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Publikasjoner

NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2019

Sammendrag

The role of soil moisture on organic matter decomposition remains poorly understood and underrepresented in coupled global climate models. Traditionally, organic matter decomposition is represented as simple first- or second order kinetics in such models, using mostly empirical functions for temperature and moisture controls, and without considering microbial interactions. We use the Dual Michaelis-Menten (DAMM) model (Davidson et al. 2012) to simulate simultaneous temperature and moisture controls on decomposition rates. Microbial controls on decomposition in relation to changes in soil moisture and temperature are implicitly simulated with DAMM: Soil moisture affects the available substrate (SOC) and oxygen available for decomposition and reduces the maximal, temperature driven decomposition rate (Vmax). We apply the DAMM model on vertically resolved data from the most recent coupled model intercomparison project (CMIP5) and gridded global SOC values (SoilGrids). We study the potential decomposition rates for a historic period (1976 - 2006) and a period under the RCP8.5 climate change scenario (2070-2099) for 5 soil layers up to 1m depth. Our key finding is that the inclusion of soil moisture controls has diverging effects on both the speed and direction of projected decomposition rates, compared to a temperature-only approach. The majority of these changes are driven by soil moisture through substrate limitation, rather than oxygen diffusion limitation. In deeper soil layers, oxygen diffusion limitation plays a stronger role. Our study highlights the need for inclusion of soil moisture interactions in coupled global climate models. Our findings could be particularly important for boreal soils, which store a major fraction of Earth’s SOC stocks and where temperature increases and soil moisture changes are expected to be largest.