01724naa a2200277 a 450000100080000000500110000800800410001910000110006024500820007126000090015352010110016265000150117365000150118865000220120365000120122565000160123765000130125365300240126665300160129065300140130665300120132070000210133270000130135370000170136677300630138310754401995-12-13       1994    bl ---       0--  u    #d1 aWU, J.  aFumigation-extraction method for the measurement of soil microbial biomass-S.  c1994  aFumigation-extraction was evaluated for the measurement of microbial biomass-S in soil. Following fumigation in CHCl3, S was extracted using 10 mM CaCl2 at a soil-to-extractant ratio of 1-to-2 (w/v). These conditions were shown to be favourable in a range of soils containing extractable-S below 30 mg S g-1 soil. Extractable-S was measured by ion chromatography following H2O2 digestion. The increase in extractable-S following fumigation (the flush) was converted to biomass-S using a conversion factor (Ks) determined using 35S-labelled biomass-S. Using a soil-to-extractant ratio of 1-to-2 gave a value for Ks of 0.31. This methodology was shown to be reliable for soils subject to arable, grassland or woodland management, with pH values above 3.7 and claycontents of 4-60%. The amounts of biomass-S measured in these soils were in the range 2.9-20 mg S g-1 soil. The data also showed that the amounts of biomass-S in soil are related to biomass-C and dependant upon soil management and fertilisation.  achloroform  afumigation  amicrobial biomass  aEnxofre  aFumigação  aPastagem  aBiomassa microbiana  aCloroformio  aGrassland  aSulphur1 aO'DONNELL, A. G.1 aHE, Z. L1 aSYERS, J. K.  tSoil Biology and Biochemistrygv.26, n.1, p.117-125, 1994.