Decomposition of heterogeneous organic matterand its long-term stabilization in soils

Ecological Monographs
By: , and 

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Abstract

Soil organic matter is a complex mixture of material with heterogeneous biological, physical, and chemical properties. Decomposition models represent this heterogeneity either as a set of discrete pools with different residence times or as a continuum of qualities. It is unclear though, whether these two different approaches yield comparable predictions of organic matter dynamics. Here, we compare predictions from these two different approaches and propose an intermediate approach to study organic matter decomposition based on concepts from continuous models implemented numerically. We found that the disagreement between discrete and continuous approaches can be considerable depending on the degree of nonlinearity of the model and simulation time. The two approaches can diverge substantially for predicting long-term processes in soils. Based on our alternative approach, which is a modification of the continuous quality theory, we explored the temporal patterns that emerge by treating substrate heterogeneity explicitly. The analysis suggests that the pattern of carbon mineralization over time is highly dependent on the degree and form of nonlinearity in the model, mostly expressed as differences in microbial growth and efficiency for different substrates. Moreover, short-term stabilization and destabilization mechanisms operating simultaneously result in long-term accumulation of carbon characterized by low decomposition rates, independent of the characteristics of the incoming litter. We show that representation of heterogeneity in the decomposition process can lead to substantial improvements in our understanding of carbon mineralization and its long-term stability in soils.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Decomposition of heterogeneous organic matterand its long-term stabilization in soils
Series title Ecological Monographs
DOI 10.1890/11-0811.1
Volume 81
Issue 4
Year Published 2011
Language English
Publisher ESA
Publisher location Ithaca, NY
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 16 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Ecological Monographs
First page 619
Last page 634