0
To mix or not to mix : evidences for the   unexpected high productivity of new    agrivoltaic and agroforestry systems    ...
To mix or not to mix?
To mix or not to mix?
Solar energy is plentiful and renewable3.5*1018MJ.year-1 = 8 000 times the current needs of humansPhotovoltaism is so far ...
Crops and trees... : agroforestryCrops and photovoltaic panels... :          agrivoltaism  Heterogeneous  and stratified s...
Agroforestry system (AF)
Agrivoltaic system (AV) ?)                             Virtual images, Sun’R corporation                                  ...
13
How to measure the productivity of mixtures•   Land Equivalent Ratio LER (Mead and Willey, 1980)• LER = Sum (Relative Yiel...
Maize and beans   Cassava and peanuts
– Common observed values for LERs :       – 0.9 to 1.1 for mixtures of annual species       – 1.0 to 1.2 for legumes/non l...
AgroforestryMeasured LER               1.36               Poplars-winter cereals                 12 year rotation
Walnut trees – winter cereals                 40 Year rotation            1.3 to 1.6LERsPredictedby models
MeasuredLER foragrivoltaicsystemswithvariousdensitiesof PVpanels                  1.3 to 1.7  Dupraz et al, 2011, Renewabl...
Surprising high yields of plants in the shade of solar panels or                             trees.                      H...
LER interpretationPractical : highWith a 1.4 LER, a 100 ha farm produces as much crop and tree products (or electricty) as...
Looking for explanations...Looking for facilitation...Light? Water? Nitrogen? First order interactions?When ?
2003       2009
Full Density of           Half Density of          panels                    panels        45 % RR                  70% RR...
In agrivoltaic and agroforestry systems,competition for light is compensated... by                 what ??
LER interpretation• LERs can be simulated with process-based models• The simulations allow to decompose the LER in various...
LER interpretation for a walnut-wheat AF system
Decomposing the LER• LER= Rytree + Rycrop•    RY =   π[relative indexes]• Exemple of decomposition :• RY =           Relat...
Decomposing the Tree RY                            Tree       Interpretation      CommentsRY                          0.52...
Decomposing the Crop RY                            Crop       Interpretation       CommentsRY                          0.7...
Hierarchy of components of a final LER                           1,6                           1,4                        ...
If the AF model is right…         Advantages in AF        Drawbacks in AF      NeutralTrees    Larger canopies         Few...
If the AV model is right…         Advantages in AV        Drawbacks in AV         NeutralSolar    Improved ventilation    ...
Integrated over 40 yearsBut what dynamics during the 40 years?
2,0                        1,8Land Equivalent Ratio                        1,5                        1,3                 ...
Absolute crop yields        Relative crop yields                Pure cropCrop yield stabilisation in temperate agroforestr...
A synthesis of probable LERs of temperate AFsAssociation         Plant Cycles    Soil     Root segre-    Water     Probabl...
Conclusions• LERs of AFs and AVs may be extremely high (part of a  second green revolution?)• Process-based models can hel...
Now available…A Textbook + 1 hour DVD(with English, Spanish and Dutch sub-titles)  Available at a special  discount price ...
To mix or not to mix: evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems. Christia...
To mix or not to mix: evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems. Christia...
To mix or not to mix: evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems. Christia...
To mix or not to mix: evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems. Christia...
To mix or not to mix: evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems. Christia...
To mix or not to mix: evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems. Christia...
Upcoming SlideShare
Loading in...5
×

To mix or not to mix: evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems. Christian Dupraz

599

Published on

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

Published in: Education, Business, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
599
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
10
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Transcript of "To mix or not to mix: evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems. Christian Dupraz"

