Influences of temperature and moisture on abiotic and biotic soil CO2 emission from a subtropical forest

Abstract

Background Soil CO2 efflux is considered to mainly derive from biotic activities, while potential contribution of abiotic processes has been mostly neglected especially in productive ecosystems with highly active soil biota. We collected a subtropical forest soil to sterilize for incubation under different temperature (20 and 30 °C) and moisture regimes (30%, 60 and 90% of water holding capacity), aiming to quantify contribution of abiotic and biotic soil CO2 emission under changing environment scenarios. Main findings: Results showed that abiotic processes accounted for a considerable proportion (15.6−60.0%) of CO2 emission in such a biologically active soil under different temperature and moisture conditions, and the abiotic soil CO2 emission was very likely to derive from degradation of soil organic carbon via thermal degradation and oxidation of reactive oxygen species. Furthermore, compared with biotically driving decomposition processes, abiotic soil CO2 emission was less sensitive to changes in temperature and moisture, causing reductions in proportion of the abiotic to total soil CO2 emission as temperature and moisture increased. Conclusions These observations highlight that abiotic soil CO2 emission is unneglectable even in productive ecosystems with high biological activities, and different responses of the abiotic and biotic processes to environmental changes could increase the uncertainty in predicting carbon cycling.

Вплив Вапнування На Обсяги Емісійних Потоків СО2 Із Дерново-Підзолистого Ґрунту В Удобрюваному Агроценозі Західного Полісся

“…Перебіг процесу дисипації СО2 до атмосфери залежить від цілої низки чинників: біологічних особливостей культур, надземної та кореневої маси, а також параметрів температури та вологості ґрунту [14]. Щорічно рослини асимілюють близько 1000 млрд т СО2.…”