24 BULLETIN 991, TJ. S. DEPARTMENT OF AGRICULTURE. 
Brome-grass has been found to lend itself well to use in a rota- 
tion. It has been a sure and reliable hay crop. There is also an 
aftermath eminently suited for fall pasture, but its value has not 
been determined in these experiments. 
Alfalfa has also proved a valuable sod crop. The only failures 
have been from rather infrequent winterkilling. Its average ton- 
nage is not quite as heavy as that of brome-grass, but it is of higher 
value. It does not lend itself to short rotations as well as brome- 
grass, because it is not desirable here to attempt to establish it by 
seeding with another crop, a practice which for 14 years has proved 
entirely practicable with brome-grass. 
The effect of alfalfa in a rotation has apparently been to depress 
the yield of the crops immediately following. Brome-grass has had 
a slightly depressing effect on the first crop following it, but suc- 
ceeding crops have neither been increased nor decreased in yield. It 
may well be that these experiments do not show what may fairly be 
expected from sod crops in rotation on a farm. Generally speaking, 
in these experiments the crops have been allowed to meet the weeds 
that attend their growth under the several cultural methods under 
trial, but it is necessary in plat work to prevent pernicious weeds, 
such as the mustards, wild oats, quack-grass, and perennial thistles, 
from becoming established, as they could not well be confined to 
single plats or rotations. As one of the effects of sod crops is to 
clean the land of weeds, it can not be said with certainty that their 
full effect has been measured in these experiments. 
The results indicate that the sod crops, while forming a part of 
the rotation, should enter into it only as it is necessary to make new 
seedings and break up the old, in order to maintain the maximum 
production of the brome-grass or alfalfa. 
The remaining ground should be in a rotation of corn on spring 
plowing, followed by wheat on disked corn ground, and it by wheat, 
oats, or barley. To make early seeding possible, fall plowing for the 
small grain is desirable. There is no objection to spring plowing ex- 
cept as it delays seeding. If it can be done in time to permit early 
seeding, it may be even better than fall plowing. 
If one-third the land not in sod were devoted to corn, there would 
be one crop of wheat on corn ground and one crop of small grain on 
wheat stubble. The relative production of corn and small grain 
probably does not justify planting so large a proportion of the land 
to corn. The adoption of such a rotation would mean a radical 
change in the agriculture of the section, which is now based chiefly 
on wheat. It would also mean a decreased total production of wheat, 
as the increased yield of wheat on the corn ground over wheat fol- 
lowing wheat would not compensate for the reduced wheat acreage. 
The rotation may be lengthened to meet the requirements by reducing 
the acreage of corn and letting small grain follow small grain for a 
greater number of years. 
WASHINGTON : GOVERNMENT PRINTING OFFICE : 1921 
