La Trobe

Long-term stabilization of crop residues and soil organic carbon affected by residue quality and initial soil pH

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posted on 2021-01-07, 02:54 authored by Xiaojuan WangXiaojuan Wang, Clayton R Butterly, Jeff A Baldock, Caixian TangCaixian Tang
© 2017 Elsevier

Residues differing in quality and carbon (C) chemistry are presumed to contribute differently to soil pH change and long-term soil organic carbon (SOC) pools. This study examined the liming effect of different crop residues (canola, chickpea and wheat) down the soil profile (0–30 cm) in two sandy soils differing in initial pH as well as the long-term stability of SOC at the amended layer (0–10 cm) using mid-infrared (MIR) and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. A field column experiment was conducted for 48 months. Chickpea- and canola-residue amendments increased soil pH at 0–10 cm in the Podzol by up to 0.47 and 0.36 units, and in the Cambisol by 0.31 and 0.18 units, respectively, at 48 months when compared with the non-residue-amended control. The decomposition of crop residues was greatly retarded in the Podzol with lower initial soil pH during the first 9 months. The MIR-predicted particulate organic C (POC) acted as the major C sink for residue-derived C in the Podzol. In contrast, depletion of POC and recovery of residue C in MIR-predicted humic organic C (HOC) were detected in the Cambisol within 3 months. Residue types showed little impact on total SOC and its chemical composition in the Cambisol at 48 months, in contrast to the Podzol. The final HOC and resistant organic C (ROC) pools in the Podzol amended with canola and chickpea residues were about 25% lower than the control. This apparent priming effect might be related to the greater liming effect of these two residues in the Podzol.

History

Publication Date

2017-01-01

Journal

Science of The Total Environment

Volume

587-588

Pagination

8p. (p. 502-509)

Publisher

Elsevier

ISSN

0048-9697

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The Author reserves all moral rights over the deposited text and must be credited if any re-use occurs. Documents deposited in OPAL are the Open Access versions of outputs published elsewhere. Changes resulting from the publishing process may therefore not be reflected in this document. The final published version may be obtained via the publisher’s DOI. Please note that additional copyright and access restrictions may apply to the published version.

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