HARMFUL EFFECTS OF ALDEHYDES IK SOILS. 21 
The material extracted in the aldehyde method was in all these 
cases extremely small and gave no aldehyde reactions, but in some 
cases it proved harmful nevertheless. What the nature of the 
harmful substance in these cases was it is impossible to state, as 
further study was excluded. If aldehyde was present, it was at least 
so small in amount that it escaped chemical detection, nor does the 
method wholly exclude the occurrence at this place of traces of other 
compounds. In the majority of cases the material was not harmful, 
occasionally even showing a slightly good or stimulating effect. 
Seventy-four soils are described in the foregoing tables. Of these 
14 were garden and greenhouse soils which had failed to grow crops, 
and 60 were field soils, under general farming conditions. Of these 
60, 30 were productive soils and 30 unproductive. These soils were 
all examined for aldehydes. Of the 14 garden soils, Hve contained 
aldehydes, and of the 60 field soils 12 contained aldehydes. 
(1 ) In soils from widely different sections. — The soils examined were 
from various parts of the United States; soils from 20 States make 
up the list. They vary from very unproductive to extremely fertile 
soils. Aldehydes were found in soils from nine States as widely 
separated as New York and Mississippi or Oklahoma. Its presence is 
therefore not confined to any locality. 
(2) In soils of different texture. — The soils in which aldehyde 
occurred are not soils of any specific type or texture. The above list 
of soils containing alhehyde comprises clays, clay loams, silt loams, 
silty clay loams, loams, stony loams, fine sandy loams, and very fine 
sandy loams. There is therefore no apparent relation with soil type, 
or texture. 
(3) In unproductive soils. — The unproductive soils examined can be 
divided into two classes: (1) Garden soils, comprising soils which 
have been highly fertilized and manured, heavily cropped and 
intensively cultivated, and later failed to produce good crops. This 
class includes several greenhouse soils. (2) Field soils, growing 
general farm crops with ordinary farm methods of cultivation. 
Fourteen poor garden soils were examined, five of which contained 
aldehydes. All of these soils were very unproductive and failed 
entirely or grew very poor garden crops. Nine of the 30 unpro- 
ductive field soils examined contained aldehydes. 
(4) In productive soils. — Of the 30 productive soils examined three 
contained aldehydes. These were the Aurora silt loam, from Miller 
County, Mo.; Norfolk very fine sandy loam, from Pender County, 
N. C. ; and Dekalb silt loam, from Preston County, W. Va. 
{5) In acid, alkaline, and neutral soils. — It is interesting to note 
that some of the soils which contained aldehydes were acid, some 
neutral, and others alkaline. Three of the garden soils were acid, one 
