scholarly journals Nitrogen balance of a boreal Scots pine forest

2013 ◽  
Vol 10 (2) ◽  
pp. 1083-1095 ◽  
Author(s):  
J. F. J. Korhonen ◽  
M. Pihlatie ◽  
J. Pumpanen ◽  
H. Aaltonen ◽  
P. Hari ◽  
...  
Keyword(s):  
Scots Pine ◽  
Boreal Forests ◽  
N2o Emission ◽  
N Deposition ◽  
Organic N ◽  
N Availability ◽  
N Saturation ◽  
Atmospheric N Deposition ◽  
Drainage Flow ◽  
Nutrient Pools

Abstract. The productivity of boreal forests is considered to be limited by low nitrogen (N) availability. Increased atmospheric N deposition has altered the functioning and N cycling of these N-sensitive ecosystems by increasing the availability of reactive nitrogen. The most important components of N pools and fluxes were measured in a boreal Scots pine stand in Hyytiälä, Southern Finland. The measurements at the site allowed direct estimations of nutrient pools in the soil and biomass, inputs from the atmosphere and outputs as drainage flow and gaseous losses from two micro-catchments. N was accumulating in the system, mainly in woody biomass, at a rate of 7 kg N ha−1 yr−1. Nitrogen input as atmospheric deposition was 7.4 kg N ha−1 yr−1. Dry deposition and organic N in wet deposition contributed over half of the inputs in deposition. Total outputs were 0.4 kg N ha−1 yr−1, the most important outputs being N2O emission to the atmosphere and organic N flux in drainage flow. Nitrogen uptake and retranslocation were equally important sources of N for plant growth. Most of the assimilated N originated from decomposition of organic matter, and the fraction of N that could originate directly from deposition was about 30%. In conclusion, atmospheric N deposition fertilizes the site considerably, but there are no signs of N saturation. Further research is needed to estimate soil N2 fluxes (emission and fixation), which may amount up to several kg N ha−1 yr−1.

scholarly journals Nitrogen balance of a boreal Scots pine forest

2012 ◽  
Vol 9 (8) ◽  
pp. 11201-11237 ◽  
Author(s):  
J. F. J. Korhonen ◽  
M. Pihlatie ◽  
J. Pumpanen ◽  
H. Aaltonen ◽  
P. Hari ◽  
...  
Keyword(s):  
Scots Pine ◽  
Boreal Forests ◽  
N2o Emission ◽  
N Deposition ◽  
Organic N ◽  
N Availability ◽  
Atmospheric N Deposition ◽  
Drainage Flow ◽  
Nutrient Pools ◽  
Scots Pine Forest

Abstract. The productivity of boreal forests is considered to be limited by low nitrogen (N) availability. Increased atmospheric N deposition has altered the functioning and N cycling of these N-sensitive ecosystems. The most important components of N pools and fluxes were measured in a boreal Scots pine stand in Hyytiälä, Southern Finland. The measurement at the site allowed direct estimations of nutrient pools in the soil and biomass, inputs from the atmosphere and outputs as drainage flow and gaseous losses from two micro-catchments. N was accumulating to the system with a rate of 7 kg N ha−1 yr−1. Nitrogen input as atmospheric deposition was 7.4 kg N ha−1 yr−1. Dry deposition and organic N in wet deposition contributed over half of the input in deposition. Total outputs were 0.4 kg N ha−1 yr−1, the most important outputs being N2O emission to the atmosphere and organic N flux in drainage flow. Nitrogen uptake and retranslocation were as important sources of N for plant growth. Most of the uptaken N originated from decomposition of organic matter, and the fraction of N that could originate directly from deposition was about 30%. In conclusion, atmospheric N deposition fertilizes the site considerably.

scholarly journals Too Much of a Good Thing? Inorganic Nitrogen (N) Inhibits Moss-Associated N2 Fixation But Organic N Can Promote It

2021 ◽  
Author(s):  
Yinliu Wang ◽  
Signe Lett ◽  
Kathrin Rousk
Keyword(s):  
Boreal Forests ◽  
Inorganic Nitrogen ◽  
N Deposition ◽  
Ecosystem Functions ◽  
Organic N ◽  
Inorganic N ◽  
Atmospheric N Deposition ◽  
Moss Species ◽  
The Impact ◽  
N Additions

