SHEEIDAN FIELD STATION, 191*7 TO 1923 
13 
wheat showed a shghtly larger yield following green manure in 1923, 
but only by a longer trial can it be determined whether this effect 
was due to the green manure. With the heavily increased cost of 
the green manure its use is not justified. 
RESULTS OF PLOWING FALLOW AT DIFFERENT TIMES 
Included in the work with fallow is an experiment designed to 
determine what difference, if any, may be expected from plowing for 
fallow at different dates. For this purpose four pairs of plats are 
used, designated as H and I, J and K, L and M, and N and O, 
respectively. One plat of each pair is in spring wheat each year 
and the other is fallowed. When plats I, K, M, and O are in crop, 
plats H, J, L, and N are in fallow. The fallow plat in the pair H 
and I is plowed for fallow as soon as practicable after the gram crop 
is removed in the fall. It is worked shortly afterward with the disk 
set nearly straight or with the spring-tooth harrow and is cultivated 
sufficiently the following summer to keep it free from weeds. Th& 
fallow plat in the pair J and K is plowed at the same time but is 
not worked down, being left rough over winter. It is given the same- 
cultivation during the next summer as the H or I plat. The fallow 
plat in the pair L and M is left in stubble over winter and is plowed 
in the spring at about the time of plowing for corn. From that time 
it is given the same cultivation as the fall-plowed fallows. The 
fallow plat in the pair N and O is plowed about a month later and 
given the minimum cultivation necessary to keep the land free from 
weeds. The yields for each year and the averages for the 6-year 
period are shown in Table 10. 
Table 10. — Annual and average yields of spring wheat with different methods of 
fallow at the Sheridan Field Station for the 6-year period from 1918 to 1923, 
inclusive 
• 
Treatment 
Yields per acre (bushels) 
Plats 
1918 
1919 
1920 
1921 
1922 
1923 
Aver- 
age 
Hand I 
J and K . 
Fall plowed; cultivated immediately 
Fall plowed; rough first winter 
24.5 
23.4 
25.2 
23.9 
4.3 
6.6 
7.1 
4.0 
19.5 
20 7 
25.2 
25 2 
26.3 
26.8 
32.2 
29.8 
29.7 
32.7 
32.8 
30.2 
21.6 
22 6 
LandM 
NandO 
Spring plowed at time of plowing for corn. 
Summer plowed; late June or early July. 
23.3 
22.0 
23.7 
20.7 
24.1 
21.8 
It will be noted that the highest 3d eld was on the fallow plowed 
early in the spring. The average yield by this method was 24.1 
bushels per acre. Plowing in the fall yielded best in only one year, 
the average yields of the fall-plov^-ed fallows being 2.5 and 1.5 bushels 
per acre, respectively, less than the yield of the fallow plowed early 
in the spring. A decrease in yield for the late plowing is noted in 
every year, the average being 2.3 bushels below that of the earlier 
plowing. Of the two plats plowed in the fall, the one left rough 
over winter averaged 1 bushel per acre more than the plat worked in 
the fall after plov/ing. 
RESULTS OF SUBSOILING AND OF LISTING 
One plat which is subsoiled and one which is listed are included in 
the continuous-cropping series of each of six crops. The subsoiled 
plat is fall plowed each year. For two years in succession it is sub- 
