Actualité scientifique
Scientific news
Can weather forecasting
help improve crop yields in
West Africa? IRD scientists
and their research
partners1, bringing
together their experience in
studying climate, agronomy
and economics, have
shown recently that millet
producers in Niger could
increase their income by
up to 30%. They do this
despite the fact that they
often have no option to use
other varieties of that
cereal. How? Simply by
adjusting their strategies in
line with forecasts for
coming rainy seasons.
Previous research investigations have highlighted
the advantage of such
predictions, but the true
impact of climate forecasts
on the agricultural
economy remains to be
determined.
Improvement of the
accuracy of predictions
and communicating them
to farmers can therefore
prove to be a strong boost
for agricultural
development, even in
countries of the Sahel like
Niger, where low irregular
rainfall lend themselves
only to crops giving low
profitability. Such advances
would make West African
farming communities more
resistant to food insecurity
in the forthcoming years
and also reduce the
poverty of a many smallscale producers.
© IRD / C. Costis
April 2011
Rainfall forecasting
could reduce food insecurity
© IRD / C. Mariac
N° 372
Actualidad cientifica
The only options farmers growing millet in Niger often have concern a small number of varieties of that cereal, which makes up 75% of national agricultural production.
The future of Sub-Saharan Africa, where starvation rates, reaching nearly 30%, are the highest
in the World, depends on the ability of the agricultural sector to guarantee food security for a
steeply rising population. The only way to meet
this challenge is to increase crop yields. Indeed,
although overall production has increased over
the past decades, this is mainly due to the extension of the areas under cultivation. Agricultural
productivity has been stagnating since the
1980s. In some countries, such as Niger, it has
even fallen.
Predicting means adapting
Among the many technical possibilities for optimizing yields (such as the zai technique 2, microfertilization), the use of climate forecasting is
both promising and inexpensive for West-African
farmers, according to research scientists from the
IRD, CIRED, CIRAD and AGRHYMET1. Data from
PRESAO 3 are issued in each country by the
national meteorological services, but the informa-
tion reaches farmers only rarely. The potential
effects of seasonal forecasts in the agricultural
economy are in fact still unknown, even though
research on this subject has suggested the
importance of this against the high variability and
uncertainties of the region’s climate.
This work has established that adapting growing
strategies each year according to the forecasts
would lead to gains in production ranging up to
80%, as a previous study showed through numerical modelling of a vir tual farm in Senegal.
However, these preliminary results only apply to
areas with quite sound levels of rainfall, such as
the Saloum Delta, where cash crops like groundnuts –highly demanding in their needs for water,
inputs and labour, but profitable– are possible.
But what is the situation in the Sahel, in areas in
Niger for instance, where low irregular rainfall
restricts cultivation to just subsistence food
crops –mainly resistant cereals, millet and
sorghum? The answer, a surprise for the scientists, is that although in Niger small-scale
For further information
growers of millet –the staple food, making up
75% of national production– have little room for
manoeuvre, they could still substantially increase
their earnings, by up to 30%.
Large gains at stake in spite of
limited room for action
Field data collected by AGRHYMET’s research
partners about the actual crop growing situations
in Niger, the alternatives open to farmers are
generally restricted to choices between a small
range of variety of the one cereal, millet, decisions on dates for sowing and on whether or not
to use fer tilizers –a risky option because the
price of inputs is high and difficulties arise in
practice because chemical fer tilizers are not
readily accessible on the markets. The research
team used agronomic modelling tools to simulate
the adaptations a Niger millet grower can make.
These produced assessments of the expected
long-term benefits of climate forecasts on farm
yields. It was based on 18 years of climate forecasts, from 1990 to 2007. It tested several scenarios depending on the accuracy of forecasts and
of information supplied to farmers. The result
was that even with the low level of detail provided
by the current system, the crop yields can be
improved by nearly 7%. More refined data
allowing better adjustments to their strategy,
could help farmers increase these by 11%.
