Labile carbon retention compensates for CO2 released by priming in forest soils. (2nd December 2013)

• Record Type: Journal Article
• Authors: Qiao, Na; Schaefer, Douglas; Blagodatskaya, Evgenia; Zou, Xiaoming; Xu, Xingliang; Kuzyakov, Yakov
• Is Part Of: Global change biology. Volume 20:Number 6(2014:Jun.)
• Page Start: 1943
• Page End: 1954
• Publication Date: 2013-12-02
• Subjects: Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.12458
• Languages: English
• ISSNs: 1354-1013

Abstract

<abstract abstract-type="main" id="gcb12458-abs-0001"> <title>Abstract</title> <p>Increase of belowground C allocation by plants under global warming or elevated CO<sub>2</sub> may promote decomposition of soil organic carbon (SOC) by priming and strongly affects SOC dynamics. The specific effects by priming of SOC depend on the amount and frequency of C inputs. Most previous priming studies have investigated single C additions, but they are not very representative for litterfall and root exudation in many terrestrial ecosystems. We evaluated effects of <sup>13</sup>C‐labeled glucose added to soil in three temporal patterns: single, repeated, and continuous on dynamics of CO<sub>2</sub> and priming of SOC decomposition over 6 months. Total and <sup>13</sup>C labeled CO<sub>2</sub> were monitored to analyze priming dynamics and net C balance between SOC loss caused by priming and the retention of added glucose‐C. Cumulative priming ranged from 1.3 to 5.5 mg C g<sup>−1</sup> SOC in the subtropical, and from −0.6 to 5.5 mg C g<sup>−1</sup> SOC in the tropical soils. Single addition induced more priming than repeated and continuous inputs. Therefore, single additions of high substrate amounts may overestimate priming effects over the short term. The amount of added glucose C remaining in soil after 6 months (subtropical: 8.1–11.2 mg C g<sup>−1</sup> SOC or 41‐56% of added glucose; tropical: 8.7–15.0 mg C g<sup>−1</sup> SOC or 43–75% of glucose) was substantially higher than the net C loss due to SOC decomposition including priming effect. This overcompensation of C losses was highest with continuous inputs and lowest with single inputs. Therefore, raised labile organic C input to soils by higher plant productivity will increase SOC content even though priming accelerates decomposition of native SOC. Consequently, higher continuous input of C belowground by plants under warming or elevated CO<sub>2</sub> can increase C stocks in soil despite accelerated C cycling by priming in soils.</p> </abstract>