HUMUS AND NITROGEN-CONTENT OF RUSSIAN RIVER SOIL. ==============+==============+=================+================ Depth in feet.| Per cent | Per cent | Per cent | Humus | Nitrogen | Humus-Nitrogen. | in soil. | in Humus. | in soil. --------------+--------------+-----------------+---------------- 1 | 1.21 | 5.30 | .064 2 | 1.16 | 4.32 | .054 3 | 1.14 | 3.87 | .044 4 | 1.17 | 3.76 | .044 5 | .74 | 2.16 | .016 6 | .60 | 2.66 | .016 7 | .47 | 2.54 | .012 8 | .78 | 1.54 | .012 9 | .54 | 2.24 | .012 10 | .52 | 1.15 | .006 11 | .53 | 1.51 | .008 12 | .44 | 1.81 | .008 --------------+--------------+-----------------+---------------- _Influence of the Original Materials on the composition of Humus._—The great variability of the composition of humus formed from different substances is well shown in the subjoined table, representing the results of experiments made by Snyder,[53] who caused various substances to humify by mixing the pulverized material intimately with a soil poor in humus, and allowing the process to continue for a year. At the end of that time the humus formed was extracted by the method of Grandeau, outlined above, and analyzed, with the following results. ========+======+======+=======+======+========+=======+========== |Sugar.| Oat | Green |Wheat |Sawdust.| Meat | Cow | |Straw.|Clover.|Flour.| |Scraps.|Manure.[54] --------+------+------+-------+------+--------+-------+---------- Carbon | 57.84| 54.30| 54.22| 51.02| 49.28 | 48.77| 41.93 Hydrogen| 3.04| 2.48| 3.40| 3.82| 3.33 | 4.30| 6.26 Nitrogen| 0.08| 2.50| 8.24| 5.02| 0.32 | 10.96| 6.16 Oxygen | 39.04| 40.72| 34.14| 40.14| 47.07 | 35.97| 45.63 --------+------+------+-------+------+--------+-------+---------- |100.00|100.00| 100.00|100.00| 100.00 | 100.00| 100.00 --------+------+------+-------+------+--------+-------+---------- [53] Bull. No. 53, Minn. Exp’t Station, p. 12, Chem. of Soils and Fertilizers, p. 94. [54] The figures for cow manure are so far out of range with any others thus far observed, that it seems reasonable to suppose that they are influenced by unchanged substances present in the excreta.