CEREALS ON THE BELLE FOURCHE EXPERIMENT FARM. 7 



In figure 3 are shown graphically the " useful " seasonal precipita- 

 tion and the yields of Kubanka durum spring wheat (C. I. No. 1516) 

 during the 12 years from 1908 to 1919, inclusive. The " useful " 

 precipitation shown is the total precipitation in rains of 0.3 inch 

 or more during the period between the emergence and ripening of the 

 Kubanka wheat each year. When the rains occurred during a period 

 of two, three, or four consecutive days the total amounts for the 



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'06 V9 70 '// 72 73 7^ VS 76 77 78 73 



.- — ••' UtS£FC/L 15E/9>^ON/4l /^/^£C/P/T/9T/0A/ 



r/£:LD PS/? ^CRE ('/3iy^H£:L<3) 



BU. 

 60 



Fig. 3. — Diagram showing the relation between the annual useful seasonal precipitation 

 and tlie yields per acre of Kubanka durum spring wheat on dry land at the Belle Fourche 

 Experiment Farm for the 12-year period from 1908 to 1919, inclusive. The broken line 

 shows the useful precipitation and the solid line the yields of Kubanka wheat. 



period were included even though less than 0.3 inch fell on some 

 of these days. The Kubanka variety of wheat was selected be- 

 cause it was the leading variety, was grown each year, and was not 

 seriously affected by rust. 



In figure 3 it will be seen that the yields of Kubanka wheat are 

 closely associated with the useful seasonal precipitation during most 

 of the years. In 1909 and 1914 the wheat was on poorer soil than 

 usual. In 1912 most of the rains came just before the wheat M^as ripe 

 and too late to be of benefit. The crop was a complete failure in 



