Apr. lo, 1916 



Soluble Nonprotein Nitrogen of Soil 



63 



added to the soils and then sufficient alkali added to make 500 c. c. of 

 a 1.5 per cent solution. In all cases, with the above-noted exceptions, 

 the purest commercially available compounds were used, but analyses 

 for nitrogen were run on the solid material when it was used, and when 

 solutions were employed aliquots were analyzed. These determinations 

 were also made by the micro method. It should be mentioned here 

 that 6 minutes was found to be quite an inadequate digestion period for 

 some of the compounds. It is believed that in some cases when appar- 

 ently more than 100 per cent of the added substance was extracted from 

 soil, faulty analysis of the substance was the cause. Insufficiency of 

 material precluded repeating tests with many of the materials. 



The soil used for all these tests was a silt loam containing 0.30 per 

 cent of nitrogen. Samples A and B, as shown in Table I, differ only in 

 that they were not taken from the field at the same time. 



Table I. — Analyses of 5-gni. portions of soil for alkali-soluble and soluble nonprotein 



nitrogen 



Soil 

 sample. 



Substance added. 



Nitro- 

 gen 

 added. 



Nitro- 

 gen in 



the 

 alkali 



ex- 

 tract. 



Nitrogen of the 

 added sub- 

 stance recov- 

 ered in the 

 alkali extract. 



Soluble 

 nonpro- 

 tein 

 nitrogen. 



Soluble non- 

 protein nitro- 

 gen recovered. 



Nothing 



Hydrolyzed casein . 

 Amino benzoic acid. 



Glutamic acid 



Hippuric acid 



Glutamic acid imid . 



Succinimid 



Guanidin sulphate . . 



Urea 



Uric acid 



Caffein 



Theobromin 



Guanin 



Hypoxanthin 



Skatol 



Nucleic acid 



Cadaverin 



Amygdalin 



Peptone (Witte) 



Casein 



Edestin 



Egg albumin 



Glucosamin 



Nothing 



Asparagin 



Acetanilid 



Benzamid 



Creatinin 



Mgm. 



Mgm. 



Mgm. 



2. 09 

 2. 14 

 2. 27 

 2. 42 

 2.36 



2-53 

 1.97 

 2.48 

 2. 42 

 2.32 

 I. 96 

 2.49 

 2.52 



1. 26 



2. 00 

 2. 00 



2. 42 



2-43 

 2. 01 



i.q8 



2. II 

 2. 14 



2. 17 

 2. 07 



93 

 99 

 08 

 26 



40 



36 



45 



725 



41 



34 



93 



90 



45 

 34 

 19 

 92 

 92 



41 

 76 

 42 

 58 

 56 

 08 



51 

 62 

 66 

 69 

 06 



2. 06 

 2.15 

 2-33 

 2.47 



2-43 

 2. 52 



1-975 

 2.48 

 2. 41 



1. 00 

 1.97 



2. 52 

 2. 42 

 I. 26 

 1.99 

 1.99 

 2.48 

 2.83 

 1.49 



•65 

 1.63 



2-15 



2. II 



2.15 

 2. 18 



1-55 



Per ci. 



9»-4 

 100. 4 

 102. 6 

 102. o 

 103.0 



99-5 



40.4 



100. o 



99.6 



43- I 



100.5 



loi. 2 



96. o 



100. o 



99-5 



99-5 



100. o 



94.9 



61.6 



26.8 



81.3 



108.5 



Mgm. 

 I. 29 



3-33 

 3-41 

 3-48 

 3-73 

 3-59 

 3.86 



Mgm. 



100. O 



100. 5 



100. 5 

 74.8 



3-27 

 2-325 

 3-42 

 1.80 



1. 67 



2.45 

 3-42 



2. 12 

 I. 29 

 I. 29 



1. 29 

 3-3^ 

 1-25 

 3-24 

 3-24 

 3-27 



2. 71 



2. 04 

 2. 12 

 2. 19 

 2.44 

 2.30 

 2-57 

 0-5S 

 2-37 

 2.49 

 .92 

 1.98 



1-035 

 2. 13 



•51 

 •38 



1. 16 



2. 13 



-83 

 o 

 o 

 o 



2. 07 



1.99 

 1.99 

 2. 02 

 I. 46 



Per ct. 



97-5 

 99.0 



96-5 



100. 8 



97-5 

 loi. 5 



28.0 



95-6 



103.0 



39-7 



101. o 



41. 6 

 84.6 

 41. 2 

 19. o 

 58.0 

 85-7 

 33- S 



o 



o 



o 



104.5 



94.2 



93- o 

 93-2 

 70-5 



It is not thought that all the compounds used are actually present in 

 soil. The substances were chosen rather to represent classes of com- 

 pounds which conceivably might be in soils. Guanin, hypoxanthin, 

 nucleic acid, peptone, and creatinin have been isolated from soil. It is 



