Plant and Soil

, Volume 110, Issue 1, pp 39–47 | Cite as

Soil mcirobial biomass estimates using 2450 MHz microwave irradiation

  • Charles W. Hendricks
  • Nanci Pascoe


The effect of microwave irradiation on two soils of different carbon content was evaluated with the intent of investigating the potential of using this treatment to estimate of soil biomass. After irradiation for various time intervals, the soil was incubated at 25±0.1°C for 10 days. The amount of CO2−C produced with the two different soils remained constant, and little or no difference was observed for microwave treatment ranging from 1–20 min (4.2×104−8.5×105J). When the CO2−C results of this study were used to calculate biomass-C estimates, the Sierra and Garden soils were 29.5±3.0 and 26.9±3.9 mgC 100g−1 dry soil, respectively. This compared with values of 35.8±0.7 and 28.8±1.2 mgC 100g−1 dry soil obtained by chloroform fumigation. These results indicate that, for the soils tested, a sufficient number of microorganisms survived microwave irradiation to metabolize nutrients released from killed cells during the controlled heating process. This approach appears to provide biomass estimates comparable to chloroform procedure without the use of fumigants.

Key words

biomass determination chloroform fumigation CO2 measurement direct cell counts microwave irradiation soil microorganisms 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Anderson J P E and Domsch K H 1978 A physiological method for the quantitative measurement of microbial biomass in soils. Soil Biol. Biochem. 10, 215–221.Google Scholar
  2. Azuma J, Tanaka F and Koshijima T 1984 Enhancement of enzymic susceptibility of lignocellulose wastes by microwave irradiation. J. Ferment. Technol. 62, 377–384.Google Scholar
  3. Bollen G J 1969 The selective effect of heat treatment on the microflora of a greenhouse soil. Neth. J. Plant Path. 75, 157–163.Google Scholar
  4. Brookes P C, Landman A, Pruden G and Jenkinson D S 1985 Chloroform fumigation and the release of soil nitrogen: A rapid direct extraction method to measure microbial biomass nitrogen in soil. Soil Biol. Biochem. 17, 837–842.Google Scholar
  5. Carter M R 1986 Microbial biomass and mineralizable nitrogen in solonetzic soils: Influence of gypsum and lime amendments. Soil Biol. Biochem. 18, 531–537.Google Scholar
  6. Chipley J R 1980 Effects of microwave irradiation on microorganisms. Adv. Appl. Microbiol. 26, 129–145.PubMedGoogle Scholar
  7. Erdman M D and Monson W G 1986In vitro digestibility of selected agricultural wastes at various moisture levels treated with microwave energy. J. Agric. Food. Chem. 34, 889–892.Google Scholar
  8. Ferriss R S 1984 Effects of microwave-oven treatment on microorganisms in soil. Phytopathology 74, 121–126.Google Scholar
  9. Ingham E R and Klein D A 1982 Relationship between fluorescein diacetate-stained hyphae and oxygen utilization, glucose utilization, and biomass of submerged fungal batch cultures. Appl. Env. Microbiol. 44, 363–370.Google Scholar
  10. Hendricks C W, Paul E A and Brooks P D 1987 Growth measurements of terrestrial microbial species by a continuous-flow technique. Plant and Soil 101, 189–195.Google Scholar
  11. Jenkinson D S 1976 The effects of biocidal treatments on metabolism in soil. IV. The decomposition of fumigated organisms in soil. Soil Biol. Biochem. 8, 203–208.Google Scholar
  12. Jenkinson D S and Ladd J N 1981 Microbial biomass in soil, measurement and turnover. pp 415–472.In Soil Biochemistry. Eds. E A Paul and J N Ladd. Vol. 5. Marcel Dekker Inc. New York.Google Scholar
