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Fertilizer and
the future
There is still a lot of misunderstanding and confusion about
mineral fertilizers. The public needs objective, science-based
information from all partners involved in nutrient
management..."
by Louise O. Fresco
Assistant Director General, FAO Agriculture Department
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 Netherlands, 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 ahead.
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 box below).
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 since 1950.
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 use.
Fertilizer application 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 world population. 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 time.
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 study recovery. 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 crops. 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 techniques. 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 progress.
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.
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