  1. 1. To mix or not to mix : evidences for the unexpected high productivity of new agrivoltaic and agroforestry systems Christian Dupraz Grégoire Talbot Hélène Marrou Jacques Wery Sébastien Roux Fabien liagre Yoann Férard* Antoine Nogier* INRA, UMR System, Montpellier, France * SunR Company, Paris, France
  2. 2. To mix or not to mix?
  3. 3. To mix or not to mix?
  4. 4. Solar energy is plentiful and renewable3.5*1018MJ.year-1 = 8 000 times the current needs of humansPhotovoltaism is so far the best conversion processCapture efficiency : 15% versus less than 3% for biomassUse chain efficiency : 150 times higher for photovoltaism + electricengine compared to biomass + combustion engineBut would compete for crop land... 4
  5. 5. Crops and trees... : agroforestryCrops and photovoltaic panels... : agrivoltaism Heterogeneous and stratified systems Facilitation wanted Competition unavoidable
  6. 6. Agroforestry system (AF)
  7. 7. Agrivoltaic system (AV) ?) Virtual images, Sun’R corporation 7
  8. 8. 13
  9. 9. How to measure the productivity of mixtures• Land Equivalent Ratio LER (Mead and Willey, 1980)• LER = Sum (Relative Yields) = Rytree or solar panels + RYcrop LER = 1
  10. 10. Maize and beans Cassava and peanuts
  11. 11. – Common observed values for LERs : – 0.9 to 1.1 for mixtures of annual species – 1.0 to 1.2 for legumes/non legumes species – What about mixtures of trees and crops, solar panels and crops? 0.9 < LER < 1.2 LER > 1 ?
  12. 12. AgroforestryMeasured LER 1.36 Poplars-winter cereals 12 year rotation
  13. 13. Walnut trees – winter cereals 40 Year rotation 1.3 to 1.6LERsPredictedby models
  14. 14. MeasuredLER foragrivoltaicsystemswithvariousdensitiesof PVpanels 1.3 to 1.7 Dupraz et al, 2011, Renewable Energy 36: 2725-2732
  15. 15. Surprising high yields of plants in the shade of solar panels or trees. High spatial variability of both light availability and plant yield (strip pattern of the shadeunder PVPs) which must be taken into account to assess the economic profitability of such systemsAV even more efficient than AF systems for land productivity
  16. 16. LER interpretationPractical : highWith a 1.4 LER, a 100 ha farm produces as much crop and tree products (or electricty) as a 140 ha farm where crops and trees (or solar panels) are separated in spaceTheoretical : poorLERs are « black box » indicators : they give no clues for the understanding of processes
  17. 17. Looking for explanations...Looking for facilitation...Light? Water? Nitrogen? First order interactions?When ?
  18. 18. 2003 2009
  19. 19. Full Density of Half Density of panels panels 45 % RR 70% RR% annual relative radiation (RR) at ground level in an agrivoltaic system (43° Latitude North) 24
  20. 20. In agrivoltaic and agroforestry systems,competition for light is compensated... by what ??
  21. 21. LER interpretation• LERs can be simulated with process-based models• The simulations allow to decompose the LER in various interacting effects• This is a way to hierarchy factors of success in agroforestry and agrivoltaism Talbot, 2011, Ph. D. thesis (Submitted to Env. Model. Soft.)
  22. 22. LER interpretation for a walnut-wheat AF system
  23. 23. Decomposing the LER• LER= Rytree + Rycrop• RY = π[relative indexes]• Exemple of decomposition :• RY = Relative density x Size Memory x Light competition x Water competition x Harvest Index
  24. 24. Decomposing the Tree RY Tree Interpretation CommentsRY 0.52 RY > RD Tree dominant Depends on thinningRelative density RD 0.36 regime Major (feed forwardSize memory 1.50 +++ effect) Significant : less shadeLight competition 1.10 + from tree to tree Not significant : AF andWater competition 1.03 0 FC trees experience same WS Forest trees invest moreHarvest index 0.85 -- in the trunk Remember : value > 1 = [AF tree > FC tree]
  25. 25. Decomposing the Crop RY Crop Interpretation CommentsRY 0.76 RY < RD Crop dominatedRelative density RD 0.93 Postive impact on leafSize memory 0.99 0 area Significant : shade majorLight competition 0.74 --- effectWater competition 1.10 + Shaded crops protectedHarvest index (1) -- Not calculated so far Remember : value > 1 = [AF crop > Monocrop]
  26. 26. Hierarchy of components of a final LER 1,6 1,4 Tree Crop 1,2Multiplicative Component 1,0 0,8 0,6 0,4 0,2 0,0 Predicted = Relative X Size X Light X Water X Harvest RY density memory competition competition index
  27. 27. If the AF model is right… Advantages in AF Drawbacks in AF NeutralTrees Larger canopies Few trees Water stress Less light competition Invest C in rootsWinter Reduced water stress Less light HarvestCrops index Longer life of leaves Reduced cropped Reduced N stress area Reduced heat stress
  28. 28. If the AV model is right… Advantages in AV Drawbacks in AV NeutralSolar Improved ventilation Cost of supporting Lightpanels structure conversionSummer Reduced heat stress Reduced lightCrops Longer life of leaves Reduced cropped Reduced N stress area Reduced water stress
  29. 29. Integrated over 40 yearsBut what dynamics during the 40 years?
  30. 30. 2,0 1,8Land Equivalent Ratio 1,5 1,3 1,0 0,8 0,5 Annual Integrated 0,3 0,0 0 5 10 15 20 25 30 35 40 Years
  31. 31. Absolute crop yields Relative crop yields Pure cropCrop yield stabilisation in temperate agroforestry systems
  32. 32. A synthesis of probable LERs of temperate AFsAssociation Plant Cycles Soil Root segre- Water Probable depth gation body in LER summerWalnut-cereal on Almost Deep High Yes 1.5plains with water complementartable ySorbus-wheat Lagged Medium Intermediate No 1.4Prunus-Medicago Close Deep Intermediate No 1.3Prunus-sunflower Synchronous Shallow Poor No 1.2Populus-maize Synchronous Poor No Yes 1.1Evergreen tree Superposed Any Variable No 1.0and summer crop Never demonstrated so far <1.0
  33. 33. Conclusions• LERs of AFs and AVs may be extremely high (part of a second green revolution?)• Process-based models can help in interpreting productivity results of AF and AV systems at various time steps.• Winter crops better in AF, summer crops better in AV (latitude-specific)
  34. 34. Now available…A Textbook + 1 hour DVD(with English, Spanish and Dutch sub-titles) Available at a special discount price today Book + DVD : 50 € Contact : Christian Dupraz dupraz@supagro.inra.fr
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×