Acta Univ. Agric. Silvic. Mendelianae Brun. 2011, 59(6), 127-134 | DOI: 10.11118/actaun201159060127

Effect of measurement time of the day on the relationship between temperature and soil CO₂ efflux

Eva Dařenová¹, M. Pavelka, D. Janouš

¹ Centrum pro výzkum globální změny - CzechGlobe AV ČR, v. v. i., Bělidla 4a, 603 00 Brno, Česká republika

In this study we investigated effect of the time of the day when manual measurements of soil CO₂ efflux are performed on estimates of seasonal sums of released carbon from the soil. We subsampled continuous measurement of soil CO₂ efflux into six sets of data in accordance to the time of the day when the measurements were taken - 0 h, 4 h, 8 h, 12 h, 16 h and 20 h. To estimate seasonal carbon flux from the soil we used continuously measured soil temperature and parameters R₁₀ (soil CO₂ efflux normalized for temperature of 10 °C) and Q₁₀ (the proportional change in CO₂ efflux caused by 10 °C increase in temperature) calculated from continuous measurements and from measurements taken at individual hours. Values of Q₁₀ calculated from 12 h and 16 h data were lower than Q₁₀ calculated from continuous measurements. On the contrary, Q₁₀ at 0 h, 4 h, 8 h and 20 h were higher. Seasonal carbon flux from the soil based on 0 h, 4 h and 8 h measurements was overestimated compare to the flux calculated from continuous measurements. On the contrary, measurements at 12 h, 16 h and 20 h measurements underestimated the carbon flux. The under- or overestimation was significant for 0 h, 4 h, 8 h and 20 h data sub-sets.

Keywords: soil CO₂ efflux, R₁₀, Q₁₀, Picea abies, seasonal carbon flux

Received: December 30, 2010; Published: March 16, 2014  Show citation