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The Measurement of Nitrous Oxide Emissions from Soil by Using Chambers
Abstract
Small flux chambers are widely used to measure emissions of nitrous oxide, N2O, from soil, the gas being determined by gas chromatography with an electron capture detector. The technique is relatively cheap, and is adaptable to a wide range of site conditions and emission rates: from the order of 1 mu g m-2 h-1 to more than 10 mg m-2 h-1. Increasingly, systems are being automated, to get more information on short-term temporal variability and to collect data over long periods to improve estimates of total annual emissions. Such systems are being used in the field and with soil monoliths installed in a greenhouse. Large chambers 50-60 m2 in area, with gas analysis by long-path infrared spectrometry, offer a way of overcoming small-scale spatial variability, and are useful in conditions where micrometeorological methods may not be applicable, or when long runs of data are needed from the same site. In studies with small closed chambers, we have measured N2O emissions from grassland ranging from negligible values to about 4 mg N2O-N m-2 h-1 (nearly 1 kg N2O-N ha-1 d-1), with total losses in the range 0.14-5.1% of the nitrogen applied as fertilizer, depending on factors such as soil structure, water potential and temperature, and the chemical form of the fertilizer. Reasonable agreement can be obtained between chamber and micrometeorological flux measurements on homogeneous sites.
... Les émissions de N 2 O, CO 2 et CH 4 sur le parcours ont été estimées au moyen de mesures ponctuelles au cours des bandes par la méthode des chambres statiques (Smith et al., 1995;Conen and Smith, 1998 ...
... The sown grassland mix consisted of 41% tall fescue, 19% lolium, 11% Kentucky bluegrass, 11% birdsfoot trefoil, 11% alsike clover, 7% white clover. The outdoor surface area per broiler was set so that the excreted N input does not exceed the threshold of 170 kg N per hectare per year (European Council, 1991), based on CORPEN (2006) Chapitre 4 -Emissions de GES sur le parcours de type prairie d'un atelier de production de poulets biologiques 129 Table Table Table Table 22 Greenhouse gas fluxes were measured using static chambers (Smith et al., 1995;Conen and Smith, 1998). Square steel chambers (L=50 * l=50 * H=30 cm) were operated manually and fluxes were measured at (a maximum of) 16 locations on the run, and also at 3 locations just outside the fence to measure background fluxes (Figure 18), using steel frames which were permanently inserted 10 cm into the soil. ...
... In the closed static method, gases were collected in the chamber for a long time (~ 1 h). Closure of the chamber for the accumulation of gas produces alterations in soil temperature and moisture in the chamber, which consequently will cause changes in the GHG efflux in the field (Smith et al. 1995;Welles et al. 2001). In addition, Errors are associated with the radial diffusion of gas in a closed static chamber method. ...
Paddy rice fields (PRFs) are a potent source of global atmospheric greenhouse gases (GHGs), particularly CH4 and CO2. Despite socio-environmental importance, the emission of GHGs has rarely been measured from Haryana agricultural fields. We have used new technology to track ambient concentration and soil flux of GHGs (CH4, CO2, and H2O) near Karnal’s Kuchpura agricultural fields, India. The observations were conducted using a Trace Gas Analyzer (TGA) and Soil Flux Smart Chamber over various parts, i.e., disturbed and undisturbed zone of PRFs. The undisturbed zone usually accounts for a maximum ambient concentration of ~ 2434.95 ppb and 492.46 ppm of CH4 and CO2, respectively, higher than the average global concentration. Soil flux of CH4 and CO2 was highly varied, ranging from 0.18 to 11.73 nmol m−2 s−1 and 0.13–4.98 μmol m−2 s−1, respectively. An insignificant correlation was observed between ambient concentration and soil flux of GHGs from PRFs. Waterlogged (i.e., irrigated and rain-fed) soil contributed slightly lower CH4 flux to the atmosphere. Interestingly, such an agricultural field shows low CO2 and CH4 fluxes compared to the field affected by the backfilling of rice husk ash (RHA). This article suggests farmers not mix RHA to increase soil fertility because of their adverse environmental effects. Also, this study is relevant in understanding the GHGs’ emissions from paddy rice fields to the atmosphere, their impacts, and mitigating measures for a healthy ecosystem.
