Drying–rewetting events reduce C and N losses from a Norway spruce forest floor

Muhr, Jan; Franke, Janine; Borken, Werner

doi:10.1016/j.soilbio.2010.03.024

Cited by 96 publications

(76 citation statements)

References 41 publications

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“…The catchment is dominated by Norway spruce (Picea abies) with Vaccinium myrtillus, Juncus effusus, Carex nigra, Carex rostrata, Carex canescens, Molinia caerulea, Eriophorum vaginatum, and also Sphagnum mosses in the understory (Matzner, 2004 > 10 m below surface, while groundwater tables are near the surface in the wetland areas (Lischeid et al, 2002). Details about the wetland and forest soil biogeochemistry have been reported elsewhere (e.g., Knorr et al, 2009;Muhr et al, 2010). Discharge and surface water chemistry were studied at the catchment outlet near site Schlöppnerbrunnen, using a pressure sensor (Solinst Canada Ltd. Georgetown, ON, Canada) immersed at a discharge flume and weir and an automatic bottle sampler (Teledyne ISCO, Lincoln, NE, USA).…”

Section: Methodsmentioning

confidence: 99%

DOC-dynamics in a small headwater catchment as driven by redox fluctuations and hydrological flow paths – are DOC exports mediated by iron reduction/oxidation cycles?

2013

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Dissolved organic carbon (DOC) exports from many catchments in Europe and North-America are steadily increasing. Several studies have sought to explain this observation. As possible causes, a decrease in acid rain or sulfate deposition, concomitant reductions in ionic strength and increasing temperatures were identified. DOC often originates from riparian wetlands; but here, despite higher DOC concentrations, ionic strength in pore waters usually exceeds that in surface waters. In the catchment under study, DOC concentrations were synchronous with dissolved iron concentrations in pore and stream water. This study aims at testing the hypothesis that DOC exports are mediated by iron reduction/oxidation cycles. Following the observed hydrographs, δ<sup>18</sup>O of water and DOC fluorescence, the wetlands were identified as the main source of DOC. Antecedent biogeochemical conditions, i.e., water table levels in the wetlands, influenced the discharge patterns of nitrate, iron and DOC during an event. The correlation of DOC with pH was positive in pore waters, but negative in surface waters; it was negative for DOC with sulfate in pore waters, but only weak in surface waters. Though, the positive correlation of DOC with iron was universal for pore and surface water. The decline of DOC and iron concentrations in transition from anoxic wetland pore water to oxic stream water suggests a flocculation of DOC with oxidising iron, leading to a drop in pH in the stream during high DOC fluxes. The pore water did not per se differ in pH. There is, thus, a need to consider processes more thoroughly of DOC mobilisation in wetlands when interpreting DOC exports from catchments. The coupling of DOC with iron fluxes suggested that increased DOC exports could at least, in part, be caused by increasing activities in iron reduction, possibly due to increases in temperature, increasing wetness of riparian wetlands, or by a shift from sulfate dominated to iron reduction dominated biogeochemical regimes

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Section: Methodsmentioning

confidence: 99%

DOC-dynamics in a small headwater catchment as driven by redox fluctuations and hydrological flow paths – are DOC exports mediated by iron reduction/oxidation cycles?

2013

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“…Based on the gas balance and inverse balance approach, the rates of nitrification, denitrification, and respiration can be calculated [18,21]. A series of previous investigations showed the good agreement in the result of soil respiration measured by BaPS and gas chromatography [22,23], and in values of gross nitrification and denitrification rates based on the BaPS system and other methods, such as 15 N-pool dilution technique. However, this technology also has some shortcomings.…”

