Download Introduction to Inorganic and Organic Nutrients

Introduction to
Inorganic and Organic Nutrients
B y D a v i d W. D i b b
T
he word nutrient is a derivation of the material in some stage of decomposition) are
word nutrition, which implies food. found in all agricultural soils and are conThe term essential nutrient, then, is stantly in transition back to their inorganic
redundant in the sense that essentiality is form. As they decompose, they contribute to
defined as necessary to sustain life and food the total soil inorganic nutrient pool necessustains life. In the plant world, an element sary to grow the world’s food requirement.
is considered essential if it
Attempting to separate
There are differences in
is necessary for the plant to
organic and inorganic nutriinorganic and organic nutricomplete its life cycle. No
ents is difficult and of limitents, but there are also simiother element can substitute
ed value because nature’s
larities. It is important to
for it completely. Of the eleprocesses are continually
understand the advantages
ments that have been identicycling them from one form
and disadvantages as well
fied by scientists, only a relto another. All nutrients go
as the limitations of both
atively small proportion is
through natural cycles, folnutrient sources.
known to be essential to
lowing various pathways to
plants and animals.
their final destination of
Plant nutrients include gases, metals, being absorbed and utilized by plants that
and non-metals. All exist naturally, in both grow all the food for humans and animals. In
inorganic and organic forms. Three of the the process, some, such as N, P, and S, cycle
nutrients, nitrogen (N), phosphorus (P), and back and forth between the inorganic and
sulfur (S), are present in both inorganic and organic pools.
organic forms. Crops grow in a very thin
It is important to note that when
layer of the Earth’s crust, so it is important supplied to plants in the organic form,
that nutrient levels be maintained by the nutrients still must cycle through the
addition of both organic (plant and animal inorganic form before becoming availresidues) and inorganic (manufactured min- able to plants. In fact, organic nutrient
eral fertilizers) sources.
sources can be differentiated from inorganic
Sometimes the word organic is used in (mineral) fertilizers in that they must be
connection with food. Often it is used to sug- decomposed before the nutrients they congest that organic foods contain only good or tain are released, hopefully at a time when
natural elements that somehow enhance crop plants can use them. On the other hand,
plant and animal health when compared to inorganic nutrients are supplied in soluble
those foods grown with synthetic chemicals. or slowly soluble forms, so the plant will
Actually, whether organic or inorganic, all have them available and take them up when
elements are chemical. The term organic they are needed.
relates to living (or the remains of once living) substances which contain carbon (C). Dr. Dibb is President of the Potash & Phosphate
Organic substances (dead plant or animal Institute, located at Norcross, Georgia.
Better Crops/Vol. 86 (2002, No. 2)
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