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Confirmation of co-denitrification in grazed grassland.

Selbie DR, Lanigan GJ, Laughlin RJ, Di HJ, Moir JL, Cameron KC, Clough TJ, Watson CJ, Grant J, Somers C, Richards KG - Sci Rep (2015)

Bottom Line: Pasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment.We report that 55.8 g N m(-2) (95%, CI 38 to 77 g m(-2)) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m(-2)), compared to only 1.1 g N m(-2) (0.4 to 2.8 g m(-2)) from denitrification.This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.

View Article: PubMed Central - PubMed

Affiliation: Teagasc, Johnstown Castle, Environmental Research Centre, County Wexford, Ireland.

ABSTRACT
Pasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment. Research has focused on losses to air and water due to the health, economic and environmental impacts of reactive N. Di-nitrogen (N2) emissions are still poorly characterized, both in terms of the processes involved and their magnitude, due to financial and methodological constraints. Relatively few studies have focused on quantifying N2 losses in vivo and fewer still have examined the relative contribution of the different N2 emission processes, particularly in grazed pastures. We used a combination of a high (15)N isotopic enrichment of applied N with a high precision of determination of (15)N isotopic enrichment by isotope-ratio mass spectrometry to measure N2 emissions in the field. We report that 55.8 g N m(-2) (95%, CI 38 to 77 g m(-2)) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m(-2)), compared to only 1.1 g N m(-2) (0.4 to 2.8 g m(-2)) from denitrification. This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.

No MeSH data available.


Related in: MedlinePlus

Mean daily N2 and N2O fluxes (g N m−2 day−1) (n = 4) from (a) co-denitrification (N2CO), and true denitrification (b) N2TRUE, and (c) N2OTRUE over a four month period following urine deposition. Error bar is the standard error of the mean (n = 4).
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f2: Mean daily N2 and N2O fluxes (g N m−2 day−1) (n = 4) from (a) co-denitrification (N2CO), and true denitrification (b) N2TRUE, and (c) N2OTRUE over a four month period following urine deposition. Error bar is the standard error of the mean (n = 4).

Mentions: Temporal profiles of gaseous N emissions revealed substantial losses associated with N2CO, with mean daily fluxes of 0.44 g N m−2 d−1 over the four-month experiment (Fig. 2a). In contrast, emissions associated with true denitrification were an order of magnitude lower; with mean daily fluxes of 0.01 g N m−2 d−1 and 0.005 g N m−2 d−1 observed for N2TRUE and N2OTRUE, respectively (Fig. 2b,c). Although N2CO was the predominant loss pathway there was no detectable N2OCO during the course of the experiment. The cumulative gaseous N losses associated with true denitrification were 1.1 and 0.66 g N m−2 for N2TRUE and N2OTRUE, respectively (Fig. 3). Emissions from N2CO were the dominant loss pathway accounting for 55.8 g N m−2 and 97% of total gaseous N loss, equivalent to 56% of the N applied. Comparisons with prior studies are limited due to the fact that only one laboratory study reports co-denitrification, to our knowledge36. Their study36 showed that 92% of the N2 emitted was due to co-denitrification and only 8% due to denitrification after applying 15N enriched NH4NO3. These findings are similar to the findings in the current study.


Confirmation of co-denitrification in grazed grassland.

Selbie DR, Lanigan GJ, Laughlin RJ, Di HJ, Moir JL, Cameron KC, Clough TJ, Watson CJ, Grant J, Somers C, Richards KG - Sci Rep (2015)

Mean daily N2 and N2O fluxes (g N m−2 day−1) (n = 4) from (a) co-denitrification (N2CO), and true denitrification (b) N2TRUE, and (c) N2OTRUE over a four month period following urine deposition. Error bar is the standard error of the mean (n = 4).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663629&req=5

f2: Mean daily N2 and N2O fluxes (g N m−2 day−1) (n = 4) from (a) co-denitrification (N2CO), and true denitrification (b) N2TRUE, and (c) N2OTRUE over a four month period following urine deposition. Error bar is the standard error of the mean (n = 4).
Mentions: Temporal profiles of gaseous N emissions revealed substantial losses associated with N2CO, with mean daily fluxes of 0.44 g N m−2 d−1 over the four-month experiment (Fig. 2a). In contrast, emissions associated with true denitrification were an order of magnitude lower; with mean daily fluxes of 0.01 g N m−2 d−1 and 0.005 g N m−2 d−1 observed for N2TRUE and N2OTRUE, respectively (Fig. 2b,c). Although N2CO was the predominant loss pathway there was no detectable N2OCO during the course of the experiment. The cumulative gaseous N losses associated with true denitrification were 1.1 and 0.66 g N m−2 for N2TRUE and N2OTRUE, respectively (Fig. 3). Emissions from N2CO were the dominant loss pathway accounting for 55.8 g N m−2 and 97% of total gaseous N loss, equivalent to 56% of the N applied. Comparisons with prior studies are limited due to the fact that only one laboratory study reports co-denitrification, to our knowledge36. Their study36 showed that 92% of the N2 emitted was due to co-denitrification and only 8% due to denitrification after applying 15N enriched NH4NO3. These findings are similar to the findings in the current study.

Bottom Line: Pasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment.We report that 55.8 g N m(-2) (95%, CI 38 to 77 g m(-2)) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m(-2)), compared to only 1.1 g N m(-2) (0.4 to 2.8 g m(-2)) from denitrification.This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.

View Article: PubMed Central - PubMed

Affiliation: Teagasc, Johnstown Castle, Environmental Research Centre, County Wexford, Ireland.

ABSTRACT
Pasture-based livestock systems are often associated with losses of reactive forms of nitrogen (N) to the environment. Research has focused on losses to air and water due to the health, economic and environmental impacts of reactive N. Di-nitrogen (N2) emissions are still poorly characterized, both in terms of the processes involved and their magnitude, due to financial and methodological constraints. Relatively few studies have focused on quantifying N2 losses in vivo and fewer still have examined the relative contribution of the different N2 emission processes, particularly in grazed pastures. We used a combination of a high (15)N isotopic enrichment of applied N with a high precision of determination of (15)N isotopic enrichment by isotope-ratio mass spectrometry to measure N2 emissions in the field. We report that 55.8 g N m(-2) (95%, CI 38 to 77 g m(-2)) was emitted as N2 by the process of co-denitrification in pastoral soils over 123 days following urine deposition (100 g N m(-2)), compared to only 1.1 g N m(-2) (0.4 to 2.8 g m(-2)) from denitrification. This study provides strong evidence for co-denitrification as a major N2 production pathway, which has significant implications for understanding the N budgets of pastoral ecosystems.

No MeSH data available.


Related in: MedlinePlus