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- Title
An isotope approach based on <sup>13</sup>C pulse-chase labelling vs. the root trenching method to separate heterotrophic and autotrophic respiration in cultivated peat lands.
- Authors
Biasi, Christina; Pitkämäki, Antti S.; Tavi, Niina M.; Koponen, Hannu T.; Martikainen, Pertti J.
- Abstract
We tested an isotope method based on 13 C pulse-chase labelling for determining the fractional contribution of soil microbial respiration to overall soil respiration in an organic soil (cutaway peat land, eastern Finland), cultivated with the bio energy crop, reed canary grass. The plants were exposed to 13CO2 for five hours and the label was thereafter determined in CO2 derived from the soil--root system. A two-pool isotope mixing model was used to separate sources of respiration. The isotopic approach showed that a minimum of 50% of the total CO2 originated from soil-microbial respiration. Even though the method uses undisturbed soil--plant systems, it has limitations concerning the experimental determination of the true isotopic signal of all components contributing to autotrophic respiration. A trenching experiment which was comparatively conducted resulted in a 71% fractional contribution of soil-microbial respiration. This value was likely overestimated. Further studies are needed to evaluate critically the output from these two partitioning approaches.
- Subjects
ITA-Suomen laani (Finland); FINLAND; PEAT; ISOTOPE separation; PLANT-soil relationships; CARBON isotopes; MICROBIAL respiration; SOIL respiration; HISTOSOLS
- Publication
Boreal Environment Research, 2012, Vol 17, Issue 3/4, p184
- ISSN
1239-6095
- Publication type
Article