18 CULTIVATION METHODS AND ROTATIONS FOR GREAT PLAINS. 



The most significant facts brought out by an inspection of the 

 figures presented in Tables I, II, and III are as follows: 



(1 ) The yields in thirteen out of the eighteen seasons cited are above 

 the normal for even the humid portions of the States where these 

 stations are located, in some cases being more than double the 

 normal. 



(2) There are surprisingly small differences between the yields 

 obtained from the three different methods used, these differences 

 being in many instances in the opposite direction from what might 

 be reasonably expected from the popular belief in the efficacy of 

 the methods followed. 



(3) There is but a single instance where summer tillage and alter- 

 nate cropping increased the yields above the ordinary methods suf- 

 ficiently to pay fully for the extra labor and expense involved. This 

 was at North Platte in 1908. The average results of the three years' 

 tests at this station do not, however, show profitable returns for sum- 

 mer tillage as compared with continuous cropping. The average 

 results of crop rotation have been more profitable than either con- 

 tinuous cropping or alternate cropping and summer tillage. (See 

 Tables XXII and XXIII.) 



(4) In all five instances (Edgeley, 1907; Hays, 1908; Garden City, 

 1909; Dalhart, 1909; and Amarillo, 1909), where severe droughts 

 were experienced, the yields for the summer-tilled plats as compared 

 with the ordinary-method plats were much greater, the ratios being 

 as follows: Edgeley — wheat 2.4 times, oats 1.7 times, barley 1.6 

 times; Hays — wheat 3.5 times, oats 2.7 times, barley 3.3 times; 

 Garden City — wheat 3.2 times, oats 4.1 times, barley 7.9 times. 

 At both Dalhart and Amarillo, in 1909, the ordinary-method plats 

 were complete failures from drought, while the yields on the summer- 

 tilled plats were as follows: Dalhart — wheat 10.5 bushels, oats 13.4 

 bushels, barley 7.5 bushels per acre; Amarillo — wheat 10.5 bushels, 

 oats 23.1 bushels, barley 17.5 bushels per acre. None of these yields 

 obtained during these dry years were sufficient to make the crops 

 profitable. 



After a careful consideration of all the data submitted and all the 

 arguments for and against the sufficiency of these data as a safe 

 basis for conclusions, the following tentative conclusions are sub- 

 mitted: 



CONCLUSIONS CONCERNING SUMMER TILLAGE AND CONTINUOUS 



CROPPING. 



(1) The practice of summer tillage and alternate cropping can 

 not be considered a safe basis for a permanent agriculture in the 

 Great Plains area, where spring-sown wheat, oats, or barley are the 

 staple crops. 



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