Soutenance pour l'habilitation à diriger les recherchesUniversité Pierre et Marie Curie, UFR des Sciences de la Terre

Benoît GABRIELLEChargé de Recherche

UMR INRA INA P-G

Environnement et Grandes

Cultures

20 Janvier 2006

L'évaluation environnementale des

agrosystèmes:

une approche intégrée pour gérer les

risques agri-environnementaux

2

Context - 1

A growing demand for agricultural produce...

Tilman et al., Agricultural sustainability and intensive production practices, Nature 418: 671-677, 2002

2050

4.0

(109 t

onne

s)

2010

Bio-fuels in EuropeDirective 2003/30 EC

3

Context - 2

...currently met with increased reliance on exogenous inputs...

b: total global use of N and P fertilisers, and area of irrigated land

c: global pesticide production and imports

(Tilman et al., 2002)

4

Context - 3

...albeit with decreasing marginal efficiency

“Pest control methods with a potential efficiency of 100% raise an issue of durability for agricultural practices [...] similarly to the problem of antibiotics becoming less effective in medicine.” (INRA-Cemagref, Joint expertise report on Pesticides, Agriculture and the Environment, 2005)

(Tilman et al., 2002)

5

Context - 4

Agriculture is being pointed out as a major source of

negative environmental impacts

IFEN,6th report on water quality inFrance (2004)

6

Context - 5

Potential impacts from agriculture

CO2

Groundwater

NO3

Fertilizers (N)Pesticides

SolSoil organicmatter

N2O, NO,NH3,Pesticides

Eutrophication

Global warming

Air pollution

Ecotoxicity

Pesticides

Acidification

7

An unresolvable quandary ?

Humans have made unprecedented change to ecosystems in

recent decades to meet growing demands for food, fresh water,

fibre and energy.

Various techniques being used increasingly in various parts of

the world allow [...] productive use of land while keeping

favorable conditions for nature.

The approach taken by the Millenium Ecosystem assessment

could provide a useful tool to enable decision-makers to

understand far better the full consequences of their action.

MILLENIUM ECOSYSTEM ASSESSMENT – UNLiving beyond our means: natural assets and human well-being – Statement of the Board

8

Methodology for environmental assessment

Need for integrated assessment, across

Compounds and environmental compartments

Elementary parts of a production chain

Time

A spatial territory relevant to the production or

environmental issue at stake

To avoid or manage trade-offs between

Environmental issues

Geographical locations

Generations !

9

Managing a production chain versus a territory

?

10

The 'functional' side: life cycle assessment (LCA)

LCA, a conceptual framework to address environmental impactsfrom the 'cradle to the grave'

Renewable carbonFertilizersPesticides

Inputs:

Outputs:CO2, CH4, NOx

Fossile carbonOther fossile resources

Products et co-products

NO3-, N20... Pesticides

In agriculture, LCA was applied to waste management, cropping systems analysis, and bio-energy chains.

11

Estimation of fluxes

Outputs

Inputs

Emissions

InputX

Indirect emissions

E = a X +/-

Industry

Direct emissionsE within several

orders of magnitude!

InputX

Agriculture

PerturbationsE = f(soil, climate , managt, X)

12

Capturing the spatial variability of field emissions

Gabrielle, Laville, et al. (submitted to Global Biogeochem. Cycles)

Simulation ofN

2O fluxes in the

Beauce region(fluxes in kg N

2O-N/ha/yr)

13

Environmental balance models – example of CERES

Atmosphere

Soil

mineral N organic N

SOIL TRANSFERS Heat (Fourier) Water (Tipping bucket) Nitrate (Convective)

absorption

C-N BIOTRANSFORMATIONS Mineralisation - Immobilisation

Nitrification - Denitrificationdrainage,nitrate

leaching

PLANT PROCESSES Phenology Ressource capture PartitioningSenescence

crop residues

Groundwater

CO2, N

2O,

NH3, NO

14

Challenges wihtin the modelling loop

Experiments

Integration into model; calibration

detailed

lighterProcess analysis

Extrapolation

Model application

Moduleselection

15

Challenges wihtin the modelling loop

Experiments

Integration into model; calibration

detailed

lighterProcess analysis

Extrapolation

Model application

Moduleselection

16

Integration of nitrous oxide emissions

Simulation by CERES with two different N2O emission modules

Gabrielle, Laville, et al., Nutr. Cycling Agroecosys. (in the press)

