Having considered in a general way the constituents of the plant, and having noticed the source of each of these constituents, it may be of interest to look at the composition of the soil as revealed by chemical analysis. "A" is the analysis of a soil from Finney county, as made in the laboratory of the Kansas State University, by the author. "B" is a soil from Wyandotte county, as reported in the report of the Kansas State Board of Agriculture for 1874. "C" is a prairie soil from Dakota, as reported by Prof. E. Richards, of the department of agriculture.
| "A" | "B" | "C" | |
| Silica and insoluble | 71.66 | 82.16 | 69.82 |
| Iron and aluminum oxides | 6.55 | 6.70 | 12.05 |
| Calcium oxide | 4.41 | .68 | .85 |
| Magnesium oxide | 1.02 | .06 | .87 |
| Phosphoric anhydride | .18 | .08 | .11 |
| Chlorine | .01 | .03 | .03 |
| Potassium oxide | .75 | .05 | .72 |
| Sodium oxide | .25 | .11 | .94 |
| Sulphuric anhydride | .06 | .39 | .12 |
| Volatile and organic matter | 3.98 | 5.44 | 8.90 |
| Moisture | 9.67 | 3.80 | 6.27 |
| Undetermined, carbonic acid, etc. | 1.48 | .30 | .22 |
| 100.00 | 100.00 | 100.00 |
In some cases it happens that there is a sufficient quantity of an ingredient in the soil, but it is not in a sufficiently soluble form to be available. It will be noticed that in the analyses quoted above the amount of the necessary constituents of the soil to plant growth is not in any case large. The nitrogen may be present in the volatile and organic matter, and upon the proportion of this complex organic matter very often depends to a great extent the fertility of the soil.
Some experiments made at one of the agricultural experiment stations upon the effect of "apple stock," that is, young trees raised for nursery purposes, on the soil, showed that in eleven tons of such stock the following quantities of ingredients were removed from the soil:
| Silica | 50.6 | lbs. |
| Phosphoric acid | 21.4 | " |
| Sulphuric acid | 14.3 | " |
| Chlorine | 1.3 | " |
| Carbonic-acid gas | 94.9 | " |
| Iron oxide | 6.1 | " |
| Lime | 138.6 | lbs. |
| Magnesia | 23.7 | " |
| Soda | 21.3 | " |
| Potash | 27.1 | " |
| Total | 399.3 | lbs. |
This is no inconsiderable quantity of material to be removed by a single crop.
Professor Goessmann, in discussing the ash of fruits, gives the following analysis of the ash of the Baldwin apple; this would represent the mineral matter taken from the soil by the fruit: Potash, 63.54 per cent.; soda, 1.71; lime, 7.28; magnesia, 5.52, and phosphoric acid, 20.87. Comparing this with the ash of other fruits, it is seen that the amount of potash required is larger than in the case of other fruits except plums and peaches, and the amount of phosphoric acid is high, but not as high as in the case of some berries. The application is obvious; in order to successfully raise apples there must be an abundance of potash and of phosphoric acid in the soil, and these ingredients must be in an available form.
If we compare the apple and the pear by an analysis for fertilizing constituents, or such constituents as are usually introduced into deficient soil by means of fertilizers, we have the following table: 1000 parts of the fruit contain, in the case of each,
| H2O | N | Ash | K2O | Na2O | CaO | MgO | P2O5 | SO3 | SiO2 | |
| Apple | 831 | 0.6 | 2.2 | 0.8 | 0.6 | 0.1 | 0.2 | 0.3 | 0.1 | 0.1 |
| Pear | 831 | 0.6 | 3.3 | 1.8 | 0.3 | 0.3 | 0.2 | 0.5 | 0.2 | 0.1 |