Gross nitrogen mineralization-, immobilization-, and nitrification rates as a function of soil C/N ratio and microbial activity

Bengtsson, Göran; Bengtson, Per; Månsson, Katarina

doi:10.1016/s0038-0717(02)00248-1

Cited by 389 publications

(245 citation statements)

References 75 publications

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“…As reported, N mineralization in forest soils may be affected separately and/or interactively by a range of factors and processes (Fig. 1), such as C/N ratios of soil organic matter (SOM) (Bengtsson et al 2003;Hodge et al 2000;Kaye and Hart 1997), soil pH (Fang et al 2004), soil microbes (e.g., microbial biomass and activity) (Bengtsson et al 2003;Tietema 1998), microbial extracellular enzymes ), and quality and decomposition of litter (e.g., C/N ratios and N content of lignin) (Janssens et al 2010).…”

Section: N Mineralizationmentioning

confidence: 95%

Effects of nitrogen deposition and fertilization on N transformations in forest soils: a review

et al. 2015

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Purpose Understanding how process-specific nitrogen (N) transformations in natural forest soils are modified by N deposition and fertilization is critically important to gain mechanistic insights on the links between global N deposition and N enrichment and loss in forest soils. Materials and methods Here we identify the general characteristics and the main mechanisms of N deposition-and fertilization-induced modifications in multiple N transformations, including N immobilization, N mineralization, nitrification (autotrophic nitrification and heterotrophic nitrification), and denitrification, in forest soils by literature survey. Results and discussion Overall, N status, soil C/N ratios, C availability, and soil pH are key factors separately and/or interactively affecting the effects of N deposition and fertilization on forest soil N transformations. In the N-limited stage, N deposition and fertilization can act as a stimulator of N mineralization by removing microbial N limitation and reducing the C/N ratios of the substrate being decomposed. In the Nunlimited stage, N added to forest ecosystems can retard N mineralization, which may primarily be a result of decreased microbial activity due to soil acidification and low C availability. The changes in N mineralization may drive a corresponding change in N immobilization, autotrophic nitrification, and denitrification. Despite the fact that ammonia-oxidizing archaea (AOA) has a higher affinity than ammonia-oxidizers (AOB) for low-concentration ammonia (NH 3 ), low NH 3 availability may still limit the rate of ammonia oxidation (autotrophic nitrification) in acidic forest soils even in the case of high NH 4 + input. Heterotrophic nitrification, however, may be favored if soil C/N ratios and pH decrease with N deposition and fertilization. The responses of denitrification and N 2 O emission to N deposition and fertilization in forests may be nonlinear, with a trend of stimulation in the short term but a decline over time, partly because soil pH has a contrast effect on denitrification capacity and N 2 O emission. Conclusions There are various effects of N deposition and fertilization on forest soil N transformations; thus, their responses to N deposition are still not well characterized and understood. N deposition-and fertilization-induced modifications in soil N transformations have important implications for N enrichment, N loss, and soil acidification in forest ecosystems. In the future, more research is required to investigate on dissimilatory nitrate reduction to ammonium (DNRA) process and link microbial community characteristics and functions of microbial extracellular enzymes with these rate processes in forest soils to narrow the uncertainty in evaluating and predicting ecosystem responses to global N deposition.

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Section: N Mineralizationmentioning

confidence: 95%

Effects of nitrogen deposition and fertilization on N transformations in forest soils: a review

et al. 2015

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“…A soil C/N ratio of 13 is in the range used by Gerber et al (2010) and Zaehle and Friend (2010) and is also supported by observations: soil C/N ratios were found to be < 10 for tropical areas and > 20 for boreal areas (Global Soil Data Task Group, 2000) and 14.2 for tropical areas and 13.2-18.9 for boreal areas (Zinke et al, 1984;Esser et al, 2011). Relating immobilisation rates to the C/N ratio is controversial as biomass and the metabolic state of microorganisms seem to be better predictors of immobilisation rates (Bengtsson et al, 2003) than soil C/N ratios. However, microbial biomass and metabolic state are not variables that are ready to be included into a global Earth System Model.…”

