FIELD TEST WITH A TOXIC SOIL CONSTITUENT: VANILLIN. 
3 
test the effect of different amounts of vanillin in several soils, each 
having different properties and being of different geological origin. 
In the following experiments wheat was used as the test crop and the 
total application of vanillin was made before the soil was potted and 
seeds planted. 
EFFECT OF VANILLIN ON WHEAT IN POTS. 
In this experiment the effect of vanillin in several soils was studied 
by growing wheat in pots. The soils used were infertile Florida sand, 
an infertile sample of Susquehanna sandy loam, and a good sample 
of Hagerstown loam. The paraffined wire pot method l was used, 
six wheat plants were grown in each pot, and two pots were used for 
each treatment. The plants grew from May 5 to May 24. Photo- 
graphs of the growing plants were taken, which show the action of 
vanillin in each soil. At the end of the experiment the green weight 
was determined. 
The Florida sand used in this experiment had grown citrus fruits 
in the field and was unproductive. A laboratory examination showed 
the soil to be acid. Vanillin was isolated from this soil in the inves- 
tigations referred to above. The Susquehanna sandy loam was taken 
from an infertile area in Maryland. The natural growth on this soil 
was poor, and its response to fertilizer and cultural treatments was 
only moderate. Its oxidizing power and life activities were found to 
be very weak. The Hagerstown loam is a fertile soil. The soil was 
taken from a productive field of the Pennsylvania Agricultural Exper- 
iment Station. The soil is neutral in reaction, has strong oxidizing 
power, and grows thrifty plants in pots. 
Vanillin was used in amounts of 100 to 500 parts per million. It 
was applied to the soil by dissolving in water and mixing the solution 
in the soil before potting. The results of the experiment on the 
effect of vanillin in the Florida sand, Susquehanna sandy loam, and 
Hagerstown loam are given in Table I. The actual green weight of 
the plants grown in the two pots are given for each treatment and 
the relative weight with the growth in the untreated soil taken as 100. 
Table I. — Effect of vanillin on viheat plants in pots grown in Florida sand, Susque- 
hanna sandy loam, and in Hagerstown loam. 
Treatment. 
Florida yellow 
sand (infertile 
sand). 
Susquehanna sand 
loam (unproduc- 
tive soil). 
Hagerstown loam 
(productive soil). 
Green 
weight. 
Relative 
weight. 
Green 
weight. 
Relative 
weight. 
Green 
weight. 
Relative 
weight. 
Soil untreated 
Grams. 
1.40 
1.32 
1.32 
1.35 
1.20 
1.18 
100 
94 
94 
98 
86 
84 
Grams. 
1.80 
1.85 
1.70 
1.33 
1.30 
1.02 
100 
103 
94 
74 
72 
57 
Grams. 
1.98 
1.87 
2.02 
2.05 
1.96 
1.95 
100 
Soil + 100 p. p. m. vanillin 
94 
Soil + 200 p. p. m. vanillin ■; 
102 
Soil + 300 p. p. m. vanillin 
103 
Soil + 400 p. p. m. vanillin 
99 
Soil + 500 p. p. m. vanillin 
99 
Cir. 18; Bureau of Soils. 
