Similaire à Dieter Nill "20 years of watershed management in Niger: Approaches, impacts and economic aspects of large scale soil and water conservation measures"
Similaire à Dieter Nill "20 years of watershed management in Niger: Approaches, impacts and economic aspects of large scale soil and water conservation measures" (20)
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Dieter Nill "20 years of watershed management in Niger: Approaches, impacts and economic aspects of large scale soil and water conservation measures"
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
Sector Project „Sustainable Agriculture" Page 1
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.
Sector Project „Sustainable Agriculture" Page 2
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.
Sector Project „Sustainable Agriculture" Page 3
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.
Sector Project „Sustainable Agriculture" Page 4
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).
Sector Project „Sustainable Agriculture" Page 8
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.
Sector Project „Sustainable Agriculture" Page 11
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.
Sector Project „Sustainable Agriculture" Page 12
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.
Sector Project „Sustainable Agriculture" Page 13
14. Thank you very much for
your attention!
Sector Project „Sustainable Agriculture" Page 14