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

14.3. Composts
FFTC (1997) reports, concerning the Asia and
Pacific region, that “there is also an urgent need to
reduce pollution from agricultural wastes. One
means of dealing with them is to compost them and
use the compost as fertilizer. Very efficient
composting methods are required for this purpose.
Malodorous gases emitted during the treatment of
livestock manure or agro-industrial waste can cause
serious air pollution. There are various means of
controlling such odours.
There are a number of composting plants.
Their products are often of poor quality and also
contain unknown quantities of chemical
fertilizers, in proportions unsuited to crop needs.
There is an urgent need to define standards for
organic fertilizers.
Because of the difficulty of quality control, most
commercial organic fertilizers are not covered by the
type of national standards which govern the quality
of chemical fertilizers”.

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40
Mineral Fertilizer Use and the Environment
15. Resources
indicated a 12-year supply. 17 years later the
USA still had a reserve:production ratio
indicating about 9 years supply.
15.1.2. Phosphate and potash
Phosphate deposits are widespread throughout
the world but their economic recovery depends
on the cost. The most accessible and higher
quality rocks tend to be mined first; according to
IFA statistics the average P
2
O
5
content of the 125
Mt of phosphate rock mined in 1980 was 32.7%,
whereas that of the 141 Mt mined in 1996 was
29.5%. At the present rate of phosphate rock
production and with production costs of the same
order as at present the “reserves” are sufficient
for at least 80 years, and at somewhat higher
cost for 200 years. The “resources” which could
be economically mined at higher cost are much
greater. On most soils almost all the phosphate
not taken up by the crop is retained in the soil. It
is possible that techniques for the recovery of this
phosphate may be developed in due course.
Phosphate losses by soil erosion can be
minimized by following Codes of Good
Agricultural Practice.
There is no concern about potash resources,
the known high quality reserves being sufficient,
at present rates of use, for several hundred years
and resources, recoverable at higher prices for at
least a thousand years. Nevertheless, prudence in
the use of phosphate and potash reserves is
advisable since there are no known replacements.
15.1.3. Land
There is evidently a limit to the area of fertile
agricultural land in the world. Even in 1975,
according to an FAO survey, 54 countries could
not feed their populations with traditional
methods of food production, and the number has
increased significantly since that date.