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1.
The open lots and manure stockpiles of dairy farm are major sources of greenhouse gas (GHG) emissions in typical dairy cow housing and manure management system in China. GHG (CO 2, CH 4 and N 2O) emissions from the ground level of brick-paved open lots and uncovered manure stockpiles were estimated according to the field measurements of a typical dairy farm in Beijing by closed chambers in four consecutive seasons. Location variation and manure removal strategy impacts were assessed on GHG emissions from the open lots. Estimated CO 2, CH 4 and N 2O emissions from the ground level of the open lots were 137.5±64.7 kg hd -1 yr -1, 0.45±0.21 kg hd -1 yr -1 and 0.13±0.08 kg hd -1 yr -1, respectively. There were remarkable location variations of GHG emissions from different zones (cubicle zone vs. aisle zone) of the open lot. However, the emissions from the whole open lot were less affected by the locations. After manure removal, lower CH 4 but higher N 2O emitted from the open lot. Estimated CO 2, CH 4 and N 2O emissions from stockpile with a stacking height of 55±12 cm were 858.9±375.8 kg hd -1 yr -1, 8.5±5.4 kg hd -1 yr -1 and 2.3±1.1 kg hd -1 yr -1, respectively. In situ storage duration, which estimated by manure volatile solid contents (VS), would affect GHG emissions from stockpiles. Much higher N 2O was emitted from stockpiles in summer due to longer manure storage. Implications: This study deals with greenhouse gas (GHG) emissions from open lots and stockpiles. It’s an increasing area of concern in some livestock producing countries. The Intergovernmental Panel on Climate Change (IPCC) methodology is commonly used for estimation of national GHG emission inventories. There is a shortage of on-farm information to evaluate the accuracy of these equations and default emission factors. This work provides valuable information for improving accounting practices within China or for similar manure management practice in other countries. 相似文献
2.
Patches of dung and urine are major contributors to the feedlot gas emissions. This study investigated the impacts of dung deposition frequency (partly reflecting animal stocking density of a feedlot), dairy feedlot floor conditions (old floor indicated with the presence of consolidated manure pad [CMP] vs. new floor with the absence of consolidated manure pad [CMPn]), and application of dicyandiamide (DCD) and hydroquinone (HQ) on nitrous oxide (N 2O) and methane (CH 4) emissions from patches in the laboratory, and the integrative impacts were expressed in terms of global warming potential (CO 2-equivalent). Dung deposition frequency, feedlot floor condition, and application of inhibitors showed inverse impacts on N 2O and CH 4 emissions from patches. Greenhouse gas (GHG) emissions from the dung, urine, and dung+urine patches on the CMP feedlot surface were approximately 7.48, 87.35, and 7.10 times those on the CMPn feedlot surface ( P < 0.05). Meanwhile, GHG emissions from CMP and CMPn feedlot surfaces under high deposition frequency condition were approximately 10 and 1.7 times those under low-frequency condition. Moreover, application of HQ slightly reduced the GHG emission from urine patches, by 14.9% ( P > 0.05), while applying DCD or DCD+HQ significantly reduced the GHG, by 60.3% and 65.0%, respectively ( P < 0.05). Overall, it is necessary to include feedlot management such as animal stocking density and feedlot floor condition to the process of determining emission factors for feedlots. In the future, field measurements to quantitatively evaluate the relative contribution of nitrification and denitrification to the N 2O emissions of feedlot surfaces are highly required for effective N 2O control. Implications: This study shows that feedlot CH4 and N2O emissions inversely respond to the dicyandiamide (DCD) application. Applying DCD significantly reduces GHG emissions of feedlot urine patches. Feedlot floor condition and stocking density strongly impact feedlot GHG emissions. Including feedlot floor condition and stocking density in the feedlot EF determining process is necessary. 相似文献
3.
