FIELD TEST WITH A TOXIC SOIL CONSTITUENT : VANILLIN, i 
whilo the vanillin plot, produced 717 pounds per acre of vines and 120 
pecks of peas. This is a reduction of 30 per cent in vines and 20 per 
cent in marketable peas, due to the presence of vanillin. 
Plate IV, figure 2, shows the harvested crop grown in the untreated 
plot and in the vanillin plot. 
EFFECT OF VANILLIN ON STRING BEANS. 
String beans were also affected by vanillin. The beans were sown 
May 21, 1913; they germinated well and came up uniformly. The 
plants in the untreated plot grew better and were more thrifty than 
those in the vanillin plot. Plate III, figure 3, shows the comparative 
growth in the early stage, and from this it is seen that the untreated 
plants are much larger. The crop was harvested July 22. The 
beans were picked from the vines and measured. The results are 
given in Table IV, 
Table IV. — ■ Yield of string beans as 'affected by vanillin in the t 
Treatment. 
Yield per plot. 
Yield per acre. 
Vines. 
Beans. 
Vines. 
Beans. 
Pounds. 
3.55 
2.94 
Pounds. 
1.90 
1.66 
Pints. 
4.75 
4.15 
Pounds. 
2,272 
1,882 
Pounds. 
1,236 
1,062 
Pecks. 
190 
Check b 
166 
3.24 
2.71 
1.78 
.55 
4.45 
1.50 
2,070 
1,734 
1,149 
352 
178 
56 
.53 
1.23 
2.95 
336 
797 
122 
The average yield for the check plots was 2,070 pounds of vines per 
acre and 178 pecks of beans per acre. The yield of the vanillin plot 
was 1,734 pounds of vines per acre and 56 pecks of beans per acre. 
This is a decrease of 336 pounds of vines per acre and 122 pecks of 
beans per acre. The harvested crop from the untreated plot and the 
vanillin plot is shown in Plate IV, figure 3. 
PRESENCE OF VANILLIN AND ITS EFFECT IN THE SOIL SIX MONTHS 
AFTER APPLICATION. 
. The question of the length of time the vanillin would persist in the 
Arlington soil and have an influence on its crop-producing power has 
also been investigated by a chemical study in the laboratory and by 
pot tests. Samples of soil for these purposes were obtained from the 
plots the last of November, six months after the substance was 
applied, and after a crop had been matured. The soils were exam- 
ined for vanillin by the method already described by Shorey. 1 The 
method, in brief, consists of making an alkaline extract of the soil. 
The extract is acidified and filtered and then shaken out with ether. 
i J. Agr. Research, 1, 357 (1914). 
