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 * 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 wheat plants in pots grown in Florida sand, Susque- 

 hanna sandy loam, and in Hagerstown loam. 



Florida yellow 



sand (infertile 



sand). 



Green Relative 

 weight. weight. 



Susquehanna sand 

 loam (unproduc- 

 tive soil). 



Green Relative 

 weight, weight. 



Hagerstown loam 

 (productive soil). 



Green Relative 

 weight, weight. 



Soil untreated 



Soil + 100 p. p. m. vanillin. 

 Soil + 200 p. p. m. vanillin. 

 Soil+ 300 p. p. m. vanillin. 

 Soil 4- 400 p. p. m. vanillin. 

 Soil + S00 p. p. m. vanillin. 



Grams. 

 1.40 

 1.32 

 1.32 

 1.35 

 1.20 

 1.18 



100 

 94 

 94 



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 



102 

 103 



1 Cir. 18, Bureau of Soils. 



