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

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7. Water
protection of waters against pollution caused by
nitrates from agricultural sources. This directive
recognized that, whilst the use of nitrogen-
containing fertilizers and manure is necessary for
EU agriculture, any over-use of fertilizers and
manure constitutes an environmental risk. It
emphasizes that common action is needed to
control the problem arising from intensive
livestock production, and that agricultural policy
must take greater account of environmental
protection.
The objectives of the directive are to ensure
that the nitrate concentration in freshwater and
groundwater supplies does not exceed the limit of
50 mg NO
3
per litre and to control the incidence
of eutrophication. Having set the overall targets,
the directive requires individual Member States,
within prescribed limits, to draw up their own
plans for meeting them. These plans involve the
preparation of a voluntary Code of Good
Agricultural Practice, the designation of zones
vulnerable to water pollution from nitrogen
compounds and the implementation of action
programmes designed to prevent pollution within
those zones. The measures include a maximum
limit for the addition of livestock manure – the
main culprit - equivalent to 170 kg nitrogen (N)
per hectare. In addition, the periods in which it is
acceptable to apply animal manure are defined.
The agricultural techniques for keeping
nitrate out of water supplies are known. The
European Fertilizer Manufacturers’ Association
(EFMA), for example, has explained these
techniques in a code of best agricultural practice
(EFMA, 1996).
In general, in developed countries, where
mineral nitrogen fertilizer is a major source of
water pollution it is usually in areas of vegetable
production or irrigated sandy soil, or where the
optimum rates are exceeded. A distinction must
There is concern that fertilizers are polluting both
surface waters and water in aquifers, although
the direct impact of the application of mineral
fertilizers on the nitrate content of waters is
poorly defined.
According to Union des Industries de la
Fertilisation (UNIFA), 1997, in France, it is
estimated that nitrogen fertilizers account for
25% of total mineral nitrogen introduced
annually into the eco-system, or 2.3 Mt N out of a
total of 9.4 Mt N. Other major inputs are from
nitrogen fixed by leguminous plant (3 Mt N) and
animal wastes (2 Mt N). In a major catchment
area in France, 42% of the nitrogen in the water
was of agricultural origin (arable and livestock),
49% domestic and 9% industrial. Labeled 
15
N
experiments indicate that not more than 5% of
fertilizer nitrogen is lost to water during the
growing season, two thirds of it due to incorrect
fertilization practices. In general the extent of
losses is not linked directly to recent fertilizer
applications. Of the agricultural losses 50% was
from soils which were left bare in winter and
33% due to poor cropping practices i.e. losses
which could be avoided.