V. R. ReddyCrop Systems and Global Change Laboratory, Beltsville Agricultural Research Center, USDA-ARS, 10300 Baltimore Ave. Beltsville, MD 20705, USA

V. AmbumozhiInstitute for Global Environmental Strategies, Kansai Research Center, Kobe 651-00, Japan

K. R. ReddyDept. of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS 39762, USA

Achieving Food Security and Mitigating Global Environmental Change: Is there a role for Crop

Models in Decision Making?

Outline

• Past and future trends in population, food production and climate change perturbations

• Global environmental change and its impact on agriculture production systems

• Role of crop simulation models in addressing future food security and climate change

Issues of 21st Century, Particularly in Developing Countries

• Meeting food demands for the growing population

• Reducing the risks of soil and ecosystem degradation

• Minimizing the risks of eutrophication and contamination of natural waters

• Decreasing the net emissions CO2 and other greenhouse gases

Trends That Shape Our Future

Year

0 500 1000 1500 2000 2500

Pop

ulat

ion

in B

illio

ns

0

2

4

6

8

10

12

14

World Population

Trends, Signs and Signatures from the EarthPast, Present and Future World Population

56% 10% 50% 120%

-5% 42% 39%

Trends, Signs and Signatures from the EarthPresent and Future World Population Trends

Trends, Signs and Signatures from the Earth Global Major Foods – Per Capita Consumption

P= 67%, and A= 46%

Trends, Signs and Signatures from the EarthMaize - Production and Yield – Selected

Counties

Trends, Signs and Signatures from the EarthRice - Production and Yield – Selected Counties

P= 60%, and A= 55%

Trends, Signs and Signatures from the EarthRice - Production and Yield – Selected Counties

Cropland area Irrigated area Salinized area

----------------------------- Mha --------------------------------

China 124.0 54.4 (22%) 7-8 (14%)

India 161.8 54.8 (31%) 10-30 (50%)

USA 177.0 22.4 (13%) 4.5 -6 (15%)

USSR 204.1 19.9 (2%) 2.5-4.5 (21%)

World 1364.2 271.7 (21%) 62-82 (37%)

Percent change since 1985

Year 2000

Trends, Signs and Signatures from the Earth Cropland area, Irrigation and Salinization

S.G. Pritchard and J. S. Amthor, 2005

Trends, Signs and Signatures from the EarthPopulation, cereal yield, arable and irrigated

area, N use

Feeding 10 Billion Mouths

• We must develop the capacity to feed 10 billion people within in the next 40 to 50 years

• The average world current cereal yield is about 3 tons per ha for about 6 billion people

• We need about 4 tons per ha for 8 billion (33 % more than the current), and 5 tons per ha for 10 billion (67 % more than the current)

• Increase in the area of land under cultivation

• Displacement of lower yielding crops by higher yielding ones (done since the dawn of domestication)

• Efficiency of crop production in terms of:Per unit of land area (yield per ha)Per unit of timePer unit of inputs such as fertilizers, water and

labor etc.

Routes to Greater Food Production

Here comes the greatest challenge of our time,

The Global Climate Change

Trends, Signs and Signatures from the Earth

• Greenhouse gases (CO2, CH4, N2O etc.)

• Temperatures

• Glaciers, oceans and sea-levels

• Precipitation patterns and drought intensities

• Extreme events

• Higher ozone and UV-B radiation

Trends, Signs and Signatures from the EarthGlobal Carbon Emissions- Sources

Year

1750 1800 1850 1900 1950 2000

Mill

ion

me

tric

to

ns

of

carb

on

0

1000

2000

3000

4000

5000

6000

7000Total

Liquids

Solids

Gases

CementFlaring

Year

1750 1775 1800 1825 1850

Mill

ion

me

tric

to

ns

of ca

rbo

n

0

10

20

30

40

50

60

Trends, Signs and Signatures from the EarthGlobal Carbon Emissions and Carbon Fixation

Year

1700 1750 1800 1850 1900 1950 2000

CO

2 C

once

ntra

tion,

ppm

250

275

300

325

350

375

400

Trends, Signs and Signatures from the EarthAtmospheric Carbon Dioxide Concentration

Trends, Signs and Signatures from the EarthProjected Global Carbon Dioxide

Concentrations

CFCs are commonly used as refrigerants, solvents, and foam blowing agents. The most common CFCs are CFC-11, CFC-12, CFC-113, CFC-114, and CFC-115.

Global Warming and the Ozone Story

Global Warming Process Ozone Depleting Process

Period CO2 Methane Nitrous oxide

Chloroflu-rocarbon-11

Hydrofluro-carbon-23

Perfluro-methane

Pre-industrial concentration (1850)

about 280 ppm

about 700 ppb

about 270 ppb

zero zero 40ppt

Concentration in 1998

365ppm

1745ppb

314ppb

268ppt

14ppt

80ppt

Rate of change

1.5ppm/yr

7.0 ppb/yr

0.8ppb/yr

-1.4ppt/yr

0.55 ppt/yr

1 ppt/yr

Atmospheric lifetime

5 to 200

years

12 years

114years

45years

260Years

>50,000 years

Trends, Signs and Signatures from the EarthPast and current levels in global greenhouse

gas concentrations, rates of change and atmospheric lifetime

Trends, Signs and Signatures from the EarthFuture trends in global carbon dioxide concentration and associated climate change, if no interventions are made

