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About Southern cultivator. (Augusta, Ga.) 1843-188? | View Entire Issue (March 1, 1869)
Soda._ .10 Sulphuric Acid 10 Phosphoric Acid, 08 Chlorine, 05 For the six cotton soils together, the average would be: Magnesia, 73 Soda 82 Lime 60 Potash, 58 Phosphoric Acid 30 Sulphuric Acid 06 Chlorine, 05 Now, a square yard of compact surface soil, six inches deep, divested of its water of evaporation, will weigh about 200 lbs. Os course different soils will vary, ac cording to their capacity to hold water ; silicious and clay soils'would bo more—loamy soils would be less. This would give us 986,000 lbs. of surface soil to the ame— in round numbers, 1,000,000 of lbs., in which, under our shallow system of culture, plants might seek their nutri ment. This would give, of Silica 848,990 lbs. Magnesia 7,300 “ Soda 6,200 “ Lime 6,000 “ Potash, 5,800 “ Phosphoric Acid, 3,000 “ Sulphuric Acid, 600 “ Chlorine, 500 “ Now if these salts were soluble, or even one per cent of them, it would be an almost inexhaustible bank for the farmer to draw upon, but unfortunately the great bulk of them is insoluble in water, and to a large extent in acids. In one of the soils above enumerated, from St. Simon’s Island, Ga., Dr. Jackson found in 1000 grains, just If grains of soluble matter —only one half a grain of which was made up of mineral salts, to-wit: Chloride of Sodium, Phosphates of Lime and Soda, Soda and Potash, Sulphate of Magnesia, and Carbonate of Lime. In another specimen, from a rich alluvial soil of Savannah river, Edgefield District, S. C., he found 9 10 of soluble mineral salts, as above. In another upland soil, from Hancock Cos., Miss., he found only half a grain. This would give us just five hundred pounds per acre of soluble salts, existing in fertile upland soils of the South. Dr. Erni found in the Georgia and Arkansas soils 42-1000 of a grain soluble in water —not a particle of which was Phosphoric Acid, or any of its combinations; 3 1000 of that salt was soluble in acid, and 92-1000 insoluble. In a thirty years course of cropping, allowing ten years to corn, ten to cotton, and five each to wheat and oats, the most fertile soil would be divested of its soluble salts, though nature and art would in that time reduce much of its insoluble matter to a soluble state. Allowing 12 bushels of corn per acre for ten years, there would be carried off nearly 50 lbs. of phosphoric acid ; over twenty lbs. in a crop of wheat and straw, 6 bushels for five years; and thirty-seven and a half lbs. in 8 bushels of oats and straw;, while 600 lbs. of seed cotton would carry off about forty lbs. of phosphoric acid in ten years. For the thirty years, there would be taken off the following amounts of different soluble salts in the crops, besides SO ITT HERN CIH/nVATOR. the untold amount that leaches beyond the reach of the plow, and tke roots of plants, after every heavy rain. 132.67 lbs. Potash. 131.81 “ Phosphoric Acid. 114.93 “ Silica. 66.93 “ Magnesia 44.88 “ Soda. 27.46 “ Lime. 23.73 “ Sulphuric Acid. 12.34 “ Carbonic Acid. 8.34 “ Chlorine. 2.09 “ Oxide of Iron. At this rate, it would take, to exhaust the soil of these salts—provided the insoluble would continue to become soluble, in proper and definite proportions—as follows: Phosphoric Acid 683 years. Sulphuric Acid 769 “ Potash 1876 “ Chlorine,.... 1798 “ Magnesia 8330 “ Soda, 4160 “ Lime * 6657 “ It is very apparent from these tables, that in produc tive cotton soils, there is no danger of exhausting the mineral salts, under a judicious system of agriculture. Insoluble salts are made soluble in several ways. By aeration from ploughing and pulverization, the carbonic and nitric acids produced by the atmosphere are brought into play, and new combinations are made. By resting and rotation, weeds and coarse grasses take up certain salts, and make them soluble, for the cereals, &c., which they could not have appropriated. Thus, corn is a coarse feeder, and makes soluble food for wheat and cotton, when the stalks decay. Fertilizers act in two ways, first by presenting soluble food to the plants, prepared by science; and second, by their solvent powers upon the insoluble substances of the soil. Phosphoric acid, potash, sulphu ric acid, ammonia and lime, all act in this way—the last mentioned on vegetable matter, the former on minerals. Hence, liming lands, where there is already a deficiency of humus, will impoverish rather than improve the soil. These tables further teach, that Phosphoric acid exists in the soil in smaller quantities than any of the salts, ex cept sulphuric acid and chlorine; that it is carried off more rapidly from the soil by cropping than any other, except potash, and would be sooner exhausted than any of them by that process. Chemistry further teaches, that it is remarkably soluble in water, and whenever a portion of »t is set free from its combinations, it is liable to be filtered away into the sub-soil. In its natural combina tions, however, the earth of bones, and the mineral apa tite, it is remarkably insoluble, and only becomes adapted to the use of plants by the slow attrition of ages. Here, as in many other instances, science stepped in and. dis covered the method of cheaply cou verting the insoluble phosphate into the soluble bi phosphate, of which a learn ed agricultural writer has truly said: “Simple as it may seem, this discovery has benefited agriculture more than all others combined.” E. M. PENDLETON. Sparta , Feb. 2d, 1869. [to je continued.] N. B.—ls Mr. Gift’s 1000 tons of manipulated manure 79
