Decreased N2O reduction by low soil pH causes high N2O emissions in a riparian ecosystem

Geobiology ◽  
2011 ◽  
Vol 9 (3) ◽  
pp. 294-300 ◽  
Author(s):  
R. N. VAN DEN HEUVEL ◽  
S. E. BAKKER ◽  
M. S. M. JETTEN ◽  
M. M. HEFTING
Keyword(s):  
Soil Ph ◽  
N2o Emissions ◽  
N2o Reduction ◽  
Riparian Ecosystem

scholarly journals Attribution of N<sub>2</sub>O sources in a grassland soil with laser spectroscopy based isotopocule analysis

2019 ◽  
Vol 16 (16) ◽  
pp. 3247-3266 ◽  
Author(s):  
Erkan Ibraim ◽  
Benjamin Wolf ◽  
Eliza Harris ◽  
Rainer Gasche ◽  
Jing Wei ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Radiative Forcing ◽  
Dispersion Model ◽  
Stratospheric Ozone ◽  
Particle Dispersion ◽  
N2o Emissions ◽  
Specific Information ◽  
N2o Reduction ◽  
Night Time ◽  
Nitrifier Denitrification

Abstract. Nitrous oxide (N2O) is the primary atmospheric constituent involved in stratospheric ozone depletion and contributes strongly to changes in the climate system through a positive radiative forcing mechanism. The atmospheric abundance of N2O has increased from 270 ppb (parts per billion, 10−9 mole mole−1) during the pre-industrial era to approx. 330 ppb in 2018. Even though it is well known that microbial processes in agricultural and natural soils are the major N2O source, the contribution of specific soil processes is still uncertain. The relative abundance of N2O isotopocules (14N14N16N, 14N15N16O, 15N14N16O, and 14N14N18O) carries process-specific information and thus can be used to trace production and consumption pathways. While isotope ratio mass spectroscopy (IRMS) was traditionally used for high-precision measurement of the isotopic composition of N2O, quantum cascade laser absorption spectroscopy (QCLAS) has been put forward as a complementary technique with the potential for on-site analysis. In recent years, pre-concentration combined with QCLAS has been presented as a technique to resolve subtle changes in ambient N2O isotopic composition. From the end of May until the beginning of August 2016, we investigated N2O emissions from an intensively managed grassland at the study site Fendt in southern Germany. In total, 612 measurements of ambient N2O were taken by combining pre-concentration with QCLAS analyses, yielding δ15Nα, δ15Nβ, δ18O, and N2O concentration with a temporal resolution of approximately 1 h and precisions of 0.46 ‰, 0.36 ‰, 0.59 ‰, and 1.24 ppb, respectively. Soil δ15N-NO3- values and concentrations of NO3- and NH4+ were measured to further constrain possible N2O-emitting source processes. Furthermore, the concentration footprint area of measured N2O was determined with a Lagrangian particle dispersion model (FLEXPART-COSMO) using local wind and turbulence observations. These simulations indicated that night-time concentration observations were largely sensitive to local fluxes. While bacterial denitrification and nitrifier denitrification were identified as the primary N2O-emitting processes, N2O reduction to N2 largely dictated the isotopic composition of measured N2O. Fungal denitrification and nitrification-derived N2O accounted for 34 %–42 % of total N2O emissions and had a clear effect on the measured isotopic source signatures. This study presents the suitability of on-site N2O isotopocule analysis for disentangling source and sink processes in situ and found that at the Fendt site bacterial denitrification or nitrifier denitrification is the major source for N2O, while N2O reduction acted as a major sink for soil-produced N2O.

Biochar mitigates the N2O emissions from acidic soil by increasing the nosZ and nirK gene abundance and soil pH

2020 ◽  
Vol 255 ◽  
pp. 109891 ◽  
Author(s):  
Muhammad Aamer ◽  
Muhammad Shaaban ◽  
Muhammad Umair Hassan ◽  
Huang Guoqin ◽  
Liu Ying ◽  
...  
Keyword(s):  
Soil Ph ◽  
Acidic Soil ◽  
N2o Emissions ◽  
Gene Abundance ◽  
Nirk Gene

scholarly journals Early season N<sub>2</sub>O emissions under variable water management in rice systems: source-partitioning emissions using isotope ratios along a depth profile

