American Cotton Planter (1853)
Power of the Soil to retain Manures
(From the Journal of Agriculture)
Prof. J. J. Mapes
Newark, N. J.

We propose in our present number to show the power of the soil to retain manures, and the means of improving this property when required.

For a long time it was supposed that all materials soluble in water would pass downward in solution, and thus be lost to plants—those who worked clayey soils claimed that, because water could not readily percolate their soils, that hence, they were not leachy, and therefore retained manures—while other operators with sandy soils argued that manures passed downward and were soon lost to the surface of the soil.

All these positions are false. It is true, that a fair proportion of alumnia is valuable to soils, and in the absence of carbonaceous matter is absolutely necessary for the retention of manures, but it is not true that the tenacious property of clay need exist to such an extent as to prevent the free filtration of pure water before the manures will be retained—for many soils which will pass pure water readily, will still retain, from impure water, all its impurities, permitting only the pure water to descend. Indeed this is true of all arable soils, and if it were not so, the water in all our wells would be unfit to drink from being surcharged with soluble organic matter.

Even the brown fluids of a barnyard will not leach downward in the soil, without leaving all the foetid matter in the surface. Dig in an old barnyard, but a few inches below where the soil has been before disturbed, and it will be found not to contain any undue proportion of the soluble matters resident at the surface, but to be like the subsoil of adjoining fields.

Alumnia (clay) has the curious property of receiving and retaining all animal and vegetable substances, and their gaseous products, until abstracted again by growing plants, and for this reason a free clayey loam will purify water during its passage through the surface soil, retaining all the fertilizing substances originally held in the solution, and permitting the pure water to pass downward. Nor does this retaining power cease with organic substances alone, for many of the alkalies are also retained, and all of them to a certain extent. Excess of lime, potash or magnesia will pass down and therefore the chemist finds variable proportions of these alkalies in our well water.

This peculiar property of clay was noted by Mr. Teschmaker of Boston, in his public addresses many years since, and in our published addresses before the American Institute, as far back as 1840, the same truths are set forth. Within the last two years, Professor Way and other English chemists are claiming this as a new discovery.

Alumnia is not the only substance in soils which has this retaining power, for carbon in every form has similar properties, and it is not important whether charcoal dust be artificially added, or exist in the soil by the decay of former vegetation or of manures; for in either case carbon is the result, and as such, has similar retaining powers to those of clay. Thus charcoal dust placed for a time near a fermenting dung heap, will receive and retain the gases arising from decomposition, and if placed in the soil will give out these gases again to the roots of growing plants. Privies, stables, &c., are rendered inodorous by the use of charcoal dust. Decomposed peat, turf, swamp muck, &c, are but varied forms of carbon, with some more partially decomposed vegetable matter. The dark color of soils is due to the presence of carbon; humus, vegetable mould, &c., are but modifications of carbon.

All know that an old and black garden soil will retain manure longer than field soils, and that a less quantity of manure will act in them, for the simple reason, that the carbon (charcoal,) contained in them, and arising from previous decay, retains the reluctant gasses from the decomposition of the manure until used up by plants.

Let any farmer try the following experiment and he will be satisfied of the truth of our statement.

Prepare four barrels by taking out the tipper beads and boring small holes in the lower heads, stand the barrels on end and fill them with the following substances:

Pour on all four barrels the brown solution from the barnyard, and it will be found, that the water running out of the bottoms of Nos. 1, 2, and 3, will be colorless and without smell, while that from No. 4 will be unaltered and as offensive as when placed on top.

The question may now be asked, "if the soluble results of vegetable decay do not filter downward, what becomes of them?" We answer, that resident in the earth's surface, from the combined influences of sun and air, they decay, and take the gaseous form; if the soil contains either clay or carbon, these gasses are absorbed by them, until abstracted by growing plants. But if these substances are not resident in the soil, then the gasses rise into the atmosphere, and are absorbed by better prepaired soils elsewhere, or are carried to the ocean and are thus lost for a time from the land.

Let our readers reflect that both the vegetable and animal productions of the earth's surface are continually decaying, and that nothing but the facts we have stated can account for continued fertility. For if the results of decay could filter downward in solution with water, long before this time, the whole amount of organic constituents would have passed below the fertile surface, all our wells would be filled with masses of filth, and both animal and vegetable life would have ceased. The simple facts are, that all organic manures do decay in the earth's surface, and are only lost by rising in the gaseous form, and not by sinking below the roots of plants, and therefore they should be plowed under to such a depth that their resultant gasses when rising shall meet with a sufficient quantity of alumnia or carbon to arrest them.