Climate variable 2025 2050 2100

Carbon dioxide concentration

405-460 ppm

445-640 ppm

540-970 ppm

Global mean temperature change from the year 1990

0.4-1.1oC

0.8-2.6oC

1.4-5.8 oC

Global mean sea-level rise from the year 1990

3-14cm

5-32cm

9-88cm

Climate Change and Crop ProductivityCotton Photosynthesis – Solar Radiation

Climate Change and Crop ProductivityPhotosynthesis – Leaf Water Potential

Well-watered Water stressed

Climate Change and Crop ProductivityCotton Photosynthesis – UV-B Radiation

Climate Change and Crop ProductivityTemperature and CO2 – Rice Growth

Baker and Allen, 1993

Climate Change and Crop ProductivityTemperature and CO2 – Rice Yield

Baker and Allen, 1993

Climate Change and Crop ProductivityRice Growing Areas

Growing season temperatures from those locations listed inthe previous slide and with an additional 5°C added to thosetemperatures relative to optimum and marginal conditions

Sites

Te

mp

era

ture

, °C

15

20

25

30

35

40

Ambient temperature: 25.36°C = 8.26 t/haAmbient plus 5°C: 30.36°C = 5.51 t//ha, 33%

20 25 30 35 40

4-week old cotton seedlings

Climate Change and Crop ProductivityTemperature and Cotton Growth

Climate Change and Crop ProductivityTemperature and CO2 – Cotton Reproductive Growth

Fruit Production Efficiency

High Temperature Effects on CottonHeat-blasted flower buds and flowers

San Joaquin Valley, California

Climate Change and Crop ProductivityTemperature Effects on Crop Yield – Several Major Crops

Crop Topt, °C

Tmax, °C

Yield

at Topt, t/ha

Yield

at 28 °C, t/ha

Yield at 32°C

t/ha

% decrease (28 to 32 °C)

Rice 25 36 7.55 6.31 2.93 54

Soybean 28 39 3.41 3.41 3.06 10

Dry bean 22 32 2.87 1.39 0.00 100

Peanut 25 40 3.38 3.22 2.58 20

Grain sorghum

26 35 12.24 11.75 6.95 41

Climate Change and Crop ProductivityTemperature and CO2 – Rangeland C4 Grass –

Big BluestemVegetative Weight and Seed Weight

Day of the Year

0 50 100 150 200 250 300 350

Tem

pera

ture

, °C

0

5

10

15

20

25

30

35

40

Phoenix, AZ

Stoneville, MS

Maros, Indonesia

Long-Term Average Temperatures

Climate Change and Crop ProductivityPresent and Projected Temperature Changes

• Even though elevated CO2 provided greater protection from abiotic stress effects on vegetative and photosynthetic processes, the damaging effects of either high temperatures or elevated UV-B levels on reproductive process were not ameliorated by elevated CO2.

• There are no beneficial effects of elevated CO2 on reproductive processes in the crops investigated (cotton, bean, rice, sorghum and soybean).

• There are no beneficial interaction of temperature or UV-B on CO2 effects on reproductive processes.

• Higher temperatures and higher UV-B aggravated the damage on many reproductive processes.

Climate Change and Crop ProductivityConclusions – Temperature and CO2 Interactions

Provide quantitative description and understandingof biological problems

Help pinpoint knowledge gaps

Design critical experiments

Synthesize knowledge about different componentsof a system

Summarize data

Transfer research results to users

Why Do We Need Models?

Farm management (e.g. planting, irrigation, fertilization and harvest scheduling)

Resource management (e.g. several Govt. agencies and private comp. use)

Climate change and policy analysis

Production forecasts (e.g. global, regional and local forecasts)

Research and development (e.g. research priorities and guide fund allocations)

Turning information into knowledge (e.g. information overflow in every area including agricultural research)

Crop Model Applications for Natural Resource Management

Model MechanicsGOSSYM: Model Structure

PMAP

COTPLT

GOSSYM

CLYMAT

SOIL

CHEM

PNET

GROWTH

PLTMAP

OUTPUT

PIX

PREP

RUTGRONITROMATAL

DATESTMPSOL

FRTLIZ

ETUPTAKECAPFLONITRIF

RIMPED

ABSCISE

FREQ

RAINFERT

RUNOFF GRAFLO

Models needs to be robust as simple models can’t predict complex process.

Like any other system, models needs to be continuously updated as new information becomes available.

Models needs to be extensively tested across diverse environments, soil conditions and cultural practices.

Information feedback from scientists, farmers and farm managers needs to be taken for user-friendliness.

Mechanistic, process-level cotton simulation model - GOSSYM

Crop Model Applications for climate Change Scenarios – Case Study

Reddy et al., 2002

Crop Model Applications for climate Change Scenarios – Regional Emphasis

Doherty et al. 2003)

• Climate change has no boundaries, and can’t be viewed in isolation.

• We should consider other stresses on food production systems such as population dynamics, habitat destruction and fragmentation, land-use changes, biodiversity and invasive species dominance.

• The current and projected changes in climate are unprecedented, and the ecosystems including managed ecosystems such as agriculture may not cope with the changes projected in climate.

Climate Change and Crop ProductivitySome Considerations

• Except limiting the causes of climate change, there are no other long-term strategies.

• For a shorter-term, we must develop crop varieties which can withstand changes projected in climate to meet the growing demands for food.

• We must also develop models that provide adequate warning or guidance for policy makers to act proactively rather than reactively.

• Everybody and every nation should participate in the process, opportunities are there for everyone.

Climate Change and Crop ProductivitySome Considerations

We will be over 10 billion by 2050 in a much different climate

than what we have today

We need to produce enough goods and services in a

sustainable way

Thanks and any Questions?

Leading America towards a better future through agricultural research and information