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Microbial indicators of fertility in arable land

Svensson, Kalle (2002). Microbial indicators of fertility in arable land. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Agraria, 1401-6249 ; 330
ISBN 91-576-6170-7
[Doctoral thesis]

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In this thesis eleven microbial variables were evaluated as indicators of soil fertility. The variables were derived from short-incubation tests based on respiration, denitrification, ammonium oxidation, and alkaline phosphatase activity. During the incubation, the formation rate of metabolic end-products or intermediates was recorded and the variables were derived by use of linear or non-linear regression. Soils from three sites of a long-term field experiment and from a short-term laboratory incubation experiment were used for the evaluation. The microbial variables were evaluated in relation to standard soil chemical variables and yields from a whole crop rotation cycle. Substrate-induced respiration (SIR) and respiration rate under phosphorus limited conditions (Max-P) were indicators of labile organic material and available P, respectively. They were also the best yield predictors in unfertilised and nitrogen fertilised systems, respectively. SIR was shown to quantify both dormant and fully active microorganisms. Substrate amendment could transform the dormant biomass into an active stage. The division of SIR into active and dormant biomass fractions holds promise that the SIR assay can be of value as an indicator of the mineralisation dynamics at two different time scales. Moreover, the concept of active and dormant microbial biomass has implications on how to model the carbon fluxes in soil. Basal respiration was influenced by temporary substrate sources and rhizodeposits and was therefore not considered as a stable soil fertility indicator. Potential denitrification (PDA) and ammonium oxidation (PAO) was governed both by pH and substrate supply. The prediction models for PDA varied markedly between the sites and exhibited a relatively low predictive capacity, which renders PDA less sutable as a soil fertility indicator. However, PDA was satisfactorily predicted by a combination of PAO and SIR. When interpreting PAO, it should be regressed on pH to check for diverging soils that may be N limited. A combination of pH and organic matter characteristics was efficient for prediction of alkaline phosphatase activity (Alk-P), which implies that Alk-P is a pH-sensitive indicator of the microbial biomass.

Authors/Creators:Svensson, Kalle
Title:Microbial indicators of fertility in arable land
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Agraria
Year of publishing :April 2002
Number of Pages:53
ALLI. Svensson K and Pell M. 2001. Soil microbial tests for discriminating between different cropping systems and fertiliser regimes. Biology and Fertility of Soils 33, 91-99. II. Svensson K and Pell M. 2002. Relations between chemical and microbiological properties in soil after 40 years of different cropping strategies. Manuscript. III. Svensson K, Pell M and Mattsson L. 2002. Microbial properties as yield indicators in 40-year-old field experiments. Manuscript. IV. Stenström J, Svensson K and Johansson M. 2001. Reversible transition between active and dormant microbial states in soil. FEMS Microbiology Ecology 36, 93-104.
Place of Publication:Uppsala
ISBN for printed version:91-576-6170-7
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P35 Soil fertility
P Natural resources > P33 Soil chemistry and physics
Subjects:Not in use, please see Agris categories
Agrovoc terms:agricultural soils, soil microorganisms, soil chemicophysical properties, soil fertility, yield forecasting
Keywords:Arable land, fertility indicators, field experiments, microorganisms, physiological state, yield prediction
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ID Code:225
Department:(NL, NJ) > Dept. of Microbiology (until 161231)
Deposited By: Staff Epsilon
Deposited On:07 Apr 2003 00:00
Metadata Last Modified:02 Dec 2014 10:02

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