Division Afrique Enhancing integrated soil fertility management through the carbon market to combat...

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)


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


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


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


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%


III. More productive, remunerative and sustainable agriculture through ISFM

maize crop establishment

maize at end of cycle

Control ISFM

Control ISFM


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.


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


• 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


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


V. Contribution of C-sequestration

Carbon credits, a small contribution to soil investments

C-sequestration in crop- , range- and forest land


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 )


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;


VI. ISFM x C-sequestration in practice

Strategic site selection, a private and a public angle of incidence

Public angle of incidence

ISFM options


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!


Agroforestry, an ISFM option


Thank you for your attention.

Division Afrique Enhancing integrated soil fertility management through the carbon market to combat...

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