One of the great improvements of the age is the adoption in husbandry
of the subsoil plow; or, as it is called in England, _Deanstonizing
system_, from Mr. Smith, of _Deanstone_, who first brought the
implement into general notice. They are designed to follow in the
furrow of a common plow, and pulverize without bringing up the soil
for eight or ten inches deeper. In ordinary soils two yoke of oxen
will work it with ease, plowing from an acre to an acre and a quarter
a day.
The use of this plow will renovate old bottom-lands, the surface of
which has been exhausted by shallow plowing and continual cropping. It
brings up from below fresh material, which the atmosphere speedily
prepares for crops.
Old fields, a long time in grass, are very much benefited.
Constant plowing at about the same depth will often form a hard
under-floor by the action of the plow, through which neither roots nor
rain can well penetrate; subsoiling will relieve a field thus
conditioned.
Soils lying upon clay or hard compact gravel are opened and remarkably
improved by the process. The wet, level, beech-lands would be greatly
benefited by deep plowing in the _fall of the year_, subjecting the
earth, to a considerable depth, to the action of the frosts, rains,
etc., and giving a downward drain for superfluous moisture.
Although we have incidentally alluded to the benefits of subsoiling,
they deserve a separate and individual enumeration.
1. In very deep molds or loams it brings up a supply of soil which has
not been exhausted by the roots.
2. In soils whose fertility is dependent upon the constant
decomposition of mineral substances, subsoil plowing is advantageous
by bringing up the disintegrated particles of rock, and exposing them
to a more rapid change by contact with atmospheric agents.
3. Subsoiling guards both against too much and too little moisture in
the soil. If there is more water than the soil can absorb, it sinks
through the pulverized under-soil. If summer droughts exhaust the
moisture of the surface they cannot reach the subsoil, which affords
abundant pasture to the roots.