June 15,1925 Effect of Crops on Yields of Succeeding Crops in Rotation 1123 
are seeded in early fall. All plots are 
fertilized uniformly, with the precipi¬ 
tated dicalcic phosphate and sulphate 
of potash at the standard rates of 40 
pounds phosphoric acid and 20 pounds 
potash per acre, respectively, for the 
hoed crops, and beginning with 1918, 
one-half these rates have been applied 
each year to the small grains. No 
nitrogen is applied to any of the plots. 
Liming has been the same as on Fields 
II and III. 
Tobacco, potatoes, and corn follow 
directly after the soiling crops, while 
the small grains are subject only to the 
residual effects of the soiling crops. 
As a nonleguminous cover crop a 
mixture of timothy, tall meadow oat, 
and orchard and Italian rye grass is 
used. Beginning with 1916 the hoed 
crops have been grown on Field IV in 
even years and on Field V in odd years. 
Legumes were first seeded on Field 
IV in 1917 after the small grains, and 
on Field V they were planted in 1916 
in preparation for the first crops of 
tobacco, potatoes, and corn. . Only 
the cowpeas 'showed effective inocu¬ 
lation in the crop of the first year, but 
all legumes have made good growth 
since the first year. Staifds of the 
various crops have been satisfactory 
in nearly all cases. 
The arrangement and treatment of 
cropping control plots are the same as 
for Fields II and III, and tobacco and 
wheat have been regularly grown in 
rotation on the plots. The average 
yields are shown in Tables X and XI. 
The data for wheat in 1918 on Field V 
are unreliable, because of damage from 
joint worm, and are not included in the 
averages. As was found to be true on 
Fields II and III, the data in these 
tables disclose several instances in 
which tobacco and wheat as indicators 
of relative soil productiveness give con¬ 
tradictory results. The most striking 
case is that of the rye division of Field 
V, represented by Plot 18 of the three 
sections, as compared with Plots 11 and 
4, representing the oats and wheat 
divisions, respectively. The results 
with tobacco indicate that the rye 
division is the more productive, but 
the yields of wheat on the control plots 
are much lower than on the control 
plots of the oats and wheat divisions. 
On the whole, Field IV seems to be 
comparatively uniform except that the 
tobacco-rye cropping unit represented 
by Plot 18 is undoubtedly somewhat 
less productive than the remainder of 
the field. On Field V the contradic¬ 
tory results as to the rye division have 
been mentioned already. The results 
with tobacco and wheat agree in indi¬ 
cating that the corn section (C) is 
some 20 to 25 per cent less productive 
than the remainder of Field V. 
Table X.— Comparative productiveness of the cropping units of Field TV as 
indicated by the average yields• of tobacco and wheat on the control plots for the 
period 1916-1922, inclusive 
Location of plot 
Tobacco 
Wheat 
Yields of leaf 
per acre 
Yields of stalks 
per acre 
Yields of grain 
per acre 
Yields of straw 
per acre 
Plot 18 
Plot 11 
Plot 4 
Plot 18 
Plot 11 
Plot 4 
Plot 18 
Plot 11 
Plot 4 
Plot 18 
Plot 11 
Plot 4 
Section A.. 
Section B. 
Section 0_ 
Lbs. 
891 
1,110 
950 
Lbs. 
1,025 
1,143 
813 
Lbs. 
1,035 
1,100 
899 
Lbs. 
520 
655 
610 
Lbs. 
s 
Lbs. 
659 
775 
698 
Bush. 
10.3 
14 
12.7 
Bush. 
13.2 
12 
13.3 
Bush. 
14 
13.-7 
16.3 
Lbs. 
1,303 
2,123 
1,807 
Lbs. 
1,873 
1,927 
1,790 
Lbs. 
1,507 
1,767 
1,933 
Table XI.— Comparative productiveness of the cropping units of Field V as 
indicated by the average yields of tobacco and wheat on the control plots for the 
period 1917-1922, inclusive 
Location of plot 
Tobacco 
Wheat 
Yield of leaf 
per acre 
Yield of stalks 
per acre 
Yield of grain 
pet acre 
Yield of straw 
per acre 
Plot 18 
Plot 11 
Plot 4 
Plot 18 
Plot 11 
Plot 4 
Plot 18 
Plot 11 
Plot 4 
Plot 18 
Plot 11 
Plot 4 
Section A. 
Section B. 
Section C. 
Lbs. 
1,041 
1,017 
754 
Lbs. 
721 
713 
Lbs. 
916 
842 
696 
Lbs. 
450 
497 
460 
Lbs. 
422 
381 
365 
Lbs. 
458 
394 
407 
Bush. 
9.8 
10 
8.5 
Bush. 
15.8 
17.5 
11.8 
Bush. 
17.8 
17.5 
14.8 
Lbs. 
980 
1,050 
850 
Lbs. 
1,600 
2,190 
1,150 
Lbs. 
1,810 
1,930 
1,360 
