1. 20 years of watershed management in Niger:
Approaches, impacts and eco­nomic aspects of
large scale soil and water conservation
Dieter Nill
Sector Project Sustainable Agriculture
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2. Context
 Man-made and natural conditions have caused severe land degradation
in the Sahel since the 60ies.
 Higher temperatures and heat waves.
 Declining and less reliable rainfall.
 Severe droughts especially during 70ies and 80ies.
 Demography increases (2-3 %) enhances pressure on land and
resources (deforestation, overgrazing).
 Progressive degradation: reduced vegetation
cover, increased runoff, wind- and water
erosion, decreasing ground water tables.
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3. Programme
 Funded by the Federal Ministry for Economic Cooperation and
Development - BMZ, GIZ / KfW/ Government of Niger have been
fighting desertification in the South of Niger for more than 20 years.
 Different soil and water conservation and restoration (SWC/R)
techniques applied to private and communal land.
 In 2010, more than 400,000 ha treated with
343 villages at a rhythm of 20.000 ha/year.
 Programme is one of the largest SWC/R
programmes of German Development
Cooperation worldwide.
 Objectives: Sustainable resource
management, food security, poverty
reduction.
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4. Approach
 Programme support only after active request and acceptance.
 A rolling approach to work with about 100 villages at the same time.
 Year 1: organizing villages, planning, pilot activities.
 Years 2 to 5: Intensive implementation.
 Years 5 and 6: Progressive shift of responsibilities to the villages.
End of support  autonomous villages.
 Population provides: free labour, local
materials and maintenance.
 Programme provides: training, basic tools and
material, trucks and tractor-ploughing of
plateaus.
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5. Techniques
• Stonebunds • Trenches • Nardi trenches
• Planting pits • Dykes • Half-moons
• Stonebunds
SWC mesures (Mulching, compost, (Planting of grass &
tree conservation) trees)
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6. Planting pits
Technics in fields
Stonebunds
Half-moons
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7. Plateaus Nardi trenches
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8. Results
Fields:
Millet grain yields more than doubled by using stonebunds, compost and/or
mulching (200  400 kg/ha) i.e. 200 kg/ha*yr more.
Straw increased by x1.6 (940  1.460 kg/ha) i.e. 520 kg/ha*yr more.
After 15 years of measurements, no decline in yield shows long-term
sustainability of the effects.
Plateaus:
Very harsh environment for vegetation.
Yields of herbaceous biomass from ~ 0 to 600/700 kg/ha*yr.
Production of wood generally around 1 stere/ha*yr.
Remark: Surplus straw production in the fields (520 kg/ha) equals around 80%
of the herbaceous production of plateaus (600-700 kg/ha).
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9. Unit costs (rounded figures)
Investment cost Population
Treatment
(FCFA/ha) (%)
Fields
Stonebunds (truck) 20.000 38 %
Stonebunds (donkey cart) 11.000 70 %
Planting pits 30.000 99 %
Plateaus
Half-moons + tree plantation 148.000 91 %
Nardi trenches + ripping +
79.000 54 %
grass + trees
10.000 FCFA = ~ $20 US or 15 €
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10. Annual benefit of different treatments
Fields Life Total Surplus Surplus Value surplus Annual
time annual cost grain straw grain + straw net
(yr) (FCFA/ha) (kg/ha/yr) (kg/ha/yr) (FCFA) benefit
(FCFA)
(1) (2) (3) (4) (5) (6) = (4) + (5) (7) = (6) – (3)
Stonebunds (truck),
15 13.406 225 1.035 43.200 29.800
manure
Stonebunds (truck) 15 10.846 86 396 16.512 5.700
Planting pits + manure 2 16.500 236 1.086 45.312 28.800
Plateaus Biomass Wood
(kg/ha) (stere/ha)
Nardi + ripping + grass
15 15.094 588 1,00 16.760 1.700
and trees
Forestry half-moons +
15 17.954 539 1,00 15.780 -2.200
tree plantation
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11. Economic results
 Stonebunds and planting pits yield high returns.
 Optimum economic use of investments on fields needs additional
agronomic measures.
 Planting pits limited by high labour input and short lifetime (2 yrs).
 Only small annual returns from the treatment of plateaus with nardi
trenches caused by high investment costs and low productivity.
 Half-moons in fields and on plateaus are not economically viable.
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12. Conclusions I
 Treatment of fields with simple stonebunds /planting holes and
manuring are low cost, profitable options, which can be applied at
large scale.
 Initial investment of 10.000 to 30.000 FCFA/ha (~ 20 to 60 $US)
produces annual grain surplus of 200 kg i.e. food for one person or
45 €/ha additional income.
 Large-scale treatment of sterile plateaus
offers low economic returns in terms of
fodder and wood production.
 Straw production in fields is more cost-
efficient than biomass production on
plateaus (1 ha of treated plateau equals
4 ha of fields)  fodder.
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13. Conclusions II
 Wood production can be substituted by agroforestry in the fields.
 Economically, SWC/R should therefore focus on fields.
 This does not mean that treatment of plateaus should be stopped but:
 Treatment of plateaus needs additional benefits i.e. protection of
infrastructure below, production of high value crops.
 Cost can be reduced by point-wise
treatment of plateaus.
 Plateaus might become water-
harvesting areas in future and
treatment is focusing on channeling
water to the fields below.
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14. Thank you very much for
your attention!
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