CENTREFORESTALTECNOLÒGICDE CATALUNYAPinares secundarios en cultivos abandonados:Evolución del stock de carbono edáficoPere...
Broadleaf (18)Conifer (65)< 900 mm (8)900 - 1200 (17)1200 - 1500 (24)> 1500 mm (12)-40 -20 0 20 40Soil carbon change (%)Gu...
Cardona (Barcelona): crop abandonment and secondary pine stands development
The replacement of crops by secondary forest, in the studiedarea of Cardona (Barcelona, Spain):1. Does it result in a net ...
Plot location: systematic comparison of aerial photographs1956 2009
Delimitation of plot typesType Dominant species 1956 2009 FeaturesCrop Triticum aestivum Crop Crop TerracingNew forest 1 P...
Organic horizons (litter): L, F and Hsampled with aluminum cylinders.8 cylinders per plot(forest plots only)Mineral soil d...
0151530Soil samplingDepth, cm
Organic horizonsMineral soil (0-30 cm)kgCm-202468CropsNew forest 1New forest 2Old forestQuantifying total C stock, down to...
H horizonKg C m-20 1 2 3 4L horizonkg C m-20.0 0.5 1.0 1.5 2.0New forests 1New forests 2Old forestsF horizon0.0 0.5 1.0 1....
5 - 15 cmKg OC m-20 1 2 3 40 - 5 cm0 1 2 3 4CropsNew forest 1New forest 2Old forest15 - 30 cm0 1 2 3 4Mineral horizons
Incubation under standard conditions:25ºC, optimal humidityC respired after 30 days (mg per g OC)60 70 80 90 100 110Depth(...
- Increases in the biochemical quality- Decreases in the physical protection- Both- ...?Why?
Evaluation of biochemical qualitySoil sampleRecalcitrantresidueHydrolysate I Hydrolysate II1M HCl3 h6M HCl24 hRecalcitranc...
Old forests0 2 4 6 8 10New forests 2Total organic Carbon (% w/w)0 2 4 6 8 10020406080100New forests 1Crops0.0 0.5 1.0 1.5 ...
Hydrolysis with hydrochloric acidRecalcitrance index for Carbon (%)25 30 35 40 45 50 55 60Depth(cm)-100102030CropsNew fore...
Mechanical shakingUltrasonic dispersionDISPERSED SOILSievingCentrifugationOrganic fragments2000 - 200 µmOrganic fragments2...
OC in the < 20 µm fraction (% of total OC)30 40 50 60 70 80 900 - 5 cm5 - 15 cm15 - 30 cmabbOverall, physical protection i...
Mineral soil (first cm not included)OCinthe<20µmfraction(%oftotalOC)2030405060708090CropsNew forest 1New forest 2Old fores...
Organic carbon (% w/w)0 1 2 3 4 5Carbonin<20µmfraction(%oftotalOC)455055606570758085 CropsNew forests 1New forests 2Old fo...
Physical protection of soil carbonOC in the < 20 µm fraction (% of total OC)20 40 60 80 100Depth(cm) 051015202530CropsNew ...
- Evolution of nitrogen forms.- Evolution of phosphorus forms and availability.- Evolution of inorganic C (carbonates).- C...
Thanks for your attention!This research was performed under the framework of the CRONOCARB project,funded by the Ministeri...
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5 rovira

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Transcript of "5 rovira"