Moreover, incorporating an additional variable
such as the dates of the onset and end of the
rainy season, gains could reach 31% !
Contacts
Benjamin SULTAN,
researcher at the IRD
Tel: +33 (0)1 44 27 84 67
benjamin.sultan@ird.fr
Laboratoire d’océanographie et du climat :
expérimentations et approches numériques
- LOCEAN (UMR IRD / CNRS / MNHN /
Université Pierre et Marie Curie - Paris 6)
Address
Université Pierre et Marie CURIE
Case 100
4, place JUSSIEU
75252 Paris cedex 05
These results confirm the potential advantages
of fine-tuning forecasts and communicating the
predictions to farmers through the broadcasting
media and Internet, for the countries of the Sahel
included. Climate forecasts, combined with a
security net in the form of an agricultural insurance system*, could help farmers make sound
decisions for their crop growing schedules,
sometimes more risky but often more profitable
and no longer geared solely to subsistence
crops. In this way, they can substantially increase
not only their income but also the crop yields, at
the same time reducing the vulnerability of
communities to food insecurity. The research
team finds that such schemes could prove useful
for boosting agricultural development in West
Africa which will be explored as part of the ANR
ESCAPE4 project.
Philippe Roudier,
researcher at the Centre
international de recherche sur
l’environnement et le
développement
Tel: +33 (0)1 43 94 73 67
roudier@centre-cired.fr
Address
CIRED
Campus du Jardin Tropical
45 bis, avenue de la Belle Gabrielle
94736 Nogent-sur-Marne Cedex
Dr. Agali ALHASSANE
Centre Régional AGRHYMET
Tel: +227 20 31 51 81/20 51 53 16,
extension 241
A.Alhassane@agrhymet.ne
Address
BP: 11011, Niamey, Niger
Copy editor – Gaëlle Courcoux - DIC, IRD
Translation – Nicholas FLAY
References
roudier p., sultan benjamin, quirion p.,
baron c., alhassane a., traoré s. b.,
muller b. An ex-ante evaluation of the use
of seasonal climate forecasts for millet
growers in sw niger. International Journal
of Climatology, 2011.
doi: 10.1002/joc.2308.
B. Sultan, B. Barbier, J. Fortilus, S.M.
Mbaye and G. Leclerc. (2010) Estimating
the potential economic value of the
seasonal forecasts in West Africa: a
long-term ex-ante assessment in Senegal.
Weather, Climate and Society, 2, 69–87.
doi:10.1175/2009WCAS1022.1.
1. These investigations were conducted in partnership with researchers from CIRED, CIRAD and the Regional Centre of AGRHYMET
(Agriculture, Hydrologie, Météorologie), a specialized institution of the CILSS (Comité permanent inter-Etats de lutte contre la
sécheresse dans le Sahel) based at Niamey in Niger.
2. The zai technique is a traditional sowing method using small hollows in the ground where water accumulates.
3. PRESAO (Prévisions Saisonnières des pluies en Afrique de l’Ouest, Seasonal Forecast for West Africa) is an annual forum which
makes a forecast in May of the amount of forthcoming rain in West Africa for the period from July to September.
4. Environmental and social changes in Africa: past, present and future : www.locean-ipsl.upmc.fr/~ESCAPE
Key words
Agriculture, climate, economy, millet, Niger
*Did you know?
Taking more risks, for example by opting for cash crops like groundnuts here in Senegal, can substantially reduce West African farmers’ vulnerability.
© IRD / M. Dukhan
© IRD / J-P Montoroi
© IRD / Y. Paris
Agricultural insurance systems –guaranteeing compensation against a poor season and which encourages
farmers to take more risky but potentially more profitable decisions– have already yielded promising results,
for example in the emerging countries like India. This type of solution has not yet been applied in Niger, but
the World Bank is planning to set up such a scheme in Senegal.
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