scholarly journals Gaseous nitrogen losses and mineral nitrogen transformation along a water table gradient in a black alder (<i>Alnus glutinosa</i> (L.) Gaertn.) forest on organic soils

2013 ◽  
Vol 10 (12) ◽  
pp. 19071-19107 ◽  
Author(s):  
T. Eickenscheidt ◽  
J. Heinichen ◽  
J. Augustin ◽  
A. Freibauer ◽  
M. Drösler
Keyword(s):  
Soil Moisture ◽  
Alnus Glutinosa ◽  
Organic Soils ◽  
Physical Factors ◽  
Net N Mineralization ◽  
Incubation Experiment ◽  
Inorganic N ◽  
Black Alder ◽  
Net Nitrification ◽  
N2o Fluxes

Abstract. Black alder (Alnus glutinosa (L.) Gaertn.) forests on peat soils have been reported to be hotspots for high nitrous oxide (N2O) losses. High emissions may be attributed to alternating water tables of peatlands and to the incorporation of high amounts of easily decomposable nitrogen (N) into the ecosystem by symbiotic dinitrogen (N2)-fixation of alder trees. Our study addressed the question to what extent drainage enhances the emissions of N2O from black alder forests and how N turnover processes and physical factors influence the production of N2O and total denitrification. The study was conducted in a drained black alder forest with variable groundwater tables at a southern German fen peatland. Fluxes of N2O were measured using the closed chamber method at two drained sites (D-1 and D-2) and one undrained site (U). Inorganic N contents and net N mineralization rates (NNM) were determined. Additionally a laboratory incubation experiment was carried out to investigate greenhouse gas and N2 fluxes at different temperature and soil moisture conditions. Significantly different inorganic N contents and NNM rates were observed which however did not result in significantly different N2O fluxes in the field, but in the laboratory experiment. Measured N2O fluxes were low for all sites, with total annual emissions of 0.51 ± 0.07 (U), 0.97 ± 0.13 (D-1) and 0.93 ± 0.08 kg N2O-N ha−1 yr−1 (D-2). Only 37% of the spatio-temporal variation in field N2O fluxes could be explained by peat temperature and groundwater level, demonstrating the complex interlinking of the controlling factors for N2O emissions. However, temperature was one of the key variables of N2O fluxes in the conducted incubation experiment. Increasing soil moisture content was found to enhance total denitrification losses during the incubation experiment, whereas N2O fluxes remained constant. At the undrained site, permanently high ground water level was found to prevent net nitrification, resulting in a limitation of available nitrate (NO3–) and negligible gaseous N losses. Up to four times higher N2O flux rates were measured in the incubation experiment. They reveal the potential of high N2O losses under changing soil physical conditions at the drained alder sites. The observed high net nitrification rates and high NO3– contents bear the risk of considerable NO3– leaching at the drained sites.

scholarly journals Nitrogen mineralization and gaseous nitrogen losses from waterlogged and drained organic soils in a black alder (<i>Alnus glutinosa</i> (L.) Gaertn.) forest

2014 ◽  
Vol 11 (11) ◽  
pp. 2961-2976 ◽  
Author(s):  
T. Eickenscheidt ◽  
J. Heinichen ◽  
J. Augustin ◽  
A. Freibauer ◽  
M. Drösler
Keyword(s):  
Soil Moisture ◽  
Groundwater Level ◽  
Alnus Glutinosa ◽  
Organic Soils ◽  
Net N Mineralization ◽  
Incubation Experiment ◽  
Inorganic N ◽  
Black Alder ◽  
Net Nitrification ◽  
N2o Fluxes