Land use conversion and fertilization have been widely reported to be important managements affecting the exchanges of greenhouse gases between soil and atmosphere. For comprehensive assessment of methane (CH 4) and nitrous oxide (N 2O) fluxes from hilly red soil induced by land use conversion and fertilization, a 14-month continuous field measurement was conducted on the newly converted citrus orchard plots with fertilization (OF) and without fertilization (ONF) and the conventional paddy plots with fertilization (PF) and without fertilization (PNF). Our results showed that land use conversion from paddy to orchard reduced the CH 4 fluxes at the expense of increasing the N 2O fluxes. Furthermore, fertilization significantly decreased the CH 4 fluxes from paddy soils in the second stage after conversion, but it failed to affect the CH 4 fluxes from orchard soils, whereas fertilizer applied to orchard and paddy increased soil N 2O emissions by 68 and 113.9 %, respectively. Thus, cumulative CH 4 emissions from the OF were 100 % lower, and N 2O emissions were 421 % higher than those from the PF. Although cumulative N 2O emissions were stimulated in the newly converted orchard, the strong reduction of CH 4 led to lower global warming potentials (GWPs) as compared to the paddy. Besides, fertilization in orchard increased GWPs but decreased GWPs of paddy soils. In addition, measurement of soil moisture, temperature, dissolved carbon contents (DOCs), and ammonia (NH 4 +-N) and nitrate (NO 3 ?-N) contents indicated a significant variation in soil properties and contributed to variations in soil CH 4 and N 2O fluxes. Results of this study suggest that land use conversion from paddy to orchard would benefit for reconciling greenhouse gas mitigation and citrus orchard cultivation would be a better agricultural system in the hilly red soils in terms of greenhouse gas emission. Moreover, selected fertilizer rate applied to paddy would lead to lower GWPs of CH 4 and N 2O. Nevertheless, more field measurements from newly converted orchard are highly needed to gain an insight into national and global accounting of CH 4 and N 2O emissions. 相似文献
4.
A field experiment was conducted in Bangladesh Agricultural University Farm to investigate the mitigating effects of soil amendments such as calcium carbide, calcium silicate, phosphogypsum, and biochar with urea fertilizer on global warming potentials (GWPs) of methane (CH 4) and nitrous oxide (N 2O) gases during rice cultivation under continuous and intermittent irrigations. Among the amendments phosphogypsum and silicate fertilizer, being potential source of electron acceptors, decreased maximum level of seasonal CH 4 flux by 25–27 % and 32–38 % in continuous and intermittent irrigations, respectively. Biochar and calcium carbide amendments, acting as nitrification inhibitors, decreased N 2O emissions by 36–40 % and 26–30 % under continuous and intermittent irrigations, respectively. The total GWP of CH 4 and N 2O gases were decreased by 7–27 % and 6–34 % with calcium carbide, phosphogypsum, and silicate fertilizer amendments under continuous and intermittent irrigations, respectively. However, biochar amendments increased overall GWP of CH 4 and N 2O gases. 相似文献
5.
Greenhouse gas (GHG) emissions from concentrated animal feeding operations vary by stage of production and management practices. The objective of this research was to study the effect of two dietary crude protein levels (12 and 16%) fed to beef steers in pens with or without corn stover bedding. Manure characteristics and GHG emissions were measured from feedlot pen surfaces. Sixteen equal-sized feedlot pens (19?×?23 m) were used. Eight were bedded approximately twice a week with corn stover and the remaining eight feedlot pens were not bedded. Angus steers (n = 138) were blocked by live weights (lighter and heavier) with 7 to 10 animals per pen. The trial was a 2?×?2 factorial design with factors of two protein levels and two bedding types (bedding vs. non bedding), with four replicates. The study was conducted from June through September and consisted of four ?28-day periods. Manure from each pen was scrapped once every 28 days and composite manure samples from each pen were collected. Air samples from pen surfaces were sampled in Tedlar bags using a Vac-U-Chamber coupled with a portable wind tunnel and analyzed with a greenhouse gas gas chromatograph within 24 hr of sampling. The manure samples were analyzed for crude protein (CP), total nitrogen (TN), ammonia (NH 3), total volatile fatty acid (TVFA), total carbon (TC), total phosphorus (TP), and potassium (K). The air samples were analyzed for methane (CH 4), carbon dioxide (CO 2), and nitrous oxide (N 2O) concentrations. The concentration of TN was significantly higher (p < 0.05) in manure from pens with cattle fed the high protein diets. The volatile fatty acids (VFAs) such as acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids concentrations were similar across both treatments. There were no significant differences in pen surface GHG emissions across manure management and dietary crude protein levels. Implications: Livestock manure produces odor and emits GHGs (CO2, CH4, and N2O) at different stages of production and management practices that have significant environmental concerns. Thus, it is important to measure GHG contributions from different sources and develop appropriate mitigation strategies for minimizing GHG contribution from livestock production facilities. Two dietary protein levels (12 and 16%) fed to beef steers in pens with or without corn stover bedding were studied. The results indicated that dietary protein levels and bedding vs. no bedding had very little effect on GHG emissions and manure composition under open feedlot conditions in North Dakota climatic conditions and management practices. 相似文献
6.
