Mineral Fertilizer Use and the Environment International Fertilizer Industry Association United Nations Environment Programme

1.1. What are fertilizers
Mineral fertilizers are materials, either natural or
manufactured, containing nutrients essential for
the normal growth and development of plants.
Plant nutrients are food for plants some of which
are used directly for human food, others to feed
animals, supply natural fibres or produce timber.
Man and all animals depend entirely on plants to
live and reproduce. The public perception of
mineral fertilizers often takes no account of these
simple facts.
Three plant nutrients have to be applied in
large quantities, nitrogen, phosphorus and
potassium. Sulphur, calcium and magnesium also
are required in substantial amounts. These
nutrients are constituents of many plant
components such as proteins, nucleic acids and
chlorophyll, and are essential for processes such
as energy transfer, maintenance of internal
pressure and enzyme action. Seven other
elements are required in small or trace quantities
and are referred to as “micronutrients” or “trace
elements”. A further five elements are required
by certain plants. These elements have a variety
of essential functions in plant metabolism. The
metals are constituents of enzymes controlling
plant processes. The deficiency of any one
nutrient can compromise the development of the
plant.
Mineral fertilizers comprise naturally
occurring elements which are essential to life.
They give life and are not biocides. Fertilizers are
used in order to:
•
supplement the natural soil nutrient supply in
order to satisfy the demand of crops with a
high yield potential and produce economically
viable yields,
•
compensate for the nutrients lost by the
removal of plant products or by leaching or
gaseous loss,

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Mineral Fertilizer Use and the Environment
Between 1989 and 1994 fertilizer
consumption in developed countries as a whole
fell from some 84 Mt nutrient in 1988 to 52 Mt
nutrient in 1994. The fall was greatest, by 80%
in total, in the formerly communist countries of
Central Europe and the former Soviet Union
(FSU). Crop production in this region also fell,
although not to the same extent. This was
because under the centrally planned system
fertilizers were used inefficiently and plant
available reserves of some nutrients had
accumulated in the soil and could now be mined
to help feed crops.
In developing countries until the 1960s
fertilizers were applied mostly to plantation crops
such as tea, coffee, oil-palm, tobacco and rubber,
while application to field crops was either small
or non-existent. Even where fertilizers were
applied, application rates had to be small in view
of the traditional tall cereal varieties which were
cultivated at that time. The introduction of high-
yielding, fertilizer-responsive dwarf varieties in
the mid to late sixties gave a considerable boost
to fertilizer consumption applied to annual field
crops. Unfortunately this development has still
not occurred in many countries of sub-Saharan
Africa, for economic and climatic reasons and
also for lack of suitable varieties.
Since 1960, fertilizer consumption in the
developing countries has increased more or less
continuously, and today accounts for about 60%
of the world total, compared with 12% in 1960,
a trend which is continuing. With their rapidly
increasing populations, many developing
countries are compelled to give agricultural
production and the development of fertilizer use
a high priority.
Between 1993/94 and 1997/98 world total
fertilizer nutrient consumption increased from
120 to 136 Mt, an average rate of increase of
about 3% p.a. Consumption in China, South Asia
and Latin America increased by 10, 5 and 2 Mt
respectively. But in most countries of sub-Saharan
Africa the quantity of fertilizer used is not only
very low, but also most of what is used is applied
in the commercial, plantation sector. Rates of
fertilizer use on food crops are particularly low.
There is a very large variation in application rates
between countries, as is shown by the examples
in the following table.