Simulated leaf litter addition causes opposite priming effects on natural forest and plantation soils

Academic Article

Abstract

  • The conversion of natural forests to tree plantations alters the quality and decreases the quantity of litter inputs into the soil, but how the alteration of litter inputs affect soil organic matter (SOM) decomposition remain unclear. We examined SOM decomposition by adding ¹³C-labeled leaf-litter of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) to soils from a natural evergreen broad-leaved forest and an adjacent Chinese fir plantation converted from a natural evergreen broad-leaved forest 42 years ago. Over 195 days, we monitored CO₂ efflux and its δ¹³C, microbial biomass, and the composition of microbial groups by phospholipid fatty acids (PLFAs). To distinguish priming mechanisms, partitioning of C sources in CO₂ and microbial biomass was determined based on δ¹³C. Leaf-litter addition to natural forest increased microbial biomass and induced up to 14% faster SOM decomposition (positive priming) than that in soil without litter. In contrast, negative priming in soils under plantation indicated preferential use of added leaf-litter rather than recalcitrant SOM. This preferential use of leaf-litter was supported by an increased fungal to bacterial ratio and litter-derived (¹³C) microbial biomass, reflecting increased substrate recalcitrance, the respective changes in microbial substrate utilization and increased C use efficiency. The magnitude and direction of priming effects depend on microbial preferential utilization of new litter or SOM. Concluding, the impact of coniferous leaf-litter inputs on the SOM priming is divergent in natural evergreen broad-leaved forests and plantations, an important consideration in understanding long-term C dynamics and cycling in natural and plantation forest ecosystems.
  • Authors

  • Vadeboncoeur, Matthew
  • Lyu, Maokui
  • Jinsheng Xie
  • Matthew A. Vadeboncoeur
  • Minhuang Wang
  • Xi Qiu
  • Yinbang Ren
  • Miaohua Jiang
  • Yusheng Yang
  • Yakov Kuzyakov
  • Status

    Publication Date

  • November 2018
  • Has Subject Area

    Published In

    Keywords

  • Land-use effects
  • Microbial community composition
  • Priming effects
  • Selective decomposition
  • Subtropical forest soils
  • Digital Object Identifier (doi)

    Start Page

  • 925
  • End Page

  • 934
  • Volume

  • 54
  • Issue

  • 8