Water management is one of the most important practices that affect methane (CH 4) and nitrous oxide (N 2O) emissions from paddy fields. A field experiment was designed to study the effects of controlled irrigation (CI) on CH 4 and N 2O emissions from paddy fields, with traditional irrigation (TI) as the control. The effects of CI on CH 4 and N 2O emissions from paddy fields were very clear. The peaks of CH 4 emissions from the CI paddies were observed 1-2 d after the water layer disappeared. Afterward, the emissions reduced rapidly and remained low until the soil was re-flooded. A slight increase of CH 4 emission was observed in a short period after re-flooding. N 2O emissions peaks from CI paddies were all observed 8-10 d after the fertilization at the WFPS ranging from 78.1% to 85.3%. Soil drying caused substantial N 2O emissions, whereas no substantial N 2O emissions were observed when the soil was re-wetted after the dry phase. Compared with TI, the cumulative CH 4 emissions from the CI fields were reduced by 81.8% on the average, whereas the cumulative N 2O emissions were increased by 135.4% on the average. The integrative global warming potential of CH 4 and N 2O on a 100-year horizon decreased by 27.3% in the CI paddy fields, whereas no significant difference in the rice yield was observed between the CI and TI fields. These results suggest that CI can effectively mitigate the integrative greenhouse effect caused by CH 4 and N 2O emissions from paddy fields while ensuring the rice yield. 相似文献
7.
Emissions of CH 4 and N 2O related to private pig farming under a tropical climate in Uvéa Island were studied in this paper. Physicochemical soil parameters such as nitrate, nitrite, ammonium, Kjeldahl nitrogen, total organic carbon, pH and moisture were measured. Gaseous soil emissions as well as physicochemical parameters were compared in two private pig farming strategies encountered on this island on two different soils (calcareous and ferralitic) in order to determine the best pig farming management: in small concrete pens or in large land pens. Ammonium levels were higher in control areas while nitrate and nitrite levels were higher in soils with pig slurry inputs, indicating that nitrification was the predominant process related to N 2O emissions. Nitrate contents in soils near concrete pens were important (≥55 μg N/g) and can thus be a threat for the groundwater. For both pig farming strategies, N 2O and CH 4 fluxes can reach high levels up to 1 mg N/m 2/h and 1 mg C/m 2/h, respectively. CH 4 emissions near concrete pens were very high (≥10.4 mg C/m 2/h). Former land pens converted into agricultural land recover low N 2O emission rates (≤0.03 mg N/m 2/h), and methane uptake dominates. N 2O emissions were related to nitrate content whereas CH 4 emissions were found to be moisture dependent. As a result relating to the physicochemical parameters as well as to the gaseous emissions, we demonstrate that pig farming in large land pens is the best strategy for sustainable family pig breeding in Uvéa Islands and therefore in similar small tropical islands. 相似文献
8.
In this research, in order to develop technology/country-specific emission factors of methane (CH 4) and nitrous oxide (N 2O), a total of 585 samples from eight gas-fired turbine combined cycle (GTCC) power plants were measured and analyzed. The research found that the emission factor for CH 4 stood at “0.82 kg/TJ”, which was an 18 % lower than the emission factor for liquefied natural gas (LNG) GTCC “1 kg/TJ” presented by Intergovernmental Panel on Climate Change (IPCC). The result was 8 % up when compared with the emission factor of Japan which stands at “0.75 kg/TJ”. The emission factor for N 2O was “0.65 kg/TJ”, which is significantly lower than “3 kg/TJ” of the emission factor for LNG GTCC presented by IPCC, but over six times higher than the default N 2O emission factor of LNG. The evaluation of uncertainty was conducted based on the estimated non-CO 2 emission factors, and the ranges of uncertainty for CH 4 and N 2O were between ?12.96 and +13.89 %, and ?11.43 and +12.86 %, respectively, which is significantly lower than uncertainties presented by IPCC. These differences proved that non-CO 2 emissions can change depending on combustion technologies; therefore, it is vital to establish country/technology-specific emission factors. 相似文献
9.
