26 
BULLETIN 108, U. S. DEPARTMENT OF AGEICULTTJEE. 
in the field the preceding season, that is, cowpeas were grown on the 
cowpea soil from the check plot and from the salicylic aldehyde plot, 
string beans on the string bean soil from both the check and treated 
plot, and garden peas on the garden pea soil from both check and 
treated plot. Two pots were used in each case and two plants were 
grown in each pot. The plants grew from December 11 to January 
6. The vegetative growth made in this experiment is given in 
Table XV. 
Table XV. — Growth of cow peas in soil from the cowpea field plots, string beans in soil 
from the string bean field plots, and garden peas in the soil from garden pea field plots. 
Collected six months after treatment with salicylic aldehyde. 
Crop grown in pots in greenhouse and previously ia the field. 
Soil from 
check plots. 
Cowpeas 
String beans. 
Garden peas. 
Grams. 
4.30 
7.80 
5.60 
Soil from 
salicylic 
aldehyde 
plots. 
Grams. 
3.80 
7.20 
4.30 
Relative 
growth, 
check=100. 
The table shows that the salicylic aldehyde treated soil was still 
harmful to the respective crops in samples collected six months after 
the application of the salicylic aldehyde, the test plants, growing about 
five months after the harvesting of the same crop in the field. It is 
also interesting to note that the relative order of toxicity shown 
toward the different crops is the same in these smaller vegetative 
experiments in the paraffined wire pots as in the case where the crops 
were harvested in the field. This would also seem to indicate that 
the observed order of toxicity toward these plants, namely, garden 
peas, cowpeas, string beans, may be more than accidental. 
SUMMARY. 
Compounds of an aldehyde nature exist in many soils. Such soils 
are usually unproductive. When separated from the soils, the alde- 
hyde material is toxic to plants in pure water and in nutrient 
solutions. 
One of these soil aldehydes is identified as salicylic aldehyde. 
This compound in very small amounts is harmful to plants in distilled 
water and in nutrient solutions. It is harmful to plants grown in 
pots of soil. It greatly decreases the yield of crops grown in the 
field. It persists in the field soils for months. 
There is some evidence which suggests that lime and phosphate 
ameliorate the effects of salicylic aldehyde. Its chemical nature sug- 
gests that increased oxidation in soils under field conditions probably 
prevents its formation or accumulation. 
o . 
WASHINGTON : GOVERNMENT PRINTING OFFICE : 1914 