Abstract. Black alder (Alnus glutinosa (L.) Gaertn.) forests on peat soils have been reported to be hotspots for high nitrous oxide (N2O) losses. High emissions may be attributed to alternating water tables of peatlands and to the incorporation of high amounts of easily decomposable nitrogen (N) into the ecosystem by symbiotic dinitrogen (N2)-fixation of alder trees. Our study addressed the question to what extent drainage enhances the emissions of N2O from black alder forests and how N turnover processes and physical factors influence the production of N2O and total denitrification. The study was conducted in a drained black alder forest with variable groundwater tables at a southern German fen peatland. Fluxes of N2O were measured using the closed chamber method at two drained sites (D-1 and D-2) and one undrained site (U). Inorganic N contents and net N mineralization rates (NNM) were determined. Additionally a laboratory incubation experiment was carried out to investigate greenhouse gas and N2 fluxes at different temperature and soil moisture conditions. Significantly different inorganic N contents and NNM rates were observed, which however did not result in significantly different N2O fluxes in the field but did in the laboratory experiment. N2O fluxes measured were low for all sites, with total annual emissions of 0.51 ± 0.07 (U), 0.97 ± 0.13 (D-1) and 0.93 ± 0.08 kg N2O–N ha−1 yr−1 (D-2). Only 37% of the spatiotemporal variation in field N2O fluxes could be explained by peat temperature and groundwater level, demonstrating the complex interlinking of the controlling factors for N2O emissions. However, temperature was one of the key variables of N2O fluxes in the incubation experiment conducted. Increasing soil moisture content was found to enhance total denitrification losses during the incubation experiment, whereas N2O fluxes remained constant. At the undrained site, permanently high groundwater level was found to prevent net nitrification, resulting in a limitation of available nitrate (NO3−) and negligible gaseous N losses. N2O flux rates that were up to four times higher were measured in the incubation experiment. They reveal the potential of high N2O losses under changing soil physical conditions at the drained alder sites. The high net nitrification rates observed and high NO3− contents bear the risk of considerable NO3− leaching at the drained sites.

Variation with slope aspect in effects of temperature on nitrogen mineralization and nitrification in mineral soil of mixed hardwood forests

2015 ◽  
Vol 45 (7) ◽  
pp. 958-962 ◽  
Author(s):  
Frank S. Gilliam ◽  
Julia E. Galloway ◽  
Jacob S. Sarmiento
Keyword(s):  
N Mineralization ◽  
Incubation Temperature ◽  
Global Climate ◽  
Mineral Soil ◽  
Slope Aspect ◽  
Net N Mineralization ◽  
Inorganic N ◽  
N Dynamics ◽  
Net Nitrification ◽  
Effects Of Temperature

This study examined the effects of temperature on soil nitrogen (N) dynamics and variation with slope aspect (northeast (NE) versus southwest (SW)) at two forested sites in West Virginia — Beech Fork Lake (BFL) and Fernow Experimental Forest (FEF) — with similar soil and overstory characteristics but with different latitudes and elevations. Previous work on mineral soil from both sites had shown sharp differences in microbial communities between SW slopes and NE slopes. Mineral soil was sampled from three and eight plots per aspect at FEF and BFL, respectively. Inorganic N was extracted from samples, which were then divided into polyethylene bags for 7-day incubations at 4 °C, 15 °C, 25 °C, and 35 °C. Following incubation, soils were extracted and analyzed for inorganic N. Net N mineralization varied significantly between aspects and temperatures but did not vary between sites; net nitrification varied significantly between aspects, temperatures, and sites. Net N mineralization increased with incubation temperature at all aspects and sites. Net nitrification rates increased with incubation temperature for BFL soils; however, maximum net nitrification rates occurred at 20–25 °C for FEF soils. Net nitrification was essentially undetectable for SW soils at either site. Results underline the complexities of the N cycle in temperate forest ecosystems, representing challenges in predicting alterations in soil N dynamics under conditions of global climate change.

scholarly journals A comparative account of the microbial biomass-N and N-mineralization of soils under natural forest, grassland and crop field from dry tropical region, India

2009 ◽  
Vol 55 (No. 6) ◽  
pp. 223-230 ◽  
Author(s):  
S. Singh Jay ◽  
D.P. Singh ◽  
A.K. Kashyap
Keyword(s):  
Soil Moisture ◽  
Microbial Biomass ◽  
N Mineralization ◽  
Mixed Forest ◽  
Microbial Biomass N ◽  
Tropical Region ◽  
Net N Mineralization ◽  
Inorganic N ◽  
Total N ◽  
Biomass N

