INVESTIGATIONS AT ARDMORE, S. DAK. 



9 



COMPARISON OF FOUR TILLAGE METHODS FOR CROPS GROWN CONTINUOUSLY 



Spring wheat, winter wheat, oats, barley, corn, sorgo, and flax 

 were grown continuously under different methods of cultivation 

 from 1913 to 1932. The four methods used were spring plowing, fall 

 plowing, subsoiling, and listing. All plots of a crop were seeded 

 on the same date with seed of the same variety. The average yields 

 of each of the crops grown by the different cultivation methods are 

 shown in table 3. 



Table 3. — Average acre yields of 7 crops grown continuously under 4 different 

 methods of cultivation at the Ardmore station for the 20 years, 1913-32 



Crop 



Spring plowed 



Fall plowed 



Subsoiled 



Listed 





Grain 



Stover 



Grain 



Stover 



Grain 



Stover 



Grain 



Stover 





Bushels 

 11.8 

 •8.2 

 23.6 

 16.8 

 3.3 

 15.2 



Pounds 



Bushels 

 11.0 

 27.9 

 24.2 

 19.0 

 3.6 

 15.5 



Pounds 



Bushels 

 10.3 



9.1 

 21.8 

 17.4 



4.3 

 14.2 



Pounds 



Bushels 

 11.1 



8.3 

 22.2 

 20.8 



3.6 

 14.0 



Pounds 













Oats 





















Flax 











Corn 



1,624 

 3.832 



1,630 



1,694 

 4,414 



1,378 





4,478 















i Late-fall plowed. 

 * Early-fall plowed. 



















The most notable feature of these yields is the comparatively small 

 differences that resulted from major differences in cultivation meth- 

 ods. Differences in individual years were sometimes high, but on 

 the average these differences balanced each other so that, with a few 

 exceptions, variations in yield in most cases represent no more than 

 the experimental error. 



Since average yields were not materially influenced by the cultiva- 

 tion method used, it follows that the selection of method may be based 

 largely on factors other than yield. The amount of labor involved, 

 the distribution of labor, and the timeliness of operations should be 

 the bases for determining the cultivation to be given land. 



For example, spring plowing and fall plowing are about equally 

 productive. There is, however, a limit to the amount of spring plow- 

 ing that can be done without unduly delaying seeding, and delayed 

 seeding almost invariably results in reduced yields. To determine 

 between spring and fall plowing one should decide whether the lesser 

 amount of power usually required for spring plowing compensates 

 for the possible loss of yield through later seeding. The fact that the 

 two methods produce nearly equal average yields permits a wide 

 latitude in choice. Fall plowing can be clone in years when moisture 

 conditions are such that plowing is not too difficult. If a dry, hard 

 soil in the fall makes plowing difficult, plowing can be postponed 

 until spring, with the assurance that no loss in yield will be ex- 

 perienced, if unfavorable weather does not too long delay seeding. 



The fact that subsoiling increases costs without increasing yields 

 eliminates this method of cultivation. 



103768 c — 37 2 