2019 ◽  
Vol 16 (2) ◽  
pp. 383-408 ◽  
Author(s):  
Elizabeth Verhoeven ◽  
Matti Barthel ◽  
Longfei Yu ◽  
Luisella Celi ◽  
Daniel Said-Pullicino ◽  
...  
Keyword(s):  
Water Management ◽  
Isotope Ratio ◽  
Isotope Ratios ◽  
Site Preference ◽  
N2o Emissions ◽  
Mixing Models ◽  
N2o Reduction ◽  
Wetting And Drying ◽  
Soil Redox Potential ◽  
Alternate Wetting And Drying

Abstract. Soil moisture strongly affects the balance between nitrification, denitrification and N2O reduction and therefore the nitrogen (N) efficiency and N losses in agricultural systems. In rice systems, there is a need to improve alternative water management practices, which are designed to save water and reduce methane emissions but may increase N2O and decrease nitrogen use efficiency. In a field experiment with three water management treatments, we measured N2O isotope ratios of emitted and pore air N2O (δ15N, δ18O and site preference, SP) over the course of 6 weeks in the early rice growing season. Isotope ratio measurements were coupled with simultaneous measurements of pore water NO3-, NH4+, dissolved organic carbon (DOC), water-filled pore space (WFPS) and soil redox potential (Eh) at three soil depths. We then used the relationship between SP × δ18O-N2O and SP × δ15N-N2O in simple two end-member mixing models to evaluate the contribution of nitrification, denitrification and fungal denitrification to total N2O emissions and to estimate N2O reduction rates. N2O emissions were higher in a dry-seeded + alternate wetting and drying (DS-AWD) treatment relative to water-seeded + alternate wetting and drying (WS-AWD) and water-seeded + conventional flooding (WS-FLD) treatments. In the DS-AWD treatment the highest emissions were associated with a high contribution from denitrification and a decrease in N2O reduction, while in the WS treatments, the highest emissions occurred when contributions from denitrification/nitrifier denitrification and nitrification/fungal denitrification were more equal. Modeled denitrification rates appeared to be tightly linked to nitrification and NO3- availability in all treatments; thus, water management affected the rate of denitrification and N2O reduction by controlling the substrate availability for each process (NO3- and N2O), likely through changes in mineralization and nitrification rates. Our model estimates of mean N2O reduction rates match well those observed in 15N fertilizer labeling studies in rice systems and show promise for the use of dual isotope ratio mixing models to estimate N2 losses.

scholarly journals Effects of fertilization and stand age on N<sub>2</sub>O and NO emissions from tea plantations: A site-scale study in a subtropical region using a modified biogeochemical model

2020 ◽  
Author(s):  
Wei Zhang ◽  
Zhisheng Yao ◽  
Xunhua Zheng ◽  
Chunyan Liu ◽  
Rui Wang ◽  
...  
Keyword(s):  
Soil Ph ◽  
Process Model ◽  
Early Stage ◽  
Stand Age ◽  
Biogeochemical Model ◽  
N2o Emissions ◽  
Model Based ◽  
Ph Reduction ◽  
Tea Plantations ◽  
No Emissions

Abstract. To meet increasing demands, tea plantations are rapidly expanding in China. Although the emissions of nitrous oxide (N2O) and nitric oxide (NO) from tea plantations may be substantially influenced by soil pH reduction and intensive nitrogen fertilization, process model-based studies on this issue are still rare. In this study, the process-oriented biogeochemical model, Catchment Nutrient Management Model – DeNitrification-DeComposition (CNMM-DNDC), was modified by adding tea growth-related processes that may induce a soil pH reduction. Using a dataset for intensively managed tea plantations at a subtropical site, the performances of the original and modified models for simulating the emissions of both gases subject to different fertilization alternatives and stand ages were evaluated. Compared with the observations in early stage of a tea plantation, the original and modified models showed comparable performances for simulating the daily gas fluxes (with Nash-Sutcliffe index (NSI) of 0.10 versus 0.18 for N2O and 0.32 versus 0.33 for NO), annual emissions (with NSI of 0.81 versus 0.94 for N2O and 0.92 versus 0.94 for NO) and annual direct emission factors (EFds). The observations and simulations consistently demonstrated that short-term replacement of urea with oilcake stimulated N2O emissions by ~ 62 % and ~ 36 % and mitigated NO emissions by ~ 25 % and ~ 14 %, respectively. The model simulations resulted in a positive dependence of EFd of either gas against nitrogen doses, implicating the importance of model-based quantification of this key parameter for inventory. In addition, the modified model with pH-related scientific processes showed overall inhibitory effects on the gases emissions in the mid to later stages during a full tea lifetime. In conclusion, the modified CNMM-DNDC exhibits the potential for quantifying N2O and NO emissions from tea plantations under various conditions. Nevertheless, wider validation is still required for simulation of long-term soil pH variations and emissions of both gases from tea plantations.

