Report of the Geological Survey in Kentucky pp. 26-27 (1857)
Underdraining in Kentucky
David Dale Owen

In thickly settled countries, where farming produce is high, and labor cheap great advantage has been obtained from under-draining. In the western country what little draining has been done has, for the most part, been effected by open ditches. Under-draining has many advantages over open ditches. It does not cut up the ground, nor foster weeds. All the water, in passing through the soil, gives up its condensed fertilizers, which are, in a great measure, lost in the flow of surface of water. In its passage downwards it removes or changes effete matters, secreted from the roots of plants, which are deleterious to vegetation. Under-draining also warms the surface-soil, and the cooler substratum condenses the moisture out of the atmosphere, which has free access to it; this, in a great measure, counteracts droughts, besides effecting all the good already indicated, as obtained by a free access of air to the soil. Under-draining is said, also, to prevent the dying out of grasses, by keeping their roots free from injurious influences; to distribute nutriment more effectually; besides removing excess of water, and thus deepening the surface-soil. It renders vegetation earlier in spring, and prevents the freezing out of the grain in winter; too rapid evaporation of the water, and the formation of a hard crust on the surface.

We are apt to regard draining as requisite only for wet and low swampy ground, but experience seems to prove that it is nearly equally beneficial in counteracting too great dryness. It is estimated by farmers, in districts where it has now become an almost universal practice, that it increases the profit on the land ten to twelve per cent.; and pays for expenses of underdraining in three years. It is said, also, and I have little doubt of the fact that it removes the malaria or whatever other cause produces intermittent fevers; so that these diseases have almost disappeared from districts affected with such disorders previous to its introduction. In addition, investments made in under-draining farms have proved to be amongst the safest now made in the farming districts of England, and the government of Great Britain encourages it by loaning money at five per cent. to aid in extending this system; and money can be obtained on easy terms from other sources for the same purpose; all of which is sufficient proof of its success in a pecuniary point of view in that country.

That it would be equally beneficial to our lands there is little doubt; whether it would pay is a question that still remains to be proved.

It may be well, in this connection, to mention that the stiff clay soils usually prevailing in Kentucky in the vicinity of the Black Devonian Shale are lands that can hardly be brought into successful cultivation without draining; and it appears that this shaly rock, when sufficiently hard and tabular in its structure, may answer as a tolerable substitute for the manufactured under-drain tile, where these cannot be obtained.

Our country is, probably, in a condition to be benefited, at present, more by sub-soil plowing; though to derive the full advantage from this system it should be combined with under-draining. According to the most approved method of subsoiling, at present practiced, the subsoil is only loosened—not turned up on the surface—and for this purpose Mapes' form of sub-soil plow is generally adopted, since it may be worked, in most cases, by a single yoke of oxen. It is considered advisable only to disturb a few inches of the sub-soil each season, as some sub-soils require considerable exposure to the air before their fertilizing effect is developed, and a mixture of too great a quantity of this at a time, with the surface-soil may, sometimes, injure the crop.

During the progress of the survey I have met with but one instance where the benefits of deep plowing and sub-soiling have been at all doubtful. That case was in Nelson county, on the waters of the Chaplin fork of Salt river, along the range of the out-crop of the silicious mudstone intercalated in the blue limestone, on Mr. Beauchamp's farm. If it really proved injurious it was probably because too large a portion of the subsoil was mixed, at one time, with the surface-soil. We shall, however, be better prepared to give an opinion on this subject in the second part of this volume, when the chemical analysis of this soil and sub-soil shall have been completed.