Biochar and soil C and N dynamics effects of pyrolysis technology and process temperature

Transcription

1 Biochar and soil C and N dynamics effects of pyrolysis technology and process temperature Henrik Hauggaard-Nielsen (hnie@risoe.dtu.dk) and Esben Wilson Bruun (esbr@risoe.dtu.dk) + From Bech et al., 2009

2 Outline Pyrolysis technology and application Effects of temperature settings of fast pyrolysis technology Effects of slow and fast pyrolysis biochar on C and N dynamics in soil Crop response and N immobilization Interreg biochar project and activities Conclusions A k Acknowledgement l d t Source: earthportal.org Source: CarbonGold Source:

3 Pyrolysis technology and applications Heating rate Temperature Retention time Source: Biochar syngas biooilil

4 How to assess biochars C sequestration potential in soil? Biochar-C degradation = [CO 2 -C biochar soil] [CO 2 -C control soil] CO2 CO2 Soil + biochar Soil (control)

5 Influence of fast pyrolysis reactor temperature on biochar degradation 0 15 c) 5 wt% (70 t ha -1 ) initial C) Carbon loss (% of Days Bruun et al. 2011a

6 Carbohydrate content of the FP-biochars Bruun 2011

7 The carbohydrate content determines the biochar degradation Bruun et al. 2011a

8 Effects of slow and fast pyrolysis biochar on C and N dynamics in soil a) Wheat straw c) SP-biochar e) FP-biochar (525 C) (525 C) Element 500 µm 500 µm 500 µm b) Wheat straw d) SP-biochar f) FP-biochar Wheat Slow Fast Feedstock (525oC) (525oC) Total C Total N C:N Ash µm Cellulose + hemicellulose µm 20 µm Bruun et al., 2011b

9 Carbon loss after soil application of fast and slow pyrolysis biochar compared to the original feedstock of initial C) 60 FP-biochar Wheat straw SP biochar SP-biochar FP biochar 40 5 wt% (70 t ha -1 ) Carbon loss (% Days Bruun et al., 2011b

10 Microbial biomass C and effects of labile biochar carbon sources 1000 A) 800 µg SMB-C g -1 soil µg DOC g -1 soil B) Soil SP-biochar FP-biochar Straw Soil SP-biochar FP-biochar Straw Days Bruun et al., 2011b

11 Biochar cause short term nitrogen immobilization soil min-n g -1 soil 0 Soil 80 SP-biochar FP-biochar Straw µg Days Bruun et al., 2011b

12 Crop response to N immobilization Conditions Crop: spring barley Temperature: 21/16 C day/night Duration: 111 days t Control 2.5 %wt biochar 5 %wt biochar g biomas ss (dw) pot Bruun Sandy soil Sandy soil + F

13 Field experiment at Risø DTU The Interreg IVB North Sea Region Programme: Biochar: climate saving soils Plot size: 6 x 8 m 2 applications spring (barley undersown with ryegrass) autumn (after winter wheat) following sowing of ryegrass 2 biochar products Skogans Kol Romchar/European Charcoal AG 20 t biochar per ha TDR for soil water content Manual chamber for CO 2 emissions i Manual chamber for N 2 O emissions

14 Farmer attitude and biochar soil application Without biochar With biochar

15 Conclusion Biochar properties are highly influenced by pyrolysis technology and temperature settings Biochar effects on temporal soil nutrient dynamics and synchrony with crop demand are required Farmers ambassadors are needed to qualify field assessments and practical obstacles and to secure dissemination and knowledge transfer. Lets not wait for the policymakers to come up with legislations Biochar needs to prove its advantages without external subsidies Important role for climatic and environmental challenges

16 Acknowledgement The studies was funded by the National Globalization Funding from the Technical University of Denmark with support from the Interreg IVB North Sea Region Programme funding the project: Biochar: climate saving soils.

17 References Bech N, Larsen M, Jensen P and Dam-Johansen K (2009). Modelling solid-convective flash pyrolysis of straw and wood in the pyrolysis centrifuge reactor. Biomass bioenergy 33, Bruun EW, Thesis (2011). Application of fast pyrolysis biochar to soil effects on carbon and nitrogen dynamics and potential for carbon sequestration. Risø-DTU. ( Bruun EW, Hauggaard-Nielsen H, Ibrahim N, Egsgaard H, Ambus P, Jensen PA and Dam-Johansen a K (2011a). Influence of fast pyrolysis ys s temperature e on biochar labile fraction and short-term carbon loss in a loamy soil. Biomass & Bioenergy 35: Bruun EW, Ambus P, Egsgaard H and Hauggaard-Nielsen H (2011b). Effects of slow and fast pyrolysis biochar on soil C and N turnover dynamics. Submitted to Soil Biology & Biochemistry Bruun EW, Müller-Stöver D, Ambus P and Hauggaard-Nielsen H (2011c). Biochar soil application and N 2 O emissions potential effects of blending biochar with anaerobically digested slurry. European Journal of Soil Science, accepted for publication Egsgaard H, Ahrenfeldt, J., Henriksen, U.B., Time resolved pyrolysis of char. In: Proceedings (CD-ROM). 14 th. European biomass conference and exhibition: Biomass for energy industry and climate protection, ti Paris (FR), Oct (ITA-Renewable Energies, Florence, 2005) p