14 BULLETIX 1331, JJ. S. DEPAETMEXT OF AGRICULiTUEE 
The season of 1923 was not so favorable for small grains as that of 
1922. The corn crop, however, was the largest that has been pro- 
duced since the station was started in 1914. 
The precipitation for 1923 was 14.41 inches, as compared with 
17.35 inches during 1922 and 16.98 inches, the 49-year average for 
this section. The rainfall during May and June was below the 
average, but that for July was above it and was mainly responsible 
for the large corn crop. 
ROTATION AND TILLAGE EXPERIMENTS 
The rotation and tillage experiments were started in 1914, when all 
crops were seeded on land uniform in cultural treatment. The 
rotations, therefore, have been in operation for the period from 1915 
to 1923, inclusive. They occupy the six series of plats constituting 
the field designated ^^H^' in Figure 1 but commonly known as the 
main field. Some of them are duplicated on a heavier soil in field 
'^C, '' commonly known as the south field. The yields reported in 
this bulletin are those from the main field and are higher than those 
on the heavier soil in the south field. 
The principal crops grown in the rotations are spring wheat, oats, 
corn, and barley. Other crops appear in certain rotations, but their 
use is much more limited. The same varieties are used in all rota- 
tions and are those considered well adapted to this area. The vari- 
eties are Kubanka (durum) spring wheat, Sixty-Day oats (from 1914 
to 1922, inclusive) and Victory oats (in 1923), Northwestern Dent 
corn, and Hannchen barley. The tillage methods followed are spring 
plowing, fall plowing, disked corn ground, summer fallow, subsoiling, 
and listing. The different crops are grown following various crops 
and tillage methods in rotations varying in length from two to six 
years. Crops are also grown continuously on the same land with 
different tillage methods. 
YIELDS OF DIFFERENT CROPS 
The average yield of a crop serves as a reliable index of its possi- 
bilities for this area. The average yield is based upon all plats and 
tillage methods for the crop under consideration and includes aU 
methods from good to poor. The yields following different tillage 
methods are of most value and importance in determining the pos- 
sibilities of increasing the average ^-ields. 
In considering the yields of small grains the results on disked corn 
ground are presented, as this is considered the best preparation for 
small grain in this area. 
Wheat. — The 9-year average acre yield of wheat following aU 
methods is 15.8 bushels, as compared with an average yield of 12 
bushels in 1923. The average acre yield on disked corn ground was 
15.3 bushels for the 9-year period and 12.1 bushels in 1923. Although 
the ^-ields from summer-fallowed land exceed those from disked corn 
about 5 bushels to the acre for the 9-year average, the latter is con- 
sidered the better method. In the case of fallow the land is used 
two years for the production of one crop. TVlien corn takes the place 
of fallow, a crop of corn is obtained in addition to the crop of wheat. 
Corn is a valuable and important feed crop in this area. 
Oats. — The average yield of oats for the 9-year period was 33.7 
bushels per acre, as compared with 25.4 bushels in 1923. On disked 
