scholarly journals Inorganic and Organic Losses of Nitrogen from Upland Regions of Britain: Concentrations and Fluxes

2001 ◽  
Vol 1 ◽  
pp. 589-596 ◽  
Author(s):  
P.J. Chapman ◽  
A.C. Edwards
Keyword(s):  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
N Deposition ◽  
Atmospheric N Deposition ◽  
Total N ◽  
Inorganic And Organic

The nitrogen (N) composition of streams draining eight upland regions of Britain was compared using monthly samples collected between April 1997 and April 1998. Stream samples were analysed for total N (TN), particulate N (PN), nitrate (NO3), ammonium (NH4), and dissolved organic nitrogen (DON). Concentrations of TN were small, generally less than 1.5 mg N l�1, were dominated by dissolved forms of N, and varied significantly between regions. NO3 accounted for the majority of variability. Concentrations of DON also varied between regions but to a smaller extent than those of NO3. There were considerable variations in TN fluxes between upland regions, which ranged between 3.8 and 16.1 kg N ha�1 year�1. The majority of the variation was due to NO3 fluxes, which were largest in regions receiving largest inputs of atmospheric N deposition and ranged between 1.4 and 13.5 kg N ha�1 year�1. Fluxes of DON ranged between 1 and 3.5 kg N ha�1 year�1, while fluxes of PN were generally less than 0.5 kg N ha�1 year�11, and NH4 fluxes ranged between 0.1 and 0.4 kg N ha�1 year�11. NO3 was the dominant fraction (47�84%) of N exported from all upland regions except the Highlands, where DON accounted for 52% of the TN flux. This study has shown that the DON fraction is an important component of the total N transported by upland streams in Britain.

Dissolved carbon and nitrogen leaching following variable logging-debris retention and competing-vegetation control in Douglas-fir plantations of western Oregon and Washington

2009 ◽  
Vol 39 (8) ◽  
pp. 1484-1497 ◽  
Author(s):  
Robert A. Slesak ◽  
Stephen H. Schoenholtz ◽  
Timothy B. Harrington ◽  
Brian D. Strahm
Keyword(s):  
Soil Water ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Total N ◽  
Vegetation Control ◽  
Dissolved Carbon ◽  
Competing Vegetation ◽  
Nitrate N ◽  
N Concentration ◽  
C And N

We examined the effect of logging-debris retention and competing-vegetation control (CVC, initial or annual applications) on dissolved organic carbon (DOC), dissolved organic nitrogen, and nitrate-N leaching to determine the relative potential of these practices to contribute to soil C and N loss at two contrasting sites. Annual CVC resulted in higher soil water nitrate-N concentration and flux, with the magnitude and duration of the effect greatest at the high-N site. Most of the increase in nitrate-N at the low-N site occurred in treatments where logging debris was retained. Dissolved organic nitrogen increased at the high-N site in March of each year following annual CVC, but the contribution of this increase to total N concentration was small (2%–4% of total N flux). There was no effect of logging-debris retention or CVC treatment on soil water DOC concentrations, indicating that DOC inputs from logging debris and competing vegetation were either retained or consumed in the mineral soil. The estimated increase in leaching flux of dissolved C and N associated with the treatments was low relative to total soil pools, making it unlikely that loss of these elements via leaching will negatively affect future soil productivity at these sites.

scholarly journals Subalpine grassland carbon balance during 7 years of increased atmospheric N deposition

2016 ◽  
Vol 13 (12) ◽  
pp. 3807-3817 ◽  
Author(s):  
Matthias Volk ◽  
Jan Enderle ◽  
Seraina Bassin
Keyword(s):  
Carbon Balance ◽  
N Deposition ◽  
Control Treatment ◽  
Atmospheric N Deposition ◽  
Total N ◽  
Plant Yield ◽  
Soil C ◽  
Grassland Ecosystems ◽  
Unimodal Response ◽  
Microbial N

