swamps.

Our ordinary cereal, root, forage and garden crops require a medium
degree of moisture, and with us it is in all cases desirable that the
soil be equally protected from excess of water and from drouth. Soils
must be thus situated either naturally, or as the result of improvement,
before any steadily good results can be obtained in their cultivation.
The remedy for excess of water in too heavy soils, is thorough drainage.
It is expensive, but effectual. It makes the earth more porous, opens
and maintains channels, through which the surplus water speedily runs
off, and permits the roots of crops to go down to a considerable depth.

What, let us consider, is the means of obviating the defects of soils
that are naturally too porous, from which the water runs off too
readily, and whose crops "burn up" in dry seasons?

In wet summers, these light soils, as we have remarked, are quite
productive if well manured. It is then plain that if we could add
anything to them which would retain the moisture of dews and rains in
spite of the summer-heats, our crops would be uniformly fair, provided
the supply of manure were kept up.

But why is it that light soils, need more manure than loamy or heavy
lands? We answer--because, in the first place the rains which quickly
descend through the open soil, wash down out of the reach of vegetation
the soluble fertilizing matters, especially the nitrates, for which the
soil has no retentive power; and in the second place, from the porosity
of the soil, the air has too great access, so that the vegetable and
animal matters of manures decay too rapidly, their volatile portions,
ammonia and carbonic acid, escape into the atmosphere, and are in
measure lost to the crops. From these combined causes we find that a
heavy dressing of well-rotted stable manure, almost if not entirely,
disappears from such soils in one season, so that another year the field
requires a renewed application; while on loamy soils the same amount of
manure would have lasted several years, and produced each year a better
effect.

We want then to _amend_ light soils by incorporating with them something
that prevents the rains from leaching through them too rapidly, and also
that renders them less open to the air, or absorbs and retains for the
use of crops the volatile products of the decay of manures.

For these purposes, vegetable matter of some sort is the best and almost
the only amendment that can be economic