This study investigated microbial biomass-N (MB-N) and N-mineralization in soils of four different vegetation systems including forest (sal), mixed forest, savanna and cropland ecosystems in the Vindhyan region, India. A change was noted in the above region due to physiographic differences and anthropogenic disturbances. Annually the soil moisture (SM) content across the different study sites ranged from 7.5 to 24.3% being maximum in forest sites compared to savanna and cropland sites. The NH<sub>4</sub><sup>+</sup>-N, NO <sup>-</sup><sub>3</sub> -N and MB-N concentrations varied from 4.3 to 10.2 &mu;g/g, 1.1 to 5.8 &mu;g/g and 21.3 to 90.2 &mu;g/g dry soil, respectively, with minimum values in the wet and maximum values in the dry season. The trend of seasonal variation in net N-mineralization was similar to that of moisture content but counter to the concentrations of inorganic-N and MB-N. The net N-mineralization rates at different investigated sites ranged from 4.5 to 37.6 &mu;g/g month. Cultivation reduced the N-mineralization and MB-N by 58.5% and 63.5%, respectively. Experiments showed that the percentage contribution of MB-N to total-N was 8.01 to 19.15%. MB-N was positively correlated with the inorganic-N (<i>n</i> = 180,<i>r</i>.80,<i>P</I> < 0.001) but negatively with soil moisture (<i>n</i> = 180, <i>r</i> = 0.79, <i>P</I> < 0.001) and net N-mineralization rates (<i>n</i> = 180, <i>r</i> = 0.92, <i>P</I> < 0.0001). The higher N-mineralization and MB-N in the soil of forest ecosystem was reported compared to savanna and cropland and the order of soil MB-N levels and net N-mineralization followed the sequence: forest (sal) > mixed forest > savanna > cropland.

scholarly journals Mature black alder shows intermittent events of high stem methane emissions

2020 ◽  
Author(s):  
Daniel Köhn ◽  
Anke Günther ◽  
Ines Schwabe ◽  
Gerald Jurasinski
Keyword(s):  
Greenhouse Gas ◽  
Alnus Glutinosa ◽  
Methane Emissions ◽  
High Variability ◽  
List Type ◽  
Relative Importance ◽  
Incubation Experiment ◽  
Black Alder ◽  
Alder Forest ◽  
Closed Chambers

SummaryTree stems can be a source of the greenhouse gas methane (CH4). However, assessments of the global importance are complicated by a lack of research and a high variability between ecosystems. Here, we determined the contribution of emissions from tree stems of mature black alder (Alnus glutinosa (L.) Gaertn.) to overall CH4 exchange in two temperate peatlands.We measured emissions from stems and soils using closed chambers in a drained and a wet alder forest over two years. Further, we studied the importance of alder leaves as substrate for methanogenesis in an incubation experiment.Stem CH4 emissions were shortlived and occurred only during times of inundation at the wet site. The drained site did not show stem emissions and the soil acted as a small CH4 sink. The contribution of stem emissions to the overall CH4 budget was below 0.3% in both sites.Our results show that also mature black alders intermittently can be a source of CH4. However, the low share of stem-mediated CH4 emissions in both forests may indicate that this pathway is only of minor relative importance in temperate peatlands.

Short lived peaks of stem methane emissions in temperate black alder forest - irrelevant for ecosystem methane budgets?

