916 



Journal of Agricultural Research 



Vol. VI, No. 23 



soil containing 2 gm. of dried blood. All the reported results are the 

 average of two or more closely agreeing determinations. 



Table IX. — Quantity of nitric nitrogen (in milligrams) formed in 100 gm. of soil 

 containing 2 gm. of dried blood 



Number 

 of deter- 

 mina- 

 tions. 



6. 

 6. 

 6. 



6. 

 6. 

 6. 

 6. 

 6. 

 6. 



6. 



6. 



6. 



6. 



6. 



6. 



6. 



6. 



6. 



Treatment. 



No water; no manure 



5 inches of water; no manure. . . 



10 inches of water; no manure . 



20 inches of water; no manure . 



30 inches of water; no manure . 



40 inches of water; no manure . 



No water; 5 tons of manure .... 



No water; 15 tons of manure. . . 



5 inches of water; 5 tons of ma- 

 nure 



5 inches of water; 15 tons of ma- 

 nure 



10 inches of water; 5 tons of ma- 

 nure 



10 inches of water; 15 tons of ma- 

 nure 



20 inches of water; 5 tons of ma- 

 nure 



20 inches of water; 15 tons of ma- 

 nure 



30 inches of water; 5 tons of ma- 

 nure 



30 inches of water; 15 tons of ma- 

 nure 



40 inches of water; 5 tons of ma- 

 nure 



40 inches of water; 15 tonsof ma- 

 nure 



Quantity of nitric nitrogen. 



May 10. 



I.50 



3-47 

 2. 27 

 1.05 



1. 40 



2. 10 

 1.6s 



45- 3 2 



20. 30 



46.80 



4.90 



47-45 

 9.27 



S3-°5 

 12.30 

 60.25 



iS-37 

 37-°5 



Aug. 9. 



i-33 

 .81 



•56 

 •50 

 •38 

 .70 

 1.80 

 8.85 



•53 

 2.66 



•58 

 2. 27 



•63 



2. 17 



.40 



15.46 



•45 

 1. 01 



Nov. 8. 



O.84 



.88 



•53 

 1.85 



•35 



i- 15 



2.45 



27.52 



3-43 

 33-65 



22. 92 



2.66 



23.80 



2.80 



4-93 



6-75 



14. 08 



Average. 



I. 22 

 I. 72 

 I. 12 

 I- 13 

 •71 

 I- 31 

 I.97 

 27.23 



8.08 



27. 70 

 4-65 



24. 21 

 4. l8 



26.34 



5- 17 

 26.88 



8.52 

 17.38 



The nitrifying powers of these soils are uniformly higher in the spring 

 months of the year than later. This occurs in all the plots, but the 

 greatest difference is found in the heavily manured plots, due probably 

 to the application of large quantities of readily nitrifiable material in 

 the manure, which is transformed later into soluble nitrates taken up by 

 the growing plant, removed in the drainage water, or transformed into 

 complex protein substances within the bodies of various microorgan- 

 isms. The results taken as a whole bear a very great similarity to those 

 obtained on the fallow soil. They are, however, as were the counts and 

 ammonifying powers, slightly higher in the fallow than in the cropped soil. 



The nitrifying powers of the unmanured soil are low throughout the 

 year. The nitrates produced by the manured soil increase with the 

 increase of manure applied. The greatest difference, however, exists 

 between the soil receiving 5 and 15 tons of manure per year. In the 

 latter the nitrifying activity is extremely active in the spring months. 

 This difference, while not as pronounced later in the year, exists through- 

 out the season. 