Abstract. Air pollution agents interact when affecting biological sinks for atmospheric CO2, e.g., the soil organic carbon (SOC) content of grassland ecosystems. Factors favoring plant productivity, like atmospheric N deposition, are usually considered to favor SOC storage. In a 7-year experiment in subalpine grassland under N- and O3-deposition treatment, we examined C fluxes and pools. Total N deposition was 4, 9, 14, 29 and 54 kg N ha−1 yr−1 (N4, N9, etc.); annual mean phytotoxic O3 dose was 49, 65 and 89 mmol m−2 projected leaf area. We hypothesized that between years SOC of this mature ecosystem would not change in control treatments and that effects of air pollutants are similar for plant yield, net ecosystem productivity (NEP) and SOC content, leading to SOC content increasing with N deposition. Cumulative plant yield showed a significant N and N  ×  N effect (+38 % in N54) but no O3 effect. In the control treatment SOC increased significantly by 9 % in 7 years. Cumulative NEP did show a strong, hump-shaped response pattern to N deposition with a +62 % increase in N14 and only +39 % increase in N54 (N effect statistically not significant, N  ×  N interaction not testable). SOC had a similar but not significant response to N, with highest C gains at intermediate N deposition rates, suggesting a unimodal response with a marginal (P = 0.09) N  ×  N interaction. We assume the strong, pollutant-independent soil C sink developed as a consequence of the management change from grazing to cutting. The non-parallel response of SOC and NEP compared to plant yield under N deposition is likely the result of increased respiratory SOC losses, following mitigated microbial N-limitation or priming effects, and a shift in plant C allocation leading to smaller C input from roots.

Impacts of fire and fire surrogate treatments on ecosystem nitrogen storage patterns: similarities and differences between forests of eastern and western North America

2008 ◽  
Vol 38 (12) ◽  
pp. 3056-3070 ◽  
Author(s):  
R. E.J. Boerner ◽  
Jianjun Huang ◽  
Stephen C. Hart
Keyword(s):  
Management Strategies ◽  
N Deposition ◽  
Atmospheric N Deposition ◽  
N Losses ◽  
Total N ◽  
Wildfire Hazard ◽  
Forest Sites ◽  
C And N ◽  
C And N Cycling ◽  
The Impact

The Fire and Fire Surrogates (FFS) network is composed of 12 forest sites that span the continental United States, all of which historically had frequent low-severity fire. The goal of the FFS study was to assess the efficacy of three management treatments (prescribed fire, mechanical thinning, and their combination) in reducing wildfire hazard and increasing ecosystem sustainability. This paper describes the impact of the FFS treatments on nitrogen (N) storage and distribution. At the network scale, total ecosystem N averaged 4480 kg·ha–1, with ∼9% in vegetation, ∼9% in forest floor, ∼2% in deadwood, and ∼80% in soil. The loss of vegetation N to fire averaged (±SE) 25 ± 11 kg·ha–1, whereas the mechanical and combined mechanical and fire treatments resulted in N losses of 133 ± 21 and 145 ± 19 kg·ha–1, respectively. Western coniferous forests lost more N from each treatment than did eastern forests. None of the manipulative FFS treatments impacted >10%–15% of total N of these ecosystems. Management strategies that maximize ecosystem carbon (C) gain by minimizing loss of N should be a focus in western forests, where C and N cycling are tightly linked, but perhaps not in those eastern forests where atmospheric N deposition has decoupled C and N cycles.

scholarly journals Organic nitrogen in precipitation across Europe

2012 ◽  
Vol 9 (7) ◽  
pp. 8093-8109 ◽  
Author(s):  
J. N. Cape ◽  
Y. S. Tang ◽  
J. González-Benítez ◽  
M. Mitošinková ◽  
U. Makkonen ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Wet Deposition ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
N Deposition ◽  
Organic N ◽  
Single Source ◽  
Total N ◽  
Nitrogen Budgets ◽  
Nitrogen Concentrations

Abstract. Measurements of total nitrogen and inorganic nitrogen in precipitation samples from NitroEurope sites across Europe permit the calculation of organic nitrogen concentrations and wet deposition, by difference. The contribution of organic N to total N in precipitation ranged from only a few % to around 40% across sites from Northern Finland to Italy, similar to results from previous individual studies. This paper presents the absolute and relative contributions of organic N to wet N deposition across Europe, and examines seasonal trends. There were only weak correlations with other solutes in precipitation. These simple statistics indicate that sources of organic N in precipitation vary across Europe, and that no single source is responsible. The organic N contributes to total N deposition, yet this input is rarely quantified in nitrogen budgets.

scholarly journals Streamwater responses to reduced nitrogen deposition at four small upland catchments in Norway

AMBIO ◽  
2020 ◽  
Vol 49 (11) ◽  
pp. 1759-1770 ◽  
Author(s):  
Øyvind Kaste ◽  
Kari Austnes ◽  
Heleen A. de Wit
Keyword(s):  
C:N Ratio ◽  
N Deposition ◽  
Major Fraction ◽  
Atmospheric N Deposition ◽  
Total N ◽  
High Precipitation ◽  
Study Sites ◽  
Term Data ◽  
Upland Catchments

