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

32
Mineral Fertilizer Use and the Environment
11. Nutrient accounting
Accounting systems based on the nutrient
input and output are used in some European
countries as a measure for the environmental
performance of farms, particularly in countries
with a manure disposal problem.
In Denmark, since 1994, farmers have had to
prepare fertilization plans and the amount of
nitrogen that may be applied to each type of crop
is regulated. Another requirement is that 65% of
the cultivated area must be covered by a green
crop in winter. There are heavy fines in the event
of infringement. In Germany a federal
“Regulation of fertilizer use” model regulation
came into effect in January 1996. The model
must now be implemented in the individual
Federal States. In Norway fertilizer plans are now
compulsory. In the Netherlands a compulsory
nutrient accounting scheme is starting in 1998.
Nutrient applications over the maximum will be
taxed. See O.L.H. Möller-Hansen et al. (1999)
Nutrient accounts may indicate a deficit as
well as a surplus. The exercise would therefore
be useful also in developing countries where soils
are being mined of their nutrients. A substantial
proportion of the nutrients which find their way
into the manure produced by intensive livestock
units originate from animal feed which has been
imported from other regions of the world, thus
depleting the nutrients in the soils of the
exporting regions. But in many developing
countries soils are also being exhausted just to
provide a subsistence for their cultivators.
Using comparisons of nutrient inputs and outputs
as a yardstick for environmental correctness of
fertilizing practices in scientific publications and
studies started during the 1980s. Different types
of nutrient balances came into use. The most
common is a comparison of nutrient inputs and
outputs at farm gate level (the alternative “soil
surface balance” is more complicated). The
account examines the relationship between
applied nutrients and nutrients removal in the
harvested crop. It considers all nutrients, whether
of mineral or organic origin, which may be
applied. The system ideally should also consider
changes in soil nutrient levels and, in some cases,
admissible losses.
Nutrient accounting is being developed by the
OECD as one of the environmental indicators.
These are national indicators K. Parris and L.
Reille (1999) require careful interpretation. For
example, a country may have a national surplus
while experiencing nitrate pollution in some areas
and nutrient depletion in others. The nutrient
balance indicator needs to be used in conjunction
with indicators on farm nutrient management,
soil quality and water quality.
Livestock wastes contain substantial amounts
of plant nutrients (see the section on Organic
Materials). It is therefore evident that all sources
of nutrients should be into account when
determining rates of mineral fertilization.

---

Mineral Fertilizer Use and the Environment