Linking decomposition rates of soil organic amendments to their chemical composition

Soil Research
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Abstract

The stock of organic carbon contained within a soil represents the balance between inputs and losses. Inputs are defined by the ability of vegetation to capture and retain carbon dioxide, effects that management practices have on the proportion of captured carbon that is added to soil and the application organic amendments. The proportion of organic amendment carbon retained is defined by its rate of mineralisation. In this study, the rate of carbon mineralisation from 85 different potential soil organic amendments (composts, manures, plant residues and biosolids) was quantified under controlled environmental conditions over a 547 day incubation period. The composition of each organic amendment was quantified using nuclear magnetic resonance and mid- and near-infrared spectroscopies. Cumulative mineralisation of organic carbon from the amendments was fitted to a two-pool exponential model. Multivariate chemometric algorithms were derived to allow the size of the fast and slow cycling pools of carbon to be predicted from the acquired spectroscopic data. However, the fast and slow decomposition rate constants could not be predicted suggesting that prediction of the residence time of organic amendment carbon in soil would likely require additional information related to soil type, environmental conditions, and management practices in use at the site of application.

Publication type Article
Publication Subtype Journal Article
Title Linking decomposition rates of soil organic amendments to their chemical composition
Series title Soil Research
DOI 10.1071/SR20269
Volume 59
Year Published 2021
Language English
Publisher CSIRO Publishing
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 14 p.
First page 630
Last page 643
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