Cultivating biodiversity to transform African agriculture

Montpellier Panel side event Fara Science Week 2013

Etienne Hainzelin

Cultivating biodiversity to transform African agriculture

Increasing the production with a brand new vision of performance

1.Natural and cultivated ecosystems are not separated any more2.Biodiversity is the driving force of this ecological intensification 3.New paradigm and needs for research

Compared intensitivity of cropping systems (adapted from M. Griffon 2013)

Natural resources + functionalities

Inputs

Products / biomass

Positive externalities

Negative externalities

Conventionally intensified

farmingsystems

Natural resources + functionalities

Inputs

Products / biomass

Positive externalities

Negative externalities

Ecologically intensified

farming systems

Compared intensitivity of cropping systems (adapted from M. Griffon 2013)

2. Agrobiodiversity is the driving force for ecological intensification

To make the best use of natural resources, we need to maximize the biomass production, by intercepting throughout the year the most of solar radiation, CO2, N, … by:

• Optimizing plant functional biodiversity at different scales and revisiting plant breeding to adapt plants to complex association;

• Optimizing functional biodiversity at different scales regulating bio-agressors;

• Amplifying biogeochemical cycles in the soil, recycling the nutrients from deep profiles and increasing microbial activities.

Increased number of cultivated species

Optimizing plant functional biodiversity means complexification of cropping systems

Ex1. Complexification of cropping systems in

Mato Grosso (1980-2010)

Source: L. Seguy et al., (2009) La symphonie inachevée du semis direct dans Brésil centralhttp://agroecologie.cirad.fr/librairie_virtuelle

Increasing functional biodiversity to control bio-agressors

Push-pullNatural enemy

conservation

Resourceconcentration

Climate change

Barriereffects

Allelopathy

CycleruptureRoot

actionPlant

biomass

Plantdiversification

Reduced pest& disease impact

Tolerance to pests & diseases

Improved plant hydric& mineral nutrition

Soil suppressiveness

Porosity Mineralisation

Below ground soilbiota diversity/

activity enhancement

Ex 2. Increased plant biodiversity to control crop pests and diseases

Natural enemy conservation

Resourceconcentration

Climate change

Barriereffects

Allelopathy

Cyclerupture

Plant biomass

Plantdiversification

Reduced pest& disease impact

Tolerance to pests & diseases

Improved plant hydric& mineral nutrition

Soil suppressiveness

Porosity Mineralisation

Below ground soilbiota diversity/

activity enhancement

Push-pull

Source: The ICIPE push-pull Platform, http://www.push-pull.net/works.shtml

Chemicals secreted by desmodium roots inhibit attachment of striga to maize roots and cause « suicidal germination » of striga seed in soil

Allelopathic effect

Association of two rice genotypes to reduce Pyricularia incidence

Various intercropping systems of crops (flax, soybean, maize) in Gansu Province, China.

Maize/soybean/flax intercropping in Gansu Province, China

Wheat/maize strip intercropping in Gansu Province, China.

Wheat/maize intercropping practiced by local famers in Ningxia, Northwest China.

Li et al., 2013 Encyclopedia of Biodiversity 2nd Edition 382-395

Multiples examples of agroforestry

From planified associated cropping …… to complex agroforests

Integration orchards / goat or poultry

Integration rice/ducks, etc.

• By minimizing the loss of nutrients (leaching, erosion,…).

• By recycling the nutrients from deep soil profiles (deep rooting species, second crop at the end of the rainy season,…).

• By increasing microbial activities and stimulating the “rhizosphere” effects (biogenic structures).

Soil SolutionPermeases

Enzymesecretion

Soil Microorganisms

Low Mol. Wtcompounds

Intracellularenzymes

1. Energy2. C,N,S,P

Low Mol. Wtcompounds

Polymers(C,N,S,P)

Soil Mineral Surfaces

Extracellularenzymes

Soil Organic Matter

Permeases Enzymesecretion

Amplifying biogeochemical cycles

Credit: H. Saint MacaryAdapted from Quiquampoix & Burns 2007

Roots

The soil « engineers »

Unveiling the hidden agrobiodiversity in the soilThe functional traits of the soil organisms

(from E. Blanchard)

Functional groups

Micro-regulators

Engineers

Shredders

DecomposersN captors + Roots

Relationship with microorganisms and

formation of biogenic structures

- The importance of local context: shift from “ready-to-use” to “custom-made” cropping systems put the producers at the center of local innovation systems, to combine technologies and traditional knowledge.

- Agrobiodiversity, a key component of resilience, must remain accessible to small farmers, as a capital for future adaptation. In situ conservation of must be supported as a complement of ex situ conservation;

- Need for sectoral policies in favor of agrobiodiversity and sustainable intensification (access to market, payment of environmental services, etc.);

- The new roles for research: importance of basic knowledge on functional ecology; rethinking plant breeding; dealing with management of complex cropping systems and coping with multi-criteria performance; taking into consideration local knowledge and remain in strong personal interactions with agricultural realities.

3. New paradigm and needs for research

A Cirad collective book with 15 authors of different viewpoints and disciplines

Agrobiodiversity for sustainable development – Beijing June 2013