HARMFUL EFFECTS OF ALDEHYDES IK SOILS. 
25 
EXAMINATION OF THE FIELD PLOTS FOR ALDEHYDE SIX MONTHS 
AFTER APPLICATION. 
That salicylic aldehyde can persist in some soils would seem to be 
indicated by the fact that the second shipment of Mount Vernon soil, 
collected six months later than the first, likewise contained salicylic 
aldehyde; also by the fact that the two samples of Aurora silt loam 
from Miller County, Mo., collected six months apart, both contained 
aldehydes. 
In order further to verify this ability of the aldehyde to persist in 
some soils, the salicylic aldehyde treated field plots were subjected to 
an examination for aldehyde as had been done with the soil samples 
from garden and field described in preceding paragraphs. Soil 
samples were collected from the cowpea plots, the string bean plots, and 
the garden pea plots, i. e., one sample from each check plot and each 
salicylic aldehyde plot. 
The six samples were examined for aldehyde. The three check 
samples contained none; the three treated plots showed the presence 
of aldehyde. The residues obtained in this procedure for separating 
aldehydes were tested with wheat seedlings, as described earlier in this 
paper. The extract from the check plots, which showed no aldehyde, 
grew plants as well as pure distilled water, whereas the extracted 
material from the aldehyde treated plots proved harmful to the wheat 
seedlings. The extract from the cowpea salicylic aldehyde plot de- 
creased growth 32 per cent, that from the string bean plot decreased 
growth 27 per cent, and that from the garden pea plot decreased 
growth 26 per cent. 
The existence of the harmful compound in the soil was also shown 
in another way by growing wheat in the greenhouse in paraffined wire 
pots, using the respective soils from the salicylic aldehyde treated 
plots and the check plots. Two pots, with six plants each, were used 
for each soil. The plants grew from December 11 to January 6. The 
results of this experiment are given in Table XIV. The table shows 
that the salicylic aldehyde in the soils of the treated plots six months 
after the salicylic aldehyde was applied was harmful to wheat. 
Table XIV. — Growth of wheat in soil taken from the field plots six months after treat- 
ment ivith salicylic aldehyde. 
Plot. 
Wheat on 
soil from 
check plots. 
Wheat on 
soil from 
salicylic 
aldehyde 
plots. 
Relative 
growth, 
check =100. 
Cowpea plot 
String bean plot 
Garden pea plot 
Grams. 
1.48 
1.54 
1.47 
Grams. 
1.18 
1.11 
1.22 
A similar experiment was made with these soils, except that the 
crops grown in the pots were identical with those which had grown 