Haplic calcisol

Redoxic luvisol

Haplic luvisol

--- Simulated o Observed

17

Challenges wihtin the modelling loop

Experiments

Integration into model; calibration

detailed

lighterProcess analysis

Extrapolation

Model application

Moduleselection

18

The 'eco-balance' experiment

19

Challenges wihtin the modelling loop

Experiments

Integration into model; calibration

detailed

lighterProcess analysis

Extrapolation

Model application

Moduleselection

20

Extrapolation to new sets of soils and climates

21

Challenges wihtin the modelling loop

Experiments

Integration into model; calibration

detailed

lighterProcess analysis

Extrapolation

Model application

Moduleselection

22

Model application: scenario analysis

Oilseed rape / wheat / barley crop rotation, on a rendzina soil (Indre)Data averaged over 30 years

ManagementScenario

Reduced inputs

“Sound” (Raisonné)

Business as usual

Fertiliser N dose

(kg N/ha)

Mean grainyield

(tonnes / ha)

Emissions in g N per tonne of wheat grain produced

Nitrate N2O NH

3

150

210

120

8.7

7.8

8.3

10.5

7.5

8.5 2.9

2.9

3.7

18.0

24.1

15.3

23

Is there really room for improvement ?

Technological “fixes” at the field-scale

Optimising fertiliser N applications (including variable-rate within

agricultural field)

Selection of crop rotations (eg, legume crops)

Introduction of new genotypes (eg, herbicide-tolerant)

Displacement of fossile resources (bio-energy, 'green chemistry')

Agricultural recycling of urban waste

24

Benefits of herbicide-tolerant crops ?

Calculated impacts on various environmental or population targets for rotations with or without herbicide-tolerant, genetically modified crops in Dijon.(Mamy, 2004)

25

Recycling of urban waste

Simulation of soil C variations inplots amended withurban waste composts(Gabrielle, Da Silveira, Houot, Michelin,Agric. Ecosys. Environ., 2005)

MSW: municipal solid wasteBIO: biodegradable wasteGWS: green waste + sludgeFYM: farmyard manure+N: complemented with fertilizer N

Integration into life cycle assessment of waste management Landfilling Incineration Composting Of which

field emissions

-5

0

5

10

15

20

25

Global warming (x100 kg eq. CO2)Acidification (g eq. H+)Eutrophication (g eq. phosphate)

26

Potential benefits on soil quality

Compost application may improve the structural

stability of soils (Annabi, 2004), and mitigate runoff

and erosion risks in loamy soils.

How to incorporate such qualitative impacts in life-

cycle assessment?

Pic

ture

s by

Y. L

e B

isso

nnai

s

27

Room for improvement? Maybe make room bigger....

Technological “fixes” at the field-scale

Cropping systems approach

Identification of 'best management practices' tailored to local

conditions

At the farm or production basin level

Optimal allocation of land use and agricultural inputs

Optimisation of nutrients and carbon flows (especially in livestock

systems)

Rural engineering

28

Territorial approach opens up new horizons

The introduction of new productions entails changes in

Physical and biogeochemical fluxes in local environment

Cropping systems management

Economic revenues and farm management

Organisation of labour, logistics, ...

Perception of agricultural activities by local stakeholders

29

Future research and problematics

Integration of environmental assessment with other

disciplines (agronomy, economics, social sciences)

To internalize determinants of agrosystems management

(including land use)

Also, internalize environmental impacts in the selection of

management strategies

Modelling (and experimenting)

To generate spatial distributions of input parameters, and validate

regional estimates

Long-term trends from repeated applications

Gaseous emissions (and depositions)

Encompassing ecological issues that can hardly be

tackled by flux-based methods (eg, soil quality)

30

Linking of bio-physical and economic models

Soil types

'Typical' farm

Environmental balance model

Micro-economicmodel

Agronomic scenarios(crop rotations,fertilization,decision rules, ...) N losses,

crop yields

Optimal management

Input costs,market prices, taxation, incentives, etc...

Profits,social costs

Environmentalperformance atterritorial level

31

Example: efficiency of agri-environmental measures

Profit associated with the optimal combination of nitrogen inputs reduction and soil vegetation cover under nitrate leaching constraint for a typical arable farm of Champagne-Ardennes. (Hardelin, J., Master's dissertation, 2005)

50

100

150

200

250

25,5

85 24 22 20 18 16 14 12

Nitrate leaching level (kg N per ha)

Fa

rm p

rofi

t (€

pe

r h

a)

PRAITERRE project, coordinated by G. Lemaire (INRA Lusignan), and funded for 2006-2008.

