SPRING WHEAT ON THE NORTHERN GREAT PLAINS. 13 
RESULTS OF FIELD EXPERIMENTS. 
The results of varietal experiments with spring wheat at 11 
different experiment stations are presented here. At ten of these 
stations the experiments have been conducted by the Office of Cereal 
Investigations, either cooperatively with the State agricultural ex- 
periment station or some other agency or independently. At the 
remaining station the data have been obtained independently by the 
State agricultural experiment station. The source of the data is 
stated in connection with each station. 
The experimental conditions, such as crop sequence, size of plat, 
width of alleys, and number of replications, vary somewhat at differ- 
ent stations. The results obtained at one station, therefore, are not 
necessarily comparable with those obtained at any other station. 
In many cases, however, they probably are directly comparable. 
The results from different varieties at the same station were nearly 
always obtained under similar conditions and may be compared 
directly. Any known exceptions to this fact are stated in the text. 
In all cases the crops were grown with only the natural rainfall and 
under conditions approximating good farm practice for the district. 
While comparative yields have been the most important results ob- 
tained, other factors have been studied. Complete agronomic notes 
have been recorded on the varieties at most stations. Samples of 
most of the varieties also have been milled and the flour baked in 
the milling and baking laboratory of the Bureau of Markets of the 
Department of Agriculture. In addition to yield, therefore, data on 
the following important factors are summarized: Days from emer- 
gence to maturity, height of plant, percentage of stem-rust infection, 
weight per bushel, percentage of crude protein, yield of flour, and 
volume of loaf. 
YIELD PER ACRE. 
The yields from the spring-wheat varieties under experiment since 
1912 are shown for each station. Varieties that have been grown for 
only one or two years are included in the station tables but are omitted 
in the summary table on yields. 
The annual and average yields obtained from spring-wheat varieties 
grown in plats at each of the 11 stations in the 7-year period 6 from 
1913 to 1919, inclusive, are shown in Tables III to XIII, together 
with the average yields obtained in the years previous to 1913. The 
probable errors for each variety grown in replicated plats also are 
shown. Where more than one plat was grown the number of plats 
of each variety is stated at the top of the column for each year. 
Finally, in the last column, the difference between the average yield 
of each variety in the years grown and that of the Marquis variety in 
6 At four of the stations cereal experiments were not conducted for the entire period. 
