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Global Change Impacts on Rice-Wheat Provision and the Environmental Consequences

Global Change Impacts on Rice-Wheat Provision and the Environmental Consequences. Peter Grace SKM - Australia Cooperative Research Centre for Greenhouse Accounting. Rice-Wheat Production Systems. Trends in Rice Yields. Trends in Wheat Yields. Reasons for Productivity Decline.

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Global Change Impacts on Rice-Wheat Provision and the Environmental Consequences

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  1. Global Change Impacts on Rice-Wheat Provision and the Environmental Consequences Peter Grace SKM - Australia Cooperative Research Centre for Greenhouse Accounting

  2. Rice-Wheat Production Systems

  3. Trends in Rice Yields

  4. Trends in Wheat Yields

  5. Reasons for Productivity Decline • Intensification-inefficient N use • Soil organic matter decline • Inappropriate water management • Soil structural decline • Micro-nutrient deficiencies • Pest and disease build-up • Narrow genetic base

  6. Reasons for Productivity Decline • Intensification-inefficient N use • Soil organic matter decline • Inappropriate water management • Soil structural decline • Micro-nutrient deficiencies • Pest and disease build-up • Narrow genetic base

  7. Reasons for Productivity Decline Intensification-inefficient N use Soil organic matter decline Soil structural decline Inappropriate water management

  8. Nitrogen Distribution in Rice-Wheat Outputs Inputs

  9. Environmental Impacts • Intensification-inefficient N use Leaching of nitrates to groundwater Greenhouse gas production - N2O

  10. Environmental Impacts • Soil organic matter decline Greenhouse gas production - CO2 + CH4

  11. Environmental Impacts • Inappropriate water management • Irrigation without adequate drainage • Groundwater rises Salinity (salt) and sodicity (Na)

  12. Environmental Impacts • Salinity (salt) and plants • Root water uptake reduced • Tolerance varies • Sodicity • Decreased microbial activity • Soils less permeable • Waterlogging • Run-off • Erosion • Lower plant available water contents

  13. Environmental Impacts • Inappropriate water management • Excessive irrigation Groundwater depletion Increased pumping - GHG production - CO2

  14. Groundwater Depletion

  15. South Asia - Water Use

  16. Environmental Impacts • Soil structural decline Waterlogging - GHG production - N2O + CH4

  17. CLIMATE CHANGE REDUCED GHGs IMPACT of climate variability on current production systems GHGs NEW PRODUCTION SYSTEMS MITIGATE further climate change CURRENT PRODUCTION SYSTEMS ADAPT to climate variability IMPROVED FOOD PRODUCTION

  18. Key Conclusions from IPCC TAR WG I • An increase in extreme weather event • Higher maximum temperatures & hot days • Higher minimum temperatures • More intense precipitation events • Increased summer drying and risk of drought • Increased Asian summer monsoon precipitation variability

  19. Climate Extremes

  20. South Asia Climate - GCM Outputs

  21. Asia - Simulated Rice Yields - ORYZA1

  22. Wheat • Losses of 1-1.5% yield/day occur with late planting after end November • Delay due to inability to sow • Late harvest of previous crop • Seedbed preparation

  23. Adaptation to Climate Change • Depends on region specific climate changes • Promote flexibility - traditional ecological knowledge • Avoid stress at critical growth stages • Adjustment of planting dates • Change cultivar

  24. Mitigation of Climate Change • Amount of residue retained • No and reduced tillage • Reduction in fallow periods • Flood reduction

  25. CLIMATE CHANGE REDUCED GHGs IMPACT of climate variability on current production systems GHGs NEW PRODUCTION SYSTEMS MITIGATE further climate change CURRENT PRODUCTION SYSTEMS ADAPT to climate variability IMPROVED FOOD PRODUCTION

  26. Global Warming Potential of Rice-Wheat Production Systems • Standard nomenclature • CH4 = 20 x CO2 • N2O = 310 x CO2 • CARBON EQUIVALENTS • CARBON to PRODUCTIVITY RATIO

  27. Rice-Wheat system - long-term trials (20 yr)

  28. Rice-Wheat system - long-term trials (20 yr) - remove and/or burn crop residues

  29. Rice-Wheat system - long-term trials (20 yr)

  30. Enhancing Rice-Wheat Provision-Conclusions • Improved agronomic management • New germplasm • Biodiversity

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