Abstract Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha−1 yr−1) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha−1 yr−1) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

scholarly journals High fire-derived nitrogen deposition on central African forests

2018 ◽  
Vol 115 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Marijn Bauters ◽  
Travis W. Drake ◽  
Hans Verbeeck ◽  
Samuel Bodé ◽  
Pedro Hervé-Fernández ◽  
...  
Keyword(s):  
Biogeochemical Cycles ◽  
N Deposition ◽  
Congo Basin ◽  
Organic N ◽  
N Availability ◽  
Natural Ecosystems ◽  
Canopy Interception ◽  
Atmospheric N Deposition ◽  
Global Biogeochemical Cycles ◽  
Indirect Impacts

Atmospheric nitrogen (N) deposition is an important determinant of N availability for natural ecosystems worldwide. Increased anthropogenic N deposition shifts the stoichiometric equilibrium of ecosystems, with direct and indirect impacts on ecosystem functioning and biogeochemical cycles. Current simulation data suggest that remote tropical forests still receive low atmospheric N deposition due to a lack of proximate industry, low rates of fossil fuel combustion, and absence of intensive agriculture. We present field-based N deposition data for forests of the central Congo Basin, and use ultrahigh-resolution mass spectrometry to characterize the organic N fraction. Additionally, we use satellite data and modeling for atmospheric N source apportionment. Our results indicate that these forests receive 18.2 kg N hectare−1years−1as wet deposition, with dry deposition via canopy interception adding considerably to this flux. We also show that roughly half of the N deposition is organic, which is often ignored in N deposition measurements and simulations. The source of atmospheric N is predominantly derived from intensive seasonal burning of biomass on the continent. This high N deposition has important implications for the ecology of the Congo Basin and for global biogeochemical cycles more broadly.

Indirect N2O emission due to atmospheric N deposition for the Netherlands

2005 ◽  
Vol 39 (32) ◽  
pp. 5827-5838 ◽  
Author(s):  
Hugo Denier van der Gon ◽  
Albert Bleeker
Keyword(s):  
The Netherlands ◽  
N2o Emission ◽  
N Deposition ◽  
Atmospheric N Deposition

scholarly journals Regional Comparison of Nitrogen Export to Japanese Forest Streams

2001 ◽  
Vol 1 ◽  
pp. 572-580 ◽  
Author(s):  
Hideaki Shibata ◽  
Koichiro Kuraji ◽  
Hiroto Toda ◽  
Kaichiro Sasa
Keyword(s):  
Comparative Studies ◽  
N Mineralization ◽  
Surface Soil ◽  
Stream Water ◽  
N Deposition ◽  
N Saturation ◽  
Atmospheric N Deposition ◽  
Forested Watersheds ◽  
Nitrate Concentrations ◽  
Forest Streams

Nitrogen (N) emissions in Asian countries are predicted to increase over the next several decades. An understanding of the mechanisms that control temporal and spatial fluctuation of N export to forest streams is important not only to quantify critical loads of N, N saturation status, and soil acidification N dynamics and budgets in Japanese forested watersheds is not clear due to the lack of regional comparative studies on stream N chemistry. To address the lack of comparative studies, we measured inorganic N (nitrate and ammonium) concentrations from June 2000 to May 2001 in streams in 18 experimental forests located throughout the Japanese archipelago and belonging to the Japanese Union of University Forests. N concentrations in stream water during base flow and high flow periods were monitored, and N mineralization potential in soil was measured using batch incubation experiments. Higher nitrate concentrations in stream water were present in central Japan, an area that receives high rates of atmospheric N deposition. In northern Japan, snowmelt resulted in increased nitrate concentrations in stream water. The potential net N mineralization rate was higher in surface soil than in subsurface soil, and the high potential for N mineralization in the surface soil partly contributed to the increase in nitrate concentration in stream water during a storm event. Regional differences in the atmospheric N deposition and seasonality of precipitation and high discharge are principal controls on the concentrations and variations of nitrates in stream water in forested watersheds of Japan.

Effect of chronic ammonium nitrate addition on the ectomycorrhizal community in a black spruce stand1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.

