Plant intraspecific competition and growth stage alter carbon and nitrogen mineralization in the rhizosphere

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  • Yue Sun
  • Huadong Zang
  • Thomas Splettstößer
  • Amit Kumar
  • Xingliang Xu
  • Yakov Kuzyakov
  • Johanna Pausch

Plant roots interact with rhizosphere microorganisms to accelerate soil organic matter (SOM) mineralization for nutrient acquisition. Root-mediated changes in SOM mineralization largely depend on root-derived carbon (root-C) input and soil nutrient status. Hence, intraspecific competition over plant development and spatiotemporal variability in the root-C input and nutrients uptake may modify SOM mineralization. To investigate the effect of intraspecific competition on SOM mineralization at three growth stages (heading, flowering, and ripening), we grew maize (C4 plant) under three planting densities on a C3 soil and determined in situ soil C- and N-mineralization by 13C-natural abundance and 15N-pool dilution approaches. From heading to ripening, soil C- and N-mineralization rates exhibit similar unimodal trends and were tightly coupled. The C-to-N-mineralization ratio (0.6 to 2.6) increased with N availability, indicating that an increase in N-mineralization with N depletion was driven by microorganisms mining N-rich SOM. With the intraspecific competition, plants increased specific root lengths as an efficient strategy to compete for resources. Root morphologic traits rather than root biomass per se were positively related to C- and N-mineralization. Overall, plant phenology and intraspecific competition controlled the intensity and mechanisms of soil C- and N- mineralization by the adaptation of root traits and nutrient mining.

Original languageEnglish
JournalPlant, Cell and Environment
Issue number4
Pages (from-to)1231-1242
Number of pages12
Publication statusPublished - 01.04.2021

Bibliographical note

Deutsche Forschungsgemeinschaft, Grant/Award Number: project PA 2377/2‐1; RUDN University, Grant/Award Number: program 5‐100; Russian Science Foundation, Grant/Award Number: 19‐77‐30012. © 2020 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

    Research areas

  • C natural abundance, N pool dilution, arable soil, carbon and nitrogen mineralization, intraspecific competition, maize, root traits, soil organic matter decomposition
  • Ecosystems Research
  • Biology