The wetlands play an important role in global carbon and nitrogen storage, and they are also natural sources of greenhouse gases such as methane (CH 4) and nitrous oxide (N 2O). Land-use change is an important factor affecting the exchange of greenhouse gases between wetlands and the atmosphere. However, few studies have investigated the effect of land-use change on CH 4 and N 2O emissions from freshwater marsh in China. Therefore, a field study was carried out over a year to investigate the seasonal changes of the emissions of CH 4 and N 2O at three sites ( Deyeuxia angustifolia marsh, dryland and rice field) in the Sanjiang Plain of Northeast China. Marsh was the source of CH 4 showing a distinct temporal variation. Maximum fluxes occurred in June and the highest value was 20.69 ± 2.57 mg CH 4 m ?2 h ?1. The seasonal change of N 2O fluxes from marsh was not obvious, consisted of a series of emission pulses. The marsh acted as a N 2O sink during winter, while became a N 2O source in the growing season. The results showed that gas exchange between soil/snow and the atmosphere in the winter season contributed greatly to the annual budgets. The winter season CH 4 flux was about 3.24% of the annual flux and the winter uptake of N 2O accounted for 13.70% of the growing-season emission. Conversion marsh to dryland resulted in a shift from a strong CH 4 source to a weak sink (from 199.12 ± 39.04 to ?1.37 ± 0.68 kg CH 4 ha ?1 yr ?1), while increased N 2O emissions somewhat (from 4.07 ± 1.72 to 4.90 ± 1.52 kg N 2O ha ?1 yr ?1). Conversion marsh to rice field significantly decreased CH 4 emission from 199.12 ± 39.04 to 94.82 ± 9.86 kg CH 4 ha ?1 yr ?1 and N 2O emission from 4.07 ± 1.72 to 2.09 ± 0.79 kg N 2O ha ?1 yr ?1. 相似文献
10.
As a convenient method, the closed chamber method has been applied to determine gaseous emission fluxes from fully open animal feeding operations despite the measured fluxes being theoretically affected by deployment time, wind speed over the emitting surface and detected gas mass. This laboratory study evaluated the effects of deployment time (0 to 120 min) and external surface wind speed (ESWS) (0.00, 0.25, 0.50, 0.75, 1.00, 1.50 and 2.00 m sec -1) on the measurement accuracy of a 300 mm (diameter) × 400 mm (height) (D300×H400) closed chamber using methane (CH 4), nitrous oxide (N 2O) and sulfur hexafluoride (SF 6) as reference gases. The results showed that the overall deviation ratio between the measured and reference CH 4 fluxes ranged from 9.99 % to -37.32 % and the flux was overestimated in the first 20 min. The measured N 2O and SF 6 emissions were smaller than the reference fluxes using the chamber. N 2O measurement accuracy decreased from -14.47 to -35.09% with deployment time extended to 120 min, while SF 6 accuracy sharply increased in the first 40 min, with the deviation stabilizing at approximately -5.00%. CH 4, N 2O and SF 6 measurements were significantly affected by deployment time and ESWS (P<0.05), and the interaction of those two factors greatly influenced CH 4 and SF 6 measurements (P<0.05). With the D300×H400 closed chamber, deployment times of 20 to 30 min and 10 to 20 min are recommended to measure CH 4 and N 2O, respectively, from the open operations of dairy farms under wind speeds lower than 2 m sec -1. Implications: This study recommended the suitable deployment times and wind speeds for using a D300 × H400 closed chamber to measure CH4, N2O, and SF6 in an open system, such as a dairy open lot and manure stockpile, to help researchers and other related industry workers get accurate data for gas emission rate. Deployment times of 20 to 30 min and 10 to 20 min were recommended to measure CH4 and N2O emissions using the D300 × H400 closed chamber, respectively, from the open operations of dairy farms under wind speeds lower than 2 m sec?1. For the measurement of SF6, a typical tracer gas, a deployment of 70 to 90 min was suggested. 相似文献
11.
