Nitrogen is essential to capture the benefit ofsummer rainfall for wheat in Mediterraneanenvironments of South Australia  ...
Climate gives rise to predictable types of ecosystems                                    Terry Chapin
Ryan et al. (2009) Advances in Agronomy 104:53-136
Background. Rainfall patterns as drivers ofcropping systemsWhat is the value of summer rainfall in regionswith winter-domi...
Three features of rainfall shapecropping systems     Amount     Seasonality     Size of events
Markham’s seasonality vectorWilliamson (2007)
Rainfall seasonality drives initial soil water                                                               maximum PAW =...
power laws describe size-structure of rainfall                          5                                (a)              ...
Size of rainfall events   Influence fate of water – evaporation, run-off, drainage                                     20 ...
Winter half yearWilliamson (2007)
SE Australia vs. Syria                       5                             (a)                                            ...
Ryan et al. (2009) Advances in Agronomy 104:53-136
Climate of SE Australia shares importantfeatures with those of the Mediterranean BasinAustralian wheat-based cropping syst...
Background. Rainfall patterns as drivers ofcropping systemsWhat is the value of summer rainfall in regionswith winter-domi...
Yield benefit from summer rainfall? Five trials @ Roseworthy, Hart, Spalding Seasons: 2009 and 2010 controls (background r...
Benefit from 20% for controls ~2 t/ha                              to 0 for controls ~6 t/ha                              ...
Background. Rainfall patterns as drivers ofcropping systemsWhat is the value of summer rainfall in regionswith winter-domi...
8000                                      control                                                                         ...
Cumulative               PAR interception (%)                              evapotranspiration (mm)                        ...
5 d after irrigation                    0                                             ***Soil depth (cm)                  ...
sowing                    0Soil depth (cm)                   -30                             control                   -60...
stem elongation                   0Soil depth (cm)                  -30                  -60                  -90         ...
flowering                    0Soil depth (cm)    -30                   -60                   -90                          ...
maturity                    0Soil depth (cm)    -30                                               *                   -60 ...
Residual water at maturity in N-deficient crops                                    Roseworthy, 2010                       ...
Grain number accounted for 88% of the variation in yield                8000                6000Yield (kg/ha)             ...
Grain number =          Grain number (per m2) and anthesis)                                            f (CGR between stem...
Variable                   0 mm    0 mm     +100mm   +100mm    P W PN P X                           Low N   High N    Low ...
Variable                   0 mm    0 mm     +100mm   +100mm    P W PN P X                           Low N   High N    Low ...
Variable                   0 mm    0 mm     +100mm   +100mm    P W PN P X                           Low N   High N    Low ...
Variable                   0 mm    0 mm     +100mm   +100mm    P W PN P X                           Low N   High N    Low ...
Variable                   0 mm    0 mm     +100mm   +100mm    P W PN P X                           Low N   High N    Low ...
N-driven trade-off between WUE and NUE                                                                    Nitrogen utilisa...
Summary1. Summer rainfall can contribute up to 20%   gains in yield of wheat in South Australia2. Yield gains are related ...
The trade-off is universal –    applies to maize in USA corn-belt                                                        N...
The trade-off is universal –     applies to rice in Philippines                                                           ...
Nitrogen is essential to capture the benefit of summer rainfall for wheat in mediterranean environments of South Australia...
Nitrogen is essential to capture the benefit of summer rainfall for wheat in mediterranean environments of South Australia...
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Nitrogen is essential to capture the benefit of summer rainfall for wheat in mediterranean environments of South Australia. Victor Sadras

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A presentation from the WCCA 2011 event held in Brisbane, Australia.

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Nitrogen is essential to capture the benefit of summer rainfall for wheat in mediterranean environments of South Australia. Victor Sadras

  1. 1. Nitrogen is essential to capture the benefit ofsummer rainfall for wheat in Mediterraneanenvironments of South Australia Victor Sadras, Chris Lawson Peter Hooper, Glenn McDonaldSouth Australian Research & Development InstituteHart Field Site, The University of AdelaideFunded by Grains R&D Corporation Brisbane, September 2011
  2. 2. Climate gives rise to predictable types of ecosystems Terry Chapin
  3. 3. Ryan et al. (2009) Advances in Agronomy 104:53-136
  4. 4. Background. Rainfall patterns as drivers ofcropping systemsWhat is the value of summer rainfall in regionswith winter-dominant rainfall?What are the physiological mechanisms involvedin the conversion of summer rainfall to yield?What is the role of nitrogen to capture the benefitof summer rainfall?
