Microbiological parameters as indicators of soil organic carbon dynamics in relation to different land use management |
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| Authors: | Mireia Llorente M Belén Turrión |
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| Institution: | (1) E.T.S.II.AA, University of Valladolid, Palencia, Spain |
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| Abstract: | Labile C fractions: microbial biomass C (MBC), K2SO4 extractable C (
\textC\textK 2 \textSO 4 {\text{C}}_{{{\text{K}}_{ 2} {\text{SO}}_{ 4} }} ) and the cumulated mineralized C in 21 days incubation at 28°C (C–CO2(21d)), were compared as land use indicators in a calcareous soil under three different management systems: native Querqus ilex forest (under and outside tree cover), a Pinus halepensis plantation, and cropped land (with cereals). Microbial biomass and activity were found to be low and coincided with high
carbonate contents. As indicators of land use,
\textC\textK 2 \textSO 4 {\text{C}}_{{{\text{K}}_{ 2} {\text{SO}}_{ 4} }} and C–CO2(21d) showed the same sensitivity as MBC. C–CO2 emissions were measured in an incubation experiment in order to study C mineralization kinetics. The data for cumulative
amounts of C–CO2 released showed a good fit (R
2 > 0.94) to the first-order kinetic model C
m = C
o(1 − e−kt
). The kinetic parameters C
o and C
o
k were affected by land use and especially by tree cover. Principal components analysis was applied to the data and the relationship
among microbial metabolic quotient (qCO2), labile C pools, and MBC revealed a decrease in efficiency of organic substrate utilization with an increase in availability
and lability of the organic matter. |
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| Keywords: | |
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