114 



Table V, and planted to oats. After the oat harvest, 

 each pot was treated as shown in the third column, and 

 planted to corn. In the fourth column, the combined 

 crop weights are given; and in the last column will be 

 found the relative combined yields, based on the un- 

 treated pots as 100. 



Table Y. Effect of repeated treatments with fertili- 

 zers, pyridine, qninoline, vanillin, pyro- 

 gallol and coumarin on crop yields in Cal- 

 lers Field soil. Crops grown in 2-gallon 

 pots in the green house, 1914-1915. 



KIND AND AMOUNT OF 

 TREATMENT TO OATS 





C M 



o 



O 



• o 



c 



ti 



-O 



O 



■■J 



•— "^ nSv. 



>. i> 

 as 



3 >, 



Check — no treatment 



Kainit, 4.5 grams 



Nitrate of soda, 4.5 grams. 



Kainit and phosphate 



K , P. cSj N 



Pyridine, 4.5 cc 



Pyridine, 9.0 cc 



Quinoline, 4.5 cc 



•Quinoline, 9. cc 



Vanillin, 4.5 grams 



Vanillin, 9.0 grams 



Pyrogallol, 4.5 grams 



Pyrogallol, 9.0 grams 



Coumarin, 4.5 grams 



14 



19 



110 



18 



234 



43 



67 



36 



61 



9 



8 



14 



12 



8 



K* 

 N. 



K. & 

 K.,P. 

 K. &: 

 K. & 

 K. Sc 

 K. c^- 

 K. cl- 

 K. S: 

 K. & 

 K. c<^- 

 K. c^- 



P. 



c^N 



P. 



P. 



P. 



P. 



P. 



P. 



P. 



P. 



P. 



100 

 136 

 463 

 136 



1585 

 400 

 894 

 472 

 739 

 148 

 130 

 124 

 121 

 139 



"K" means 4.5 gram.s of kainit; "N" nican.s 4.5. grams of 

 nitrate; "P" means 4.5 grams of phosphate. 



The repeated application of toxic compounds like 

 vanillin and coumarin proved to be more injurious for 

 oats than was the first application; on the other hand, 

 the repeated application of pyrogallol had practically 

 no effect on the yields of either of the two crops. The 

 oat crop followed immediately after the various 

 treatments had been applied to the pots; and the yields 

 of this crop seem to have been reduced somewhat by 

 the presence of vanillin and coiunarin. But the corn 

 •crop, which followed several months after the addi- 

 tion of these toxic compounds, was apparently bene- 

 fited to a slight degree by their presence, or rather, by 