  5. 5. Three features of rainfall shapecropping systems Amount Seasonality Size of events
  6. 6. Markham’s seasonality vectorWilliamson (2007)
  7. 7. Rainfall seasonality drives initial soil water maximum PAW = 146 mm North-eastern environment South-eastern environment summer rainfall winter rainfall 50 (a) Emerald 50 (b) Horsham 40 median = 124 mm 40 median = 27 mm Frequency (%) 30 30 20 20 10 10 0 0 0 20 40 60 80 100 120 140 160 0 20 40 60 80 100 120 140 160 Plant available water at sowing (mm)Sadras & Rodriguez (2009) Australian J Agr Res 58:657-669
  8. 8. power laws describe size-structure of rainfall 5 (a) Horsham Emerald 4 = -3.1 log number of events 3 2 = -1.9 1 0 0.0 0.5 1.0 1.5 2.0 2.5 log size of event lowSadras -1.6 & Rodriguez (2007) Australian J Agr Res 58:657
  9. 9. Size of rainfall events Influence fate of water – evaporation, run-off, drainage 20 (a) Runoff (mm) 15 10 5 0 150 200 250 300 350 400 Seasonal rainfall (mm) 12 (b) Residuals (mm) 8 P < 0.0001 4 0 -4 2.8 3 3.2 3.4 3.6 3.8Sadras (2003) Australian J Agr Res 54:341-351
  10. 10. Winter half yearWilliamson (2007)
  11. 11. SE Australia vs. Syria 5 (a) Horsham 4 = -3.1 Tel Hadyalog number of events 3 = -3.0 2 1 0 0.0 0.5 1.0 1.5 2.0 log size of event
  12. 12. Ryan et al. (2009) Advances in Agronomy 104:53-136
  13. 13. Climate of SE Australia shares importantfeatures with those of the Mediterranean BasinAustralian wheat-based cropping systems matchthe systems that evolved over centuries in theMediterranean basinAustralian wheat-based cropping systems arenot ill-adapted European transplants
  14. 14. Background. Rainfall patterns as drivers ofcropping systemsWhat is the value of summer rainfall in regionswith winter-dominant rainfall?What are the physiological mechanisms involvedin the conversion of summer rainfall to yield?What is the role of nitrogen to capture the benefitof summer rainfall?
  15. 15. Yield benefit from summer rainfall? Five trials @ Roseworthy, Hart, Spalding Seasons: 2009 and 2010 controls (background rain) vs “summer rainfall” (+50 or 100 mm)Sadras et al (2011) European Journal of Agronomy, in press
  16. 16. Benefit from 20% for controls ~2 t/ha to 0 for controls ~6 t/ha measured modelledYield of crops with additional summer water supply (t/ha) 8 slope = 0.81 ± 0.097 slope = 0.75 ± 0.070 intercept = 1.4 ± 0.46 intercept = 1.7 ± 0.30 6 4 2 y=x y=x 0 0 2 4 6 80 2 4 6 8 Yield of controls (t/ha)
  17. 17. Background. Rainfall patterns as drivers ofcropping systemsWhat is the value of summer rainfall in regionswith winter-dominant rainfall?What are the physiological mechanisms involvedin the conversion of summer rainfall to yield?What is the role of nitrogen to capture the benefitof summer rainfall?
  18. 18. 8000 control ***Shoot dry matter (kg/ha) +50 mm +100 mm ** 6000 4000 *** 2000 GS 32 GS 65 GS 95 0 0 50 100 150 200 Days after sowing
  19. 19. Cumulative PAR interception (%) evapotranspiration (mm) 0 100 200 300 0 20 40 60 80 100 0 50 100Days after sowing 150 200
  20. 20. 5 d after irrigation 0 ***Soil depth (cm) *** -30 *** * * -60 ** ** * -90 control * +50 mm * +100 mm *** -120 *** 0 10 20 30 40 Soil water content (mm)
  21. 21. sowing 0Soil depth (cm) -30 control -60 * +100mm * -90 ** ** ** -120 ** 0 10 20 30 40 Soil water content (mm)
  22. 22. stem elongation 0Soil depth (cm) -30 -60 -90 control * * ** -120 ** 0 10 20 30 40 Soil water content (mm)
  23. 23. flowering 0Soil depth (cm) -30 -60 -90 * -120 ** 0 10 20 30 40 Soil water content (mm)
  24. 24. maturity 0Soil depth (cm) -30 * -60 -90 * -120 * 0 10 20 30 40 Soil water content (mm)
  25. 25. Residual water at maturity in N-deficient crops Roseworthy, 2010 0 maturity Soil depth (cm) -20 -40 low N -60 high N -80 -100 0 5 10 15 Soil water content (mm)
