Abstract
How soil microbes assimilate carbon-C, nitrogen-N, phosphorus-P, and sulfur-S is fundamental for understanding nutrient cycling in terrestrial ecosystems. We compiled a global database of C, N, P, and S concentrations in soils and microbes and developed relationships between them by using a power function model. The C:N:P:S was estimated to be 287:17:1:0.8 for soils, and 42:6:1:0.4 for microbes. We found a convergence of the relationships between elements in soils and in soil microbial biomass across C, N, P, and S. The element concentrations in soil microbial biomass follow a homeostatic regulation curve with soil element concentrations across C, N, P and S, implying a unifying mechanism of microbial assimilating soil elements. This correlation explains the well-constrained C:N:P:S stoichiometry with a slightly larger variation in soils than in microbial biomass. Meanwhile, it is estimated that the minimum requirements of soil elements for soil microbes are 0.8 mmol C Kg 1 dry soil, 0.1 mmol N Kg 1 dry soil, 0.1 mmol P Kg 1 dry soil, and 0.1 mmol S Kg 1 dry soil, respectively. These findings provide a mathematical explanation of element imbalance in soils and soil microbial biomass, and offer insights for incorporating microbial contribution to nutrient cycling into Earth system models.
| Original language | English |
|---|---|
| Article number | 17445 |
| Journal | Scientific Reports |
| Volume | 5 |
| DOIs | |
| State | Published - Nov 27 2015 |
Funding
The authors thank Drs. William H. Schlesinger and Jay Gulledge for their constructive comments and suggestions, and Drs. Robert Jackson, Wilfred W. Post, and Joshua Schimel for discussions on this work at early stage. We appreciate two anonymous reviewers whose comments are valuable for the manuscript improvement. This research was sponsored by the US Department of Energy, Office of Science, Biological and Environmental Research (BER) program and performed at Oak Ridge National Laboratory (ORNL). ORNL is managed by UT-Battelle, LLC, for the US Department of Energy under contract DE-AC05-00OR2725. X.X. and X.S acknowledge the financial support from the University of Texas at El Paso. L.Z. was supported by the National Natural Science Foundation of China (41371111, 40801037) and the “Strategic Priority Research Program” of the Chinese Academy of Sciences (Grant No. XDA05050406-06).