32

Large-scale simulations of N gas emissions:

Nitro-Europe

Integrated Project coordinated by M. Sutton (CEH Edinburgh), and funded under the 6th EU FP for 2006-2010.

WP 4NEU Landscape

Analysis

WP 3 NEU Plot Scale

Modelling

WP 2 NEU Ecosystem

Manipulation

WP 1 NEU

Flux NetworkWP 5

NEU EuropeanIntegration

WP 6 NEU Verification

& Reliability

CarboEurope IP plus other EU & national activities

33

Bio-energy, a model frame-work for assessment ?

Regional case-studies and chain implementation may be provided by

the R&D Cluster on Agro-Resources (in Picardie-Champagne-

Ardennes)

With support from national and European programmes (BioEnergy

Network of excellence)

Life cycle assessment may be

implemented at supply basin level,

Thereby integrating land-use change

and territorial impacts

(tentative Ph.D. Programme with INRA Laon/Reims/Mons),

With links to other sustainability indicators: economic, social,

ecological (UT Troyes)

34

Conclusion: challenges ahead

From a scientific perspective

Develop bio-physical models for environmental

assessment

Broaden the scope of the assessment and tackle

territorial impacts

...and from a personal perspective

Foster collaboration with thematically- or

geographically-distant groups

Entrust work to students (graduates or post'docs) and

colleagues

35

Merci à tous !

36

Lecture Outline

Context and issues

Méthodologie de l 'évaluation intégrée

Exemples de résultats

Conclusion: vers une approche systémique

37

A range of available methods

Physical variability (soil, climatic zone)

Methods based on cropping practices

Methods based on fluxes of matter and energy

SIRIS ranking;IDEA

INDIGO

Tem

po

ral

vari

abil

ity

Static

Mean environment

Local environment

Agri-environmental indicators

Static

Dynamic

Life cycle assessment

38

Why use biophysical models ?

0

1

2

3

4

5

6

7N

ote

d'im

pact

Oilseed rape Sugar Beet Maize

Châlons

Toulouse

DijonChâlons

Toulouse

DijonChâlons

Dijon

Impacts on “fresh water” target, across soil and crop types (model-based)

Ph. D. thesis by L. Mamy, 2004

GM cropnon-GM crop

Low risk7

0

2

4

6

8

10

Châlons

Toulouse

DijonChâlons

Toulouse

DijonChâlons

Dijon

Values of indicator I-Phy for the chemical weeding of GM and non-GM crops

39

Application to natural systems: a source of controversy

LCA of bio-diesel from oilseed rape

N2O

emission

kg/ha/yr

NH3

emission

kg/ha/yr

NO3

leaching

kg/ha/yr

Report by

IFEU/UBA

1992-Germany

~3 0 ~70

Report by

Ecobilan

1993-France

~0.3 0 negligible

« Ecobalance of

oilseed rape»

1996-INRA

~0.1 13 8

40

From field to production system: PRAITERRE

Typology and drivers of farms

Impact assessmentEconomic functions

Pilot farmsSupport for innovations

Adoption of innovations

Impact assessmentEconomic functions

Posterior models Simulation of future environmental impacts Economic analysis

Impact assessmentEconomic functions

Prior modelsSelection of

suitable innovationsAgri-

environmental engineering

Innovative systems design

Project coordinated by G. Lemaire (INRA Lusignan), and funded for 2006-2008.

41

Using straw for combined heat and power production

Global warming impact of one litre of bio-ethanol produced with either pure natural gas or 50% wheat straw. Direct emissions (field)are estimated with a biophysical model, including climate variability.

42

Eat local: common sense or real progress?

Life cycle impacts of the production of one litre of milk produced by cows fed with locally-produced oilseed rape cake or imported soymeal.(Lehuger, S., Master's dissertation, 2005)

0

20

40

60

80

100

Ressou

rces

Effet d

e se

rre

Couche

d'ozo

ne

Tox. h

umaine

Ecoto

x. Aqu

a.

Ecoto

x. Aqu

a. mar

ine

Ecoto

x. te

rrestr

e

Pol. p

hotoch

imiqu

e

Acidific

ation

Eutro

phisa

tion

%

Soja

Colza ITK céréalier

Colza ITKlaitier

Colzamoyen

43

Research issues in a nutshell

Modelling (and experimenting)

Long-term trends from repeated applications

Gaseous emissions (and depositions)

Generating spatial distributions of input parameters,

and validating regional estimates

Encompassing ecological issues that can hardly be

tackled by life cycle assessment (eg, soil quality)

Expanding physical system to internalize

management rules