20 BULLETIN 108, U. S. DEPARTMENT OE AGRICULTURE. 



field. The subsoil of both good and poor soil is a light, calcareous 

 clay. Both soils are alkaline in reaction, and both showed the same 

 content of water soluble salts (0.03 per cent). The good sample 

 contained no aldehydes, and such residue as was obtained proved 

 only slightly harmful to wheat seedlings, whereas the poor sample 

 contained considerable aldehydes, which proved very harmful to 

 wheat seedlings in the cultural tests, reducing growth 30 per cent. 



Returning now to a discussion of Table IX as a whole, it is shown 

 that the aldehyde extract is uniformly harmful to the test plants. 

 This is apparent from the next to the last column of the table. 



In the third column is given the field record of the soils as to their 

 productivity, the data being furnished by the collector. The garden 

 soils already mentioned were all soils with which trouble of one kind or 

 another had been experienced. In general, this column shows that 

 the soils containing the aldehyde were also poor soils in garden and 

 field, with some few exceptions. In this column is found one notable 

 exception, in the Aurora silt loam, good .(No. 7, Table IX), from 

 Miller County, Mo. This soil contained aldehyde, whereas the cor- 

 responding poor sample (No. 31, in Table X), from another farm, 

 gave no indication of the presence of aldehyde. This observation 

 was confirmed by procuring a new sample from the farmer on the 

 good soil six months later. The other exceptions are the Norfolk 

 very fine sandy loam, good (No. 8, Table IX), and the Dekalb silty 

 clay loam, good (No. 16, Table IX), in which aldehyde was found, 

 but it will be noticed that in both these cases the poor soil contained 

 the aldehyde also (Nos. 9 and 17, Table IX). It would appear 

 therefore that both the good and poor soil samples contained some 

 aldehyde. It might be further pointed out that in both cases the 

 greater productivity of the sample designated as good is doubtless 

 due to the direct fertilizing value of the applied manure, the less 

 productive samples having no manure applied. That manure is not 

 antagonistic to aldehyde is indicated by its presence in the exceed- 

 ingly well-manured garden soils, in the same table (see notes in last 

 column), as well as by some of the field results already given. 



Some of the soils given in Table X, showing no aldehydes, have 

 been discussed in connection with the preceding table. The 

 remainder require no further discussion here, inasmuch as no aldehyde 

 was found in either the good or poor samples. 



From these two tables it is at once apparent that only a relatively 

 small number of the poor soils showed the presence of aldehyde, 

 which means that the poorness of many of the soils in Table X must 

 be attributed to other causes, since soil infertility may be due to a 

 great many factors other than the presence of toxic compounds, and 

 especially any particular toxic compound. 