Nitrous oxide (N 2O) is a trace gas contributing to stratospheric ozone depletion and global warming. Although a large quantity of information exists about N 2O emissions from various ecosystems, this study was initiated to demonstrate the features of N 2O emissions from sea-based waste disposal sites in Osaka City in relation to CH 4 emissions. Average N 2O emissions at an active landfill (S-Site) were several times higher than those at a closed landfill (N Site). Average CH 4 emissions were also much greater at the S-Site. Regarding the nature of N 2O emissions, remarkable emissions often were observed with aerobic waste layers at the N-Site, suggesting almost inversely related N 2O emissions with CH 4 production at the N-Site. However, at the S-Site a few exceptionally high N 2O emissions were noted in cases of high CH 4 emissions. 相似文献
12.
Great efforts have been devoted to assessing the effects of straw managements on greenhouse gas (GHG) emissions, global warming potential (GWP), and net economic budget in rice monoculture (RM). However, few studies have evaluated the effects of straw managements on GHG emissions and net ecosystem economic budget (NEEB) in integrated rice-crayfish farming (RC). Here, a randomized block field experiment was performed to comprehensively evaluate the effects of aquatic breeding practices (feeding or no feeding of forage) and straw managements (rice straw returning or removal) on soil NH4+–N and NO?3–N contents, redox potential (Eh), CH4 and N2O emissions, GWP, and NEEB of fluvo-aquic paddy soil in a rice-crayfish co-culture system in Jianghan Plain of China. We also compared the differences in CH4 and N2O emissions, GWP, and NEEB between RM and RC. Straw returning significantly increased CH4 and N2O emissions by 34.9–46.1% and 6.2–23.1% respectively compared with straw removal. Feeding of forage decreased CH4 emissions by 13.9–18.7% but enhanced N2O emissions by 24.4–33.2% relative to no feeding. Compared with RM treatment, RC treatment decreased CH4 emissions by 18.1–19.6% but increased N2O emissions by 16.8–21.0%. Moreover, RC treatment decreased GWP by 16.8–22.0% while increased NEEB by 26.9–75.6% relative to RM treatment, suggesting that the RC model may be a promising option for mitigating GWP and increasing economic benefits of paddy fields. However, the RC model resulted in a lower grain yield compared with the RM model, indicating that more efforts are needed to simultaneously increase grain yield and NEEB and decrease GWP under RC model. 相似文献
13.
Manure-based soil amendments (herein “amendments”) are important fertility sources, but differences among amendment types and management can significantly affect their nutrient value and environmental impacts. A 6-month in situ decomposition experiment was conducted to determine how protection from wintertime rainfall affected nutrient losses and greenhouse gas (GHG) emissions in poultry (broiler chicken and turkey) and horse amendments. Changes in total nutrient concentration were measured every 3 months, changes in ammonium (NH 4+) and nitrate (NO 3?) concentrations every month, and GHG emissions of carbon dioxide (CO 2), methane (CH 4), and nitrous oxide (N 2O) every 7–14 days. Poultry amendments maintained higher nutrient concentrations (except for K), higher emissions of CO 2 and N 2O, and lower CH 4 emissions than horse amendments. Exposing amendments to rainfall increased total N and NH 4+ losses in poultry amendments, P losses in turkey and horse amendments, and K losses and cumulative N 2O emissions for all amendments. However, it did not affect CO 2 or CH 4 emissions. Overall, rainfall exposure would decrease total N inputs by 37% (horse), 59% (broiler chicken), or 74% (turkey) for a given application rate (wet weight basis) after 6 months of decomposition, with similar losses for NH 4+ (69–96%), P (41–73%), and K (91–97%). This study confirms the benefits of facilities protected from rainfall to reduce nutrient losses and GHG emissions during amendment decomposition. Implications: The impact of rainfall protection on nutrient losses and GHG emissions was monitored during the decomposition of broiler chicken, turkey, and horse manure-based soil amendments. Amendments exposed to rainfall had large ammonium and potassium losses, resulting in a 37–74% decrease in N inputs when compared with amendments protected from rainfall. Nitrous oxide emissions were also higher with rainfall exposure, although it had no effect on carbon dioxide and methane emissions. Overall, this work highlights the benefits of rainfall protection during amendment decomposition to reduce nutrient losses and GHG emissions. 相似文献
14.