2021 ◽  
Author(s):  
Daniel Köhn ◽  
Anke Günther ◽  
Gerald Jurasinski
Keyword(s):  
Greenhouse Gas ◽  
Hydrological Regime ◽  
Alnus Glutinosa ◽  
Methane Emissions ◽  
High Variability ◽  
Incubation Experiment ◽  
Black Alder ◽  
Alder Forest ◽  
Methane Budget ◽  
Closed Chambers

&lt;p&gt;Tree stems can be a source of the greenhouse gas methane (CH&lt;sub&gt;4&lt;/sub&gt;) and locally as regionally important to the overall GHG budget. Stem emissions even hold the potential of narrowing down knowledge gap in the global methane budget. However, assessments of the global importance of stem CH&lt;sub&gt;4&lt;/sub&gt;&amp;#160;emissions are complicated by a lack of research and high variability between individual ecosystems. Here, we determined the contribution of emissions from stems of mature black alder (&lt;em&gt;Alnus glutinosa&lt;/em&gt;&amp;#160;(L.) Gaertn.) to overall CH&lt;sub&gt;4&lt;/sub&gt; exchange in two temperate peatlands. We measured emissions from stems and soils using closed chambers in a drained and an undrained alder forest over 2 years. Furthermore, we studied the importance of alder leaves as substrate for methanogenesis in an incubation experiment. Stem CH&lt;sub&gt;4&lt;/sub&gt; emissions at the undrained alder forest were very variable in time and only persisted for a few weeks during the year. Generally the drained alder forest did not soil nor stem CH&lt;sub&gt;4&lt;/sub&gt; emissions. Different upscaling approaches were assessed and all approaches showed that stem CH&lt;sub&gt;4&lt;/sub&gt; emissions contributed less than 0.3 % to the total ecosystem CH&lt;sub&gt;4&lt;/sub&gt; budget. However, stem CH&lt;sub&gt;4&lt;/sub&gt; seem to depend strongly on the hydrological regime and therefore vary strongly between ecosystems. Hence, every ecosystem must be consdidered attentively with respect to their stem CH&lt;sub&gt;4&lt;/sub&gt; emissions.&lt;/p&gt;

scholarly journals Inorganic Nitrogen Production and Removal along the Sediment Gradient of a Stormwater Infiltration Basin

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 320
Author(s):  
Qianyao Si ◽  
Mary G. Lusk ◽  
Patrick W. Inglett
Keyword(s):  
Removal Efficiency ◽  
N Mineralization ◽  
Inorganic Nitrogen ◽  
Dry Season ◽  
Pollutant Removal ◽  
Net N Mineralization ◽  
Wet Season ◽  
Inorganic N ◽  
N Removal ◽  
Stormwater Infiltration

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.

scholarly journals Effects of experimental freezing on soil nitrogen dynamics in soils from a net nitrification gradient in a nitrogen-saturated hardwood forest ecosystem

2010 ◽  
Vol 40 (3) ◽  
pp. 436-444 ◽  
Author(s):  
Frank S. Gilliam ◽  
Adam Cook ◽  
Salina Lyter
Keyword(s):  
N Mineralization ◽  
Soil Freezing ◽  
N Saturation ◽  
Net N Mineralization ◽  
N Dynamics ◽  
Net Nitrification ◽  
Soil Nitrogen Dynamics ◽  
Soil N Cycle ◽  
N Mineralization Potential ◽  
Fernow Experimental Forest

This study examined effects of soil freezing on N dynamics in soil along an N processing gradient within a mixed hardwood dominated watershed at Fernow Experimental Forest, West Virginia. Sites were designated as LN (low rates of N processing), ML (moderately low), MH (moderately high), and HN (high). Soils underwent three 7-day freezing treatments (0, –20, or –80 °C) in the laboratory. Responses varied between temperature treatments and along the gradient. Initial effects differed among freezing treatments for net N mineralization, but not nitrification, in soils across the gradient, generally maintained at LN < ML ≤ MH < HN for all treatments. Net N mineralization potential was higher following freezing at –20 and –80 °C than control; all were higher than at 0 °C. Net nitrification potential exhibited similar patterns. LN was an exception, with net nitrification low regardless of treatment. Freezing response of N mineralization differed greatly from that of nitrification, suggesting that soil freezing may decouple two processes of the soil N cycle that are otherwise tightly linked at our site. Results also suggest that soil freezing at temperatures commonly experienced at this site can further increase net nitrification in soils already exhibiting high nitrification from N saturation.

Sign in / Sign up

Export Citation Format

Share Document