It thus appears that while the first extraction removed the main portion of the organic matter, the inorganic matters dissolved were not greatly diminished in subsequent leachings; and that phosphoric acid continued to come off to the last. The rich soil used in this case gave results corresponding in general to these from the Bonn soil, in the previous table. From a poorer soil similarly treated by Ulbricht, described by him as a ferruginous sand from Dahme, the leaching of which was continued for thirty days in periods of three days each, with a total of forty times its weight of water, the results were as follows:
SOIL OF LOW PRODUCTION FROM DAHME (Ulbricht).
THE SEVERAL EXTRACTS CONTAINED IN 1,000,000 PARTS:
| First Extract. | Second Extract. | Third Extract. | Fourth Extract. | Fifth Extract. | Sixth Extract. | |
|---|---|---|---|---|---|---|
| Potash | 7 | 6 | 7 | 7 | 3 | |
| Soda | 41 | 11 | 26 | 17 | 8 | |
| Lime | 96 | 70 | 55 | 48 | 62 | |
| Magnesia | 14 | 10 | 9 | 7 | 8 | |
| Phosphoric acid | trace | 2 | trace | 1 | ||
| Totals | 158 | 99 | 97 | 80 | 70 | 11 |
It will be seen that there is a considerable difference both in the total amounts of matters dissolved and in the phosphoric acid taken out by the water, as compared with the rich soil treated by Schultze. The uniformity of the amounts of potash removed at the successive leachings is remarkable.
King’s Results.—The same general features are again strikingly illustrated by King’s results, as given in the following table. King’s first leachings were always made by shaking up the soil with ten times its dry weight of water for three minutes, then after subsidence filtering the solutions through a Chamberland (porcelain biscuit) filter, and then (without evaporation) determining the ingredients dissolved, by very delicate, mostly colorimetric methods. Subsequent leachings were made by packing the soil around the filters and washing with five times the weight of water, taking about fifteen minutes each time; but drying the soil at 120 degrees C. between successive leachings.
WATER EXTRACTION OF SOILS OF
LOW AND HIGH PRODUCTION,
By F. H. KING.
PARTS PER MILLION.
| Extractions | Potash, K₂O. | Lime, CaO. | Magnesia, MgO. | Nitric Acid, N₂O₅. | ||
|---|---|---|---|---|---|---|
| SOILS OF LOW PRODUCTION. | ||||||
| Sassafras sandy | 1 | 12.62 | 74.39 | 17.82 | 18.03 | |
| soil. | 11 | 218.25 | 135.35 | 147.45 | 21.76 | |
| Norfolk, North | 1 | 21.17 | 58.30 | 22.91 | 30.64 | |
| Carolina sandy soil | 11 | 66.08 | 162.98 | 125.00 | 27.11 | |
| Average. | 192.60 | 149.20 | 136.23 | 24.44 | ||
| SOILS OF HIGH PRODUCTION. | ||||||
| Janesville, Wis. | 1 | 25.35 | 135.30 | 51.72 | 55.10 | |
| Loam. | 11 | 313.70 | 1120.30 | 500.60 | 51.42 | |
| Hagerst’wn, Pa. | 1 | 21.73 | 165.25 | 76.88 | 25.72 | |
| Clay loam. | 11 | 301.55 | 967.80 | 463.15 | 96.04 | |
| Average. | 307.60 | 1044.05 | 487.88 | 73.73 | ||
| Extractions | Phosphoric Acid, P₂O₅. | Sulfuric Acid, SO₃. | Carbonic Acid, CO₂. | Chlorin, Cl₂. | Silica SiO₂. | |
| SOILS OF LOW PRODUCTION. | ||||||
| Sassafras sandy | 1 | 7.41 | 53.84 | 13.94 | 1 | 5.60 |
| soil. | 11 | 64.16 | 203.96 | 221.33 | 2 | 70.20 |
| Norfolk, North | 1 | 10.15 | 42.82 | 20.42 | 1 | 8.24 |
| Carolina sandy soil | 11 | 80.34 | 172.42 | 148.52 | 2 | 122.20 |
| Average. | 72.25 | 126.13 | 184.93 | 2.- | 146.20 | |
| SOILS OF HIGH PRODUCTION. | ||||||
| Janesville, Wis | 1 | 16.96 | 125.43 | 29.31 | 2.67 | 40.28 |
| Loam. | 11 | 418.85 | 592.75 | 472.95 | 0.00 | 414.50 |
| Hagerst’wn, Pa. | 1 | 11.51 | 187.59 | 97.09 | 1.67 | 21.17 |
| Clay loam. | 11 | 136.21 | 502.82 | 620.00 | 0.00 | 283.80 |
| Average. | 277.03 | 547.79 | 546.48 | 0.00 | 349.15 | |