... The close chamber method (Smith et al., 1995;Moretti et al., 2020) was used to assess N 2 O direct emissions from soils from December 2018 to December 2020. Cylindrical static chambers (40 cm diameter and 25 cm high) were made of polyvinyl chloride (PVC) with a light color to reduce the impact of direct radiating heat during samplings. ...
Intensive irrigation and nitrogen (N) fertilization are often linked to low N-fertilizer efficiency, and to high emissions of the greenhouse gas nitrous oxide (N2O). Efficient irrigation systems (e.g. subsurface drip irrigation [SDI]) combined with N-fertigation in a no-till agroecosystem can promote N-use efficiency, thereby curbing N2O emissions without depressing crop yield. Yet, crop type and SDI plant settings (and management) such as dripline spacing may determine the agronomic and environmental performance of SDI. In this two-year field study on maize (Zea mays L.) - soybean (Glycine max [L.] Merr.) rotation with conservation agriculture management (no-till and cover crops), we investigated the effects of three different irrigation/fertilization systems (SDI with a narrow dripline spacing (70 cm) + fertigation with ammonium sulphate, SDI with a large dripline spacing (140 cm) + fertigation with ammonium sulphate, and sprinkler irrigation [SPR] + granular urea application) on yield, N-fertilizer efficiency, and N2O emissions in a fine-textured soil. We hypothesized that SDI systems (especially with narrow dripline distance) would increase yield and mitigate N2O compared with SPR, and particularly for maize due to its higher water and nutrient demand. We found that SDI increased maize yield (+31%) and N-fertilizer efficiency (+43–71%). These positive results were only observed during the drier year in which irrigation supplied ca. 80% of maize water requirements. The narrower dripline spacing mitigated N2O emissions compared with sprinkler irrigation (by 44%) and with the wider spacing (by 36%), due to a more homogeneous distribution of N in soil, and to a lower soil moisture content. Soybean yield and N-use efficiency were not affected by the irrigation systems. We also found that SPR enhanced cover crop residue decomposition, thus promoting the release of C and N into the soil and increasing N2O emissions. Overall, our study provides important insights on key management decisions that define the sustainability of novel irrigation systems; in particular SDI with a 70 cm dripline distance should be promoted for maize to increase productivity and decrease N2O emissions in fine-textured soils.
... The pressure for sustainable agriculture with a decreased nitrous oxide (N 2 O) emission footprinta potent greenhouse gascan be seen in the increased number of studies aiming to identify emission drivers (e.g., Pelster et al. 2013;Risk et al. 2013;Zhu et al. 2013;Charles et al. 2017;Machado et al. 2020a;Tosi et al. 2020) and evaluate N 2 O emissions in response to the adoption of climate-smart management practices (e.g., Grant et al. 2004;Garland et al. 2011;Tenuta et al. 2016;Cambareri et al. 2017a;Pelster et al. 2020). The bulk of published studies to quantify N 2 O fluxes from soilplant systems deploy chambers (Rochette 2011;Clough et al. 2020;de Klein et al. 2020), a method relatively cheap and adjustable to a wide range of environmental conditions and flux ranges (Smith et al. 1995). Nitrous oxide emissions from soils result mostly from biological processes of nitrification and denitrification (Charles et al. 2017) and are controlled simultaneously by several soil properties (McDaniel et al. 2017;Liang et al. 2018;Kuang et al. 2019;Linton et al. 2020;Machado et al. 2020a). ...
