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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