Biology and Fertility of Soils

, Volume 23, Issue 1, pp 38–42

Activity and biomass of soil microorganisms at different depths

  • M. F. E. Lavahun
  • R. G. Joergensen
  • B. Meyer
Original Paper

DOI: 10.1007/BF00335816

Cite this article as:
Lavahun, M.F.E., Joergensen, R.G. & Meyer, B. Biol Fertil Soils (1996) 23: 38. doi:10.1007/BF00335816

Abstract

We measured microbial biomass C and soil organic C in soils from one grassland and two arable sites at depths of between 0 and 90 cm. The microbial biomass C content decreased from a maximum of 1147 (0–10 cm layer) to 24 μg g-1 soil (70–90 cm layer) at the grassland site, from 178 (acidic site) and 264 μg g-1 soil (neutral site) at 10–20 cm to values of between 13 and 12 μg g-1 soil (70–90 cm layer) at the two arable sites. No significant depth gradient was observed within the plough layer (0–30 cm depth) for biomass C and soil organic C contents. In general, the microbial biomass C to soil organic C ratio decreased with depth from a maximum of between 1.4 and 2.6% to a minimum of between 0.5 and 0.7% at 70–90 cm in the three soils. Over a 24-week incubation period at 25°C, we examined the survival of microbial biomass in our three soils at depths of between 0 and 90 cm without external substrate. At the end of the incubation experiment, the contents of microbial biomass C at 0–30 cm were significantly lower than the initial values. At depths of between 30 and 90 cm, the microbial biomass C content showed no significant decline in any of the four soils and remained constant up to the end of the experiment. On average, 5.8% of soil organic C was mineralized at 0–30 cm in the three soils and 4.8% at 30–90 cm. Generally, the metabolic quotient qCO2 values increased with depth and were especially large at 70–90 cm in depth.

Key words

Microbial biomassDepth profileFumigation-extraction methodSoil organic matterDormant population

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • M. F. E. Lavahun
    • 1
  • R. G. Joergensen
    • 1
  • B. Meyer
    • 1
  1. 1.Institut für BodenwissenschaftGöttingenGermany