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Sammanfattning

The delta(13)C of soil-respired CO2 (delta(r)) is frequently determined using static closed chamber methods. 6, is obtained as the intercept of the least squares linear regression of delta vs 1/C*, where measured delta(13)C-CO2 (delta) and volume fraction Of CO2 (C*) values of chamber headspace samples are used. Theoretically, we show that the variance of the estimate Of delta(r) can be reduced by extending the 1/C* interval of the regression towards (i) higher or (ii) lower values, or (iii) distributing the 1/C* values optimally within the pre-selected headspace CO2 sampling time period. Experimental applications of these approaches indicated that: (1) lowering the initial CO2 level, thereby increasing 1/C*, yielded a positive bias to the 6, result. (2) It was feasible to obtain lower variance in the 6, estimate by lowering 1/C* values through extended CO2 sampling time. We also recommend that each chamber is sampled only once, mainly because this allows freedom to select the sampling times, in order to optimize the distribution of 1/C* values. (c) 2005 Elsevier Ltd. All rights reserved

Publicerad i

Soil Biology and Biochemistry
2005, volym: 37, nummer: 12, sidor: 2273-2276
Utgivare: PERGAMON-ELSEVIER SCIENCE LTD

SLU författare

  • Ohlsson, Anders

    • Institutionen för skogsekologi, Sveriges lantbruksuniversitet

  • Nordgren, Anders

    • Institutionen för skogsekologi, Sveriges lantbruksuniversitet

  • Lövdahl, Lars

    • Institutionen för skogsekologi, Sveriges lantbruksuniversitet

  • Högberg, Peter

    • Institutionen för skogsekologi, Sveriges lantbruksuniversitet

UKÄ forskningsämne

Miljö- och naturvårdsvetenskap

Publikationens identifierare

  • DOI: https://doi.org/10.1016/j.soilbio.2005.03.023

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/6020