Current methods for measuring microbial biomass C in soil: Potentials and limitations

Martens, Rainer

doi:10.1007/bf00336142

Cited by 233 publications

(87 citation statements)

References 55 publications

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“…Nonetheless, this study clearly demonstrated that abundance of functional guilds, and probably also total bacteria, is greatly affected by fertilization regimes. The density of nitrate reducers (narG), denitrifiers (nirS, nirK and nosZ) and ammonia oxidizers (AOB and AOA amoA) per biomass unit (mg CO 2 -C per g dw soil per h), estimated by substrate-induced respiration (Martens, 1995), was significantly lower in the ammonium sulfate treatment (data not shown). As also the 16S rRNA gene copy number per biomass unit was lower in the ammonium sulfate plots, it is likely that the microbial biomass was dominated by fungi in this treatment.…”

Section: Resultsmentioning

confidence: 99%

Relationship between N-cycling communities and ecosystem functioning in a 50-year-old fertilization experiment

et al. 2009

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The relative importance of size and composition of microbial communities in ecosystem functioning is poorly understood. Here, we investigated how community composition and size of selected functional guilds in the nitrogen cycle correlated with agroecosystem functioning, which was defined as microbial process rates, total crop yield and nitrogen content in the crop. Soil was sampled from a 50-year fertilizer trial and the treatments comprised unfertilized bare fallow, unfertilized with crop, and plots with crop fertilized with calcium nitrate, ammonium sulfate, solid cattle manure or sewage sludge. The size of the functional guilds and the total bacterial community were greatly affected by the fertilization regimes, especially by the sewage sludge and ammonium sulfate treatments. The community size results were combined with previously published data on the composition of the corresponding communities, potential ammonia oxidation, denitrification, basal and substrate-induced respiration rates, in addition to crop yield for an integrated analysis. It was found that differences in size, rather than composition, correlated with differences in process rates for the denitrifier and ammonia-oxidizing archaeal and total bacterial communities, whereas neither differences in size nor composition was correlated with differences in process rates for the ammonia-oxidizing bacterial community. In contrast, the composition of nitrate-reducing, denitrifying and total bacterial communities co-varied with primary production and both were strongly linked to soil properties.

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Section: Resultsmentioning

confidence: 99%

Relationship between N-cycling communities and ecosystem functioning in a 50-year-old fertilization experiment

et al. 2009

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“…The SIR method, similar to CFE, is also calibrated against the CFI method (Jenkinson 1988). Martens (1995) suggested the following regression between SIR and CFI:…”

Section: Smb Methodologymentioning

confidence: 99%

Interpretation of microbial biomass measurements for soil quality assessment in humid temperate regions

Carter¹,

Gregorich²,

Angers³

et al. 1999

Can. J. Soil. Sci.

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Interpretation of microbial biomass measurements for soil quality assessment in humid temperate regions. Can. J. Soil Sci. 79: 507-520. Soil microbial biomass (SMB) measurements are often used in soil biological analysis; however, their interpretation can be problematic. In this review, both the limitations and benefits of indirect (both CHCl 3 fumigation incubation and fumigation extraction, and substrate-induced respiration) SMB measurements are outlined, along with their value and interpretation as attributes or indicators to assess some soil quality (SQ) functions (e.g., enhance plant growth, maintain aggregation, regulate energy) for mainly humid, temperate soils, with specific emphasis on research conducted in eastern Canada and New Zealand. Indirect SMB methods are subject to limitations analogous to "soil test" procedures (e.g., soil sampling and handling, water content, storage prior to treatment), and also the difficulties with establishing an acceptable "control" and fraction (i.e., k value) of SMB mineralized or extracted. In many cases, such limitations present a need for some degree of standardization (e.g., pre-conditions of 7-to 10-d incubation at 25°C and -0.001MPa water potential) prior to SMB measurement. However, for SQ assessment, where "comparative" rather than "absolute" values of SMB are often of interest, use of commonly derived k values seem appropriate for surface soils.Soil ecological factors govern SMB and often underlie much of the spatial and temporal variation in SMB. Plant species composition, mainly through net primary productivity and litter quality, can affect SMB measurements along with trophic cascades in soil, where interactions among soil organisms can influence microbial activity. Benefits of SMB measurements relate mainly to the assessment of both soil C turnover and management induced changes in organic matter. The combination of SMB and δ 13 C to elucidate the transformations and fate of organic C in cropping and soil management systems has also shown that both temporal and spatial redistribution of C inputs, and soil type (i.e., particle size distribution) are dominant factors in turnover and nutrient flow through the SMB.For SQ assessment, SMB is not a useful indicator for the function of soil as a "medium for plant growth" in regard to plant productivity for intensively farmed temperate soils. For the function of soil to "maintain aggregation", where SMB is one agent only of a multi-faceted process, the relationship between SMB and soil aggregation is not always present and tends to be site-specific. In regard to the "regulate energy" soil function, SMB is related to some degree with decomposition and mineralization processes. The main role of SMB for SQ assessment is to serve within a minimum data set of other indicators (e.g., macroorganic C) to monitor soil organic C storage and change.Key words: Soil microbial biomass, humid climate, soil quality Carter, M. R., Gregorich, E. G., Angers, D. A., Beare, M. H., Sparling, G. P., Wardle, D. A. et Voroney, R. P. 1999. ...