scholarly journals Short- and long-term temperature responses of soil denitrifier net N<sub>2</sub>O efflux rates, inter-profile N<sub>2</sub>O dynamics, and microbial genetic potentials

SOIL ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 399-412
Author(s):  
Kate M. Buckeridge ◽  
Kate A. Edwards ◽  
Kyungjin Min ◽  
Susan E. Ziegler ◽  
Sharon A. Billings
Keyword(s):  
Mineral Soil ◽  
Mean Annual Temperature ◽  
N2o Emissions ◽  
Soil Horizons ◽  
N2o Reduction ◽  
Short Term ◽  
N2o Production ◽  
Short Term Exposure ◽  
Temperature Responses

Abstract. Production and reduction of nitrous oxide (N2O) by soil denitrifiers influence atmospheric concentrations of this potent greenhouse gas. Accurate projections of the net N2O flux have three key uncertainties: (1) short- vs. long-term responses to warming, (2) interactions among soil horizons, and (3) temperature responses of different steps in the denitrification pathway. We addressed these uncertainties by sampling soil from a boreal forest climate transect encompassing a 5.2 ∘C difference in the mean annual temperature and incubating the soil horizons in isolation and together at three ecologically relevant temperatures in conditions that promote denitrification. Both short-term exposure to warmer temperatures and long-term exposure to a warmer climate increased N2O emissions from organic and mineral soils; an isotopic tracer suggested that an increase in N2O production was more important than a decline in N2O reduction. Short-term warming promoted the reduction of organic horizon-derived N2O by mineral soil when these horizons were incubated together. The abundance of nirS (a precursor gene for N2O production) was not sensitive to temperature, whereas that of nosZ clade I (a gene for N2O reduction) decreased with short-term warming in both horizons and was higher from a warmer climate. These results suggest a decoupling of gene abundance and process rates in these soils that differs across horizons and timescales. In spite of these variations, our results suggest a consistent, positive response of denitrifier-mediated net N2O efflux rates to temperature across timescales in these boreal forests. Our work also highlights the importance of understanding cross-horizon N2O fluxes for developing a predictive understanding of net N2O efflux from soils.

Influence of soil pH on NOxand N2O emissions from bovine urine applied to soil columns

2011 ◽  
Vol 54 (4) ◽  
pp. 285-301 ◽  
Author(s):  
S Khan ◽  
TJ Clough ◽  
KM Goh ◽  
RR Sherlock
Keyword(s):  
Soil Ph ◽  
N2o Emissions ◽  
Soil Columns ◽  
Bovine Urine

scholarly journals Biochar as electron donor for reduction of N2O by Paracoccus denitrificans

2020 ◽  
Vol 96 (8) ◽  
Author(s):  
Mª Blanca Pascual ◽  
Miguel Ángel Sánchez-Monedero ◽  
María L Cayuela ◽  
Shun Li ◽  
Stefan B Haderlein ◽  
...  
Keyword(s):  
Surface Area ◽  
Electron Donor ◽  
Paracoccus Denitrificans ◽  
Exchange Capacity ◽  
Microbial Reduction ◽  
Ash Content ◽  
N2o Emissions ◽  
N2o Reduction ◽  
Redox Capacity ◽  
Microbial Denitrification

ABSTRACT Biochar (BC) has been shown to influence microbial denitrification and mitigate soil N2O emissions. However, it is unclear if BC is able to directly stimulate the microbial reduction of N2O to N2. We hypothesized that the ability of BC to lower N2O emissions could be related not only to its ability to store electrons, but to donate them to bacteria that enzymatically reduce N2O. Therefore, we carried out anoxic incubations with Paracoccus denitrificans, known amounts of N2O, and nine contrasting BCs, in the absence of any other electron donor or acceptor. We found a strong and direct correlation between the extent and rates of N2O reduction with BC's EDC/EEC (electron donating capacity/electron exchange capacity). Apart from the redox capacity, other BC properties were found to regulate the BC's ability to increase N2O reduction by P. denitrificans. For this specific BC series, we found that a high H/C and ash content, low surface area and poor lignin feedstocks favored N2O reduction. This provides valuable information for producing tailored BCs with the potential to assist and promote the reduction of N2O in the pursuit of reducing this greenhouse gas emissions.

