Up to 1916 the varieties were grown in single plats both 
with and without check plats. During this early period the plats 
used varied in size. In 1916 the replication of plats was begun but 
without check plats. From three to five replications have been 
used, but four has been the most common number. The 1/50-acre 
unit was used in most cases. 
NURSERY EXPERIMENTS. 
Nursery experiments have comprised a large part of the cereal 
investigations at Chico. Up to and including 1914 a limited amount 
of this work was done, consisting principally of varietal comparisons 
with wheat, barley, and oats. In 1915 the first wheat-classification 
nursery was grown, and in the following year a wheat-hybrid nursery 
was added. In 1918 large numbers of pure-line head selections of 
wheat and barley were grown, and in 1920 the dormancy experiment 
with barley and the date-of -seeding experiments with wheat, barley, *| 
oats, and flax were begun. 
Table 7 lists the different kinds of material of each cereal which 
were grown and the number of individuals of each with the approxi- 
mate number of rows (including replications) grown annually. 
The nursery experiments may be divided into two general classes, 
comparative experiments and miscellaneous experiments. The com- 
parative experiments have included comparisons of varieties, pure- 
line selections, and dates of seeding. 
In the comparative experiments the rows were sown 1 foot apart 
and of varying length. During the early years the row was either 
1, 2, or 8 rods long for all cereals. During the later years the length 
of the row depended upon the cereal used. For wheat it was 16 feet; 
for barley, 20 feet; for oats, 15 feet; and for flax, 17 feet. These 
lengths were chosen so that the following simple rule could be applied 
in calculating yields in bushels per acre when they were recorded in 
grams per row: For wheat, barley, and flax multiply the yield in 
grams by one-tenth or move the decimal point one place to the left. 
For oats, multiply by two and point off one place to the left. 
