1234. Stagnant water may be considered as injurious to all land plants, by depriving them of a sufficiency of atmospheric air, and thus diseasing their roots and submerged parts. Where the surface-soil is properly constituted, and rests on a subsoil moderately porous, both will hold water by capillary attraction; and what is not so retained, will sink into the interior strata by its gravity; but where the subsoil is retentive, it will resist, or not admit with sufficient rapidity, the percolation of water to the strata below, which accumulating in the surface-soil till its proportion becomes excessive as a component part, not only carries off the extractive matter, but diseases the plants. Hence the origin of surface-draining, that is, laying land in ridges or beds, or intersecting it with small open gutters.
