10 
BULLETIN 108, U. S. DEPARTMENT OF AGRICULTURE. 
Table \'Ll. — Effect of salicylic aldehyde on wheat in nutrient culture solutions composed 
of phosphate, nitrate, and potash. 
Composition of culture 
solution. 
Without 
salicylic 
aldehyde. 
With 
salicylic 
aldehyde. 
Composition of culture 
solution. 
Without 
salicylic 
aldehyde. 
With 
salicylic 
aldehyde. 
P 2 5 NH 3 
K 2 
Green 
weight. 
Green 
weight. 
P 2 5 
NH 3 ! K 2 
Green 
weight. 
Green 
weight. 
Parts per 
million. 
32 
32 
32 
Parts per 
million. 
16 
24 
32 
Parts per 
million. 
32 
24 
16 
Grams. 
2.94 
3.12 
2.84 
Grams. 
1.86 
2.30 
1.97 
Parts per 
million. 
24 
24 
16 
Parts per '■ Parts per 
million. million. 
24 32 
32 24 
32 1 32 
Grams. 
3.68 
3.00 
3.34 
Grams. 
2.04 
2.00 
2.20 
From the foregoing results it is seen that salicylic aldehyde in 
amounts as small as 10 parts per million is harmful to the growth of 
wheat in nutrient solutions. In regard to the composition of the 
nutrient solutions affecting the harmfuhiess of the aldehyde it might 
be said that an analysis of the total green weights obtained in the 
case of the mainly phosphatic, the mainly nitrogenous, and the 
mainly potassic fertilizers given in Tables IV, V, and VI, respectively, 
shows that the least harmful effects are noted in the phosphatic 
group of cultures. This group as a whole shows a depression due 
to salicylic aldehyde of approximately 20 per cent in growth, w r hile 
the other two groups show r ed approximately 27 and 29 per cent 
below the respective group of cultures without the aldehyde. 
ABSORPTION OF NUTRIENT SALTS. 
As salicylic aldehyde has been shown to be harmful to growth in 
culture solutions containing nutrient salts, it will be interesting to 
study its effect on the removal of nutrients from the solutions during 
the growth of the plant. 
As stated above the concentration differences produced by the 
growth of the plants in the various cultures was determined by 
making an analysis for nitrates at the termination of every three- 
day change, and of phosphate and potassium on a composite of the 
solutions from the four changes. 1 It is possible, therefore, to com- 
pare the results obtained in the normal cultures without salicylic 
aldehyde and in the cultures where 10 parts per million of salicylic 
aldehyde were present in the solution. 
The sum total of P 2 5 , NH 3 , and K 2 removed from solution by the 
growing plants in all of the cultures under study was 1,646.6 milli- 
grams in the normal cultures and 1,332.3 milligrams hi the nutrient 
cultures containing salicylic aldehyde. The figures show the total 
of plant nutrients removed to be less in the cultures containing 
salicylic aldehyde than in the normal cultures, which indicates that 
the salicylic aldehyde cultures used less nutrients than the normal. 
The results of the examination of the three constituents separately 
are as follows: 
1 These determinations were made colorimetrically as described in Bui. 31 and Bui. 70, Bureau of Soils, 
U. S. Dept. of Agriculture. 