Energy supply utilities release significant amounts of greenhouse gases (GHGs) into the atmosphere. It is essential to accurately estimate GHG emissions with their uncertainties, for reducing GHG emissions and mitigating climate change. GHG emissions can be calculated by an activity-based method (i.e., fuel consumption) and continuous emission measurement (CEM). In this study, GHG emissions such as CO 2, CH 4, and N 2O are estimated for a heat generation utility, which uses bituminous coal as fuel, by applying both the activity-based method and CEM. CO 2 emissions by the activity-based method are 12–19% less than that by the CEM, while N 2O and CH 4 emissions by the activity-based method are two orders of magnitude and 60% less than those by the CEM, respectively. Comparing GHG emissions (as CO 2 equivalent) from both methods, total GHG emissions by the activity-based methods are 12–27% lower than that by the CEM, as CO 2 and N 2O emissions are lower than those by the CEM. Results from uncertainty estimation show that uncertainties in the GHG emissions by the activity-based methods range from 3.4% to about 20%, from 67% to 900%, and from about 70% to about 200% for CO 2, N 2O, and CH 4, respectively, while uncertainties in the GHG emissions by the CEM range from 4% to 4.5%. For the activity-based methods, an uncertainty in the Intergovernmental Panel on Climate Change (IPCC) default net calorific value (NCV) is the major uncertainty contributor to CO 2 emissions, while an uncertainty in the IPCC default emission factor is the major uncertainty contributor to CH 4 and N 2O emissions. For the CEM, an uncertainty in volumetric flow measurement, especially for the distribution of the volumetric flow rate in a stack, is the major uncertainty contributor to all GHG emissions, while uncertainties in concentration measurements contribute a little to uncertainties in the GHG emissions. Implications:Energy supply utilities contribute a significant portion of the global greenhouse gas (GHG) emissions. It is important to accurately estimate GHG emissions with their uncertainties for reducing GHG emissions and mitigating climate change. GHG emissions can be estimated by an activity-based method and by continuous emission measurement (CEM), yet little study has been done to calculate GHG emissions with uncertainty analysis. This study estimates GHG emissions and their uncertainties, and also identifies major uncertainty contributors for each method. 相似文献
15.
Municipal solid waste landfills are the significant anthropogenic sources of N 2O due to the cooxidation of ammonia by methane-oxidizing bacteria in cover soils. Such bacteria could be developed through CH 4 fumigation, as evidenced by both laboratory incubation and field measurement. During a 10-day incubation with leachate addition, the average N 2O fluxes in the soil samples, collected from the three selected landfill covers, were multiplied by 1.75 ( p < 0.01), 3.56 ( p < 0.01), and 2.12 ( p < 0.01) from the soil samples preincubated with 5% CH 4 for three months when compared with the control, respectively. Among the three selected landfill sites, N 2O fluxes in two landfill sites were significantly correlated with the variations of the CH 4 emissions without landfill gas recovery ( p < 0.001). N 2O fluxes were also elevated by the increase of the CH 4 emissions with landfill gas recovery in another landfill site ( p > 0.05). The annual average N 2O flux was 176 ± 566 μg N 2O–N m ?2 h ?1 ( p < 0.01) from sandy soil–covered landfill site, which was 72% ( p < 0.05) and 173% ( p < 0.01) lower than the other two clay soil covered landfill sites, respectively. The magnitude order of N 2O emissions in three landfill sites was also coincident by the results of laboratory incubation, suggesting the sandy soil cover could mitigate landfill N 2O emissions. 相似文献
16.
Agriculture is an important source of NH 3, which contributes to acidification and eutrophication, as well as emissions of the greenhouse gases CH 4 and N 2O. Because of their common sources, emission reduction measures for one of these gases may affect emissions of others. These interrelations are often ignored in policy making. This study presents an analysis of the effects of measures to reduce NH 3 emissions on emissions of N 2O and CH 4 from agriculture in Europe. The analysis combines information from the NH 3 module of the Regional Air pollution INformation and Simulation (RAINS) model for Europe with the IPCC method for national greenhouse gas inventories. The IPCC method for estimating agricultural emissions of N 2O and CH 4 is adjusted in order to use it in combination with the RAINS database for the European agricultural sector. As an example, we applied the adjusted method to the agricultural sector in the Netherlands and found that application of several NH 3 abatement options may result in a substantial increase in N 2O emissions while the effect on CH 4 emissions is relatively small. In Part 2 of this paper we focus on the resulting emissions for all European countries for 1990 and 2010. 相似文献
17.
