Soil organic matter formation is controlled by the chemistry and bioavailability of organic carbon inputs across different land uses

Bahadori, Mohammad, Chen, Chengrong, Lewis, Stephen, Boyd, Sue, Rashti, Mehran, Esfandbod, Maryam, Van Zwieten, Lukas, and Kuzyakov, Yakov (2021) Soil organic matter formation is controlled by the chemistry and bioavailability of organic carbon inputs across different land uses. Science of the Total Environment, 770. 145307.

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Abstract

Soil organic matter (SOM) formation involves microbial transformation of plant materials of various quality with physico-chemical stabilisation via soil aggregation. Land use and vegetation type can affect the litter chemistry and bioavailability of organic carbon (OC), and consequently influence the processing and stabilisation of OC into SOM. We used 13C nuclear magnetic resonance (13C NMR) and hot-water extraction to assess the changes in chemical composition and labile OC fractions during the transformation processes from leaf to litter to SOM depending on land use and vegetation type. The hot-water-extractable OC (HWEOC) decreased from leaf (43–65 g kg−1) to litter (19–23 g kg−1) to SOM (8–16 g kg−1) similar in four land use types: grassland, sugarcane, forest and banana. These trends demonstrated the uniform converging pathways of OC transformation and increasing stability by SOM formation. The preferential decomposition and decrease of labile OC fractions (∑% di-O-alkyl, O-alkyl and methoxyl) from leaf (54–69%) to SOM (41–43%) confirmed the increasing stability of the remaining compounds. Despite differences in the biochemical composition of the leaf tissues among the vegetation types, the proportions of labile OC fractions in SOM were similar across land uses. The OC content of soil was higher in forest (7.9%) and grassland (5.2%) compared to sugarcane (2.3%) and banana (3.0%). Consequently, the HWEOC per unit of soil weight was higher in forest and grassland (2.0 and 1.2 g kg−1 soil, respectively) compared to sugarcane and banana (0.3 and 0.4 g kg soil−1, respectively).

Item ID: 73361
Item Type: Article (Research - C1)
ISSN: 1879-1026
Keywords: 13C CPMAS NMR, Hot water extractable C and N, Carbon sequestration
Copyright Information: © 2021 Elsevier B.V. All rights reserved.
Date Deposited: 04 Apr 2022 23:00
FoR Codes: 41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410402 Environmental assessment and monitoring @ 100%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1802 Coastal and estuarine systems and management > 180201 Assessment and management of coastal and estuarine ecosystems @ 100%
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