HARMFUL EFFECTS OF ALDEHYDES IN 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, five 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 