2012 ◽  
Vol 42 (7) ◽  
pp. 1204-1212 ◽  
Author(s):  
Sergio Rossi ◽  
Adam Bordeleau ◽  
Daniel Houle ◽  
Hubert Morin
Keyword(s):  
Ammonium Nitrate ◽  
Boreal Forests ◽  
Black Spruce ◽  
N Deposition ◽  
Fungal Species ◽  
Root Tip ◽  
Soil Conditions ◽  
Root Tips ◽  
Atmospheric N Deposition ◽  
Host Trees

Observed modifications of ectomycorrhizal (ECM) communities have been connected to the increased N depositions of the 20th century. Because of their narrow niche width, small disturbances of soil conditions can produce greater effects on the fungal species than on their host trees. This study investigated the ECM community in a black spruce ( Picea mariana (Mill.) BSP) stand subjected to long-term additions of 9 and 30 kg N·ha–1·year–1 of ammonium nitrate, representing 3 and 10 times the atmospheric N deposition at the site, respectively. Root tip vitality and ECM presence were detected on samples collected from the organic horizon and ECM were classified into morphotypes according to their morphological and anatomical characters. In the control, 80.6% of the root tips were vital, 76.5% of them showing ECM colonization. Higher root tip vitality and mycorrhization were observed in the treated plots. Forty-one morphotypes were identified, most of them detected at the higher N inputs. Results diverging from the expectations of a reduction in ECM presence and diversity could be related to a higher growth rate of the trees following fertilization. The repeated application of small N doses could have been a better imitation of natural inputs from atmospheric deposition and could have provided more reliable responses of ECM to treatment.

scholarly journals N fluxes in two nitrogen saturated forested catchments in Germany: dynamics and modelling with INCA

2002 ◽  
Vol 6 (3) ◽  
pp. 383-394 ◽  
Author(s):  
J.-J. Langusch ◽  
E. Matzner
Keyword(s):  
Soil Depth ◽  
N Deposition ◽  
Model Complexity ◽  
N Saturation ◽  
Atmospheric N Deposition ◽  
Catchment Scale ◽  
Forested Catchments ◽  
Mineral N ◽  
N Fluxes ◽  
The Impact

Abstract. The N cycle in forests of the temperate zone in Europe has been changed substantially by the impact of atmospheric N deposition. Here, the fluxes and concentrations of mineral N in throughfall, soil solution and runoff in two German catchments, receiving high N inputs are investigated to test the applicability of an Integrated Nitrogen Model for European Catchments (INCA) to small forested catchments. The Lehstenbach catchment (419 ha) is located in the German Fichtelgebirge (NO Bavaria, 690-871 m asl.) and is stocked with Norway spruce (Picea abies (L.) Karst.) of different ages. The Steinkreuz catchment (55 ha) with European beech (Fagus sylvatica L.) as the dominant tree species is located in the Steigerwald (NW Bavaria, 400-460 m asl.). The mean annual N fluxes with throughfall were slightly higher at the Lehstenbach (24.6 kg N ha-1) than at the Steinkreuz (20.4 kg N ha-1). In both catchments the N fluxes in the soil are dominated by NO3. At Lehstenbach, the N output with seepage at 90 cm soil depth was similar to the N flux with throughfall. At Steinkreuz more than 50 % of the N deposited was retained in the upper soil horizons. In both catchments, the NO3 fluxes with runoff were lower than those with seepage. The average annual NO3 concentrations in runoff in both catchments were between 0.7 to 1.4 mg NO3-N L-1 and no temporal trend was observed. The N budgets at the catchment scale indicated similar amounts of N retention (Lehstenbach: 19 kg N ha-1yr-1 ; Steinkreuz: 17 kg N ha-1yr-1). The parameter settings of the INCA model were simplified to reduce the model complexity. In both catchments, the NO3 concentrations and fluxes in runoff were matched well by the model. The seasonal patterns with lower NO3 runoff concentrations in summer at the Lehstenbach catchment were replicated. INCA underestimated the increased N3 concentrations during short periods of rewetting in late autumn at the Steinkreuz catchment. The model will be a helpful tool for the calculation of "critical loads" for the N deposition in Central European forests including different hydrological regimes. Keywords: forest ecosystem, modelling, N budgets, N saturation, NO3 leaching, water quality, INCA

scholarly journals Aridity and plant uptake interact to make dryland soils hotspots for nitric oxide (NO) emissions

