Agriculture Reference
In-Depth Information
INTRODUCTION
Show me your [classiÝcation] system and I will tell you how far you have come in the perceptions
of your research (Kubina, 1948).
Soil is so universal that all people know of its existence, and therefore have individual concepts
of what soil is and what soil does. The universality of soil, the individuality of people, and the
limited geographic exposure to soil each person has experienced ensure an inÝnite array of philos-
ophies about how to classify soils. To some people, soil is a singular entity, but many have some
appreciation for more than one kind of soil, abstractly referring to simplistic classiÝcations of
fertile, wet, black, red, sandy, clayey, etc. Others classify soil by association with geology, geog-
raphy, climate, and vegetation. Philosophies of soil classiÝcation are fascinating.
INDIGENOUS CLASSIFICATIONS
Everyone who uses soil classiÝes it. Most indigenous classiÝcations are in reference to a speciÝc
use. Indigenous people are directly interested in what a soil does with respect to their intended use
of the land. Indigenous classiÝcations are often quite colorful and informative. At an early age, I
understood that Ñpush-dirtÒ in southern Wisconsin referred to soil that adhered to the plow, and, if
slightly too wet, would not be inverted by a moldboard plow. I later learned Ñpush-dirtÒ was an
apt classiÝcation for some Newglarus (Ýne-silty over clayey, mixed, superactive, mesic Typic
Hapludalfs) soils, wherein a moldboard plow sometimes reached into the upper part of the clay-
textured 2Bt2 horizon that, early in the spring, was often wetter than was predicted by looking at
the surface soil. The wet, sticky 2Bt2 material adhered to the moldboard and pushed forward, rather
than inverting as intended. ÑBlack Jack,Ò Ñpipe clay,Ò and ÑBeeswaxÒ land (Hearn and Brinkley,
1912) referred to distinct soils on the piedmont of North Carolina. Local farmers were said to also
call them Ñdinner-bellÒ soils because they were too wet to plow in the morning and so dry and
hard in the afternoon that a mule could not pull the plow. Plowing was best done at noon, i.e.,
dinner-time on the farm. We now know Ñdinner-bellÒ or ÑBlack JackÒ soils as an Iredell (Ýne,
mixed, active, thermic Oxyaquic Vertic Hapludalfs).
Indigenous people who till the soil are concerned with what a soil
does
when it is interacting
with their activities. Soil scientists attempt to identify what a soil
is
and to classify it using
measurable chemical and physical criteria.
ANTHOLOGY OF SOIL CLASSIFICATIONS
century were actively seeking to deÝne soil in a context
that separated soil science from geology. Dokuchaev (1883) related soil properties to elements of
vegetation and climate, in addition to the inÞuence of geologic parent material. Vegetation and
climate were not considered to inÞuence geology, and soil could be deÝned as a scientiÝc entity
apart from geology. In 1927, Glinka (quoted in Jenny, 1941) reported that Russian soil scientists
regarded soil type as a summary of the external and internal properties of a soil, so as to include
climate, vegetation, and animal life as a unit for soil classiÝcation, rather than as volumes of soil,
i.e., modern day pedons.
Although he clearly recognized soil as an independent entity, Hilgard (1914) deÝned soil as
Ñthe more or less loose and friable material in which plants, by means of their roots, may or do
Ýnd a foothold and nourishment, as well as other conditions of growth.Ò Thus he considered soil
primarily to be a means of plant production. Perhaps the inscription on Hilgard Hall on the
University of California-Berkeley campus best relates his concern for the concepts of soil held
Scientists in the latter part of the 19
th
