INVESTIGATIONS AT ARDMORE, S. DAK. 7 



The average yield of spring wheat was 3.4 bushels per acre higher 

 than that of winter wheat. In only 2 years out of 20 did the yield 

 of winter wheat exceed that of spring wheat. In the fall preceding 

 each of these years the September precipitation was exceptionally 

 high. This indicates that if winter wheat is to be grown, it is 

 likely to be superior to spring wheat only in years following heavy 

 fall precipitation. 



Loss of stand of winter wheat is much more frequently due to soil 

 blowing in the early spring than to winter-killing. Wheat does not 

 make enough growth in the fall to form a cover for the soil. Freez- 

 ing and thawing during the winter put plowed and cultivated soil in 

 a friable condition that is almost certain to blow enough in the 

 spring to injure winter wheat in its then weakened state. Winter 

 wheat offers the greatest chance of success when planted in standing 

 cornstalks or in clean grain stubble. 



The yields of spring wheat and oats in pounds of grain per acre 

 do not differ materially. Wheat averaged 984 pounds per acre and 

 oats 1,018 pounds. As wheat usually is more valuable, pound for 

 pound, than oats, it is a better crop to grow for sale. 



The average acre yield of barley was 1,032 pounds. This is a 

 little higher than that of oats, but does not represent the true differ- 

 ence in yield between the two crops. A greater proportion of the 

 barley plots than of the other principal grain crops were grown under 

 poor methods of cultivation, and other varieties of barley have been 

 found to yield more than the ones used in the rotations from 1913 

 to 1921. A comparison of crops by cultural methods, which appears 

 in later pages, shows the relative yields of the two crops under 

 comparable conditions. 



The importance of the choice of varieties is shown by a compari- 

 son of barley and oats. The same variety of oats was used through- 

 out the 20 years. During the period 1913-21 six-rowed barleys of 

 the Manchuria type were grown. During this period the average 

 yields per acre were 1,142 pounds of oats and 965 pounds of barley. 

 White Smyrna barley was used from 1922 to 1932. During this 

 period oats produced an average yield of 915 pounds per acre and 

 barley 1,090 pounds. The relative producing power of barley as 

 compared to oats was increased approximately 350 pounds per acre 

 through the use of a better adapted variety. 



Flax produced an average yield of only 3.9 bushels per acre. As 

 a speculative crop on new breaking, flax sometimes may be very 

 profitable. It does not seem to be adapted to a regular place in a 

 permanent farming system in this section. 



As only one plot of winter rye was harvested, it must be com- 

 pared with other grains on the basis of plots grown under the same 

 type of soil treatment. The 5-year average yield of rye was 8.3 

 bushels per acre. Winter wheat grown under the same preparation 

 during the same period of years averaged 7.3 bushels per acre. The 

 yield of winter rye did not exceed that of winter wheat enough to 

 make up for the usual difference in price. 



The delayed-seeding wheat was produced on a group of plots 

 handled in exactly the same way as a group of plots on which seed- 

 ing was done at the normal date, except that seeding was delayed 

 1 month and the plots were cultivated to destroy weeds before seed- 



