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Greening the Sahel:
improved technologies
for irrigated rice farming
 A
package of high-yielding rice varieties, integrated crop
management options and post-harvest equipment is
bringing new hope to the irrigated rice farmers in the
Sahel. The improved technologies, developed by the
Africa Rice Center (WARDA) and its national partners,
have doubled average rice yield in Mauritania and have
contributed more than $30 million to Senegal between
1995/96 and 2000/01.
Improved rice varieties
Access to appropriate varieties was a major constraint
to improving the production of irrigated rice in the
Senegal River Valley. To address this problem, WARDA
launched an initiative with national partners in Senegal
to make available productive and adapted varieties.
Following extensive evaluation with farmers, three new
varieties (Sahel 108, Sahel 201 and Sahel 202 with mean
yields of 6 to 7 t per ha on farmers’ fields) were
released in the mid-90s in the Senegal River Valley,
where the total area under rice cultivation is between
30 000 to 35 000 ha.
These varieties have become so popular with farmers that
the the proportion of the total area under the Sahel
varieties increased from 3% in 1995/96 to more than 70%
in 2000/2001. The total volume of paddy from the Sahel
varieties increased from about 3000 t to more than
115,000 t during the same period and accumulated revenue
gains from the Sahel varieties exceeded $30 million.
Recently, five new Sahel varieties were released in the
Senegal River Valley.
Postharvest technologies
In the irrigated rice systems of West Africa, threshing
and cleaning are manually carried out mostly by women,
who spend hours on these backbreaking operations. This
not only affects their health, but also the grain
quality and profitability of rice.
 The
Africa Rice Center in association with a wide range of
partners developed the ASI thresher-cleaner to address
these problems. Based on a prototype from the
International Rice Research Institute (IRRI), ASI has
gone through several adaptations to match the Senegal
River Valley conditions.
ASI has a threshing capacity of 6 tonnes of paddy rice
per day (compared to 2 tonnes for Votex—the other
widely used thresher) and grain-straw separation rate of
99%. It is not surprising, therefore, that over 250 ASIs
have been constructed in Senegal since its official
release and over 50% of the total paddy harvested in the
Senegal River Valley is now threshed with ASI, making it
the most widely used thresher in the area.
Its contribution was recognized in 2003 when the
President of Senegal presented the ASI team with the
‘Grand Prix du Président de la République pour les
Sciences’ — Senegal’s highest award for Science. The ASI
team includes the Institut sénégalais de recherches
agricoles (ISRA), the Société d’aménagement et
d’exploitation des terres du delta du fleuve Sénégal (SAED),
WARDA-Senegal, local manufacturers and farmers.
ASI’s popularity has grown so rapidly that it has now
spread to other countries in the region, and WARDA has
been collaborating with partners in Mali, Mauritania,
Ghana, Côte d’Ivoire and Burkina Faso to develop
appropriate prototypes. The Africa Rice Center, ISRA and
SAED are now using this ASI partnership model in an
alliance for a further development of rice harvesting
technology.
Integrated Crop Management (ICM)
The Sahelian environment is very complex and the
constraints and priorities within the same region vary
considerably as do farmers’ perceptions and knowledge
base. Realizing that irrigated-rice farmers need a wide
range of improved technologies from which to choose,
combine and adapt to suit their specific conditions, the
Africa Rice Center and its partners have introduced the
ICM approach that offers farmers ample flexibility and
autonomy.
As part of this approach, a wide range of improved
technologies that are still in the prototype phase are
made available to farmers and are then adapted to the
locally prevailing conditions through a progressive
integration process.
The ICM basket includes options for improved fertilizer,
weed, and water management, improved varieties and
efficient post-harvest technologies as well as
decision-making tools, such as optimum sowing date,
seeding and fertilizer rates and timing of fertilizer
application, based on crop modeling research. The ICM
technologies are fine-tuned in farmers’ fields, with a
high degree of farmer involvement in the adaptation
process.
To ensure the success of ICM in the long term, WARDA is
placing greater emphasis on the sustainable management
of the natural resource base, including maintenance of
soil fertility, avoidance of salinity build-up, and
biodiversity conservation.
WARDA scientists have found that farmers could
significantly increase productivity and profitability by
use of ICM. A major attraction is that the ICM
components emphasize better management of available
resources without significant increases in input levels.
Farmers in two study sites realized 60% and 85%
increases in yields and profits, respectively. On-going
and future research will emphasize the adaptation of the
technology options to the broad range of irrigated rice
production environments in sub-Saharan Africa.
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