WINTER-WHEAT PEODUCTIOISr AT FORT HAYS STATIOlSr. 25 



sidered in the following pages, and it is also low in comparison with 

 wheat on alternate fallow in methods of fallow. These latter are in 

 fairly good agreement. It has been shown that kafir has a very 

 depressing effect upon the yield of wheat that follows it immediately, 

 but the evidence as a whole indicates that this effect is eliminated 

 by a fallow. No. 402 is an' adjoining rotation of kafir listed, fallow, 

 winter wheat on fallow, and kafir listed. The wheat on fallow in 

 this rotation has averaged only 17.6 bushels. This seems to show 

 that the growth of two crops of kafir in succession establishes a de- 

 pressing effect that persists through a fallow. This possible con- 

 clusion is subject to a reasonable doubt by the yields in 1914, when 

 the rotations had not run long enough to differentiate the wheat on 

 fallow in rotations Nos. 401 and 402, but when the yield of wheat in 

 No. 402 was low. 



The kafir following wheat in rotation No. 410 has averaged 22.6 

 bushels per acre; following wheat in rotation No. 402 it has averaged 

 20.4 bushels, and following kafir in the same rotation it has averaged 

 only 14.7 bushels. Wliile a potential difference of soil and location 

 might be established between rotations Nos. 401 and 402, the two plats 

 of kafir in No. 402, like the two plats of wheat in No. 401, are grown 

 on the same ground, one following the other from year to year over the 

 four plats that constitute the rotation. 



These 4-year rotations were started for comparisons with the 3-year 

 rotations of kafiir, fallow, and wheat that are considered in the fol- 

 lowing pages to determine the effect of lengthening them by intro- 

 ducing a second crop of wheat or a second crop of kafir. Their 

 evidence is very positive. The second crop of wheat (wheat on early- 

 plowed stubble of wheat raised on fallow) has an exceptionally 

 favored position. The rotations should be lengthened by increasing 

 the number of wheat crops. On the other hand, the second crop of 

 kafir (kafir following kafir) is depressed to about two-thirds the 

 yield of kafir following wheat. There is also uidication, although 

 the evidence is by no means conclusive, that this doubling of the 

 kafir crop establishes a depressing effect that is not entirely eliminated 

 by a year of fallow. 



In 1916 two 4-year rotations were started. Rotation No. 403 is 

 corn on spring plowing, barley on disked corn ground, winter wheat 

 on fall-plowed barley stubble, and winter wheat on fall-plowed wheat 

 stubble. Rotation No. 404 is the same in all respects except that kafir 

 takes the place of corn. 



The 4-year average yield of the wheat on fall-plowed barley stubble 

 has been 17 bushels in each rotation. The wheat following wheat has 

 averaged 17.2 bushels in rotation No. 403 and 16.1 bushels in No. 404. 



The barley has averaged 23.8 bushels following corn and 22.5 

 bushels following kafir. These rotations show httle or no depression 