  13. Jenkinson D S and Powlson D S 1976 The effects of biocidal treatments on metabolism in soil. V. A method for measuring soil biomass. Soil Biol. Biochem. 8, 209–213.Google Scholar
  14. Khan A R, Johnson J S and Robinson R J 1979 Degradation of starch polymers by microwave energy. Cereal Chem. 56, 303–304.Google Scholar
  15. Kormanik P P and McGraw A C 1982 Quantification of vascular-arbuscular mycorrhizae in plant roots. pp 37–45.In Methods and Principles of Mycorrhizal Research. Ed. N C Schenck. The American Phytopathological Society St. Paul MN.Google Scholar
  16. Kingston J M and Jassie L B 1986 Microwave energy for acid decomposition at elevated temperatures and pressures using biological and botanical samples. Anal. Chem. 58, 2534–2541.PubMedGoogle Scholar
  17. Merckx R and Martin J K 1987 Extraction of microbial biomass components from rhizosphere soils. Soil Biol. Biochem. 19, 371–376.Google Scholar
  18. Nannipieri P, Johnson R L and Paul E A 1978 Criteria for measurement of microbial growth and activity in soil. Soil Biol. Biochem. 10, 223–229.Google Scholar
  19. Olsen S R and Dean L A 1965 Phosphorus. pp 1035–1049.In Methods of Soil Analysis. Part 2. Chemical and Microbiological Properties. Agronomy Monograph No. 9, ASASSSA. Madison WI.Google Scholar
  20. Ou L T, Rothwell D F and Mesa M V 1985 Soil sterilization by 2450 MHz microwave radiation. Soil Crop Soc. Florida Proc. 44, 77–80.Google Scholar
  21. Paul E A and Voroney R P 1984 Field interpretation of microbial biomass activity measurements. pp 509–514.In Current Perspectives in Microbial Ecology. Eds. M J Klug and C A Reddy. American Society for Microbiology, Washington D.C.Google Scholar
  22. Skipper H D and Westermann D T 1973 Comparative effects of propylene oxide, sodium azide, and autoclaving on selected soil properties. Soil Biol. Biochem. 5, 409–414.Google Scholar
  23. Sparling G P, Speir T W and Whale K 1986 Changes in microbial biomass C, ATP content, soil phospho-monoesterase, and phospho-diesterase activity followin air-drying of soils. Soil Biol. Biochem. 18, 363–370.Google Scholar
  24. Speir T W, Cowling J C, Sparling G P, West A W and Corderoy D M 1986 Effects of microwave radiation on the microbial biomass, phosphatase activity, and levels of extractable N and P in a low fertility soil under pasture. Soil Biol. Biochem. 18, 377–382.Google Scholar
  25. U.S. Environmental Protection Agency 1983 Methods for Chemical Analysis of Water and Wastes. EPA-600/4-79-020. U.S. Environmental Protection Agency, Washington, D.C.Google Scholar
  26. Van Veen J A and Paul E A 1979 Conversion of biovolume measurements of soil organisms, grown under various moisture tensions, to biomass and their nutrient content. Appl. Env. Microbiol. 37, 686–692.Google Scholar
  27. Vela G R, Wu J R and Smith D 1976 Effect of 2450 MHz microwave radiation on some soil microorganisms in situ. Soil Sci. 121, 44–51.Google Scholar
  28. Voroney R P and Paul E A 1984 Determination of KC and KN in situ for calibration of the chloroform fumigationincubation method. Soil Biol. Biochem. 16, 9–14.Google Scholar
  29. West A W, Ross D J and Cowling J C 1986 Changes in microbial C, N, P and ATP contents, numbers, and respiration on storage of soil. Soil Biol. Biochem. 18, 141–148.Google Scholar

Copyright information

© Kluwer Academic Publishers 1988

Authors and Affiliations

  • Charles W. Hendricks
    • 1
    • 2
  • Nanci Pascoe
    • 1
    • 2
  1. 1.Environmental Research LaboratoryU.S. Environmental Protection AgencyCorvallisUSA
  2. 2.Department of Forest ScienceOregon State UniversityCorvallisUSA

Personalised recommendations