THE LIME IN SOILS
_Limestone Land._ Soil analyses are serviceable only within certain
limits, and in the case of the normal soils that comprise the very great
part of the entire humid region of the United States the practical man
gives little heed to what special analyses might show him when deciding
upon the purchase of a farm. He does know, however, that a limestone
soil has great natural strength, and recovers from mistreatment more
readily than land low in lime. It has staying powers, and is dependable,
unless through natural processes the lime leaches out or loses
availability. All limestone areas have gained reputation for themselves
as producers of grain and grass.
_Other Calcareous Soils._ It is not only the limestone areas that stand
high in esteem. There are types of soil with every varying percentage of
lime down to clear sand or to peat, and some of the types are finely
calcareous, containing such a high percentage of lime that nothing more
could be desired.
The actual percentage is not the determining factor, a clay soil needing
greater richness in this material than a loam, and a sandy soil giving a
good account of itself with an even less total content of lime, but in
its way the particular soil type must be well supplied by nature with
lime if its trees and other vegetation bear evidences of its strength
and good agricultural value.
_Natural Deficiency._ It is interesting to note the differences in
evidences of prosperity that are associated with lime percentages. The
areas that are able to produce the vegetation characteristic of
calcareous soils are obviously the most prosperous. The decidedly
lime-deficient sections, advertising their state by the kind of original
timber, and later by unfriendliness to the clovers, do not attract
buyers except through relatively low prices for farms. Such areas are
extensive and have well marked boundaries in places.
It does not follow that every farm in such limestone valleys as the
Shenandoah, Cumberland, and Lebanon, or in the great corn belt having a
naturally calcareous soil, is prosperous, or that a multitude of owners
of such lime-deficient areas as the belt in a portion of southern New
York and northern Pennsylvania, or the sandstone and shale regions of
many states, have not overmatched natural conditions with fine skill. We
treat only of averages when saying that a "lime country" shows a
prosperity in its farm buildings and general appearance that does not
come naturally and easily to any lime-deficient territory. In the latter
a man rows against the current, and if livestock farming is not employed
to furnish manure, and if the manure is not supplemented by tillage and
drainage to secure aeration, or if lime is not applied, the land reaches
such a degree of acidity that it loses the power to yield any profit.
_Nature's Short Supply._ The total area of lime-deficient soil is large,
comprising certainly much more than half of all the land east of the
semi-arid belt of the United States. No small part of this area was not
deficient at one time, as the nature of the original timber indicates,
and it is well within the knowledge of practical men that land which
once produced the walnut and ash and shellbark hickory can be brought
back to productivity with reasonable ease after very hard usage. It has
a good inheritance. It is a disconcerting fact in our American
agriculture that, fertile as our country is as a whole, very great areas
were so deficient in lime before they came under man's control that the
chestnut, pine, and the oaks of mean growth were fully at home. The
gradation from low lime content to high, and its relation to soil type,
give us all sorts of mixtures of lime-loving and acid-resistant
varieties of trees in original forests, but our agriculture is hampered
by the high percentage of land for which nature made no great provision
of lime, and on this land farming lags.
_Effect of Irrational Farming._ Interest in liming might well have been
due to the amendment of all this soil, but the rational use of lime that
has been the subject of much study in the last quarter of a century
concerns chiefly great areas that probably could have been kept in
alkaline condition and friendly to the clovers for a long time despite a
short natural supply as compared with the content of our limestone
lands. The success of individual farmers in areas now admittedly acid as
a whole is convincing on this point. Nature tries constantly to cure
the ills of her soil through the addition of vegetable matter. An excess
of water or a deficiency is atoned for in a degree by the leaves and
rotted wood of her forests. Aeration is kept possible. The lime in the
product of the soil goes back to it. A system of farming that involves
the application of manure, thorough tillage, drainage where needed, and
the free use of sods in some way, has kept portions of these
non-calcareous soils out of the distinctly acid class. Clover grows
satisfactorily, grass sods are heavy, and there is no acute lime
problem. Such farms are relatively few in the great stretches of land
now classed as acid soil, and probably the most of the lime that is
being applied goes only on ground that once was sufficiently alkaline to
grow the clovers. The loss of organic matter through failure to use the
best methods of farming is responsible for no small part of the
widespread need of lime today. This subtracts nothing from the urgency
of its use to restore a condition favoring clover and grass sods, but it
does teach a lesson of the highest value. The day of destructive soil
acidity can be retarded by good farming, but in the long run the
inevitable losses of lime from most soils must be met by applications.
_Limestone Soils._ The old-time practice of making heavy applications of
fresh burned lime to stiff limestone soils to make them friable, and to
make their plant food available, led to disuse of all lime in some
sections on account of the exhaustion that followed dependence upon
these large amounts as a manure. Queerly enough, these original
limestone soils have latterly been going into the acid class through
loss of their distinctive elements, and they, too, have become dependent
upon means for the correction of acidity.