Rensselaer Union, Volume 3, Number 15, Rensselaer, Jasper County, 5 January 1871 — The Absorptive Power of Soil. [ARTICLE]

The Absorptive Power of Soil.

It is an important discovery of recent date that soils have the power of separating, not only ammonia, but other l>ases also, from their solutions, and of holding them with great tenacity after their absorption. Thus 100 grains of clay soil, taken from the plant ie clay formation of England, absorbed 1,050 grains of potash from a solution of caustic potash containing one per rent, of the alkali. It is interesting to observe that the liquid was not in this cAse filtered through the soil, but the cold solution was merely left in contact with it for twelve hours. It has been ftirther shown that soils have the ability to separate tlie alkaline bases from the acids with they are combined. When saline solutions were slowly filtered through soils five or six inches deep, the liquids which irnssul through were deprived of their alkaline bases, as potash, soda, ammonia, and magnesia, and only the acids were to be found in combination with some other base. Thus when muriate of ammonia was filtered through the soil, the ammonia was removed, and a corresponding quantity of lime, in combination with muriatic acid, was found in the filtered liquid. In the same way sulphate of potash was deprived of its base, nnd the liquid collected gave sulphate of lime on analysis. Those soils which have the greatest amount of capillary porosity will condense the greatest amount of manorial substances on their internal surfaces; will retain them longest against the adverse, solvent action of water, and will give them out most readily to the rootlets of the growing plant. A mass of adhesive clay will absorb but a very* slight amount of available manure; but if this same mass is rendered friable by processes, its power of absorption is amazingly increased, in view of what has been stated, it is very' clear that one way in which plowing increases the fertility of land, is by increasing its porosity by pulverization. Again, many manurial substances exist in the soil, which, being insoluble, exercise no action on the growth of plants, and contribute nothing to their nutrition; but by the slow, though regular action of the frosts and the rain, the air and the sunshine, insoluble and refractory compounds, are reduced to a soluble state and are appropriated and held on deposit by the soil to the credit of the next cultivated crop. This explains the well known fact that soils that have been cropped to the very verge of barrenness will recover their fertility, if allowed to remain long enough under the action of climatic influences, to saturate the soil witli the necessary plantfood which they have unlocked from their chemical combinations, and given to the soil in a proper physical condition. These changes are brought • about more rapidly when certain mechanical changes of condition are wrought upon the soil. Carbonic acid is one of the most active of the agents employed in bringing the insoluble organic matter in the soil into that physical condition in whicli it becomes available as plant food; in order that this acid may be formed it is essential that the carbonaceous matters in the soil should be brought into direct contact with the atmosphere, from which they procure the oxygen necessary to convert them into carbonic acid. So long as stagnant water remains in the soil, or so long as the soil is in a dense or a very com|iact condition, it is impossible for the carbon to lie converted into acid.— Bouton Journal of Chemistry.