Marco Bindi and Jørgen E. OlesenDept. of Plant, Soil and Environmental Science - University of Florence

Piazzale delle Cascine 18 - 50144 Firenze, Italy. Email: marco.bindi@unifi.itDept. of Agroecology and Environment – Aarhus University, Blichers Allé 20, P.O. BOX

50, DK-8830 Tjele, Denmark. Email: JorgenE.Olesen@agrsci.dk

Agro2010 – Montpellier

S3.2.2: Cropping systems which aim at improving resource efficiency and at reducing the emission of greenhouse gases

Cropping systems

Climate Change

GHGsconcentration

Interactions between Climate change and Cropping systemsInteractions between Climate change and Cropping systems

Emissions

• RUE and WUE• Suitable area for cultivation• Length of growing season• Availability of water for irrigation

• RUE and WUE• Suitable area for cultivation• Length of growing season• Availability of water for irrigation

• CO2 from microbial decay or burning of plant litter and soil organic matter

• CH4 from stored manures, and from rice grown

• N2O from microbial transformation of nitrogen in soils and manures

• CO2 from microbial decay or burning of plant litter and soil organic matter

• CH4 from stored manures, and from rice grown

• N2O from microbial transformation of nitrogen in soils and manures

(Feedbacks)

(Feedbacks)

from FARfrom FAR--IPCC WGI for 2100: IPCC WGI for 2100:

•• Atmospheric COAtmospheric CO22 concentration: concentration: from 550 from 550 ppmppm (B1) to 950 (B1) to 950 ppmppm(A1F)(A1F)

•• Mean Temperatures:Mean Temperatures: increases increases from 1.8from 1.8ººC (B1) to 4.0C (B1) to 4.0ººC (A1F)C (A1F)

•• Total rainfall: Total rainfall: small increase over small increase over lands (lands ( in most subtropical in most subtropical land regions, land regions, high latitude and high latitude and tropical Pacific)tropical Pacific)

•• Increases in extreme eventsIncreases in extreme events::•• Heat wavesHeat waves

•• Precipitation intensityPrecipitation intensity

•• Dry spells Dry spells

Predicted Climatic changes affecting cropping systemsPredicted Climatic changes affecting cropping systems

from FARfrom FAR--IPCC WGII: IPCC WGII:

•• ““ ……. . moderate warming (1moderate warming (1--33ººC) C) can have small beneficial can have small beneficial impacts on crop yields, but impacts on crop yields, but even slight warming decreases even slight warming decreases yields yields ……”……”

•• “…“…. . Increases in the Increases in the frequency and severity of frequency and severity of extreme climate eventsextreme climate events have have significant consequences for significant consequences for food crops in addition to food crops in addition to impacts of projected mean impacts of projected mean climate climate ……..””

Climate change impacts on cropping

systems

Climate change impacts on cropping

systems

from FARfrom FAR--IPCC WGIII: IPCC WGIII:

•• “…“…. for 2005, . for 2005, agriculture agriculture accounted for an accounted for an estimated emission of estimated emission of 1010––12% of anthropogenic 12% of anthropogenic emissions of emissions of GHGsGHGs::•• CHCH44 about 60%about 60%

•• NN22O about 50%O about 50%

•• COCO22 about 0.08%about 0.08%

•• ““ ……. without additional . without additional policies, policies, agricultural Nagricultural N22O O and CHand CH44 emissions are emissions are projected to increase projected to increase by by 3535––60% and ~60%, 60% and ~60%, respectively, to 2030respectively, to 2030””

Trends in GHGs emission from agriculture

Trends in GHGs emission from agriculture

Adaptation and mitigation strategies to cope with CCAdaptation and mitigation strategies to cope with CC

Crops

Climate Change

GHGs concentration

Strategies

Impacts

Emissions

– Adaptation strategies actions to alleviate the effects (e.g. improve crop management and increase water retention)

– Mitigation strategies actions on the causes (e.g. reduction CH4and NxO emissions, and increase CO2storage)

Adaptation strategies will aim to limit losses and exploit possible positive effects:

The economic strategies are intended to render the agricultural costs of climate change smallerThe agronomic strategies intend to offset either partially or completely the loss of productivity caused by climate change:

• short-term adjustment • long-term adaptation

Adaptation strategies: economic and agronomic

strategies

Adaptation strategies: economic and agronomic

strategies

Short-term adjustments first defence tools to optimise production with minor system changes through:

• The management of cropping systems:

• Changes in crop varieties (varieties with different thermal requirements, varieties given less variable yields)

• Changes in agronomic practices (sowing/planting dates)

• Changes in fertiliser and pesticide use

• The conservation of soil moisture:• Introduction of moisture conserving tillage methods

(minimum tillage, conservation tillage, stubble mulching, etc.)

• Management of irrigation (amount and efficiency)

Adaptation strategies: short-term adjustments

Adaptation strategies: short-term adjustments

Long-term adaptations complementary defence tools to optimise production via larger structural system changes:

• Changes in land allocation to optimise or stabilise production

• Development of “designer-cultivars” to rapidly adapt to climate change stresses (heat, water, pest and disease, etc.)