Nitrous oxide (N2O) emissions from soils have been widely studied in the literature–mostly with the chamber method–due to the importance of this gas to climate change. Emissions of N2O derive from biological reactions and are controlled by soil parameters, which are by nature heterogeneous (i.e., “hot spots” for N2O emissions)–a source of uncertainty in chamber-based studies. Spatial variation in N2O fluxes has been assessed in the literature, but information is still needed for contrasting soil management practices (e.g., tillage) and for specific bioclimatic situations (e.g., non-growing seasons under cold weather–NGS). Here, we sub-sampled daily N2O data to assess within-plot and between-block spatial variation from an agronomic experiment under conventional (CT) and no-tillage (NT), identifying if patterns differ between growing season (GS) and NGS datasets. Within-plot spatial variation in N2O fluxes was a small source of uncertainties, but half of the comparisons in GS datasets presented a slope different from 1 for the regression of N2O averages from two vs. one chamber per plot–a source of uncertainty mitigated when within-plot duplication occurred during N2O “hot moments”. Between-block spatial variation in N2O emissions was much larger than within-plot errors–an effect more accentuated for NGS and CT than GS and NT datasets. Decreasing the number of sampled blocks resulted in averages that did not represent the N2O daily average of the whole field – but exceptions occurred. The methodology proposed here may be used in other locations, after appropriate verification, for improved planning and maximization of the resources associated with N2O measurements.
... Soil N 2 O fluxes were measured with the accumulation technique using eight static chambers [29,30]; four chambers were located on the sandy-loam site and four on the clay site. Chambers (0.20 m diameter, 0.15 m height, and 4.7 L) were inserted at a 0.03 m depth into the soil and were left there for the entire measurement period. ...
Crop management and soil properties affect greenhouse gas (GHG) emissions from cropping systems. Irrigation is one of the agronomical management practices that deeply affects soil nitrous oxide (N2O) emissions. Careful management of irrigation, also concerning to soil type, might mitigate the emissions of this powerful GHG from agricultural soils. In the Mediterranean area, despite the relevance of the agricultural sector to the overall economy and sustainable development, the topic of N2O emissions does not have the same importance as N2O fluxes in temperate agricultural areas. Only some research has discussed N2O emissions from Mediterranean cropping systems. Therefore, in this study, N2O emissions from different soil types (sandy-loam and clay soils) were analyzed in relation to the irrigation of a maize crop grown in two contrasting seasons (2009–2010). The irrigation was done using a center pivot irrigation system about twice a week. The N2O emissions were monitored throughout the two-years of maize crop growth. The emissions were measured with the accumulation technique using eight static chambers (four chambers per site). Nitrogen fertilizer was applied in the form of ammonium sulphate and urea with 3,4 dimethylpyrazole phosphate (DMPP) nitrification inhibitors. In 2009, the N2O emissions and crop biomass measured in both soil types were lower than those measured in 2010. This situation was a lower amount of water and nitrogen (N) available to the crop. In 2010, the N2O fluxes were higher in the clay site than those in the sandy-loam site after the first fertilization, whereas an opposite trend was found after the second fertilization. The soil temperature, N content, and soil humidity were the main drivers for N2O emission during 2009, whereas during 2010, only the N content and soil humidity affected the nitrous oxide emissions. The research has demonstrated that crop water management deeply affects soil N2O emissions, acting differently for denitrification and nitrification. The soil properties affect N2O emission by influencing the microclimate conditions in the root zone, conditioning the N2O production.
... The analyzed sites present different soil managements, fertilization rates and site characteristics. At all sites N 2 O fluxes were measured using closed static PVC chambers (Hutchinson and Mosier 1981;Smith et al. 1995) coupled with GC or Photoacustic analyser. Specific technical details on experimental set up and procedures can be found in the literature cited in Table 9.1. ...
... N 2 O emission was measured by closed static chambers (50 cm length by 50 cm width by 25 cm height) (Smith et al., 1995) daily from 27 November to 3 December, and on 11, 12 and 16 December, with five replications. Measurements were suspended between 4 and 10 December when N 2 O emission was expected to be minimal because there was no rainfall and the soil (0-10 cm) was dry (volumetric soil moisture b20%, measured by soil moisture sensor ThetaProbe type ML2x). ...