Section: Determination Of Nitrification Denitrification and Soil Rementioning

confidence: 98%

Effect of Salinity on Soil Respiration and Nitrogen Dynamics

Zeng¹,

Xu²,

Wu³

et al. 2013

Ecological Chemistry and Engineering S

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A facility of BaPS (Barometric Process Separation) and indoor incubation experiments were used to determine the effect of soil salinity on soil respiration and nitrogen transformation. The rates of soil respiration, gross nitrification, denitrification, ammonium and nitrate nitrogen concentrations and relevant soil parameters were measured. Results showed that soil respiration and nitrification and denitrification rates were all affected by soil salinity. Furthermore, the effect of soil salinity level on nitrification and denitrification rates had a threshold value (EC1:5 = 1.13 dS/m). When soil salinity level was smaller to this threshold value, the rates of nitrification and denitrification increased with soil salinity while they were reduced when soil salinity level was larger than the threshold value. Moreover, the changing law of soil respiration rate with soil salinity was similar with the nitrification and denitrification rates while the variation tendency was opposite. In addition, the transformation form urea to ammonium and nitrate nitrogen was also reduced with the increase of soil salinity and the reduced effect could be expressed by exponential functions.

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“…The cumulative net N mineralization rate is difficult to measure in the field because accurately quantifying plant N uptake and all N losses to the environment is nearly impossible. Laboratory studies using root-free soils have found mixed effects of dryinge wetting on cumulative net N mineralization, ranging from inhibition (Pulleman and Tietema, 1999;Mikha et al, 2005;Muhr et al, 2010) to stimulation (Miller et al, 2005;Gordon et al, 2008;Xiang et al, 2008), depending on factors such as soil type, experimental setup, and measurement method (Borken and Matzner, 2009). As the presence of plants could affect soil gross and net N mineralization through rhizosphere processes (Frank and Groffman, 2009), future studies should use approaches to measure soil N cycling in intact plant communities to better predict soil N availability in a changing environment.…”

Section: Do Dryingewetting Cycles Stimulate Cumulative Soil C and N Mmentioning

confidence: 99%

Impacts of drying–wetting cycles on rhizosphere respiration and soil organic matter decomposition

Zhu

Cheng

2013

Soil Biology and Biochemistry

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a b s t r a c tDryingewetting cycles influence both soil organic matter (SOM) decomposition and rhizosphere processes. Rhizosphere processes also affect SOM decomposition through rhizosphere priming. However, little is known about how dryingewetting cycles regulate SOM decomposition with rhizosphere priming, because most previous studies incubated root-free soils and omitted the rhizosphere effect. To investigate the effect of dryingewetting cycles on SOM decomposition in the presence of plants, we grew sunflower (Helianthus annuus) and soybean (Glycine max) in a sandy loam soil under the treatments of either constant moisture or 12 dryingewetting cycles, and used a continuous 13 C-labeling method to partition soil respiration into rhizosphere respiration and SOM decomposition. We found that compared to the constantly-moist treatment, the severe dryingewetting cycles in soils planted with sunflower significantly reduced shoot biomass (32%), root biomass (52%), rhizosphere respiration (29%), and SOM decomposition (22%), while the moderate dryingewetting cycles in soils planted with soybean did not significantly affect these variables. Moreover, SOM decomposition rates in the planted treatment subjected to constantly-moist or dryingewetting conditions were significantly higher compared with the constantly-moist unplanted treatment, indicating a positive rhizosphere priming effect under both soil moisture regimes. However, dryingewetting reduced the rhizosphere priming of sunflower (69% versus 33%) likely due to lower plant biomass and rhizodeposition, but produced similar rhizosphere priming of soybean (82% versus 85%). Overall, dryingewetting cycles significantly modulated rhizosphere respiration and SOM decomposition, with the magnitude depending on soil drying intensity and plant growth performance.Published by Elsevier Ltd.

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Drying–rewetting events reduce C and N losses from a Norway spruce forest floor

Cited by 96 publications

References 41 publications

DOC-dynamics in a small headwater catchment as driven by redox fluctuations and hydrological flow paths – are DOC exports mediated by iron reduction/oxidation cycles?

DOC-dynamics in a small headwater catchment as driven by redox fluctuations and hydrological flow paths – are DOC exports mediated by iron reduction/oxidation cycles?

Effect of Salinity on Soil Respiration and Nitrogen Dynamics

Impacts of drying–wetting cycles on rhizosphere respiration and soil organic matter decomposition

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