52 
BULLETIX 1039, U. S. DEPARTMENT OF AGRICULTURE. 
greater yielding power and rust resistance of Kubanka, the yields 
of spring wheat doubtless would have been much higher had this 
variety been sown in the earlier years of the experiment. 
The annual and average yields of spring and winter wheat in 
these experiments are shown in Table XXXVIII. 
Table XXXVIII. — Yields of lointer and .spring wheat varieties grown continu- 
ously in adjoining plats on irrigated land on the Belle Fourche Experiment 
Farm. 1913 to 1919. inclusive. 
K 
Group. 
Yields per acre (bushels). b 
1913 
1914 
1915 
1916 1917 . 1918 
1919 
Aver- 
age. 
Winter . . . 
Spring c . . 
15.5 
29.4 
19.2 
32.7 
20.0 
10.9 IS. 1 i 19.2 
8. 6 24. 5 1 17. 4 
12.4 
13.4 
Is 6 
16.9 
° Data from rotation experiments of the Office of Western Irrigation Agriculture. 
6 Single plats in 1913 and 1914 : average of two plats. 1915 to 1919. inclusive. 
c Regenerated Defiance. C. I. No. 3703. in 1913. 1914, and 1915: Marquis. C. I. 
3276, in 1916 ; and Kuoanka, C. I., No. 1440, in 1917, 1918, and 1919. 
No. 
Winter wheat outyielded spring wheat in these experiments in four 
out of seven years. The 7-year average yield of Turkey winter 
wheat was 18.6 bushels per acre. The adjoining plats of spring 
wheat produced an average yield of 16.9 bushels during the same 
period. In general, winter wheat may be slightly more productive 
than spring wheat under irrigation, but in many seasons the reverse 
is true. Winter wheat is not as well suited to growing under irriga- 
tion as spring wheat because of the rotation scheme. Wheat on 
irrigated land is usually sown after an intertilled crop, such as corn, 
roots, or potatoes. These crops are usually not removed from the 
ground until rather late for sowing winter wheat. When winter 
wheat is sown following a small-grain crop, it is necessary to plow 
and irrigate the land rather promptly after the previous crop is 
thrashed. Spring wheat also is a more convenient nurse crop for 
alfalfa, sweet clover, or grasses, which frequently are sown with the 
grain. 
EXPERIMENTS WITH OATS. 
VARIETAL EXPERIMENTS. 
The experiments with oat varieties under irrigation were begun 
in 1912. Fifteen varieties have been grown in plats, but only four 
of these were grown during all of the eight years. Fair or good 
crops were obtained each season, but the yields are not large. The 
crop was almost free from diseases or other injury, so that the yields 
were chiefly limited by the character of the growing season, seed bed, 
and soil fertilitv. The yields of the oat varieties are shown in Table 
XXXIX. 
