01608naa a2200169 a 450000100080000000500110000800800410001910000200006024500870008026000090016752011520017665000090132865000090133770000160134670000170136277300590137917863692017-04-07       1985    bl ---       0--  u    #d1 aSPARLING, G. P.  aInterference from plant roots on the estimation of soil microbial ATP, C, N and P.  c1985  aExcised solution-grown roots of maize or ryegrass added to two pasture soils at the rate of 6.0 mg g-1 and 13.8 mg g-1, respectively, ,increased the flush (fumigated mkinus control values) of CO2-C by up to 1.89-fold, KCl extractable N by up to 1.88-fold and NaHCO, extractable P by 3.28-fold. The ATP content of the soil was increased by up to 1.42-fold. Because of high variability the effects of the roots on the C and N flueshes was not significant at P&lt0.05. Incubation of the root-amemnded soils for 7 days at 25 C prior to fumigation much decreased the contribution from the roots to the C and N flush and to the ATP content. There was, however, still a large significant effect of the roots on the P-flush, this being up to 3 times greater than the equivalent soil without roots. In soil samples with a high viable root density (&gt6 mg g) such as may occur in dense pastures, greenhouse pot experiment or rhizosphere soil samples, it is recommended that they be incubated for 7 days prior to fumigation and analysis. Whitout such prior incubation there is the risk that root material may be included in the microbial biomass estimation.  asoil  aSolo1 aWEST, A. W.1 aWHALE, K. N.  tSoil Biology Biochemistrygv.17, n.3, p.275-278, 1985.