70 



A study of the data presented in table I. shows clearly 

 that, of all the compounds used, and m each of the 

 three different soils, naphthjdamine and quinoline in 

 soil No. 2, were the only substances w^hich were not 

 nitrified. Of the three soils used, No. 1 is most acid, 

 and No.2 is least acid. Quinoline was apparently not 

 nitrified in the least acid soil, but in the soils which 

 were inoderately or strongly acid, this basic compound 

 was nitrified to quite an appreciable degree. Further, 

 the addition of lime to the least acid soil inhibited 

 nitrification, but only reduced the process in the more 

 acid soil. In both limed and unlimed conditions, pyri- 

 dine was nitrified in each of the soils used. But the 

 effect of lime on the nitrification of this basic com- 

 pound is not nearly so great as in the case of dried 

 blood or the other non-basic materials. The fact that 

 so stable a compound as pyridine, which is unaffected 

 by boiling nitric acid, or chromic acid, is nitrified in 

 these soils, illustrates in a very definite way the enor- 

 mously destructive chemical and biochemical action 

 that may take place in soils. Piperidine was nitrified 

 in each of the soils, the addition of lime increasing the 

 amount of nitrification in each case; this too, in spite 

 of the fact that the compound is of a strong basic 

 character. In the unlimed acid soils, guanidine car- 

 bonate, another basic compound, was readily nitrified; 

 in the limed series, however, nitrification was inhibited. 

 Nucleic acid, alloxan, asparagine and naphthylamine 

 were used in but one soil. Of these, only naphthyla- 

 mine was not nitrified. As in the case of dried blood, 

 the decomposition of these non-basic substances was 

 greatly increased by the addition of lime. 



The Effects of Varying Amounts of Nitrogenous 

 Compounds on Nitrification 



The effect of concentration of the nitrogenous com- 

 pounds on nitrification was also studied. The soil used 

 in this case was a poor, sandy soil which had been left 

 undisturbed in the green house for several months, and 

 had accumulated quite a large amount of nitrates. 

 Each tumbler contained ninety-seven grams of this 

 poor sand, one gram of fertile soil and two grams of 

 lime. The period of incubation lasted from Julv 11th 

 to September 8th, 1915. 