Effects of copper on nitrous oxide (N2O) reduction in denitrifiers and N2O emissions from agricultural soils

2019 ◽  
Vol 56 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Weishou Shen ◽  
Huaiwen Xue ◽  
Nan Gao ◽  
Yutaka Shiratori ◽  
Takehiro Kamiya ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Agricultural Soils ◽  
N2o Emissions ◽  
N2o Reduction

Nitrous oxide emission from two acidic soils as affected by dolomite application

Soil Research ◽  
2014 ◽  
Vol 52 (8) ◽  
pp. 841 ◽  
Author(s):  
Muhammad Shaaban ◽  
Qian Peng ◽  
Shan Lin ◽  
Yupeng Wu ◽  
Jinsong Zhao ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Ph ◽  
Microbial Biomass Carbon ◽  
Rice Paddy ◽  
N2o Emission ◽  
N2o Emissions ◽  
Biomass Carbon ◽  
Acidic Soils

The effect of dolomite (CaMg(CO3)2) application on nitrous oxide (N2O) emission was examined in a laboratory study with soil from a rice paddy–rapeseed rotation (PR soil, pH 5.25) and from a rice paddy–fallow–flooded rotation soil (PF soil, pH 5.52). The soils were treated with 0, 0.5 (L) and 1.5 (H) g dolomite 100 g–1 soil. Results showed that N2O emissions were higher in control treatments (untreated dolomite) in both soils. Application of dolomite decreased N2O emissions significantly (P ≤ 0.001) as soil pH increased in both soils. The H treatment was more effective than the L treatment for the reduction of N2O emissions. The H treatment decreased the cumulative N2O emissions by up to 73.77% in PR soil and 64.07% in PF soil compared with the control. The application of dolomite also affected concentrations of dissolved organic carbon, microbial biomass carbon, ammonium and nitrate in soils, which related to N2O emission. The results suggest that dolomite not only counteracts soil acidification but also has the potential to mitigate N2O emissions in acidic soils.

scholarly journals The combined effects of nitrification inhibitor and biochar incorporation on yield-scaled N<sub>2</sub>O emissions from an intensively managed vegetable field in southeastern China

2014 ◽  
Vol 11 (10) ◽  
pp. 15185-15214 ◽  
Author(s):  
B. Li ◽  
C. H. Fan ◽  
Z. Q. Xiong ◽  
Q. L. Li ◽  
M. Zhang
Keyword(s):  
Soil Ph ◽  
Nitrification Inhibitor ◽  
N2o Emissions ◽  
Southeastern China ◽  
Vegetable Field ◽  
Significant Difference ◽  
Group Treatments ◽  
Intensively Managed ◽  
Vegetable Yield ◽  
Biochar Amendment

Abstract. The influences of nitrification inhibitor (NI) and biochar incorporation on yield-scaled N2O in a vegetable field were studied using the static chamber method and gas chromatography. An experiment was conducted in an intensively managed vegetable field with 7 consecutive vegetable crops in 2012–2014 in southeastern China. With equal annual amounts of N (1217.3 kg N ha−1 yr−1), 6 treatments under 3 biochar amendment rates, namely, 0 t ha−1 (C0), 20 t ha−1 (C1), and 40 t ha−1 (C2), with compound fertilizer (CF) or urea mixed with chlorinated pyridine (CP) as NI, were studied in these field experiments. The results showed that although no significant influence on soil organic carbon (SOC) content or total nitrogen (TN), CP could result in a significant increase in soil pH during the experimental period. CP significantly decreased cumulative N2O emissions by 15.9–32.1% while increasing vegetable yield by 9.8–41.9%. Thus, it also decreased yield-scaled N2O emissions significantly. In addition to the differential responses of the soil pH, biochar amendment significantly increased SOC and TN. Additionally, compared with the treatments without biochar addition, cumulative N2O emissions showed no significant difference in the CF or the CP group treatments but increased slightly (but not significantly) by 7.9–18.3% in the CP group treatments. Vegetable yield was enhanced by 7.1–49.5% compared with the treatments without biochar amendment, and the yield-scaled N2O emissions were thus decreased significantly. Furthermore, treatments applied with CP and biochar incorporation slightly increased yield-scaled N2O emissions by 9.4%, on average, compared with CP-C0. Therefore, the incorporation of CP could serve as an appropriate practice for increasing vegetable yield and mitigating N2O emissions in intensively managed vegetable fields and should be further examined in various agroecosystems.

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