Carbon Sources for Bacterial Denitrification

Beauchamp, E. G.; Trevors, J. T.; Paul, J. W.

doi:10.1007/978-1-4613-8847-0_3

Cited by 242 publications

(143 citation statements)

References 139 publications

(129 reference statements)

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“…The denitrifying genes are reported to be widespread in phylogenetically distant organisms (Linne von Berg and Bothe, 1992) in surface water, soil and groundwater (Beauchamp et al, 1989) and at great depths in aquifers (Neilsen et al, 2006), but their 22 expression requires favourable environmental conditions. Our results are in agreement with Cavigelli and Robertson (2000) who also found that the abundance of denitrifying genes was similar among wells and sites but that gene expression was controlled by hydrogeochemical conditions which in turn controlled the denitrification process.…”

Section: Abundances Of Denitrifier Functional Genes In Groundwatermentioning

confidence: 99%

Denitrification and indirect N2O emissions in groundwater: Hydrologic and biogeochemical influences

Jahangir

Johnston

Barrett

et al. 2013

Journal of Contaminant Hydrology

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Identification of specific landscape areas with high and low groundwater denitrification potential is critical for improved management of agricultural nitrogen (N) export to ground and surface waters and indirect nitrous oxide (N 2 O) emissions. Denitrification products together with concurrent hydrogeochemical properties were analysed over two years at three depths at two low (L) and two high (H) permeability agricultural sites in Ireland. Mean N 2 O-N at H sites were significantly higher than L sites, and decreased with depth. Conversely, excess N 2 -N were significantly higher at L sites than H sites and did not vary with depth. Denitrifier functional genes were similar at all sites and depths. Data showed that highly favourable conditions prevailed for denitrification to occur -multiple electron donors, low redox potential (Eh <100 mV), low DO (<2 mg L -1 ), low permeability (k s <0.005 m d -1 ) and a shallow unsaturated zone (<2 m). Quantification of excess N 2 -N in groundwater helps to close N balances at the local, regional and global scales.

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Section: Abundances Of Denitrifier Functional Genes In Groundwatermentioning

confidence: 99%

Denitrification and indirect N2O emissions in groundwater: Hydrologic and biogeochemical influences

Jahangir

Johnston

Barrett

et al. 2013

Journal of Contaminant Hydrology

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“…Organic manures contain both a range of easily degradable organic C and N and mineral N compounds (Beauchamp et al, 1989). Studies have shown that repeated long-term applications of organic manures will enhance soil organic C and N contents, particularly the more labile soil organic matter, as well as soil microbial biomass and enzyme activity (Hao et al, 2003;Kirchmann et al, 2004;Mallory and Griffin, 2007;Zaman et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Effects of repeated fertilizer and cattle slurry applications over 38 years on N dynamics in a temperate grassland soil

Müller

Laughlin²,

Christie³

et al. 2011

Soil Biology and Biochemistry

115

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The effects of repeated synthetic fertilizer or cattle slurry applications at annual rates of 50, 100 or 200 m 3 ha À1 yr À1 over a 38 year period were investigated with respect to herbage yield, N uptake and gross soil N dynamics at a permanent grassland site. While synthetic fertilizer had a sustained and constant effect on herbage yield and N uptake, increasing cattle slurry application rates increased the herbage yield and N uptake linearly over the entire observation period. Cattle slurry applications, two and four times the recommended rate (50 m 3 ha À1 yr À1 , 170 kg N ha À1 ), increased N uptake by 46 and 78%, respectively after 38 years. To explain the long-term effect, a 15 N tracing study was carried out to identify the potential change in N dynamics under the various treatments. The analysis model evaluated process-specific rates, such as mineralization, from two organic-N pools, as well as nitrification from NH 4 þ and organic-N oxidation. Total mineralization was similar in all treatments. However, while in an unfertilized control treatment more than 90% of NH 4 þ production was related to mineralization of recalcitrant organic-N, a shift occurred toward a predominance of mineralization from labile organic-N in the cattle slurry treatments and this proportion increased with the increase in slurry application rate. Furthermore, the oxidation of recalcitrant organic-N shifted from a predominant NH 4 þ production in the control treatment, toward a predominant NO 3 À production (heterotrophic nitrification) in the cattle slurry treatments. The concomitant increase in heterotrophic nitrification and NH 4 þ oxidation with increasing cattle slurry application rate was mainly responsible for the increase in net NO 3 À production rate. Thus the increase in N uptake and herbage yield on the cattle slurry treatments could be related to NO 3 À rather than NH 4 þ production. The 15 N tracing study was successful in revealing process-specific changes in the N cycle in relationship to long-term repeated amendments.

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“…However, Beauchamp et al (1989) suggested that a significant proportion of water-extracted C was not available to denitrifying microorganisms.…”

Section: Introducitonmentioning

confidence: 99%

Availability of organic carbon in soluble and particle-size fractions from a soil profile

Nelson

Dictor

Soulas

1994

Soil Biology and Biochemistry

106

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Summary-In an agricultural soil profile, the availability of soil organic C for microbial activity decreased from 0 to 100 cm depth in winter, spring and summer. Availability was defined as the ratio of respiration rate to total organic C, or the ratio of microbial biomass C to total organic C. The amount and availability oforganic C in various soil fractions was measured. Fractions consisted of aqueous extracts from throughout the profile, and particle-size and density fractions from the O-20 and SO-100 cm layers. The fractions were incubated with soil inoculum for 24 or 28 days. Availability of organic C in soluble fractions was measured by the decrease in dissolved organic C. Availability of organic C in insoluble fractions was measured by the increase in inorganic C. Availability of organic C in all fractions was similar at each depth, except for the weakly-adsorbed and clay fractions, in which organic C was less available at depth. Availability was least in the silt fractions. Approximately half of the organic C mineralized during incubations originated from the clay fraction in both the &lo and SO-100 cm layers. Of the remainder, at the surface a higher proportion was in the silt and light (> 50 km, d< 2 g cm-3, fractions, due to a larger proportion of total organic C in those fractions. At depth, a higher proportion was in the extracted fractions. The decrease in the availability of total organic C with depth appeared mainly to be due to a decrease in the accessibility of organic C to microorganisms, and a decrease in the availability of clay fraction organic C.

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Carbon Sources for Bacterial Denitrification

Cited by 242 publications

References 139 publications

Denitrification and indirect N2O emissions in groundwater: Hydrologic and biogeochemical influences

Denitrification and indirect N2O emissions in groundwater: Hydrologic and biogeochemical influences

Effects of repeated fertilizer and cattle slurry applications over 38 years on N dynamics in a temperate grassland soil

Availability of organic carbon in soluble and particle-size fractions from a soil profile

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