02223nam a2200265 a 450000100080000000500110000800800410001910000170006024500670007726000430014430000100018749000230019750000510022052015450027165000120181665000190182865000090184765000200185665000130187665000160188965000120190565000090191765300120192665300190193816215711997-07-04       1983    bl uuuu  m   00u1 u    #d1 aGRISI, B. M.  aA Comparison of methods for estimating soil microbial biomass.  aEssex: University of Essex, Jan.c1983  a147p.  aTese de Doutorado.  aTese de Doutorado. Orientada por: T.R.G. Gray.  aThe "standing crop" or biomass of microorganisms, that stores important nutrients in soil (nitrogen, phosphorus, sulphur) should be a useful guide to evaluate changes in soil microbial populations, caused by many factors concerning the use and management of soils. In the present study four methods devised to estimate soil microbial biomass were compared: A) biomass determined from microorganisms killed by fumigation with alcohol-free chloroform; b) biomass determined from the substrate-induced maximum initial respiration rate after addition of glucose to soil; c) ATP content of soil; d) microbial biovolumes of hyphae, and of spherical and nearly spherical microorganisms, estimated by fluorescence microscopy. The biovolumes were converted to biomass. These methods were used simultaneously with the same samples from nine different soils (woodlands soils, agricultural and grassland ones) for determining their microbial biomasses. Strong and significant correlations were obtained between the biomass determined by the fumigation method (termed here fumigation biomass or FB) and ATP content of soil (r+ 0,94) and respiration rate in response to glucose (termed were RRG) (r= 0,85). ATP content correlated strongly and significantly with RRG (r= 0,95). The correlation of FB with biomass calculated from total biovolume of fungi and of spherical and nearly spherical microorganismd (termed here B-TBv) was poor and non-significant (r= 0,39). B-TBv did not correlate significantly with ATP content of soil (r= 0,52). B-TBv ........  abiomass  amicroorganisms  asoil  asoil fumigation  aBiomassa  aFumigação  aMétodo  aSolo  aMethods  aMicroorganismo