Influence of biochars on flux of N₂O and CO₂ from Ferrosol

Van Zwieten, Lukas; Kimber, Stephen; Morris, S; Downie, A; Berger, E; Rust, J; Scheer, C

doi:10.1071/SR10004

Author(s)

Van Zwieten, Lukas

Kimber, Stephen

Morris, S

Downie, A

Berger, E

Rust, J

Scheer, C

Publication Date

2010

Abstract

Biochars produced by slow pyrolysis of greenwaste (GW), poultry litter (PL), papermill waste (PS), and biosolids (BS) were shown to reduce NO emissions from an acidic Ferrosol. Similar reductions were observed for the untreated GW feedstock. Soil was amended with biochar or feedstock giving application rates of 1 and 5%. Following an initial incubation, nitrogen (N) was added at 165 kg/ha as urea. Microcosms were again incubated before being brought to 100% water-filled porosity and held at this water content for a further 47 days. The flooding phase accounted for the majority (<80%) of total N₂O emissions. The control soil released 3165 mg N₂O-N/m², or 15.1% of the available N as N₂O. Amendment with 1 and 5% GW feedstock significantly reduced emissions to 1470 and 636 mg N₂O-N/m², respectively. This was equivalent to 8.6 and 3.8% of applied N. The GW biochar produced at 350°C was least effective in reducing emissions, resulting in 1625 and 1705 mg N₂O-N/m² for 1 and 5% amendments. Amendment with BS biochar at 5% had the greatest impact, reducing emissions to 518 mg N₂O-N/m², or 2.2% of the applied N over the incubation period. Metabolic activity as measured by CO₂ production could not explain the differences in N₂O emissions between controls and amendments, nor could NH₄⁺ or NO₃⁻ concentrations in biochar-amended soils. A decrease in NH₄⁺ and NO₃⁻ following GW feedstock application is likely to have been responsible for reducing N₂O emissions from this amendment. Reduction in N₂O emissions from the biochar-amended soils was attributed to increased adsorption of NO₃⁻ . Small reductions are possible due to improved aeration and porosity leading to lower levels of denitrification and N₂O emissions. Alternatively, increased pH was observed, which can drive denitrification through to dinitrogen during soil flooding.

Citation

Australian Journal of Soil Research, 48(7), p. 555-568

ISSN

0004-9573

1446-568X

1838-6768

1838-675X

Link

https://hdl.handle.net/1959.11/16209

Language

en

Publisher

CSIRO Publishing

Title

Influence of biochars on flux of N₂O and CO₂ from Ferrosol

Type of document

Journal Article

Entity Type

Publication

Author(s)	Van Zwieten, Lukas Kimber, Stephen Morris, S Downie, A Berger, E Rust, J Scheer, C
Publication Date	2010
Abstract	Biochars produced by slow pyrolysis of greenwaste (GW), poultry litter (PL), papermill waste (PS), and biosolids (BS) were shown to reduce NO emissions from an acidic Ferrosol. Similar reductions were observed for the untreated GW feedstock. Soil was amended with biochar or feedstock giving application rates of 1 and 5%. Following an initial incubation, nitrogen (N) was added at 165 kg/ha as urea. Microcosms were again incubated before being brought to 100% water-filled porosity and held at this water content for a further 47 days. The flooding phase accounted for the majority (<80%) of total N₂O emissions. The control soil released 3165 mg N₂O-N/m², or 15.1% of the available N as N₂O. Amendment with 1 and 5% GW feedstock significantly reduced emissions to 1470 and 636 mg N₂O-N/m², respectively. This was equivalent to 8.6 and 3.8% of applied N. The GW biochar produced at 350°C was least effective in reducing emissions, resulting in 1625 and 1705 mg N₂O-N/m² for 1 and 5% amendments. Amendment with BS biochar at 5% had the greatest impact, reducing emissions to 518 mg N₂O-N/m², or 2.2% of the applied N over the incubation period. Metabolic activity as measured by CO₂ production could not explain the differences in N₂O emissions between controls and amendments, nor could NH₄⁺ or NO₃⁻ concentrations in biochar-amended soils. A decrease in NH₄⁺ and NO₃⁻ following GW feedstock application is likely to have been responsible for reducing N₂O emissions from this amendment. Reduction in N₂O emissions from the biochar-amended soils was attributed to increased adsorption of NO₃⁻ . Small reductions are possible due to improved aeration and porosity leading to lower levels of denitrification and N₂O emissions. Alternatively, increased pH was observed, which can drive denitrification through to dinitrogen during soil flooding.
Citation	Australian Journal of Soil Research, 48(7), p. 555-568
ISSN	0004-9573 1446-568X 1838-6768 1838-675X
Link	https://hdl.handle.net/1959.11/16209
Language	en
Publisher	CSIRO Publishing
Title	Influence of biochars on flux of N₂O and CO₂ from Ferrosol
Type of document	Journal Article
Entity Type	Publication

Influence of biochars on flux of N₂O and CO₂ from Ferrosol

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