« AnteriorContinuar »
drop of it,—and it ought not to be allowed to show itself within the reach of the roots of ordinary plants. It has fallen on other land, and, presumably, has there done its appointed work, and ought not to be allowed to convert our soil into a mere outlet passage for its removal.
The ooze water,—that which soaks out from adjoining land,—is subject to all the objections which hold against spring water, and should be rigidly excluded.
But the surface water which comes over the surface of higher ground in the vicinity, should be allowed every opportunity, which is consistent with good husbandry, to work its slow course over our soil,—not to run in such streams as will cut away the surface, nor in such quantities as to make the ground inconveniently wet, but to spread itself in beneficent irrigation, and to deposit the fertilizing matters which it contains, then to descend through a well drained subsoil, to a free outlet.
Prom whatever source the water comes, it cannot remain stagnant in any soil without permanent injury to its fertility.
The Objection to too much Water in the Soil will be understood from the following explanation of the process of germination, (sprouting,) and growth. Other grave reasons why it is injurious will be treated in their proper order.
The first growth of the embryo plant, (in the seed,) is merely a change of form and position of the material which the seed itself contains. It requires none of the elementi of the soil, and would, under the same conditions, take plac« as well in moist saw-dust as in the richest mold. The conditions required are, the exclusion of light; a certain degree of heat; and the presence of atmospheric air, and moisture. Any material which, without entirely excluding the air, will shade the seed from the light, yield the needed quantity of moisture, and allow the accupuliation of the requisite heat, will favor the chemical changes which, under these conditions, take place in the living seed. In proportion as the heat is reduced by the chilling effect of evaporation, and as atmospheric air is excluded by water, will the germination of the seed be retarded; and, in case of complete saturation for a long time, absolute decay will ensue, and the germ will die.
The accompanying illustrations, (Figures 1,2 and 3,) from the "Minutes of Information" on Drainage, submitted by the General Board of Health to the British Parliament in 1852, represent the different conditions of the soil as to moisture, and the effect of these conditions on the germination of seeds. The figures are thus explained by Dr. Madden, from whose lecture they are taken:
"Soil, examined mechanically, is found to consist entirely "of particles of all shapes and sizes, from stones and peb"bles down to the finest powder; and, on account of their "extreme irregularity of shape, they cannot lie so close to "one another as to prevent there being passages between "them, owing to which circumstance soil in the mass is "always more or less porous. If, however, we proceed to "examine one of the smallest particles of which soil is "made up, we shall find that even this is not alw ays solid, "but is much more frequently porous, like soil in the mass. "A considerable proportion of this finely-divided part of "soil, the impalpable matter, as it is generally called, is "found, by the aid of the microscope, to consist of broken "down vegetable tissue, so that when a small portion of "the finest dust from a garden or field is placed under the "microscope, we have exhibited to us particles of every "variety of shape and structure, of which a certain part is "evidently of vegetable origin.
"In these figures I have given a very rude representation "of these particles; and I must beg you particularly to "remember that they are not meant to represent by any "means accurately what the microscope exhibits, but an "only designed to serve as a plan by which to illustrate "the mechanical properties of the soil. On referring to "Fig. 1, we perceive that there are two distinct classes of "pores,—first, the large ones, which exist between the par"tides of soil, and second, the very minute ones, which "occur in the particles themselves; and you will at the
"same time notice that, "whereas all the larger "pores,—those between the "particles of soil, — com"municate most freely with "each other, so that they "form canals, the small "pores, however freely they "may communicate with "one another in the interior "of the particle in which Fig. 1.—A Dky Soil. "they occur, have no direct
"connection with the pores of the surrounding particles. "Let us now, therefore, trace the effect of this arrangement. "In Fig. 1 we perceive that "these canals and pores are "all empty, the soil being 11 perfectly dry; and the "canals communicating free"ly at the surface with the "surrounding atmosphere, "the whole will of course "be filled with air. If in "this condition a seed be "placed in the soil, at a, "you at once perceive that FiS- 2—A WET son" "it is freely supplied with air, but there is no moisture; "therefore, when soil is perfectly dry, a seed cannot grow.
"Let us turn our attention now to Fig. 2. Here we
To one writing in advocacy of improvements, of any kind, there is always a temptation to throw a tub to the popular whale, and to suggest some make-shift, by which a certain advantage may be obtained at half-price. It is proposed in this essay to resist that temptation, and to adhere to the rule that " whatever is worth doing, is worth doing well," in the belief that this rule applies in no other department of industry with more force than in the draining of land, whether for agricultural or for sanitary improvement. Therefore, it will not be recommended that draining be ever confined to the wettest lands only; that, in the pursuance of a penny-wisdom, drains be constructed with stones, or brush, or boards; that the antiquated horse-shoe tiles be used, because they cost less money; or that it will, in any case, be economical to make only such drains as are necessary to remove the water of large springs. The doctrine herein advanced is, that, so far as draining is applied at all, it should be done in the most thorough and complete manner, and that it is better that, in commencing this improvement, a single field be really well drained, than that the whole farm be half drained.
Of course, there are some farms which suffer from too much water, which are not worth draining at present; many more which, at the present price of frontier lands, are only worth relieving of the water which stands on the surface; and not a few on which the quantity of stone to be removed suggests the propriety of making wide ditches, in which to hide them, (using the ditches, incidentally, as drains). A hand-book of draining is not needed by the owners of these farms; their operations are simple, and they require no especial instruction for their performance. This work is addressed especially to those who occupy lands of sufficient value, from their proximity to market, to make it cheaper to cultivate well, than to buy more land for the sake of getting a larger return from poor cultivation.
As plants grow under the same conditions, as to soil, that are necessary for the germination of seeds, the foregoing explanation of the relation of water to the particles of the soil is perfectly applicable to the whole period of vegetable growth. The soil, to the entire depth occupied by roots, which, with most cultivated plants is, in drained land, two or three feet, sometimes even more, should be maintained, as nearly as possible, in the condition represented in Fig. 3,—that is, the particles of soil should hold water by attraction, (absorption,) and the spaces between the particles should be filled with air. Heavy soils which require drainage are not in this condition. When they are not saturated with water, they are generally dried into lumps, which are almost as impenetrable by roots as so many stones. The moisture which these clods contain is aot available to plants, and their surfaces are liable to be dried by the too free circulation of air among the wide fissures between them. It is also worthy of incidental remark, that the cracking of heavy soils, shrinking by drought, is attended by the tearing asunder of the smaller roots which may have penetrated them.
The Injurious Effects of Standing Water in the Subsoil may be best explained in connection with the description of a soil which needs under-draining. It would be tedious, and superfluous, to attempt to detail the various geological formations and conditions which make the soil unprofitably wet, and render draining necessary. Nor,—as this work is intended as a hand-book for practical use,—is it deemed advisable to introduce the geological charts and sections, which are so often employed to illustrate th« various sources of under-ground water; interesting as they are to students of the theories of agriculture, and important as the study is, their consideration here would consume space, which it is desired to devote only to the reasons for, and the praotice of, thorough-draining