Agriculture Reference
In-Depth Information
4
CHAPTER
Conceptual Basis for Soil Classification:
Lessons from the Past
Richard W. Arnold and Hari Eswaran
CONTENTS
Abstract ............................................................................................................................................27
Introduction ......................................................................................................................................28
Why Soils .........................................................................................................................................29
What is Soil? ....................................................................................................................................29
Why ClassiÝcation? .........................................................................................................................30
What Objectives? .............................................................................................................................30
The Architecture of the System .......................................................................................................30
Hierarchies ..............................................................................................................................31
Principles ................................................................................................................................35
The Categories of the System ................................................................................................36
Accomplishing the Objective...........................................................................................................36
Purpose ...................................................................................................................................36
Minimizing Prejudice for the Future ...............................................................................................40
ReÝning the System: ÑRules of EngagementÒ ................................................................................41
References ........................................................................................................................................41
ABSTRACT
The publication of a second edition of Soil Taxonomy in 1999 was a benchmark event that,
among other things, enabled us to evaluate the progress of soil classiÝcation over Ýve decades. The
quest for a single international system will continue to be elusive for another few decades, and Soil
Taxonomy will still have imperfections. However, it is a living system in the sense that it serves a
function. Because of this and the fact that it has been amenable to changes without major alterations
to the basic structure, the system will continue to serve in the future, needing reÝning only when
knowledge and applications warrant it. Facts determined by precise observation, experimentation,
and measurement minimize prejudicing the future, and are the building blocks of a classiÝcation
system. Systems built solely on empirical relationships among facts or genetic theories falter
quickly. As there are relics of classiÝcation systems around the world, we considered that it would
be useful to elucidate some of the lessons learned during this glorious period of Pedology. These
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