  1. 1. CENTREFORESTALTECNOLÒGICDE CATALUNYAPinares secundarios en cultivos abandonados:Evolución del stock de carbono edáficoPere Rovira & Aida SalaSolsona
  2. 2. Broadleaf (18)Conifer (65)< 900 mm (8)900 - 1200 (17)1200 - 1500 (24)> 1500 mm (12)-40 -20 0 20 40Soil carbon change (%)Guo L.B. & Gifford R.M. (2002). Global Change Biology 8, 345-360.From crop abandon to forest: changes in soil C stock
  3. 3. Cardona (Barcelona): crop abandonment and secondary pine stands development
  4. 4. The replacement of crops by secondary forest, in the studiedarea of Cardona (Barcelona, Spain):1. Does it result in a net carbon sequestration?2. Where do the changes in the total C stock occur?3. How the C stock is affected by these changes?- Biochemical quality (labile / recalcitrant fractions)- Physical protection (POM / organomineral complexes)4. How the stability of the accumulated C is affected by thesechanges?Defining challenges
  5. 5. Plot location: systematic comparison of aerial photographs1956 2009
  6. 6. Delimitation of plot typesType Dominant species 1956 2009 FeaturesCrop Triticum aestivum Crop Crop TerracingNew forest 1 Pinus nigra Crop Forest TerracingNew forest 2 Pinus nigra Forest Forest TerracingOld forest Pinus nigra Forest Forest No terracing; nevercropped apparentlyIn all cases:Marl-type substrate, rich in carbonates, lclay-loam textures.
  7. 7. Organic horizons (litter): L, F and Hsampled with aluminum cylinders.8 cylinders per plot(forest plots only)Mineral soil down to 30 cm:sampled with prismatic core samplers.5 cores per forest plot,4 cores per agricultural plot.Soil sampling
  8. 8. 0151530Soil samplingDepth, cm
  9. 9. Organic horizonsMineral soil (0-30 cm)kgCm-202468CropsNew forest 1New forest 2Old forestQuantifying total C stock, down to 30 cm depth-2Carbon sequestration potential, on the very long term: about 3 kg C mAbout 1 kg in the mineral soil, about 2 kg in the litter horizonsDeep soil (> 30 cm depth): much more difficult to predict.
  10. 10. H horizonKg C m-20 1 2 3 4L horizonkg C m-20.0 0.5 1.0 1.5 2.0New forests 1New forests 2Old forestsF horizon0.0 0.5 1.0 1.5 2.0Total organic horizons0 1 2 3 4Organic horizons
  11. 11. 5 - 15 cmKg OC m-20 1 2 3 40 - 5 cm0 1 2 3 4CropsNew forest 1New forest 2Old forest15 - 30 cm0 1 2 3 4Mineral horizons
  12. 12. Incubation under standard conditions:25ºC, optimal humidityC respired after 30 days (mg per g OC)60 70 80 90 100 110Depth(cm)-100102030CropsNew forests 1New forests 2Old forestsLitterMineral soilDifferences not significant overallHow does stability of soil C change?
  13. 13. - Increases in the biochemical quality- Decreases in the physical protection- Both- ...?Why?
  14. 14. Evaluation of biochemical qualitySoil sampleRecalcitrantresidueHydrolysate I Hydrolysate II1M HCl3 h6M HCl24 hRecalcitrance index =Unhydrolyzed CTotal C
  15. 15. Old forests0 2 4 6 8 10New forests 2Total organic Carbon (% w/w)0 2 4 6 8 10020406080100New forests 1Crops0.0 0.5 1.0 1.5 2.0RecalcitranceindexforCarbon(%)020406080100Recalcitrance is related to OC content
  16. 16. Hydrolysis with hydrochloric acidRecalcitrance index for Carbon (%)25 30 35 40 45 50 55 60Depth(cm)-100102030CropsNew forests 1New forests 2Old forestsLitterMineral soilRecalcitrance is related to land useChanges in OC biochemical quality do not explain its lower stability in forests.
  17. 17. Mechanical shakingUltrasonic dispersionDISPERSED SOILSievingCentrifugationOrganic fragments2000 - 200 µmOrganic fragments200 - 50 µmOrganic fragments50 - 20 µmOrgano-mineralcomplexes< 20 µmParticulateOrganic Matter(POM > 20 µm)SOIL SAMPLE(air-dried, 2 mm-sieved)Evaluation of physical protection of C: size fractionation
  18. 18. OC in the < 20 µm fraction (% of total OC)30 40 50 60 70 80 900 - 5 cm5 - 15 cm15 - 30 cmabbOverall, physical protection increases with depth
  19. 19. Mineral soil (first cm not included)OCinthe<20µmfraction(%oftotalOC)2030405060708090CropsNew forest 1New forest 2Old forestP < 0.001a b b bPhysical protection as related to land useOverall, the replacement of crops by forests results in a decreasein the degree of physical protection of soil organic matter.
  20. 20. Organic carbon (% w/w)0 1 2 3 4 5Carbonin<20µmfraction(%oftotalOC)455055606570758085 CropsNew forests 1New forests 2Old forestsR 2= 0.2026 **Physical protection as related to OC content of the horizon
  21. 21. Physical protection of soil carbonOC in the < 20 µm fraction (% of total OC)20 40 60 80 100Depth(cm) 051015202530CropsNew forest 1New forest 2Old forestPhysical protection as related to land use and position within the soil profile
  22. 22. - Evolution of nitrogen forms.- Evolution of phosphorus forms and availability.- Evolution of inorganic C (carbonates).- Chemical fertility: Cation exchange capacity, exchangeable cations...etc.To be continued!Work under way...
  23. 23. Thanks for your attention!This research was performed under the framework of the CRONOCARB project,funded by the Ministerio de Ciencia y Tecnología, Spain.

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