• Crop substitution to conserve soil moisture (e.g. sorghum is more tolerant of hot and dry conditions than maize)

• Microclimate modification to improve water use efficiency in agriculture (e.g. windbreaks, intercropping, multi-cropping techniques)

• Changes in nutrient management to reflect the modified growth and yield of crops

Adaptation strategies: long-term adaptations

Adaptation strategies: long-term adaptations

Effects of adaptation strategiesEffects of adaptation strategies

– Adaptations strategies(e.g. changes in planting, changes in cultivar, and shifts from rainfed to irrigated conditions) may allow to shift the temperature increase thresholds determining yield reductions from:

•0.5-1.5ººCC to 2.5-3ººCC in tropical regions

•1-3.5ººCC to 4.5 to 5ººCC in temperate regions

__ no adaptation __ with adaptationWGII, FAR-IPCC, 2007

Strategies for mitigating GHGs in agriculture fall into three broad categories:

– Reducing emissions: by more efficient management of carbon and nitrogen flows in agricultural ecosystems.

– Enhancing removals: through improved management, thereby withdrawing atmospheric CO2.

– Avoiding (or displacing) emissions: crops and residues from agricultural lands can be used as a source of fuel.

Mitigation strategies: reduction and sequestration of GHGs

Mitigation strategies: reduction and sequestration of GHGs

• Cropland management: Agronomy, Nutrient management, Tillage/residue management, Water management, Rice management, Agro-forestry, Set-aside, land-use change

• Grazing land management and pasture improvement: Grazing intensity, Increased productivity, Nutrient management, Fire management, Species introduction

• Management of organic/peaty soils: Avoid drainage of wetlands

• Restoration of degraded lands: Erosion control, organic amendments, nutrient amendments

• Livestock management: Improved feeding practices, Specific agents and dietary additives, Longer term structural and management changes and animal breeding

• Manure management: Improved storage and handling, Anaerobic digestion, More efficient use as nutrient source

• Bio-energy: Energy crops, solid, liquid, biogas, residues

Mitigation strategies: major category of measures

Mitigation strategies: major category of measures

Croplands offer many opportunities to impose practices that reduce net GHG emissions (intensively managed):

FAR-IPCC from Smith et al., 2007

Mitigation strategies: cropland management

Mitigation strategies: cropland management

• Agronomic practices: increasing yields and generate higher inputs of carbon residues (improved crop varieties; extending crop rotations; avoiding or reducing use of bare fallow)

• Nutrient management: improving N use efficiency (adjusting application rates, using slow- or controlled-release fertilizer forms or nitrification inhibitors, applying N just prior to plant uptake, placing the N more Precisely)

• Set-aside and LUC: often increases carbon storage and reduced N2O emissions from lower N inputs (e.g. from cultivated land to grassland)

0

1

2

3

4

5

6

CO2 CH4 N2O ALL GHG

tCO2‐eq/ha/y

Agronomy

Nutrient management

Set‐aside and LUC

0

1

2

3

4

5

6

CO2 CH4 N2O ALL GHG

tCO2‐eq/ha/y

Agronomy

Nutrient management

Set‐aside and LUC

cool-wet areas

warm-dry areas

FAR-IPCC from Smith et al., 2007

Mitigation strategies: cropland management

Mitigation strategies: cropland management

• Tillage/residue management:

• reduced- or no-till agriculture often results in soil carbon gain, while effect on N2O emissions depend on soil and climate

• residue management tends to increase soil carbon

• Water management: using more effective irrigation measures can enhance carbon storage in soils through enhanced yields and residue returns, but these may be offset by N2O emissions from higher moisture and fertilizer N inputs

• Agro-forestry: standing stock of carbon above ground is usually higher than the equivalent land use without trees

0

0.2

0.4

0.6

0.8

1

1.2

CO2 CH4 N2O ALL GHG

tCO2‐eq/ha/y

Tillage and residue mangement

Water management

Agro‐forestry

0

0.2

0.4

0.6

0.8

1

1.2

CO2 CH4 N2O ALL GHG

tCO2‐eq/ha/y

Tillage and residue mangement

Water managementAgro‐forestry

cool-wet areas

warm-dry areas

Ada

ptat

ion

mea

sure

Soil

eros

ion

cont

rol

Nut

rient

loss

re

duct

ion

Soi

l wat

er

cons

erva

tion

Gen

etic

di

vers

ity

Mic

rocl

imat

e m

odifi

catio

n La

nd u

se

chan

ge

Mitigation measure

Catch crops etc + + –

Reduced tillage + +

Residue management + + –

Extensification +

Fertiliser application +

Fertiliser type +

Rotation species + + +

Adding legumes + + +

Permanent crops + + – +

Agroforestry + + +

Grass in orchards, vineyards + + – –

Optimising grazing intensity +

Length and timing of grazing +

Grassland renovation +

Application to crops vs grassl +

Peatland management +

Adaptation and Mitigation strategies: inter-linkages

Adaptation and Mitigation strategies: inter-linkages

Most categories of mitigation options have positive impacts on adaptation:

Catch crops soil erosion and nutrient lossesReduced tillage soil erosion and soil water conservationRotation species soil erosion, nutrient losses, genetic diversityAgroforestry soil erosion, nutrient losses and microclimate modification

Quantitative inter-linkages are not very well explored

+ shows synergy– shows antagonism

from PICCMAT Project , 2008

Barriers that limit the adoption of adaptation and mitigation measures:

Adaptation and Mitigation strategies: barriers

Adaptation and Mitigation strategies: barriers

Uncertainties in the estimation of the potential adaptation and mitigation effects,

Absence of regulation or incentives for farmers

Lack of information and education at the local farm level

Interference with other regulations

Financial constraints (access to credits)

More permanent crop cover and less intensive soil tillage

Perennial crops to sequester carbon and reduce N2O emissions

Combination of bioenergy, feed (food) and biomaterial production

Diversity to improve resilience and increase carbon capture

Cropping systems with improved water use efficiency

Future cultivate field management based on: introdution

of adaptation and mitigation measures

Future cultivate field management based on: introdution

of adaptation and mitigation measures