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“…At present, SOC pools with different turnover times, such as the active, slow, and passive pools used in the Century model (Parton et al 1987), only exist conceptually, and cannot be determined experimentally, Consequently, the sizes of these C pools are assigned arbitrarily, and more often subjectively (Campbell et al 1999a, b). Technically, soil microbial biomass C should be a part of labile soil organic matter (Gregorich et al 1994), but, spatial and temporal variability along with technical difficulty in measurements and methodologies make its utility difficult as an index of labile fraction of soil organic matter (Martens 1995). The size of LFOC is usually as much as 10 time greater than that of microbial biomass C (Liang et al 1998).…”

Section: Effect Of Tillagementioning

confidence: 99%

Effect of tillage and crop rotations on the light fraction organic carbon and carbon mineralization in Chernozemic soils of Saskatchewan

Liang¹,

McConkey²,

Schoenau³

et al. 2003

Can. J. Soil. Sci.

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H. 2003. Effect of tillage and crop rotations on the light fraction organic carbon and carbon mineralization in Chernozemic soils of Saskatchewan. Can J. Soil Sci. 83: 65-72. Light fraction of soil organic C (LFOC) represents a major portion of labile soil organic C (SOC) and is a key attribute of soil quality. Soil respiration (C min ) is an important index depicting the potential activity of the labile SOC. Six field experiments, varying in duration (8 to 25 yr), in location (Brown, Dark Brown and Black Chernozemic soil zones of Saskatchewan) and soil texture, were conducted to evaluate the impact of tillage and crop rotations on crop production and soil quality. We sampled the 0-7.5-cm depth of soil in these experiments to determine the treatment effects on LFOC, the proportion of LFOC in the SOC (LFOC/SOC) and C min . Increasing the frequency of summer fallow in cropping systems decreased the LFOC in all soil zones; it also decreased the proportion of LFOC in SOC and C min . Tillage had little impact on LFOC in the Brown and Dark Brown Chernozemic soil zones, although it significantly decreased LFOC in the Black Chernozemic soil zone. Thus, crop rotation had a greater impact on LFOC than tillage. Tillage did not influence C min in any soil zone. Because adoption of no-till management increased SOC in all soil zones, we concluded that LFOC was not a sensitive indicator of the impact of tillage on this soil quality attribute for these Chernozemic soils in Saskatchewan. We also found that LFOC/SOC is directly proportional to sand content. This relationship may assist us in partitioning SOC pools with differing turnover times when modeling SOC dynamics.Key words: Soil organic C, light fraction organic C, tillage, crop rotations, texture, mineralizable C Liang, B. C., McConkey, B. G., Schoenau, J., Curtin, D., Campbell, C. A., Moulin, A. P., Lafond, G. P., Brandt, S. A. et Wang, H. 2003. Incidence du travail du sol et de l'assolement sur la fraction légère du carbone organique et sur la minéralisation du carbone dans les sols tchernozémiques de la Saskatchewan. Can. J. Soil Sci. 83: 65-72. La fraction légère du C organique du sol (FLCO) constitue une part importante du C organique du sol (COS) labile et elle figure parmi les principaux paramètres qualitatifs du sol. La respiration (C min ) est un indice important caractérisant l'activité potentielle du COS labile. Les auteurs ont entrepris six expériences d'une durée variable (de 8 à 25 ans), à divers endroits (zones de sols bruns, de sols brun foncé et de sols noirs tchernozémiques de la Saskatchewan) et sur des sols de texture différente, afin d'évaluer l'incidence du travail du sol et de l'assolement sur la production végétale et la qualité du sol. Ils ont prélevé des échantillons de sol à une profondeur de 0 à 7,5 cm et déterminé l'effet des traitements sur la FLCO, la proportion de FLCO dans le COS (FLCO/COS) et la C min . Des jachères d'été plus fréquentes réduisent la FLCO dans toutes les zones de sols; elles diminuent aussi le rapport FLCO/COS et la C m...

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Current methods for measuring microbial biomass C in soil: Potentials and limitations

Cited by 233 publications

References 55 publications

Relationship between N-cycling communities and ecosystem functioning in a 50-year-old fertilization experiment

Relationship between N-cycling communities and ecosystem functioning in a 50-year-old fertilization experiment

Interpretation of microbial biomass measurements for soil quality assessment in humid temperate regions

Effect of tillage and crop rotations on the light fraction organic carbon and carbon mineralization in Chernozemic soils of Saskatchewan

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