Denitrification is one of the key processes of the global nitrogen (N) cycle driven by bacteria. It has been widely known for more than 100 years as a process by which the biogeochemical N-cycle is balanced. To study this process, we develop an individual-based model called INDISIM-Denitrification. The model embeds a thermodynamic model for bacterial yield prediction inside the individual-based model INDISIM and is designed to simulate in aerobic and anaerobic conditions the cell growth kinetics of denitrifying bacteria. INDISIM-Denitrification simulates a bioreactor that contains a culture medium with succinate as a carbon source, ammonium as nitrogen source and various electron acceptors. To implement INDISIM-Denitrification, the individual-based model INDISIM was used to give sub-models for nutrient uptake, stirring and reproduction cycle. Using a thermodynamic approach, the denitrification pathway, cellular maintenance and individual mass degradation were modeled using microbial metabolic reactions. These equations are the basis of the sub-models for metabolic maintenance, individual mass synthesis and reducing internal cytotoxic products. The model was implemented in the open-access platform NetLogo. INDISIM-Denitrification is validated using a set of experimental data of two denitrifying bacteria in two different experimental conditions. This provides an interactive tool to study the denitrification process carried out by any denitrifying bacterium since INDISIM-Denitrification allows changes in the microbial empirical formula and in the energy-transfer-efficiency used to represent the metabolic pathways involved in the denitrification process. The simulator can be obtained from the authors on request.
Urease and nitrification inhibitors are designed to mitigate ammonia (NH3) volatilization and nitrous oxide (N2O) emission, but uncertainties on the agronomic and economic benefits of these inhibitors prevent their widespread adoption in pasture systems, particularly in subtropical regions where no such information is available. Here we report a field experiment that was conducted in a subtropical pasture in Queensland, Australia to examine whether the use of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT, applied as Green UreaNV®) and the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP, applied as Urea with ENTEC®) is environmentally, agronomically and economically viable. We found that Green UreaNV® and Urea with ENTEC® decreased NH3 volatilization and N2O emission by 44 and 15%, respectively, compared to granular urea. Pasture biomass and nitrogen (N) uptake were increased by 22–36% and 23–32%, respectively, with application of the inhibitors compared to granular urea. A simple economic assessment indicates that the fertilizer cost for pasture production was 5.4, 4.4 and 6.0 Australian cents per kg dry matter for urea, Green UreaNV® and Urea with ENTEC® respectively, during the experimental period. The mitigation of N loss using the inhibitors can reduce the environmental cost associated with pasture production. These results suggest that the use of these inhibitors can provide environmental, agronomic and economic benefits to a subtropical pasture.
Nitrous oxide emissions from a network of agricultural experiments in Europe and Zimbabwe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared within replicated experimental designs in plot based experiments. Arable experiments were conducted at Beano in Italy, El Encin in Spain, Foulum in Denmark, Logården in Sweden, Maulde in Belgium, Paulinenaue in Germany, Harare in Zimbabwe and Tulloch in the UK. Grassland experiments were conducted at Crichton, Nafferton and Peaknaze in the UK, Gödöllö in Hungary, Rzecin in Poland, Zarnekow in Germany and Theix in France. Nitrous oxide emissions were measured at each site over a period of at least two years using static chambers. Emissions varied widely between sites and as a result of manipulation treatments. Average site emissions (throughout the study period) varied between 0.04 and 21.21 kg N<sub>2</sub>O-N ha<sup>−1</sup> yr<sup>−1</sup>, with the largest fluxes and variability associated with the grassland sites. Total nitrogen addition was found to be the single most important determinant of emissions, accounting for 15% of the variance (using linear regression) in the data from the arable sites ( p < 0.0001), and 77% in the grassland sites. The annual emissions from arable sites were significantly greater than those that would be predicted by IPCC default emission factors. Variability in N<sub>2</sub>O within sites that occurred as a result of manipulation treatments was greater than that resulting from site to site and year to year variation, highlighting the importance of management interventions in contributing to greenhouse gas mitigation.
Nitrous oxide (N2O) emissions from agriculture can be tackled by reducing demand for, and consumption of, nitrogen (N) inputs via diet modification and waste reduction, and/or through technologies applied at the field level. Here we focus on the latter options. Opportunities for mitigating N2O emissions at the field level can be advanced by a clearer scientific understanding of the system complexities leading to emissions, while maintaining agricultural system sustainability and productivity. A range of technologies are available to reduce emissions, but rather than focus specifically on emissions, the broader management and policy focus should be on improved N use efficiency and effectiveness; for lower N2O emissions per unit of crop and animal product, or per unit of land area.
