Geoscience Reference
In-Depth Information
a summer” when the majority of food crops in the Northern Hemisphere were
destroyed by a
volcanic winter
caused by a large cloud cover composed of volcanic
dust, lack of sunshine, and the global famine that ensued. Thanks partly to Liebig's
introduction of fertilizers in agriculture, the 1816 famine was called the last food
crisis in the Western world.
Liebig's life in sciences did not start in a simple way. He attended the University
of Erlangen, but due to his involvement with a radical student organization and due
to his criticism that not enough advanced development of chemical studies was
available at the university, he left Erlangen without gaining the doctor title. He
obtained it later, was appointed a full professor at Giessen University at the early
age of 21, and soon after developed a famous, unique chemical center. After World
War II the university was offi cially renamed after him. He founded and edited from
1832 the leading journal in chemistry, Annalen der Chemie, which was renamed to
Justus Liebig's Annalen der Chemie after his death. In this journal he also published
about the role of
humus
in plant
nutrition
and discovered the important role of nitro-
gen compounds in the feeding of plants. One of his most recognized accomplish-
ments was the invention of nitrogen-based fertilizers substituting for “natural”
sources of nitrogen like plant remnants, manure, animal dung, etc. Many of his
actions as well as his theoretical manner of proceeding formulated before experi-
mentation can be characterized by his sentences: “…the production of all organic
substances no longer belongs just to the organism. It must be viewed as not only
probable but as certain that we shall produce them in our laboratories.”
He was frequently named as father of production of fertilizers and their applica-
tion in modern agronomy. When he studied plant nutrients, he formulated the Law
of Minimum that a plant's development is limited by the element that is in a rela-
tively shortest supply. The law is simply named “Liebig's barrel”; see also our Sect.
11.2
and Fig.
11.3
. This Liebig's Law of Minimum was later extended by ecologists
to all forms of life outside the vegetable kingdom. The law was later also criticized
for its static character and that it does not consider the dynamic system in which the
lack of one factor or element could be partly and in certain limits compensated by
the action of another factor.
Liebig's infl uence upon soil science research was enormous with soil chemistry
being studied according to his ideas for several decades leading into the twentieth
century. Toward the end of that time span, many universities and research institutes
began putting an equal sign between soil science and soil chemistry of plant nutri-
ents. Their promotion of this overly simplifi ed equality, never accepted by Liebig,
soon started to break down his inspirational message for others to continue and
expand their scientifi c explorations to better understand all of the intricate concepts
and processes within soils.
During the same time of Liebig's dominance, geologists were also identifying
various kinds of soils, but their concept was limited to the description of soils as
weathering products that were later transported either by wind as, for example, the
loess, or by water when alluvial soils developed. Examples of many other types
include diluvial deposits on the bottom part of slopes or old moraines after the pre-
vious existence of glaciers. All those results of geological research are correct, but
