TY - JOUR A1 - Bergmann, Joana A1 - Verbruggen, Erik A1 - Heinze, Johannes A1 - Xiang, Dan A1 - Chen, Baodong A1 - Joshi, Jasmin Radha A1 - Rillig, Matthias C. T1 - The interplay between soil structure, roots, and microbiota as a determinant of plant-soil feedback JF - Ecology and evolution N2 - Plant-soil feedback (PSF) can influence plant community structure via changes in the soil microbiome. However, how these feedbacks depend on the soil environment remains poorly understood. We hypothesized that disintegrating a naturally aggregated soil may influence the outcome of PSF by affecting microbial communities. Furthermore, we expected plants to differentially interact with soil structure and the microbial communities due to varying root morphology. We carried out a feedback experiment with nine plant species (five forbs and four grasses) where the training phase consisted of aggregated versus disintegrated soil. In the feedback phase, a uniform soil was inoculated in a fully factorial design with soil washings from conspecific- versus heterospecific-trained soil that had been either disintegrated or aggregated. This way, the effects of prior soil structure on plant performance in terms of biomass production and allocation were examined. In the training phase, soil structure did not affect plant biomass. But on disintegrated soil, plants with lower specific root length (SRL) allocated more biomass aboveground. PSF in the feedback phase was negative overall. With training on disintegrated soil, conspecific feedback was positively correlated with SRL and significantly differed between grasses and forbs. Plants with higher SRL were likely able to easily explore the disintegrated soil with smaller pores, while plants with lower SRL invested in belowground biomass for soil exploration and seemed to be more susceptible to fungal pathogens. This suggests that plants with low SRL could be more limited by PSF on disintegrated soils of early successional stages. This study is the first to examine the influence of soil structure on PSF. Our results suggest that soil structure determines the outcome of PSF mediated by SRL. We recommend to further explore the effects of soil structure and propose to include root performance when working with PSF. KW - arbuscular mycorrhizal fungi KW - biomass allocation KW - plant functional traits KW - plant-soil (belowground) interactions KW - soil aggregation KW - specific root length KW - succession KW - water-stable aggregates Y1 - 2016 U6 - https://doi.org/10.1002/ece3.2456 SN - 2045-7758 VL - 6 SP - 7633 EP - 7644 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Milcu, Alexandru A1 - Heim, Angela A1 - Ellis, Richard J. A1 - Scheu, Stefan A1 - Manning, Pete T1 - Identification of general patterns of nutrient and labile carbon control on soil carbon dynamics across a successional gradient JF - Ecosystems N2 - Carbon (C) inputs and nutrient availability are known to affect soil organic carbon (SOC) stocks. However, general rules regarding the operation of these factors across a range of soil nutrient availabilities and substrate qualities are unidentified. "Priming" (stimulated decomposition by labile C inputs) and 'preferential substrate utilization' (retarded decomposition due to shifts in community composition towards microbes that do not mineralize SOC) are two hypotheses to explain effects of labile C additions on SOC dynamics. For effects of nutrient additions (nitrogen and phosphorus) on SOC dynamics, the stoichiometric (faster decomposition of materials of low carbon-to-nutrient ratios) and 'microbial mining' (that is, reduced breakdown of recalcitrant C forms for nutrients under fertile conditions) hypotheses have been proposed. Using the natural gradient of soil nutrient availability and substrate quality of a chronosequence, combined with labile C and nutrient amendments, we explored the support for these contrasting hypotheses. Additions of labile C, nitrogen (N), phosphorus (P), and combinations of C and N and C and P were applied to three sites: 2-year fallow grassland, mature grassland and forest, and the effects of site and nutrient additions on litter decomposition and soil C dynamics were assessed. The response to C addition supported the preferential substrate hypothesis for easily degradable litter C and the priming hypothesis for SOC, but only in nitrogen-enriched soils of the forest site. Responses to N addition supported the microbial mining hypothesis irrespective of C substrate (litter or SOC), but only in the forest site. Further, P addition effects on SOC support the stoichiometric hypothesis; P availability appeared key to soil C release (priming) in the forest site if labile C and N is available. These results clearly link previously contrasting hypotheses of the factors controlling SOC with the natural gradient in litter quality and nutrient availability that exists in ecosystems at different successional stages. A holistic theory that incorporates this variability of responses, due to different mechanisms, depending on nutrient availability and substrate quality is essential for devising management strategies to safeguard soil C stocks. KW - carbon sequestration KW - priming effect KW - microbial mining KW - succession KW - microorganisms KW - litter decomposition Y1 - 2011 U6 - https://doi.org/10.1007/s10021-011-9440-z SN - 1432-9840 VL - 14 IS - 5 SP - 710 EP - 719 PB - Springer CY - New York ER -