May IS. 191S 



Hydrocyanic- Acid Content of Sorghum 



181 



adequately, and after about eight weeks of slow growth the leaves turned 

 yellow and frosts came before the plants were well headed out. This 

 condition, together with the use of the fertilizer, gave us an opportunity 

 to study the occurrence of prussic acid in poorly nourished plants and 

 to compare them with those having a better supply of nitrogen. 



In the samples from this plot the whole plant was ground up for the 

 determination of hydrocyanic acid. In general, the cane in the rows 

 which received fertilizer grew a little better than that which did not, but 

 Table I shows that the increase in hydrocyanic acid is inappreciable. It 

 can be detected only by comparing the average of the two check rows 

 %\'ith the average of Rows \* and VI, which received the heaviest applica- 

 tions of fertilizer. This comparison is shown in figure i, plot W, the 

 dotted lines representing the average of Rows I and IV and the solid line 

 that of Rows V and VI. In a measure these results substantiate the work 

 of some of the investigators mentioned above, in that the soils \vith the 

 better supply of nitrogen were found to have produced plants with a 

 higher content of hydrocyanic acid. The difference, however, is very 

 slight, and the findings of Alway and Trumbull (i) rather than those of 

 Avery (2) are supported, for the reason that the stunted plants showed 

 less hvdrocvanic acid than the thrifty ones. In these plots the amount of 

 the acid in the early stages was higher than in the plots having good soil 

 (fig. I, plots 30 and 2>5U but it persisted through a much shorter period 

 of the plant's life. 



TABtE I. — Effect of available nitrogen on the hydrocyanic-acid content of sorghum 



[Percentage of hydrocyanic acid is reported on a drj'-matter basis] 



PLOT vr 



Row or plot and sample number. Height. 



Row I a 



RowII:& 



6 



7. ... 



Row III:c 

 10. . . . 



13. .. 

 Row IV :a 



14 



15 



16 



17 



a Check. 



90271° 



Inekes. 



28 



39 

 42 

 61 



19 

 31 

 40 



57 



20 

 34 

 40 



56 



26 



34 

 40 



56 



Age. 



Days. 



f> Fertilized at rate of loo pounds per acre. 



—15 7 



31 

 38 

 52 

 55 

 62 



31 

 38 

 45 

 62 



45 

 62 



32 

 39 

 45 

 62 



Percentage of hydroc>-anic acid. 



Stalks. 



L eaves . Whole plant. 



O.0S3 

 .032 

 . 000 

 .007 

 . 002 



.083 

 .027 

 .025 

 . cxx> 



.0S3 



. 022 



.032 



• 005 

 . 064 



• 043 



. 024 



. 007 



r Fertilixed at rate of mo poands per acre. 