Abstract Reduced emissions of nitrogen (N) in Europe have resulted in decreasing atmospheric deposition since 1990. Long-term data (1988–2017) from four small Norwegian catchments located along gradients in N deposition, rainfall, and organic carbon (C) show different responses to 25–30% reductions in N deposition during the same period. At three sites the decreased N deposition caused reduced leaching of nitrate to surface water, whereas the westernmost site showed no decrease, probably due to thin soils with low C:N ratio, poor vegetation cover and high precipitation. The loss of total N to streamwater constituted 30–50% of the N deposition. Losses via denitrification are unknown but assumed to be low, as a major fraction of the catchments are well-drained. Hence, the study sites seem to continue to accumulate N, presumably mostly in soil organic matter. Although atmospheric N deposition has declined, ambient loads might still exceed long-term sustainable levels in these vulnerable ecosystems.

scholarly journals Wet and dry deposition of atmospheric nitrogen at ten sites in Northern China

2012 ◽  
Vol 12 (1) ◽  
pp. 753-785 ◽  
Author(s):  
Y. P. Pan ◽  
Y. S. Wang ◽  
G. Q. Tang ◽  
D. Wu
Keyword(s):  
Atmospheric Deposition ◽  
Dry Deposition ◽  
Northern China ◽  
N Deposition ◽  
Ecological Impacts ◽  
Total Flux ◽  
Spatial And Temporal Variation ◽  
Monitoring Networks ◽  
Atmospheric N Deposition ◽  
Total N

Abstract. Emissions of reactive nitrogen (N) species can affect surrounding ecosystems via atmospheric deposition. However, few long-term and multi-site measurements have focused on both the wet and the dry deposition of individual N species in large areas of Northern China. Thus, the magnitude of atmospheric deposition of various N species in Northern China remains uncertain. In this study, the wet and dry atmospheric deposition of different N species was investigated during a three-year observation campaign at ten selected sites in Northern China. The results indicate that N deposition levels in Northern China were high with a ten-site, three-year average of 60.6 kg N ha−1 yr−1. The deposition levels showed spatial and temporal variation in the range of 28.5–100.4 kg N ha−1 yr−1. Of the annual total deposition, 40% was deposited via precipitation, and the remaining 60% was comprised of dry-deposited forms. Compared with gaseous N species, particulate N species were not the major contributor of dry-deposited N; they contributed approximately 10% to the total flux. On an annual basis, oxidized species accounted for 21% of total N deposition, thereby implying that other forms of gaseous N, such as NH3, comprised a dominant portion of the total flux. The contribution of NO3− to N deposition was enhanced in certain urban and industrial areas. As expected, the total N deposition in Northern China was significantly larger than the values reported by national scale monitoring networks in Europe, North America and East Asia because of high rates of wet deposition and gaseous NH3 dry deposition. The results have three important implications. First, atmospheric N deposition in Northern China falls within the range of critical loads for temperate forests and grasslands, a threshold above which harmful ecological effects to specified parts of temperate ecosystems often occur. Second, the magnitude, patterns and forms of N deposition will help to inform simulated N addition experiments, which are used to evaluate ecological impacts on receiving ecosystems. Third, the field-based evidence in this unique deposition dataset validates emission inventories of reactive N species and will help policy-makers control atmospheric pollution. Taken together, these findings show that NH3 emissions should be abated to mitigate high N deposition and associated potential impacts on ecosystems in Northern China.

scholarly journals Organic nitrogen in precipitation across Europe

2012 ◽  
Vol 9 (11) ◽  
pp. 4401-4409 ◽  
Author(s):  
J. N. Cape ◽  
Y. S. Tang ◽  
J. M. González-Beníez ◽  
M. Mitošinková ◽  
U. Makkonen ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Wet Deposition ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
N Deposition ◽  
Organic N ◽  
Single Source ◽  
Total N ◽  
Nitrogen Budgets ◽  
Nitrogen Concentrations

Abstract. Measurements of total nitrogen and inorganic nitrogen in precipitation samples from NitroEurope sites across Europe permit the calculation of organic nitrogen concentrations and wet deposition, by difference. The contribution of organic N to total N in precipitation ranged from only a few % to around 40% across 18 sites from northern Finland to Italy, similar to results from previous individual studies. This paper presents the absolute and relative contributions of organic N to wet N deposition across Europe, and examines seasonal trends. There were only weak correlations with other solutes in precipitation. These simple statistics indicate that sources of organic N in precipitation vary across Europe, and that no single source is responsible. The organic N contributes to total N deposition, yet this input is rarely quantified in nitrogen budgets.

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