Fluxes peaked five days after fertilization and were one sixth of their maxima by April 24. Spatial differences observed initially were generally maintained. Incubation of cores with 10% acetylene suggested that the N2O was produced by denitrification in the top 5 cm of soil, and in situ soil N2O measurements confirmed that the concentration was highest close to the surface. In a regression model of the flux from the ungrazed area (including the pre- to postfertilization transition), air temperature, recent rainfall, and NO-3-N could account for 52% of the temporal variability. The total N2O-N losses (1.7 and 5.1% of applied N from the ungrazed and grazed areas, respectively) confirm that fertilized grassland can contribute substantially to global N2O emissions. -from Authors
Nitrous oxide emissions from soils, through the processes of nitrification and denitrification, are increased by N fertiliser application. The effect of choosing a form of N fertiliser appropriate to the environmental conditions, and the effect of nitrification inhibitors, on N2O emissions, were studied on a grassland site over two growing seasons. Total emissions were greatest from urea fertiliser, with the greatest losses coming from urea applications in the warmer, drier months of June and August, suggesting that the N2O was formed mainly via nitrification. The greatest emissions of N2O from ammonium nitrate fertiliser occurred after applications in April in relatively wet conditions, when the emissions from urea and ammonium sulphate were low, indicating that denitrification was probably responsible. The application of the nitrification inhibitor dicyandiamide (DCD) reduced emissions from the ammonium-based fertilisers by up to 64%. A single application of nitrapyrin reduced emissions by up to 52%. When urea fertiliser was applied in the spring, followed by ammonium nitrate later in the growing season, the emissions of N2O were lower than when only urea or only ammonium nitrate were used throughout the season; the reduction was similar to that obtained using the nitrification inhibitors.
New N fertilizer products-organically enhanced NS plus and organically enhanced NS plus with Fe, manufactured by using sterilized and chemically converted organic additives extracted from municipal wastewater biosolids, were evaluated for N mineralization, ammonia (NH3-N) volatilization, N leaching, and effects on soil acidification, relative to urea. Laboratory incubations at three temperatures (20, 30, and 40 degrees C), two leaching schemes (continuous and intermittent irrigation regimes), and ammonia volatilization experiments under aerobic (upland) and anaerobic (flooded) conditions were conducted in four appropriate soils (Greenville loam [fine, kaolinitic, thermic Rhodic Kandiudults], Lakeland sand [thermic, coated Typic Quartzipsamments], Guthrie silty-clay [fine-silty, siliceous, thermic Typic Fragiauults], and Sumter clay [fine-silty, carbonatic, thermic Rendollic Eutrudepts]). The two organically enhanced fertilizers had significantly lower nitrification than urea. At all three temperature levels in Greenville soil, the lag phase during the nitrification process was 28.6 d for organically enhanced fertilizers compared to 5.5 d for urea. The longer lag phase duration with organically enhanced fertilizers could result in reduced nitrate losses. Amending Guthrie soil with organically enhanced fertilizers had NH3-N volatilization losses (5 and 22% of applied N) significantly lower than those of the urea-fertilized Guthrie soil (33 and 58% of applied N) under aerobic and anaerobic conditions, respectively. Nitrate leaching with the two irrigation regimes in Lakeland sand was significantly lower for organically enhanced fertilizers than urea. Thus, the organically enhanced fertilizers could be an attractive N source. The environmental and food security benefits of organically enhanced fertilizers result from both recycling of sterilized and converted organic wastes (C, amino acids, and micronutrients) and minimizing the N losses from land to atmosphere and from land to water, which are characteristic of a disrupted N cycle and meet the standards on nutrient management set by NRCS.
A 3-year study was carried out in Canterbury, New Zealand, to determine the effect of a nitrification inhibitor dicyandiamide (DCD) on N2O emissions, nitrate () leaching and pasture yield. In all 3 years, DCD was highly effective in reducing N2O emissions from urine-nitrogen (N) applied in autumn (April and May), decreasing the N2O emission factor by 41%–82%. In addition, DCD consistently reduced -N leaching losses by 48%–69% from the animal urine applied in April. Pasture yield responses to DCD application varied from 0%–17%, probably due to other growth limiting factors and/or the methodology used in the pasture yield measurement. The reductions in leaching are of particular value at this point in time due to the increasingly strict regional council regulations that are being imposed on farmers to reduce N leaching losses.