18 BULLETIN 991, U. S. DEPARTMENT OF AGRICULTURE. 



No. 12 is the same rotation lengthened one year by raising a flax 

 crop on the brome-grass sod. The sod has been broken in the spring 

 immediately before seeding to flax. This has usually been about the 

 middle of May, the actual dates ranging from May 7 to June 2. 

 This practice can not be considered a success from the standpoint 

 of flax production. In some years the sod has been too dry to ger- 

 minate and grow the flax, in some of the wetter years the flax has 

 been choked out by the brome-grass, and in some years there has been 

 loss from flax wilt. The highest yield was 13.2 bushels in 1909. 

 In 6 of the 13 years the crop has been a total failure, reducing the 

 13-year average yield to 2.9 bushels per acre. Data from other sta- 

 tions indicate that better results might be obtained by breaking the 

 sod the preceding summer, the same as is done for oats in rotation 

 No. 10. 



The flax ground is fall plowed for oats. The oats in this rotation 

 have averaged about 4 bushels of grain and 500 pounds of straw per 

 acre more than the oats in rotation No. 10. where they are the first 

 crop following the brome-grass. The corn following the oats seems 

 to have been increased about 500 pounds per acre in total yield by the 

 introduction of the flax crop, but the wheat following the corn shows 

 little or no effect from it. 



The brome-grass in rotation No. 12 has yielded heavier than in 

 rotation No. 10. As there is no good reason for this in the rotations 

 themselves, it seems that it should be attributed to a difference in the 

 soil, which might also account for the heavier corn yields in rotation 

 No. 12. 



For the 13 years, 1907 to 1919, the first-year yield of hay has aver- 

 aged 2,332 pounds in No. 10 and 2,868 pounds in No. 12. The sec- 

 ond-year yield has been 2,714 pounds in No. 10 and 3,083 pounds in 

 No. 12. 



No. 42 is a 6-year rotation consisting of oats on alfalfa sod broken 

 the previous fall, corn on fall-plowed oat stubble, wheat on disked 

 corn ground, one year for seeding to alfalfa on fall-plowed wheat 

 stubble, and two years of alfalfa meadow. 



In only two years, 1915 and 1916, have the oats following the 

 alfalfa outyielded the oats following brome-grass in rotations Nos. 

 10 and 12. The 12-year average yield is about 3 bushels per acre 

 greater on the brome-grass sod of rotation No. 10 than it is on the 

 alfalfa sod of No. 42. The only oat plat in the field that has aver- 

 aged less than the one on alfalfa sod is the plat continuously cropped 

 to oats on fall plowing. 



The yield of corn following oats in the alfalfa rotation is also 

 less than in the brome-grass rotations. It is also less than following 

 oats in either 3-year or 4-year rotations. 



The yield of wheat is about 3 bushels less in the alfalfa rotation 

 than in the brome-grass rotations ; rotation No. 42 is somewhat sepa- 

 rated from rotations Nos. 10 and 12 in the field, and its apparent 



