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Seasonal patterns of soil CO 2 efflux and soil air CO 2 concentration in a Scots pine forest: comparison of two chamber techniques
Author(s) -
PUMPANEN JUKKA,
ILVESNIEMI HANNU,
PERÄMÄKi MARTTI,
HARI PERTTI
Publication year - 2003
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.2003.00588.x
Subject(s) - scots pine , soil horizon , environmental science , seasonality , chemistry , efflux , zoology , environmental chemistry , humus , soil water , hydrology (agriculture) , soil science , ecology , botany , biology , geology , pinus <genus> , biochemistry , geotechnical engineering
A non‐vented non‐steady state flow‐through chamber and a non‐vented non‐steady state non‐flow‐through chamber technique were used to measure CO 2 efflux of a young Scots pine forest on a fertile till soil in southern Finland. Soil temperature, soil moisture and soil CO 2 concentration were measured concurrently with CO 2 efflux for two and a half successive years. The CO 2 efflux showed a seasonal pattern, effluxes ranging from low 0.0–0.1 g CO 2 m − 2 h − 1 in winter to peak values of 2.3 g CO 2 m − 2 h − 1 occurring in late June and in July. The daily average effluxes in July measured by flow through chambers were 1.23 and 0.98 g CO 2 m − 2 h − 1 in 1998 and 1999, respectively. The annual accumulated CO 2 efflux was 3117 and 3326 g CO 2 m − 2 in 1998 and 1999, respectively. The spatial variation in CO 2 efflux was high (CV 0.18–0.45) and increased with increasing efflux. Soil air CO 2 concentration showed similar seasonal pattern the peak concentrations occurring in July–August. The CO 2 concentrations ranged from 580 to 780 µ mol mol − 1 in the humus layer to 13 620–14 470 µ mol mol − 1 in the C‐horizon. In winter the soil air CO 2 concentrations were lower, especially in deeper soil layers. Drought decreased CO 2 efflux and soil air CO 2 concentration. The in situ comparison on forest soil between the chamber methods showed the non‐flow‐through chamber to give ∼∼50% lower efflux values than that of the flow‐through chamber. When calibrated against known CO 2 efflux ranging from 0.4 to 0.8 g CO 2 m − 2 h − 1 generated with a diffusion box method developed by Widén and Lindroth [Acta Universitatis Agriculturae Suecia Silvestria, 2001], the flow‐through chamber gave equal effluxes at the lower end of the calibration range, but overestimated high effluxes by 20%. Non‐flow‐through chamber underestimated the CO 2 efflux by 30%.