. Elements of practical agriculture; comprehending the cultivation of plants, the husbandry of the domestic animals, and the economy of the farm. 184 PREPARATION OF LAND FOR CROPS. If we shall penetrate a little way into the looser portion of the earth, we shall generally find a series of strata, consisting of gravel, sand, or clay, of different degrees of density. These strata are frequently horizontal, frequently they follow nearly the inclination of the surface, and frequently they are broken and irregular. Sometimes the stratum is very thin, as a few inches in thickness, and sometimes it i
. Elements of practical agriculture; comprehending the cultivation of plants, the husbandry of the domestic animals, and the economy of the farm. 184 PREPARATION OF LAND FOR CROPS. If we shall penetrate a little way into the looser portion of the earth, we shall generally find a series of strata, consisting of gravel, sand, or clay, of different degrees of density. These strata are frequently horizontal, frequently they follow nearly the inclination of the surface, and frequently they are broken and irregular. Sometimes the stratum is very thin, as a few inches in thickness, and sometimes it is several feet thick ; and sometimes the traces of stratification disappear, and we find only, to a great depth, a large mass of clay or other homo- geneous substance. When these substances are of a clayey nature, water finds its way through them with difficulty ; when they are of a looser texture, water percolates through them freely. These last, ac- cordingly, form natural conduits or channels for the water which is below the surface, when finding its way from a higher to a lower level. When any bed or stratum of this kind, in which water is percolating, crops out to the surface, the water which it con- tains will flow out and form a burst or spring, oozing over and saturating the ground, as in the following figure, which repre- sents a section of the ground, from C to D. Fig. 101. When water is, in like manner, percolating through one of these pervious strata, and meets any obstruction, as a rock or bed of clay at A, Fig. 102, it is stopped in its progress, and, by the pressure of the water from a higher source, it is forced upwards, and thus saturates the superjacent soil, as from D to E, forming springs, or a general oozing. In either of these cases, and they are the most frequent that occur in practice, the object of the drainer is to reach the water. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability
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