Section: Organic Poolsmentioning

confidence: 64%

Carbon-nitrogen feedbacks in the UVic ESCM

et al. 2012

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Abstract.A representation of the terrestrial nitrogen cycle is introduced into the UVic Earth System Climate Model (UVic ESCM). The UVic ESCM now contains five terrestrial carbon pools and seven terrestrial nitrogen pools: soil, litter, leaves, stem and roots for both elements and ammonium and nitrate in the soil for nitrogen. Nitrogen cycles through plant tissue, litter, soil and the mineral pools before being taken up again by the plant. Biological N 2 fixation and nitrogen deposition represent external inputs to the plant-soil system while losses occur via leaching. Simulated carbon and nitrogen pools and fluxes are in the range of other models and observations. Gross primary production (GPP) for the 1990s in the CN-coupled version is 129.6 Pg C a −1 and net C uptake is 0.83 Pg C a −1 , whereas the C-only version results in a GPP of 133.1 Pg C a −1 and a net C uptake of 1.57 Pg C a −1 . At the end of a transient experiment for the years 1800-1999, where radiative forcing is held constant but CO 2 fertilisation for vegetation is permitted to occur, the CN-coupled version shows an enhanced net C uptake of 1.05 Pg C a −1 , whereas in the experiment where CO 2 is held constant and temperature is transient the land turns into a C source of 0.60 Pg C a −1 by the 1990s. The arithmetic sum of the temperature and CO 2 effects is 0.45 Pg C a −1 , 0.38 Pg C a −1 lower than seen in the fully forced model, suggesting a strong nonlinearity in the CN-coupled version. Anthropogenic N deposition has a positive effect on Net Ecosystem Production of 0.35 Pg C a −1 . Overall, the UVic CN-coupled version shows similar characteristics to other CN-coupled Earth System Models, as measured by net C balance and sensitivity to changes in climate, CO 2 and temperature.

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“…Nitrification is driven by the density and activity of the microbial community (Bengtsson et al, 2003), and shows high spatial variability Devito et al, 1999). Increased NO 3 -N availability and elevated groundwater table levels after clear-cutting can initiate denitrification and N losses to the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Water and nitrogen processes along a typical water flowpath and streamwater exports from a forested catchment and changes after clear-cutting: a modelling study

Laurén¹,

Finér

Koivusalo³

et al. 2005

Hydrol. Earth Syst. Sci.

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A two dimensional model, FEMMA, to describe water and nitrogen (N) fluxes within and from a forested first-order catchment (Kangasvaara in Eastern Finland) was constructed by linking the most significant processes affecting the fluxes of water, ammonium, nitrate and dissolved organic nitrogen along a hillslope from the water divide to the stream. The hillslope represents the average flowpath of water in the catchment and the model was used to estimate the N fluxes for a catchment in eastern Finland before and after clear-cutting. The simulated results were in reasonable agreement with the nitrate, dissolved organic N and dissolved total N measurements from the study catchment and with other results in the literature. According to the simulations, the major sinks of N after clear-cutting were immobilisation by soil microbes, uptake by ground vegetation and sorption to soil. These sinks increased downslope from the clear-cut area, indicating the importance of an uncut buffer zone between the stream and the clear-cut area in reducing N exports. The buffer zone retained 76% of the N flux coming from the clear-cut area. Nitrification was a key process in controlling the N export after clear-cutting and N increases were mainly as nitrate. Most of the annual N export took place during the spring flood, when uptake of N by plants was minimal.

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Gross nitrogen mineralization-, immobilization-, and nitrification rates as a function of soil C/N ratio and microbial activity

Cited by 389 publications

References 75 publications

Effects of nitrogen deposition and fertilization on N transformations in forest soils: a review

Effects of nitrogen deposition and fertilization on N transformations in forest soils: a review

Carbon-nitrogen feedbacks in the UVic ESCM

Water and nitrogen processes along a typical water flowpath and streamwater exports from a forested catchment and changes after clear-cutting: a modelling study

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