Can flexibility be built into cropping systems for adapting to climate uncertainty? - Darshan Sharma


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Can flexibility be built into cropping systems for adapting to climate uncertainty? - Darshan Sharma

  1. 1. Can flexibility be built into cropping systems for adapting to climate uncertainty? (practical, on ground, farming systems) Presenter: Darshan Sharma Centre for Cropping Systems Northam, WA This project DAW00202 'Demonstrating adaptation to climate change in the wheatbelt of Western Australia through innovative on-farm and virtual farm approaches' is funded by the Department of Agriculture and Food, Western Australia , the Grains Research and Development Corporation and the Australian Government's Climate Change Research Program . WA DAFWA Team: Caroline Peek, Glen Riethmuller, David Bowran, Doug Abrecht, Geraldine Pasqual, Meredith Fairbanks, David Gray,
  2. 2. <ul><li>Leon C. Megginson (1963) </li></ul><ul><li>(Professor of Management and Marketing at Louisiana State University at Baton Rouge) </li></ul><ul><li>‘ According to Darwin’s Origin of Species, it is not the most intellectual of the species that survives; it is not the strongest that survives ; but the species that survives is the one that is able best to adapt and adjust to the changing environment in which it finds itself.’ </li></ul><ul><li>- implies flexibility would win under variable env </li></ul><ul><li>- but opens the challenge: </li></ul><ul><ul><li>how can cropping systems be adjusted to changing climate? </li></ul></ul>
  3. 3. Background
  4. 4. Background Challenge How to adapt farming system to ± ? We agree Climate is changing/changed In most of the Southwest of WA Temperature:  ± Rainfall : ↓ ± Source: IOCI
  5. 5. Hypothesis
  6. 6. Hypothesis <ul><li>Flexibility in cropping systems by: </li></ul><ul><li>Growing a variety that exhibits desirable plasticity/stability of yield components </li></ul><ul><li>Strategically structured plant populations to maximise crop buffering </li></ul><ul><li>Population control where farmers could kill a part of the crop under water deficient conditions </li></ul>
  7. 7. Rationale
  8. 8. 1. Plasticity/Stability <ul><li>Wheat Grain yield = </li></ul><ul><ul><li>Number of grains/spike X Mean Grain weight X Number of spikes/area </li></ul></ul><ul><ul><li>Some varieties are more plastic for some traits than others. </li></ul></ul>Spike size change : Grain weight change e.g. Eagle Rock is more stable for Grain weight while Carnamah is more plastic for Grain weight
  9. 9. 2. Population structure <ul><li>Mix the seed of different varieties to build buffering capacity </li></ul><ul><li>Varietal blends have been used to buffer disease resistance </li></ul><ul><li>Wheat blends may also offer a small yield advantage even in the absence of severe stress…. Gallandt et al (2001); Cowger and Weisz (2008) </li></ul><ul><li>We think, carefully devised varietal mixtures can be used to stabilise yield against seasonal uncertainty- such as frost, end of season drought, good spring rains </li></ul>
  10. 10. for example- Population structure <ul><li>Say, </li></ul><ul><ul><li>4t/ha anthesis Biomass ~ 2.4t/ha gy potential </li></ul></ul><ul><ul><li>20mm post-frost R/F ~ 3 additional filling days </li></ul></ul><ul><ul><li>4% grain fill/day </li></ul></ul><ul><li>Additional grain Mixture ~ 3 times </li></ul>
  11. 11. 3. Population control High plant density may reduce grain yield in rapidly warming and drying conditions.
  12. 12. <ul><li>BUT there are reasons to start with high plant density </li></ul><ul><li>Optimum plant density- changes with season </li></ul><ul><li>High plant density- good for weed control </li></ul><ul><li>High seed rate- good for uncertain crop establishment </li></ul><ul><li>High plant density- good for early wind erosion </li></ul><ul><li>High plant density- good for wider rows (what works for crop, also works for weeds) </li></ul><ul><li>As such, Growers would often wish if some plants could be sacrificed LATER in the season according to latest weather forecast for remainder of the season! </li></ul>
  13. 13. We think, Shandying herbicide tolerant and intolerant varieties- a possible option to create an EXTRA decision point that MAY be used LATER in the season Photograph by: Harmohinder Dhammu Tolerant + Intolerant + Spray = Half the population
  14. 14. Conclusion
  15. 15. Conclusions <ul><li>Flexibility of cropping systems for adapting to climate uncertainty seems achievable. </li></ul><ul><li>Some technologies for adapting to climate change are already there but need objective testing within the emerging farming systems . </li></ul>