Abstract
Abstract. Interactions between different qualities of soil organic matter (SOM) affecting their turnover are rarely represented in models. In this study, we propose three mathematical strategies at different levels of abstraction to represent those interactions. By implementing these strategies into the Introductory Carbon Balance Model (ICBM) and applying them to several scenarios of litter input, we show that the different levels of abstraction are applicable at different timescales. We present a simple one-parameter equation of substrate limitation that can straightforwardly be implemented into other models of SOM dynamics at decadal timescale. The study demonstrates how substrate quality interactions can explain patterns of priming effects, accelerate turnover in FACE experiments, and the slowdown of decomposition in long-term bare fallow experiments as an effect of energy limitation of microbial biomass. The mechanisms of those interactions need to be further scrutinized empirically for a more complete understanding. Overall, substrate quality interactions contribute to both understanding and quantitatively modelling SOM dynamics.
Highlights
Introduction cent overview see Manzoni andPorporato (2009)
Enhanced primary production associated with eninto the Introductory Carbon Balance Model (ICBM) and vironmental change may increase decomposition of the large applying them to several scenarios of litter input, we show that the different levels of abstraction are applicable at different timescales
The priming effect, i.e. the enhanced or retarded soil organic matter (SOM) decomposition due to amendment of fresh SOM or mineral nitrogen (Jenkinson et al, 1985; Kuzyakov et al, 2000), and the role of microbial biomass controlling decomposition rates have received increasing attention during the last years (Todd-Brown et al 2012; Treseder et al 2011; Allison et al 2010; Guenet et al 2010; Blagodatskaya and Kuzyakov 2008; Fontaine et al 2003, but see older works of Lohnis 1926; Parnas 1975; Smith 1979; Panikov itly account for co-metabolization of different SOM qualitpileasinbysutbhsetrmatiecrionbteiarlaTcbhtiiooemnsaCsasnrdoyfoparscimtpivihengederecefofemctpsos(eFrontotaeinxeand Barot, 2005; Fang et al, 2005; Wutzler and Reichstein, 2008; Blagodatsky et al, 2010; Neill and Gignoux, 2006; Moorhead and Sinsabaugh, 2006; Poll et al, 2010)
Summary
The priming effect, i.e. the enhanced or retarded soil organic matter (SOM) decomposition due to amendment of fresh SOM or mineral nitrogen (Jenkinson et al, 1985; Kuzyakov et al, 2000), and the role of microbial biomass controlling decomposition rates have received increasing attention during the last years (Todd-Brown et al 2012; Treseder et al 2011; Allison et al 2010; Guenet et al 2010; Blagodatskaya and Kuzyakov 2008; Fontaine et al 2003, but see older works of Lohnis 1926; Parnas 1975; Smith 1979; Panikov itly account for co-metabolization of different SOM qualitpileasinbysutbhsetrmatiecrionbteiarlaTcbhtiiooemnsaCsasnrdoyfoparscimtpivihengederecefofemctpsos(eFrontotaeinxeand Barot, 2005; Fang et al, 2005; Wutzler and Reichstein, 2008; Blagodatsky et al, 2010; Neill and Gignoux, 2006; Moorhead and Sinsabaugh, 2006; Poll et al, 2010). It is timely to implement those processes into ecosystem models and test whether the SOM quality interactions matter at larger spatial and temporal scales.
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