52 



BULLETIN 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 icinter and spring iclieat ■varieties grown continu- 

 ously in adjoining plats on irrigated land on the Belle Fonrche Experiment 

 Farm, 1913 to 1919, inclusive."- 





Group. 



Yields per acre (bushels). 6 





1913 



1914 



1915 



1916 



1917 



1918 



1919 



Aver- 

 age. 





7.7 

 15.5 



29.4 

 19.2 



32.7 

 20.0 



10. 9 18. 1 

 8. 6 24. 5 



19.2 

 17.4 



12.4 

 13.4 



18.6 





16.9 











" Data from rotation experiments of the Office of Western Irrigation Agriculture. 

 * Single plats in 1913 and 1914 ; average of two plats, 1915 to 1919, inclusive. 

 « Regenerated Defiance, C. I. No. 3703. in 1913, 1914, and 1915: Marquis. C. I., No. 

 3276, in 1916 ; and Kuhanlja, C. I., No. 1440, in 1917,. 1918, and 1919. 



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 on\j 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 injuiy, so that the yields 

 were chiefly limited by the character of the growing season, seed bed, 

 and soil fertility. The yields of the oat varieties are shown in Table 

 XXXIX. 



