Louise O. Fresco Asst D.G,
FAO Agriculture Department
is still a lot of misunderstanding and confusion about
mineral fertilizers. The public needs objective,
science-based information from all partners involved in
Fertilizer seems to have a
bad name, and in some surprising circles. During a recent
visit to my alma mater, the University of Wageningen, in the
I was amazed to hear
several students say that raising crop yields with
fertilizers was very dangerous and even immoral,
particularly for African soils.
It is time to dispel some
myths about mineral fertilizers, to appreciate the role they
play in feeding the world, and to assess how best they can
help agriculture meet the challenges it faces in the decades
There is a general consensus
about the way agriculture is evolving in response to
demographic and economic trends. World population will
probably peak at some 8,000 million around 2030, when two
out of every three people will live in towns and cities.
Rising incomes will create a
disproportionally higher demand for food, meaning that over
the next three decades food production will need to increase
by about 60%.
Nearly all of the increase in
production will have to come from developing countries
through intensification of agriculture, i.e. more yield per
unit time and per unit area.
As urbanization reduces the
rural workforce, agriculture will also need to adopt new
forms of mechanization and shift to land use
intensification, with all of its connotations.
Those scenarios point to an
increase in use efficiencies of all natural resources,
particularly water, and to the need for greater - although
not proportionally greater - use of mineral fertilizer (see
Yield increases. Half a century ago, farmers applied only 17
million tonnes of mineral fertilizers to their land. Today,
they apply eight times as much. In northern Europe,
fertilizer use has increased from about 45 kg/ha to 250kg/ha
In the same period, wheat
yields in France increased every year, from about 1.8 tonnes/ha
to more than 7 tonnes/ha.
The growth in fertilizer use
is certainly lower than the increase in yields, and confirms
the overall pattern of increasing efficiency in fertilizer
currently accounts for 43% of the nutrients that global crop
production extracts each year, and the contribution may be
as high as 84% in the years to come.
Contrary to some public
opinion, non-mineral nutrient sources are unlikely to
challenge mineral fertilizer in the future: while there will
be more manure available as livestock production increases,
and urbanization produces more waste, especially sewage,
their efficiencies are considerably lower and the current
cost of using waste for crops is still quite high.
Organic agriculture, which eliminates the use of synthetic
inputs, does not appear to be a feasible alternative. At FAO,
we have done some very tentative calculations of what
organic agriculture would mean on a global scale if market
demand for organic produce increased substantially.
The consequences are quite
staggering: a large amount of land that would have to be
brought under rotation with legumes or under animal
production to make up for the lack of mineral fertilizer.
While organic agriculture does fill a niche market, its
limits - and its dangers, in terms of nutrient depletion -
need thorough review.
More for less.. FAO's study World agriculture: towards
2015/2030 says "increased use of fertilizer is becoming even
more crucial in view of other factors, such as the impact on
soil fertility of more intensive cultivation practices".
However, increases in food
production are possible with a less than proportional
increase in fertilizer nutrient use. For example, the study
says, maize farmers in North America have increased nutrient
use efficiency by adopting improved management practices.
Other research suggests that
techniques such as precision agriculture could help
substitute "information for fertilizer". See World
agriculture: towards 2015/2030...
The question is not whether but by how much fertilizer use
will need to increase. At the World Food Summit in 1996,
governments committed themselves to halving the number of
hungry people by the year 2015.
There is a direct link
between that WFS goal and fertilizer use. Possibly, it means
an 8% increase in fertilizer applications compared to the
"business-as-usual" scenario. That does not seem very much,
but in terms of its tonnage, it is considerable.
Enhanced fertilizer use to
meet WFS goals is particularly important in countries such
as China and India, which make up a large proportion of the
But it may be even more
important in Africa, where increases of 2.7% or more a year
are needed in order to make up for nutrient losses, and in
the humid tropics, where unfertilized annual cropping takes
a heavy toll of soil organic matter.
Fertilizer use efficiency.
Improving the efficiency of fertilizer use is the challenge
of the future. One possible direction is improving
fertilizer use and plant nutrient uptake efficiency through
biotechnology. Hardly any current work in biotechnology
addresses abiotic stresses or biological nitrogen fixation.
While there may be scope for
such research, we should be very careful about promising too
much, too quickly. In any case, there is still a lot to gain
from conventional plant breeding.
For example, considerable
work has been done on the so-called "staying green"
characteristics of crops such as sorghum - the longer the
crop stays green, the more fertilizer uptake there is over
Another promising area for research is soil biology.
Although it remains an isolated field, we do know that soil
organic matter and soil biology are important in nutrient
management, and that nutrient recovery for fertilizer is
much better with soil improvement.
In Africa, where the recovery
of nutrients is very low, more systematic work is needed on
soil organic matter and on soil quality in physical,
biological and chemical terms. Since biological nitrogen
fixation produces mixed results, scientists need to link it
to the application of more conventional fertilizers and
Results would probably show
that biological nitrogen fixation is not a miracle solution
by itself, but is successful under certain conditions.
Integrated management of production systems offer a proven
path to greater fertilizer use efficiency. Remarkable
results in rationalizing pesticide application have been
achieved by making farmers more aware of integrated pest
management through field schools, where they learn to
observe crops closely and discuss the management of the
pests and pathogens.
These activities are
increasingly linked to integrated nutrient management -
farmers are being trained to observe the real impact of
nutrient application rather than, for example, applying more
and more urea simply because it is the cheapest fertilizer.
Farmers also need to understand the effects of over-use of
nitrogen on certain pathogens and other stress factors in
This may convince them of the
need to buy non-nitrogen fertilizer and adopt much more
balanced fertilizer applications.
Private/public partnerships. The gains to be made from
fertilizer use efficiency, even from a purely economic
standpoint, could be significant. However, those gains
depend on a broad range of factors that determine fertilizer
use and fertilizer application by farmers.
We need private/public
partnerships, much better systems of distribution and
quality control, and the array of marketing tools that goes
with it. The fertilizer industry should become more creative
in ensuring that the farmer actually obtains the maximum
benefit from existing crop and fertilizer application
This means looking
systematically at ways of reducing labour demand, which is
particularly important as the availability of agricultural
labour declines. For example, new polymer-coated fertilizers
could offer a much better recovery rate.
The industry should also look
at the total cycle of nutrient use and nutrient recovery,
remembering that the automobile manufacturing industry heard
the same plea 20 years ago and has since made considerable
There is still a lot of misunderstanding and confusion about
soil nutrients and, in particular, mineral fertilizers. The
public needs objective, science-based information from all
partners involved in nutrient management.
We must, in other words, tell
people what we know. We know productivity gains are
necessary and possible. We know that more fertilizers are
needed. We know that fertilizer use can be far more
productive and efficient, if we do it in the right way and
in the right context.
This article is based on an address to the IFA/FAO
Agriculture Conference on "Global food security and the role
of sustainability fertilization" (Rome, Italy, 26-28 March
2003) Get detailed Plant nutrition information from
our Land and Plant Nutrition Management Service.