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Application of the GIS-based EPIC model for the
analysis of water-food relations and policy
implications in China with a focus on winter
wheat
Hong Yang Junguo Liu Alexander Zehnder
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An overview of Chinas water resources
distribution and wheat production
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Chinas nine major watersheds
The HHH Region
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Wheat production in the HHH provinces,2004
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(No Transcript)
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Water resources and water use at the river basin
level 2002.
10 8 million m3
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(No Transcript)
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Questions to answer

• Fundamental question how can we use the limited
  water resources to meet the increasing wheat
  demand while protecting ecosystem/environmental
  sustainability?
• Direct questions
• How much water is used for wheat production?
• What are the water productivities of wheat in
  different regions and what are the major
  influencing factors?
• What would be the impact of changes (reduction)
  in irrigation water supply on wheat production?

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2. Development of GEPIC for the analysis of
water and food relations
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What is EPIC?

• Environmental Policy Integrated Climate (EPIC)
  developed by USDA-ARS and TAES (Texas
  Agricultural Experiment Station)

• Daily time step to simulate crop yield and crop
  water requirement by considering different factors

Climate
Irrigation
Tillage
Crop Growth
Hydrology
Erosion
Soil Temperature
Crop and Soil Management
Nutrient Cycle
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Flowchart of GIS-EPIC integration
(kg m-3)
m3 ha-1
ET
kg ha-1
Y
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Interface of GEPIC
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3. Application of GEPIC for the analysis of
water use in winter wheat production in China
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Testing the model performance, 2000
Spatial resolution 5 arc-minutes (approximately
8.3 km near the equator)
Rainfed winter wheat
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Simulated winter wheat water productivity under
rainfed conditions
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Simulated winter wheat water productivity under
irrigation
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Contribution of irrigation to wheat production
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Impacts of reducing irrigated water supply on
winter wheat production in the North China Plain
S1 Reduce irrigation depth S2 Reduce irrigated
areas
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4. Outlook of GEPIC applications
Socio-economic factors Population Food demand
Water- shed
Local
Country
Globe

• Environmental
• Policy
• Integrated
• Climate (EPIC)

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Thank you!
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Statistic and simulated winter wheat yield in
selected provinces, 2000
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Estimated irrigation depth