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

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 (13) C 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…

• NN
  National Natural Science Foundation of China
• CA
  Chinese Academy of Sciences
• NK
  National Key Research and Development Program of China