Nyttiggørelse af biochar

Transkript

1 Seminar om termisk forgasning i Danmark, Nyttiggørelse af biochar muligheder og begrænsninger ved brug af biochar til jordforbedring Lektor Lars Elsgaard Institut for Agroøkologi, Aarhus Universitet, Foulum 1

2 Muligheder og begrænsninger Tilfører jorden en stabil kulstof pulje Har kalkningsvirkning (øger jordens ph) Øger jordens vandholdende evne Øger høstet biomasse og udbytte Nedsætter lattergas emission fra jord Nedsætter udvaskning af nitrat og pesticider Biochar Biochar Indeholder tungmetaller og organiske forureninger For dyrt at bruge i praksis Bliver underlagt EU regulering 2 2

3 Biochar from thermal gasification ph 3

4 Biochar is porous carbon Wood 100 µm Straw 20 µm (Lehmann & Joseph, 2009) 4

5 Biochar is long-term stable in soil Biochar from 14-C labelled grass Under field conditions: T½ = 2780 years (Kuzyakov et al. 2014) 5 5

6 Biochar affects soil properties Physical Properties Chemical Properties Biological Properties Density WHC Soption ph CEC Nutrients Protection (?) Substrate (?) Inhibition (?) 6 6

7 Biochar improves WHC Matric potential, pf Soil+biochar Soil Hyper-dry Dry 2 Wet Gravimetric water content, W (%) 7 7

8 Biochar improves WHC Matric potential, pf Soil+biochar Soil Hyper-dry Dry 2 Wet Gravimetric water content, W (%) 8 8

9 BC mostly has low nutrient content straw wood bone 9 9

10 Biochar may lead to yield increases Yield response at 3 Mg/ha N = 84 Global mean, 10% Crane-Droesch et al. (2013) 10 10

11 Biochar interactions with soil N cycling Meta-analysis shows biochar on average to reduce soil N 2 O emissions by 49% (Cayuela et al. 2015) 25 g CO 2 -eq/mj RME Field op Pesticides Irrigation Liming N production Direct N 2 O Indirect N 2 O 11

12 Straw biochar reduces N 2 O emission GC N 2 O CH 4 CO 2 Biochar rates: 0.2% (1 t/ha) 2% (10 t/ha) Soil 12

13 Straw biochar reduces N 2 O emission 15 Cumulative N 2 O emission, 21 d (µg N 2 O g -1 dry wt soil) Halm biochar 0 Ref Ref + N Ref + N + PS 0.2% BC + N 0.2% BC + N + PS 2.0% BC + N 2.0% BC + N + PS 13

14 Biochar lysimeter facilities at AU Askov Askov Denmark 124 lysimeters; 3 soil types sandy (JB1), sandy loam (JB5), clayey (JB7) 14 14

15 Biochar lysimeter facilities at AU Askov Straw-based biochar Mixed in top 0-20 cm Rates: 0, ½, 1, 2% Each soil type, 4 reps 1 st yr crop, ryegrass Depth, 1.5 m Area, 0.83 m

16 Lysimeter reseach activities Yield registrations in ryegrass winter wheat (spraying with glyphosate after ryegrass) Collection of leachate for analyses of dissolved organic carbon, NO 3-, ph, glyphosate and AMPA Chamber measurements of N 2 O emissions and soil profile measurements of N 2 O 16

17 First-year results with ryegrass 17 17

18 Biochar Biochar Pine wood, pyrolysed at ca. 500 C Temp ( C) ph (H 2 O) SSA Reference (m 2 g -1 ) Gaskin et al. (2008) Hina et al. (2010) Spokas et al. (2011) Kwapinski et al. (2010) Amunito et al. (2011) Rajkovich et al. (2010) Keiluweit et al. (2010) 18 18

19 BC may contain PAH and heavy metals Main potential risk from polyaromatic hydrocarbons (PAH) and heavy metals Use of microbial functions as early indicators of pertubations (e.g., autotrophic potential nitrification) 19 19

20 Microbiological test for ecotoxicity Potential nitrification by autotrophic microorganisms are sensitive to chemical disturbances (NH 3 NO 2 - NO 3- ) 0 1 d 1 wk 3 wk Soil + biochar (6-7 doses) Sandy loam soil, ph ~6 Potential nitrification (PN) 20 20

21 Biochar has low microbial ecotoxicity 0 1 d 1 wk 3 wk PN [% of control] EC

22 Economy of biochar as soil improver Biochar pris, 500 pr ton Annette V. Vestergaard, SEGES (pers. comm.) 22 22

23 EU Fertilizer Regulation EC 2003/2003 Gødnings-forordningen (GF) Lever et produkt op til kravene i GF, kan det produceres og markedsføres i alle EU lande som EC fertiliser Kun mineralske gødninger er reguleret på EU 28 niveau GF omfatter ikke organisk gødning og jordforbedringsmidler I sin nuværende form dækker GF ikke biochar GF forhindrer ikke nationale regler (i Danmark fx Bioaskebekendtørelsen og Slam-bekendtgørelsen) Gensidig anerkendelse mellem EU medlemslande er mulig, men kompliceres af forskellige lovgivninger i de enkelte lande 23 23

24 Different drafts of biochar standards 24 24

25 Regulation of heavy metal content Heavy metal (mg/kg) EBC IBI BQM REFERTIL SB/BAB Cadmium /5-20 Chromium Copper /- Lead Mercury Nickel /60 Zinc /

26 Regulation of organic pollutants Compound (mg/kg) EBC IBI BQM REFERTIL SB/BAB ƩPAH (EPA-16) /12 Dioxins/Furans (in ng/kg) 26 26

27 Biochar under REACH regulation REACH is the EC regulation on chemicals and their safe use (Registration, Evaluation and Authorization of Chemicals). REACH is considered the world s strictest regulation on toxic chemicals, aiming to e.g., improve the protection of human health and the environment from the risks that can be posed by chemicals. Companies have the responsibility of collecting information on the properties and the uses of substances that they manufacture or import at or above one tonne per year

28 Muligheder og begrænsninger Tilfører jorden en stabil kulstof pulje Har kalkningsvirkning (øger jordens ph) Øger jordens vandholdende evne Øger høstet biomasse og udbytte Nedsætter lattergas emission fra jord Nedsætter udvaskning af nitrat og pesticider Biochar Biochar Indeholder tungmetaller og organiske forureninger For dyrt at bruge i praksis Bliver underlagt EU regulering 28 28

29 Acknowledgements REFERTIL, EU FP NimaChar, Region Midt, FRICHS A/S) Cost Action, EU FP7, Biochar 29 29

30 Field research activities (Askov) 8 m 3 m 8 m 3 m 8 m 3 m 8 m 3 m 8 m 3 m 8 m 3 m 8 m 3 m 8 m 3 m 5 m halm kontrol mix fibre kontrol halm kontrol mix 3 m 5 m fibre mix halm kontrol mix fibre fibre halm 3 m UNIVERSITY OF AARHUS 30