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IOWA ACADEMY OF SCIENCE 
l 
This eliminated all bacteria, both the special clover bacteria and 
the numerous fermentations and decomposition bacteria. 
Following are the green weights taken May 3d, one hundred and 
twenty-four days after planting: 
Pot 
Treatment 
Wt. Crop 
g- 
Average 
No. of 
Plants 
Wt. per 
Plant g. 
Average 
40 
Horse Man. 
38.9 
17 
2.29 
41 
Cattle Man. 
53.3 
30 
1.71 
42 
Mixed I 
45.4 
47. 
15 
3.03 
2.35 
43 
Mixed II 
50.2 
21 
2.39 
44 
0 
7.2 
7.2 
6 
1.20 
1.20* 
45 
Horse M. Ster. 
54.6 
15 
3.64 
46 
Cattle M. Ster. 
51.7 
45. 
36 
1.44 
4.31 
47 
Mixed I. Ster. 
34.2 
6 
5.70 
48 
Mixed II. Ster. 
38.9 
6 
6.48 
The stand varies so much that it is hard to make exact compari- 
son, but surely the sterilized manure suffers nothing by the com- 
parison, however we look at it. No. 40, horse manure, and No. 45> 
the same sterilized, have the same stand practically, but the ster- 
ilized pot has 40% heavier crop. The average of the four unster- 
ilized pots is 47 grams per pot, and the sterilized pots 45 grams. 
Surely very close together. We see though that the unsterilized 
pots had much the heavier stand and when comparison is made on 
the weight per plant, the sterilized pots are very far ahead, 80% 
better in fact. However, where the stand was thinner the plants 
would have a much better chance to develop, so a comparison on 
this basis is not altogether fair. But taking everything into consid- 
eration, we feel safe in saying that sterilization has not lessened 
the benefit to be derived from the manure. In fact it really seems 
to have helped it. 
In a later series this question was tested again. 71 was a check 
pot, 73 had cattle manure added and 74 had the same sterilized. 
They w T ere planted February 24th. April 14th a study of the pots 
showed that manure had a decidedly beneficial effect, but no dif- 
ference was noted between the sterilized and unsterilized pots. 
There is a decided benefit from the use of stable manure and 
sterilizing it does not seem to decrease this effect. 
Notes were taken at this time and again May 24th. Final green 
weights were obtained June 1st. The following table gives all these 
data. The pots are compared with each other by rating the check 
pot 100 and giving the relative standing of the others : 
