division afrique enhancing integrated soil fertility management through the carbon market to combat...
TRANSCRIPT
IFDC Division Afrique
Enhancing integrated soil fertility management through the carbon
market to combat resource degradation in overpopulated
Sahelian countries
H. Breman, A. Gakou, A. Mando and M. Wopereis
IFDC-Africa (Lomé TOGO)
IFDC Division Afrique
I. Introduction
why C-sequestration as tool for more sustainable agriculture has a better chance of success than as goal in itself
how C-sequestration can be part of an enabling environment for more sustainable agriculture in the Sahel
Goal Explaining
why C-sequestration is a difficult task for Sahelian countries
IFDC Division Afrique
More productive, remunerative and sustainable agriculture through Integrated Soil Fertility Management (ISFM)
Contribution of C-sequestration
Overpopulation, a serious bottleneck for sustainable land use and C-sequestration
Structure
ISFM x C-sequestration in practice
IFDC Division Afrique
II Overpopulation, a serious bottleneck for sustainable land use and C-sequestration
Overexploitation = negative C-balance
Simple solution (= use of fertilizer) has limited accessibility
Overpopulation = overexploitation of natural resources
IFDC Division Afrique
Carrying capacity of agro-pastoral systems of Sahelian countries and their population density
zone carrying capacity 1) population density 1)
2)
North Sahel 1 0 – 12
South Sahel 11 12 – 46
Soudanian savannah
37 12 – 112
Guinea savannah 51 + 42
1) persons / km2 ; 2) in view of the 1985 density and a growth rate of 3%
IFDC Division Afrique
III. More productive, remunerative and sustainable agriculture through ISFM
maize crop establishment
maize at end of cycle
Control ISFM
Control ISFM
IFDC Division Afrique
ISFM improvement of crop yield and fertilizer profitability in West Africa.
farmer’s practices after 4 years of ISFM
cereal yield kg/ha
VCR fertilizers1)
cereal yield kg/ha
VCR fertilizers1)
maize; bush field
750 2 – 5 2) 2,750 4
maize; compound field
3,000 5 2) 4,600 12
sorghum 1,000 2 – 5 2) 1,800 8
cotton 1,150 5 2,000 8
irrigated rice 3,000 8 5,500 12
1) value incremental yield/fertilizer cost; 2) no fertilizer use by farmers; estimates, based on fertilizer recovery
data.
IFDC Division Afrique
IV. An enabling environment for change
Strategic site selection enables local change
ISFM more than technology
Improved socio-economic and policy environment enables general change
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• Criteria: isfm potential (not representativiness)
Strategic site selection: favorable conditions for fertiliser use
• isfm potential:
favorable soil and climate
irrigation systems
market access; reasonable prices
efficient transport and distribution
IFDC Division Afrique
Conditions to be fulfilled
• Socio-economic and policy environment, enabling
farmers to invest in their soil;
private sector to invest in input and output market development
• Functioning development triangle, effective cooperation between farmers’ organizations, the private sector and public services
IFDC Division Afrique
V. Contribution of C-sequestration
Carbon credits, a small contribution to soil investments
C-sequestration in crop- , range- and forest land
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Variability of above and below ground OM (t/ha dry matter) under different conditions in Sahelian countries Sahel Soudanian
SavannahGuineaSavannah 1)
SOM
well protected natural vegetation 27 54 106
exploited present vegetations 18 36 71
cropland and over-exploited rangeland 10 19 38
intensive and sustainable agriculture 18 37 37
above and below ground plant biomass
well protected natural vegetation 4 19 63
exploited present vegetations 3 15 55
cropland and over-exploited rangeland 2 9 25
intensive and sustainable agriculture 5 16 28
1) Careful ( limited data )
IFDC Division Afrique
The carbon sequestration potential of Sahelian coun
Sahel Soudanian Savannah
GuineaSavannah
improving cropland 1)
SOM 1 to 9 4 to 19 - 8 to + 7
roots 0.5 to 1 0.5 to 3 - 1 to + 5
above ground 0.5 to 1 0.5 to 3 - 4 to + 5
Total 1) 2 to 11 5 to 25 - 13 to + 19
improving range and forestland
SOM 5 10 20
roots 0.5 1 2
above ground 0.5 2 3
Total 6 13 25
1) two extremes, intensive agriculture based on annual crops, all trees eliminated from the fields to allow for tractor plowing, and agroforestry;
IFDC Division Afrique
VI. ISFM x C-sequestration in practice
Strategic site selection, a private and a public angle of incidence
Public angle of incidence
ISFM options
IFDC Division Afrique
ISFM production systems favorable for C-sequestration in dry West Africa with agro-ecological recommendation domains
fertilizer use, crop by-product recirculation and:
recommendation domain
semi-arid
improved fodder situation and range management
pastoral production
improved crop production and resources managem.
agro(-pastoral) production
sub-humid
perennial fodder banks pastoral production
leguminous fodder or perennial pastures 1)
agro(-pastoral) production
park land agro(-pastoral) production
1) in rotation with cereals and other crops!