Get access
Advertisement

Soil C and N availability determine the priming effect: microbial N mining and stoichiometric decomposition theories

Authors

  • Ruirui Chen,

    1. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
    2. Institute of Plant Nutrition and Soil Science, Christian-Albrecht University Kiel, Kiel, Germany
    Search for more papers by this author
  • Mehmet Senbayram,

    1. Institute of Plant Nutrition and Soil Science, Christian-Albrecht University Kiel, Kiel, Germany
    2. Institute of Applied Plant Nutrition, Georg-August University Goettingen, Goettingen, Germany
    Search for more papers by this author
  • Sergey Blagodatsky,

    1. Institute for Plant Production and Agroecology in the Tropics and Subtropics, University of Hohenheim, Stuttgart, Germany
    2. Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, Russia
    Search for more papers by this author
  • Olga Myachina,

    1. Institute of General and Inorganic Chemistry, Tashkent, Uzbekistan
    Search for more papers by this author
  • Klaus Dittert,

    1. Institute of Plant Nutrition and Soil Science, Christian-Albrecht University Kiel, Kiel, Germany
    2. Institute of Applied Plant Nutrition, Georg-August University Goettingen, Goettingen, Germany
    Search for more papers by this author
  • Xiangui Lin,

    1. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
    Search for more papers by this author
  • Evgenia Blagodatskaya,

    Corresponding author
    1. Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, Russia
    2. Department of Soil Science of Temperate Ecosystems, Georg-August University of Göttingen, Göttingen, Germany
    • Correspondence: Evgenia Blagodatskaya, tel. +49551 3920509; fax +49551 3933310, e-mail: janeblag@mail.ru

    Search for more papers by this author
  • Yakov Kuzyakov

    1. Department of Soil Science of Temperate Ecosystems, Georg-August University of Göttingen, Göttingen, Germany
    2. Department of Agricultural Soil Science, Georg-August University of Göttingen, Göttingen, Germany
    Search for more papers by this author

Abstract

The increasing input of anthropogenically derived nitrogen (N) to ecosystems raises a crucial question: how does available N modify the decomposer community and thus affects the mineralization of soil organic matter (SOM). Moreover, N input modifies the priming effect (PE), that is, the effect of fresh organics on the microbial decomposition of SOM. We studied the interactive effects of C and N on SOM mineralization (by natural 13C labelling adding C4-sucrose or C4-maize straw to C3-soil) in relation to microbial growth kinetics and to the activities of five hydrolytic enzymes. This encompasses the groups of parameters governing two mechanisms of priming effects – microbial N mining and stoichiometric decomposition theories. In sole C treatments, positive PE was accompanied by a decrease in specific microbial growth rates, confirming a greater contribution of K-strategists to the decomposition of native SOM. Sucrose addition with N significantly accelerated mineralization of native SOM, whereas mineral N added with plant residues accelerated decomposition of plant residues. This supports the microbial mining theory in terms of N limitation. Sucrose addition with N was accompanied by accelerated microbial growth, increased activities of β-glucosidase and cellobiohydrolase, and decreased activities of xylanase and leucine amino peptidase. This indicated an increased contribution of r-strategists to the PE and to decomposition of cellulose but the decreased hemicellulolytic and proteolytic activities. Thus, the acceleration of the C cycle was primed by exogenous organic C and was controlled by N. This confirms the stoichiometric decomposition theory. Both K- and r-strategists were beneficial for priming effects, with an increasing contribution of K-selected species under N limitation. Thus, the priming phenomenon described in ‘microbial N mining’ theory can be ascribed to K-strategists. In contrast, ‘stoichiometric decomposition’ theory, that is, accelerated OM mineralization due to balanced microbial growth, is explained by domination of r-strategists.

Get access to the full text of this article

Ancillary