2016 ◽  
Vol 113 (19) ◽  
pp. E2608-E2616 ◽  
Author(s):  
Peter M. Homyak ◽  
Joseph C. Blankinship ◽  
Kenneth Marchus ◽  
Delores M. Lucero ◽  
James O. Sickman ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
N Uptake ◽  
N Deposition ◽  
N Availability ◽  
Plant N Uptake ◽  
N Loss ◽  
Atmospheric N Deposition ◽  
Soil Microbial ◽  
California Grassland ◽  
No Emissions

Nitric oxide (NO) is an important trace gas and regulator of atmospheric photochemistry. Theory suggests moist soils optimize NO emissions, whereas wet or dry soils constrain them. In drylands, however, NO emissions can be greatest in dry soils and when dry soils are rewet. To understand how aridity and vegetation interact to generate this pattern, we measured NO fluxes in a California grassland, where we manipulated vegetation cover and the length of the dry season and measured [δ15-N]NO and [δ18-O]NO following rewetting with15N-labeled substrates. Plant N uptake reduced NO emissions by limiting N availability. In the absence of plants, soil N pools increased and NO emissions more than doubled. In dry soils, NO-producing substrates concentrated in hydrologically disconnected microsites. Upon rewetting, these concentrated N pools underwent rapid abiotic reaction, producing large NO pulses. Biological processes did not substantially contribute to the initial NO pulse but governed NO emissions within 24 h postwetting. Plants acted as an N sink, limiting NO emissions under optimal soil moisture. When soils were dry, however, the shutdown in plant N uptake, along with the activation of chemical mechanisms and the resuscitation of soil microbial processes upon rewetting, governed N loss. Aridity and vegetation interact to maintain a leaky N cycle during periods when plant N uptake is low, and hydrologically disconnected soils favor both microbial and abiotic NO-producing mechanisms. Under increasing rates of atmospheric N deposition and intensifying droughts, NO gas evasion may become an increasingly important pathway for ecosystem N loss in drylands.

Plant phenols contents and their changes with nitrogen availability in peatlands of northeastern China

2020 ◽  
Vol 13 (6) ◽  
pp. 713-721
Author(s):  
Di Wu ◽  
Xian-Wei Wang ◽  
Shi-Qi Xu ◽  
Chong-Juan Chen ◽  
Rong Mao ◽  
...  
Keyword(s):  
Climate Warming ◽  
Nutrient Availability ◽  
Nitrogen Availability ◽  
Resource Competition ◽  
N Deposition ◽  
Northeastern China ◽  
Organic N ◽  
N Availability ◽  
Boreal Peatlands ◽  
Leaf N

Abstract Aims Climate warming and increasing nitrogen (N) deposition have influenced plant nutrient status and thus plant carbon (C) fixation and vegetation composition in boreal peatlands. Phenols, which are secondary metabolites in plants for defense and adaptation, also play important roles in regulating peatland C dynamics due to their anti-decomposition properties. However, how the phenolic levels of different functional types of plants vary depending on nutrient availability remain unclear in boreal peatlands. Methods Here, we investigated total phenols contents (TPC) and total tannins contents in leaves of 11 plant species in 18 peatlands of the Great Hing’an Mountains area in northeastern China, and examined their variations with leaf N and phosphorus (P) and underlying mechanisms. Important Findings Shrubs had higher TPC than graminoids, indicating less C allocation to defense and less uptake of organic N in faster-growing and nonmycorrhizal graminoids than in slower-growing and mycorrhizal shrubs. For shrubs, leaf TPC decreased with increasing N contents but was not influenced by changing leaf phosphorus (P) contents, which suggested that shrubs would reduce the C investment for defense with increasing N availability. Differently, leaf TPC of graminoids increased with leaf N contents and decreased with leaf P contents. As graminoids are more N-limited and less P-limited, we inferred that graminoids would increase the defensive C investment under increased nutrient availability. We concluded that shrubs would invest more C in growth than in defense with increasing N availability, but it was just opposite for graminoids, which might be an important mechanism to explain the resource competition and encroachment of shrubs in boreal peatlands in the context of climate warming and ever-increasing N deposition.

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