Cleveland,C.C. and Liptzin,D.(2007): C:N:P stoichiometry in soil: is there a “Redfield ratio” for the microbial biomass? Biogeochemistry, 85, 235-252.


 Well-constrained carbon:nitrogen:phosphorus (C:N:P) ratios in planktonic biomass, and their importance in advancing our understanding of biological processes and nutrient cycling in marine ecosystems, has motivated ecologists to search for similar patterns in terrestrial ecosystems. Recent analyses indicate the existence of “Redfield-like” ratios in plants, and such data may provide insight into the nature of nutrient limitation in terrestrial ecosystems. We searched for analogous patterns in the soil and the soil microbial biomass by conducting a review of the literature. although soil is characterized by high biological diversity, structural complexity and spatial heterogeneity, we found remarkably consistent C:N:P ratios in both total soil pools and the soil microbial biomass. Our analysis indicates that, similar to marine phytoplankton, element concentrations of individual phylogenetic groups within the soil microbial community may vary, but on average, atomic C:N:P ratios in both the soil (186:13:1) and the soil microbial biomass (60:7:1) are well-constrained at the global scale. We did see significant variation in soil and microbial element ratios between vegetation types (i.e., forest versus grassland),but in most cases, the similarities in soil and microbial element ratios among sites and across large scales were more apparent than the differences. Consistent microbial biomass element ratios, combined with data linking specific patterns of microbial element stoichiometry with direct evidence of microbial nutrient limitation, suggest that measuring the proportions of C, N and P in the microbial biomass may represent another useful tool for assessing nutrient limitation of ecosystem processes in terrestrial ecosystems.

Keywords: Carbon; Microbial biomass; Nitrogen; Phosphorus; Soil; Stoichiometry

The environment not only determines the conditions under which life exists, but the organisms influence the conditions prevailing in the environment.−Alfred Redfield (1958)』

 Literature review
 Quantifying soil microbial biomass: the chloroform fumigation and extraction (FE) technique
 Data analyses
Results and discussion
 Total soil C:N:P ratios
 C:N:P ratios in the soil microbial biomass
 Relationships between soil and microbial element ratios
 Do Redfield-like ratios exist for the soil microbial biomass?
 Soil microbial biomass element ratios as indices of nutrient limitation