  26. 26. Grain number accounted for 88% of the variation in yield 8000 6000Yield (kg/ha) 4000 2000 bare ground, Exps 1, 2 stubble, Exps 1, 2 high H, Exps 3-5 r = 0.94 low N, Exps 3-5 P <0.0001 0 0 5000 10000 15000 20000 2 Grain number (per m )
  27. 27. Grain number = Grain number (per m2) and anthesis) f (CGR between stem elongation 20000 (c)Grain number (per m ) (b)2 P < 0. Low N 15000 10000 5000 bare ground, Exps 1, 2 stubble, Exps 1, 2 high H, Exps 3-5 r = 0.65 low N, Exps 3-5 P <0.002 0 0 50 100 150 200 low Crop growth rate (kg/ha/d) Nitrog
  28. 28. Variable 0 mm 0 mm +100mm +100mm P W PN P X Low N High N Low N High NShoot biomass (t/ha) 12.3 11.8 12.2 15.6 ** ** **Yield (t/ha) 5.8 5.6 5.7 7.2 ** ** **Grain number (103 x m-2) 13.0 13.8 12.8 17.1 * ** *Harvest Index 0.42 0.42 0.42 0.42 - - -Grain size (mg) 42.7 39.3 42.5 40.2 - - -RUE (g/MJ) 1.64 1.57 1.50 1.89 - * **Biomass/ET (kg/ha. mm) 34.9 33.0 32.2 40.0 - - **Yield/ ET (kg/ha. mm) 15.9 15.3 14.5 18.0 - * **
  29. 29. Variable 0 mm 0 mm +100mm +100mm P W PN P X Low N High N Low N High NShoot biomass (t/ha) 12.3 11.8 12.2 15.6 ** ** **Yield (t/ha) 5.8 5.6 5.7 7.2 ** ** **Grain number (103 x m-2) 13.0 13.8 12.8 17.1 * ** *Harvest Index 0.42 0.42 0.42 0.42 - - -Grain size (mg) 42.7 39.3 42.5 40.2 - - -RUE (g/MJ) 1.64 1.57 1.50 1.89 - * **Biomass/ET (kg/ha. mm) 34.9 33.0 32.2 40.0 - - **Yield/ ET (kg/ha. mm) 15.9 15.3 14.5 18.0 - * **
  30. 30. Variable 0 mm 0 mm +100mm +100mm P W PN P X Low N High N Low N High NShoot biomass (t/ha) 12.3 11.8 12.2 15.6 ** ** **Yield (t/ha) 5.8 5.6 5.7 7.2 ** ** **Grain number (103 x m-2) 13.0 13.8 12.8 17.1 * ** *Harvest Index 0.42 0.42 0.42 0.42 - - -Grain size (mg) 42.7 39.3 42.5 40.2 - - -RUE (g/MJ) 1.64 1.57 1.50 1.89 - * **Biomass/ET (kg/ha. mm) 34.9 33.0 32.2 40.0 - - **Yield/ ET (kg/ha. mm) 15.9 15.3 14.5 18.0 - * **
  31. 31. Variable 0 mm 0 mm +100mm +100mm P W PN P X Low N High N Low N High NShoot biomass (t/ha) 12.3 11.8 12.2 15.6 ** ** **Yield (t/ha) 5.8 5.6 5.7 7.2 ** ** **Grain number (103 x m-2) 13.0 13.8 12.8 17.1 * ** *Harvest Index 0.42 0.42 0.42 0.42 - - -Grain size (mg) 42.7 39.3 42.5 40.2 - - -RUE (g/MJ) 1.64 1.57 1.50 1.89 - * **Biomass/ET (kg/ha. mm) 34.9 33.0 32.2 40.0 - - **Yield/ ET (kg/ha. mm) 15.9 15.3 14.5 18.0 - * **
  32. 32. Variable 0 mm 0 mm +100mm +100mm P W PN P X Low N High N Low N High NShoot biomass (t/ha) 12.3 11.8 12.2 15.6 ** ** **Yield (t/ha) 5.8 5.6 5.7 7.2 ** ** **Grain number (103 x m-2) 13.0 13.8 12.8 17.1 * ** *Harvest Index 0.42 0.42 0.42 0.42 - - -Grain size (mg) 42.7 39.3 42.5 40.2 - - -RUE (g/MJ) 1.64 1.57 1.50 1.89 - * **Biomass/ET (kg/ha. mm) 34.9 33.0 32.2 40.0 - - **Yield/ ET (kg/ha. mm) 15.9 15.3 14.5 18.0 - * **
  33. 33. N-driven trade-off between WUE and NUE Nitrogen utilisation efficiency 40 Water use efficiency 20 NUE (kg grain/kgN) 30 (kg/ha mm) 15 10 20 5 10 WUE 0 0 0 100 200 300 Nitrogen rate (kg N/ha)Sadras & Rodriguez (2010) Field Crops Research 118, 297–305.
  34. 34. Summary1. Summer rainfall can contribute up to 20% gains in yield of wheat in South Australia2. Yield gains are related to early growth and grain number3. Grain number is a function of growth rate in the window between stem elongation and anthesis4. Supply of both nitrogen and water in this critical window is essential5. Has the balance between growth before and after anthesis been overemphasised?
  35. 35. The trade-off is universal – applies to maize in USA corn-belt Nitrogen utilisation efficiency 30 80Water use efficiency WUE (kg grain per kg N) (kg/ha/mm) 70 25 60 20 NUE 50 15 40 0 50 100 150 Nitrogen rate (kg N/ha)
  36. 36. The trade-off is universal – applies to rice in Philippines Nitrogen utilisation efficiency 65Water use efficiency 6 WUE (kg grain/kg N) (kg/ha/mm) 60 4 55 2 NUE 0 50 0 150 Nitrogen rate (kg N/ha)
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