The document presents a conceptual framework for linking soil biodiversity, water regulation, and agricultural production. It outlines a model that shows soil biodiversity has both productive value by increasing agricultural production and insurance value by decreasing production variability and protecting against risks. The results show that for areas with poor soil, small increases in soil biodiversity can lead to large gains in production and decreases in variability. The model also finds that farmers growing low water productivity crops are more likely to rely on soil biodiversity for its insurance benefits. Additionally, the framework suggests soil biodiversity management as a means of alternative water management and risk mitigation under climate change.

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A water-secure world
Linking soil biodiversity, water regulation and agricultural
production: a conceptual framework
Yoro Sidibe
International Water Management Institute
Sebastien Foudi (BC3), Unai Pascual (BC3), Mette Termansen (Aarhus University)

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A water-secure world
Outline of the talk
 Motivation
 Problem
 Result
 Policy recommendations and Conclusions

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A water-secure world
Motivation
Water management
Increase Agricultural production
Reduce productive Risks
Construct a more resilient agricultural system. Resilience
viewed “as the capacity to absorb extreme events”.
 Alleviate poverty
 Increase agricultural income
 Improve food security

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A water-secure world
Motivation
Management of water through large infrastructures:
Dams, Canals, Pumping stations, Etc.
Very often failure because of
- High costs
- Managerial difficulties
- No control of smallholder farmers
- Environmental impacts

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A water-secure world
Motivation
Idea: look into alternative sustainable and resilient
solutions
These alternatives solutions do not need to conflict with large
scale infrastructures but complement and optimize their use.
EcoFinder project + Africa RISING project :
What role can soil biodiversity play in agricultural production?
What soil biodiversity conservation strategy in a changing climate?

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A water-secure world
Problem
Is it possible to conceptually show the role and value of soil
biodiversity (through soil water regulation)?
What value does soil biodiversity have (production and
insurance) ?
How to adaptively use soil biodiversity to climate change?
Questions answered with a simple modeling approach

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A water-secure world
Problem
Climate Soil Biodiversity Production Economy

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A water-secure world
Problem
Biodiversity rich soil
Biodiversity poor soil

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A water-secure world
Problem
The model
Economics
Climate Bio-Soil Water Crop
Assumption Variable rainfall Biodiversity
shape soil
Water
dynamics
depends on soil
Production
depend on
water
Model
Economic
Assumption
Rational farmer ( Risk averse)
Economic
Model

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A water-secure world
Results
What is the impact of soil biodiversity on average
production ? (productive value)
0
1
2
3
4
5
6
7
8
0 2 4 6 8 10
Averageproduction
Soil Biodiversity
Production
Production

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A water-secure world
Results
What is the impact of soil biodiversity on average
production ? (productive value)
0
1
2
3
4
5
6
7
8
0 2 4 6 8 10
Averageproduction
Soil Biodiversity
Production
Production

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A water-secure world
Results
What is the impact of soil biodiversity on average
production ? (productive value)
 Soil biodiversity has a production value
 For areas with poor soil, a small increase in soil biodiversity
can result in large increases in agricultural production

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A water-secure world
Results
What is the impact of soil biodiversity on production
variance ? (insurance value)

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A water-secure world
Results
What is the impact of soil biodiversity on production
variance ? (insurance value)

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A water-secure world
Results
What is the impact of soil biodiversity on production
variance ? (insurance value)
 Soil biodiversity has a an insurance value up to a certain
level.
 For areas with poor soil, a small increase in soil biodiversity
can result in large decreases in agricultural production
variability.
Soil biodiversity can be important in protecting against risks
in areas with poor agricultural insurance services.

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A water-secure world
Results
What is the optimal biodiversity decision of a rational
farmer?
 Farmers growing crops with high water productivity are
more likely to rely on soil biodiversity for its productive use.
 Farmers growing crops with low water productivity are
more likely to rely on soil biodiversity for its productive and
insurance use.
Solution

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A water-secure world
Results
What is the effect of climate change on biodiversity
conservation strategy?
0
5
10
15
20
25
30
35
40
45
50
0 0.2 0.4 0.6 0.8 1
SoilBiodiversity
Drought frequency
λ=0
λ=0,01
λ=0,03
λ=0,05

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A water-secure world
Policy recommendations and Conclusions
 Promote on land soil management (through biodiversity) as a
significant alternative way to manage water.
 Promote soil biodiversity management as risk management tool
in areas with poor insurance services.
 Modulate the intervention strategies according to exogenous
factors (climate, soil, risk aversion) etc.
 Empirical investigation is still to be done to provide quantitative
recommendations beyond the qualitative results presented
here.

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A water-secure world
Thank you for your attention