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Root influence on soil nitrogen availability and microbial community dynamics results in contrasting rhizosphere priming effects in pine and spruce soil

Citation

Li, Jian; Alaei, Saeed; Zhou, Moyan; Bengtson, Per (2021), Root influence on soil nitrogen availability and microbial community dynamics results in contrasting rhizosphere priming effects in pine and spruce soil, Dryad, Dataset, https://doi.org/10.5061/dryad.pzgmsbckt

Abstract

1. The rhizosphere priming effect (RPE) is increasingly considered an important regulator of belowground C and N cycling, with implications for terrestrial ecosystem feedback to global change. Even so there is a lack of knowledge about the mechanisms underlying RPEs. 2. We used novel stable isotope probing methods to investigate RPEs in an experiment with Scots pine and Norway spruce seedlings, two of the most common boreal forest species. We determined root exudation rates, RPEs on SOM decomposition and gross N mineralization, and the contribution of different microbial functional groups to the observed RPEs. 3. Pine induced positive and spruce negative RPEs on SOM decomposition, while no RPE on gross N mineralization was observed. Negative RPEs in the spruce treatment were attributed to an opportunistic subset of the fungal community that was growing on root-derived 13C while depleting available N, thus reducing the activity of microbial SOM decomposers. In the pine treatment, available N was likely sufficient to support root induced decomposition activities of fungal decomposers, resulting in positive RPEs. 4. The findings suggest that RPEs, promoted by root stimulation of distinct subsets of the microbial community, can either contribute to conserving the soil C stock or to depleting it, depending on plant species and soil N availability.

Methods

Data were acquired in a greenhouse experiment performed at Lund University.

Usage Notes

Data are provided in the Excel workbook. Variables that are not self explanatory are defined in the "Description" sheet of the excel workbook.

Funding

Vetenskapsrådet, Award: 2016-04710

Knut och Alice Wallenbergs Stiftelse, Award: 2013.0073