Page 3

THE SOILS OF WISCONSIN
  The soils of Wisconsin constitute a layer as much as 4 or 5
feet thick that has a dry weight of nearly 300 billion tons and
covers about 35 million acres. We are not used to thinking of
our soil resource in terms of tonnages as we think of gravel
deposits and ores. The fact is that soil is a prime organo-
mineral resource of importance to the stability of buildings and
highways, the economy of our cities, the productivity of our
farms and forests, the quality of our nutrition, and the vitality
of wildlife and wilderness areas. Eroded soil materials in the
nearly one million acres of Wisconsin now under lakes and
streams influence water quality by yielding or by adsorbing
pollutants. The soils of this state have been the subject of ex-
tensive soil investigation for nearly a century, during which
time a vast amount of information on specific areas and soils
has been reported. Three colored wall maps of the soils of the
state have been published (in 1882, 1927, and 1968). Our pres-
ent knowledge of the soils of Wisconsin, of which this report is
a summary, is a basis for sound land management and for
future research in pedology and soil-water conservation.
  Areal analysis of the soil map (Plate 1) indicates that Wis-
consin subsoil materials are deep (more than 2 feet thick over
consolidated bedrock in 95% of the state). A third of the soil
area is derived from glacial outwash sand and gravel, a third
from glacial till loams, a tenth from deposits in ancient glacial
lakes, and a tenth from bedrock-derived residuum. Wetland
soils (both organic and inorganic) are shown on the map to
cover nearly 10% of the state, but bodies too small to show
probably more than equal that. About 40% of the land is cov-
ered with a foot or more of weathered bess, from which some of
the most productive soils have formed. Wisconsin is crossed by
a southeast-trending climatic and ecological tension zone that
separates cool-summer forest soils on the northeast from warm-
summer prairie and prairie-forest transition soils on the south-
west. Forest soils have formed on two thirds of the area, and
prairie- and savanna-influenced soils have developed on the
remaining third. Clayey soils cover about 10% of the state; silty
soils, about 40%; loams and sandy loams, 25%; sands, 20%;
and peats and mucks, about 5%.
  The state has nine major soil regions, with interspersed wet-
lands constituting a tenth unit. (A) The southwestern region is
a two-story landscape with productive ridge and valley soils
separated by wooded steep shallow soils and rockland. The
great variety of soils and topography contributes to a scenic
landscape, but demands careful land and water management
to handle problems of erosion and waste disposal. (B) The
southeastern upland has an intricate soil pattern of wetlands
and plains, hills, drumlins, and ridges, including the promi-
nent Kettle Moraine. The contribution of dolomitic limestone
to subsurface materials is associated with a high level of native
subsoil fertility. (C) Soils of the central sandy uplands and
plains inherit their coarse texture from Cambrian sandstone
and deposits of sandy outwash from the melting of glaciers
thousands of years ago. Buried silts and clays of ancient lake
beds, rocky sandstone crags of scattered mounds and mesas,
and intermixtures of dry and wet soils are features of the land-
scape of the central sandy region. (D) Soils of the western sand-
                                  CHAPTER     1
                                Introduction
stone uplands, valley slopes, and plains include shallow silt
loams and deep sandy loams, some steep stony land, and im-
perfectly drained fiats. (E) Northern and eastern sandy and
loamy reddish drift uplands and plains have a mixture of
sands, reddish silts, and clays, interlayered in some areas. (F)
The northern silty uplands and plains are characterized by shal-
low to moderately deep silty soils over compact acid loamy and
sandy glacial drift. Soil drainage is a problem in many places.
(G) The vast northern loamy uplands and plains consist of acid
stony and somewhat sandy soils on glacial moraines, drumlins,
eskers, and outwash flats. (H) The northern sandy uplands and
plains include sands of extensive pine and oak barrens on
pitted glacial drift and nearly level outwash plains. (I) Soils of
the northern and eastern clayey and loamy reddish drift up-
lands and plains have high clay content and plant nutrient
levels. Management problems on these soils include tillage,
drainage, and disposal of liquid wastes. (J) Stream bottoms and
wetlands of the state are occupied by mineral soils and peats
and mucks with high water tables. Naturally well-drained allu-
vial soils are not extensive.
DEFINITION OF SOIL
  Soil is considered here as a natural unit in a pedological (soil
science) or ecological sense, rather than in an engineering
sense. It is geologic material altered by plants and animals and
climate. Soil is a body of mineral and organic matter occurring
naturally on the land surface of the earth, interrupted by bodies
of 'not-soil,' which include rock outcrops, lakes, and streams.
The soil envelope of the earth, sometimes called the pedo-
sphere, lies at the interface between the biosphere and the litho-
sphere. It is a blend of the biologic and geologic materials. The
pedosphere may bethought of as a mosaic, made up of specific
soil bodies. In plowed fields, dark bodies of soil commonly
show up distinctly in a setting of higher lying, light-colored soil
bodies. Thus, examples of the basic unit of soil classification,
the soil body, may be easily seen in the landscape when the
fields are newly plowed. Soil bodies in Wisconsin range from 1
to 7 feet deep, and are commonly 4 feet thick. The lower sur-
face of a soil body is marked by the limit of leaching of nat-
urally occurring lime (carbonates) in many soils and by the
lower limit of common rooting of native perennial plants in all
soils. Loose material below this level is not considered soil in
the pedological sense, as indeed loose material on the moon is
not.
  Because soil bodies are hundreds or thousands of feet across,