INVESTIGATION'S AT ARDMORE, S. DAK. 



25 



COMPARISON OF CORN AND SORGO AS PREPARATIONS FOR WHEAT AND OATS 



The value of a cultivated crop in rotations is determined to a 

 considerable extent by the yields of grains following it. Results show 

 that sorgo as a crop is well adapted to the section. The question 

 arises whether yields of grain crops following sorgo are likely to 

 be lower than following corn. For the purpose of determining the 

 fact, four 2-year rotations were established in small fields in 1916. 

 In all of these rotations the grain was grown on disked corn or 

 sorgo stubble and the cultivated crop on fall-plowed grain land. 

 The rotations were as follows: Corn and wheat, sorgo and wheat, 

 corn and oats, and sorgo and oats. 



The yields of grain in these rotations are given in table 9. The 

 year 1916 is not included, because the preceding crop and preparation 

 were uniform. 



Table 9. — Annual and average acre yields of wheat and oats folloimng corn 

 sorgo at the Ardmore station for the 16 years, 1917-32 



and 



Crop 



1917 



1918 



1919 



1920 



1921 



19221 



1923 



1924 



1925 



1926 



1927 



1928 



1929 



1930 



1931 



1932 



Aver- 

 age 



Wheat following corn... 

 Wheat following sorgo. . 



Oats following corn 



Oats following sorgo 



Bu. 



6.8 

 4.8 

 24.3 

 26.0 



Bu. 



35.2 

 24.6 

 57.2 

 61.1 



Bu. 

 15.9 

 14.5 

 19.3 

 20.4 



Bu. 



18.5 

 28.6 

 43.9 



58.7 



Bu. 

 17.7 

 13.1 

 41.1 

 24.4 



Bu. 





 

 

 



Bu. 



23.9 

 22.4 

 63.8 

 60.2 



Bu. 



7.1 

 10.0 

 12.8 

 16.0 



Bu. 

 20.0 

 15.7 

 32.4 

 37.7 



Bu. 

 10.2 

 13.0 

 22.7 

 22.5 



Bu. 



23.6 

 19.8 

 39.9 

 55.6 



Bu. 

 17.5 

 17.9 

 37.9 

 39.2 



Bu. 



11.9 

 12.6 

 17.5 

 18.0 



Bu. 



11.9 

 11.4 

 30.8 



27.8 



Bu. 



4.5 

 2.6 

 10.7 

 2.8 



Bu. 

 7.2 

 10.7 

 22.5 

 24.8 



Bu. 

 14.5 

 13.9 

 29.8 

 31.0 



Crops destroyed by hail. 



The averages indicate that the yields of grain following sorgo may 

 be expected to equal or nearly equal those obtained on corn ground. 

 The relative acreages of corn and sorgo should be determined from 

 the value of the crops themselves, without reference to the yield of 

 grain that may be grown following them. 



FEED-CROP ROTATIONS 



A rotation to determine whether a more certain production of feed 

 could be assured through a definite rotation was started in 1916. 

 This rotation contained sorgo, corn, oats ? and fallow, the fallow being 

 heavily manured. The heavy application of manure was designed 

 not only to show the effect of manure on crop production, but to 

 determine whether it would correct a bad physical condition of the 

 soil. 



The soil at the time the experiment was started contained many 

 aikalied or slick spots that crusted badly on drying and prevented 

 emergence of crops. The quantity of manure added to this field was 

 sufficient to correct this condition, and when the work ended in 1932 

 the soil appeared to be as mellow and to cultivate as readily as that 

 of some of the more favorably situated fields. The manure induced 

 a heavier vegetative growth of grains than was noted on fields not 

 receiving manure. In good years this resulted in increased yields, 

 but in some adverse years it reduced them. In 1927, when moisture 

 for small-grain production was ample, the yield of oats from this 



