IOWA ACADEMY OP SCIENCE 
IIS 
drained from a can of manure. This was allowed to stand until all fermenta- 
tion ceased. It was then filtered and analyzed for nitrogen. 2,400 c. c. con- 
tained as much nitrogen as the regular amount of the manure. The potassium 
and phosphorus were assumed to be in about the same proportion. The same 
amount of nitrogen and approximately the same amount of potassium, and 
phosphorus were applied in the leachings as in the manure. One-half and one- 
fourth of the above amount of leachings were applied to other pots to test the 
effect of smaller amounts. 
Pictures were taken May 3d, and the main pots of the series are shown in 
Plate III,. 
This picture shows the decided benefit of the manure, that the “leachings” 
gave more benefit than the manure itself and that the “extract” appears to be 
as good as the manure. 
The series was harvested June 8th, and the following table gives the treat- 
ments of the different pots of the series and the results obtained. 
LIQUID MANURE SERIES. 
o 
ft 
d 
12: 
Treatment 
Green 
wt. g 
No. of 
plants 
Average 
per plant 
Relative 
weight 
100 
Check __ __ — - 
14.63 
12 
1.22 
100 
101 
Manure _ _ 
32.3 
13 
2.48 
203 
102 
1-2 amt. manure.— I ___ . 
24.7 
13 
1.89 
155 
103 
1-4 amt. manure. . . ... . 
22.3 
13 
1.71 
140 
104 
2400 c. c.. leachings 
47.7 
12 
3.97 
323 
105 
1200 c. c. leachings... .. . ... 
.37.15 
13 
2.86 
234 
106' 
600 c. c. leachings.. . 
22.. 5 5 
13 
1.73 
142 
107 
Manure extract ... .. 
32.25 
12 
2.68 
22'0 
A study of this table shows that the “leachings” containing the same amount 
of plant food as the manure, gave twice the growth of clover. In fact, half 
the amount of “leachings” produced a little better gain than the full amount 
of the manure. It also shows that the “manure extract,” or the soluble part 
of the manure, produced the same effect as the whole manure. This can only 
mean that the benefit lies in the soluble part of the manure, and as the soluble 
part of the manure certainly has much smaller physical effect than the insoluble 
part, it makes it very unlikely that the physical effect of the manure has any 
thing to do with the better growth of the clover. 
We have arrived at the same conclusion, namely, that the physical effect 
of the manure is not responsible for the better growth of the clover, by three 
different lines of argument. To be sure no one of them amounts to absolute 
demonstration, still the accumulation of evidence is sufficient to justify the 
conclusion that in the greenhouse, other properties of the manure are respon- 
sible for the better growth of the clover on the manured soil. 
THE BACTERIOLOGICAL RELATIONS. 
The question of the influence of the bacteria brought by the manure, and 
the influence of the manure on the bacterial growth in the Soil was studied, 
and has already been reported.^ 
^See Proc. Iowa Acad, of Science, XIV, 1907, p. 177. 
8 
