Laboratory Assessment of Forest Soil Respiration Affected by Wildfires under Various Environments of Russia

Evgeny Abakumov,Ekaterina Maksimova,Anna Tsibart ,George Shamilishviliy

doi:10.1155/2017/3985631

Evgeny Abakumov, Ekaterina Maksimova + Show 2 more

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https://doi.org/10.1155/2017/3985631

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Abstract

Pyrogenic carbon emission rates were estimated in the soils of three natural zones in Russia: forest-tundra, south-taiga, and forest-steppe. Postfire soils were found to be characterized by essential losses of soil C due to the combustion fire effect. Soils lost 3 or 5 parts of initial carbon content and showed an essential decrease in the C/N ratio during the fire effect. The pH values increased due to soil enrichment by ash during the fire events. CO2 emission rates were highest in natural soil samples, because the amount of organic matter affected by mineralization in those soils was higher than in natural ones. Simultaneously, the total values of mineralized carbon were higher in postfire soils because the SOM quality and composition were altered due to the fire effect. The only exception was in forest-tundra soils, where a high portion of dissolved organic compounds was released during the surface fire. The quality of initial SOM and intensity of the wildfire play the most important roles in the fate of SOM in postfire environments. Further study of CO2 emissions is needed to better characterize postfire SOM dynamics and develop an approach to model this process.

Highlights

Great attention has been paid to soil organic matter (SOM) mineralization and possible CO2 emissions from soil, due to their important effects on the global carbon cycle and ecosystem stability
The aim of this study is to examine the mineralization of soil organic carbon (SOC) from different types of postfire soils from different environments in Russia, using laboratory incubation with special attention to carbon mineralization rates and CO2 emissions
The postfire soil samples are characterized by decreased total organic carbon (TOC) content and increased Nitrogen content, which in turn decreased the C/N ratio compared to unaffected soil

Summary

Introduction

Great attention has been paid to soil organic matter (SOM) mineralization and possible CO2 emissions from soil, due to their important effects on the global carbon cycle and ecosystem stability. There is an intensive accumulation of ash on the topsoil [14, 15], ash redistribution in landscapes and the leaching of nutrients and minerals into deeper horizons [16, 17], surface overcompaction and crust accumulation, and soil structure transformation of [4]. The most expressed consequence of wildfires is uncontrolled CO2 emission due to changes in soil organic matter stability that occur in high temperatures [18, 19]. The mass loss (i.e., gravimetric concentrations) of soil organic carbon in postfire environments is typically underestimated by researchers in terms of rates and balance units [20, 21]

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