18 BULLETIN 901, 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, 190T 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 Xos. 
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 
