Jan. 27, 1919 Influence of Salts on Nitric Nitrogen in Soil 



113 



Table IV. — Percentage of nitric nitrogen formed in 100 gm. of soil containing 2 gm. 

 of dried blood and varying amounts and different forms of potassizim 



[The untreated soil is taken as 100 per cent] 



Amount of potassium. 



P. p. m 



None 



6.1 



12. 2 



24-4 



48.4 



97-8 



195- 5 



391-0 



782. o 



1,564-0 



2,346.0 



Percentage of nitric nitrogen formed in presence of — 



Potassium 

 chlorid. 



93 



86 



106 



Potassium 

 sulphate. 



Potassium 

 nitrate. 



100. O 

 106. 4 



74-7 

 08.6 



92-5 



100.5 



71. I 



33-5 

 20. o 



2-5 

 — 41. 2 



Potassium 

 carbonate. 



100. O 

 99. I 

 92.7 

 81.3 

 80.3 

 69. o 



70.9 

 63-7 



55-4 

 41.8 

 14.8 



Potassium carbonate in the lower concentrations is less injurious than 

 is the sulphate, but in higher concentrations it becomes much more 

 toxic. 



It may be seen that the action of the chlorid and carbonate are very 

 similar, and one must conclude that the anion, in addition to the cation, 

 exerts a very marked effect upon the nitrifying organisms of the soil. 

 The nitrifying powers of the soil are reduced to about half-normal with 

 nearly the same concentration of potassium in the form of the chlorid, 

 sulphate, and carbonate, whereas the nitrate reduces it to half-normal 

 when one-fourth the concentration has been reached. 



The influence of equivalent molecular proportions on the various 

 potassium salts is given in Table V. 



Table V. — Percentage of nitric tiitrogen formed in 100 gm. of soil containing 2 gm. of 

 dried blood and varying amounts and forms of potassium, salts in equal molecular pro- 

 portions 



[The untreated soil is taken as 100 per cent] 



Fraction of molecular weight in 100 gm. of soil. 



Percentage of nitric nitrogen formed in presence of — 



Potassium 

 chlorid . 



None 



156X10-^ 



312X10-^ 



625X10-^ 



125X10-® 



25X10-S 



5X10-" 



lXlO-3 



2X10-^ 



4X10-3 



100. o 



93-5 



86.8 



106.5 



102. 3 



84. 

 84. 

 78. 



35- 



Potassium 

 sulphate. 



100. O 

 95-7 

 95-0 

 93-8 

 73-4 

 76.4 

 67. 2 

 62.3 



51-5 

 32-4 



Potassium 

 nitrate. 



100. 



106. 4 



74-7 

 98.6 



92-5 



100.5 



71. I 



33-5 

 20. o 



2-5 



Potassium 

 carbonate. 



100. O 

 92.7 

 81.3 

 80.3 

 69. o 

 71. o 



63-7 



55-4 

 41.8 

 14.8 