To investigate the spatial and seasonal variations of nitrous oxide (N 2O) fluxes and understand the key controlling factors, we explored N 2O fluxes and environmental variables in high marsh (HM), middle marsh (MM), low marsh (LM), and mudflat (MF) in the Yellow River estuary throughout a year. Fluxes of N 2O differed significantly between sampling periods as well as between sampling positions. During all times of day and the seasons measured, N 2O fluxes ranged from ?0.0051 to 0.0805 mg N 2O m ?2 h ?1, and high N 2O emissions occurred during spring (0.0278 mg N 2O m ?2 h ?1) and winter (0.0139 mg N 2O m ?2 h ?1) while low fluxes were observed during summer (0.0065 mg N 2O m ?2 h ?1) and autumn (0.0060 mg N 2O m ?2 h ?1). The annual average N 2O flux from the intertidal zone was 0.0117 mg N 2O m ?2 h ?1, and the cumulative N 2O emission throughout a year was 113.03 mg N 2O m ?2, indicating that coastal marsh acted as N 2O source. Over all seasons, N 2O fluxes from the four marshes were significantly different ( p?<?0.05), in the order of HM (0.0256?±?0.0040 mg N 2O m ?2 h ?1)?>?MF (0.0107?±?0.0027 mg N 2O m ?2 h ?1)?>?LM (0.0073?±?0.0020 mg N 2O m ?2 h ?1)?>?MM (0.0026?±?0.0011 mg N 2O m ?2 h ?1). Temporal variations of N 2O emissions were related to the vegetations ( Suaeda salsa, Phragmites australis, and Tamarix chinensis) and the limited C and mineral N in soils during summer and autumn and the frequent freeze/thaw cycles in soils during spring and winter, while spatial variations were mainly affected by tidal fluctuation and plant composition at spatial scale. This study indicated the importance of seasonal N 2O contributions (particularly during non-growing season) to the estimation of local N 2O inventory, and highlighted both the large spatial variation of N 2O fluxes across the coastal marsh (CV?=?158.31 %) and the potential effect of exogenous nitrogen loading to the Yellow River estuary on N 2O emission should be considered before the annual or local N 2O inventory was evaluated accurately. 相似文献
19.
Agriculture is an important source of NH 3, which contributes to acidification and eutrophication, as well as emissions of the greenhouse gases CH 4 and N 2O. Because of their common sources, emission reduction measures for one of these gases may affect emissions of others. These interrelations are often ignored in policy making. This study presents an analysis of the effects of measures to reduce NH 3 emissions on emissions of N 2O and CH 4 from agriculture in Europe. The analysis combines information from the NH 3 module of the Regional Air pollution INformation and Simulation (RAINS) model for Europe with the IPCC method for national greenhouse gas inventories. The IPCC method for estimating agricultural emissions of N 2O and CH 4 is adjusted in order to use it in combination with the RAINS database for the European agricultural sector. As an example, we applied the adjusted method to the agricultural sector in the Netherlands and found that application of several NH 3 abatement options may result in a substantial increase in N 2O emissions while the effect on CH 4 emissions is relatively small. In Part 2 of this paper we focus on the resulting emissions for all European countries for 1990 and 2010. 相似文献
20.
In this paper the authors have estimated for 1990 and 1995 the inventory of greenhouse gases CO 2, CH 4 and N 2O for India at a national and sub-regional district level. The district level estimates are important for improving the national inventories as well as for developing sound mitigation strategies at manageable smaller scales. Our estimates indicate that the total CO 2, CH 4 and N 2O emissions from India were 592.5, 17, 0.2 and 778, 18, 0.3 Tg in 1990 and 1995, respectively. The compounded annual growth rate (CAGR) of these gases over this period were 6.3, 1.2 and 3.3%, respectively. The districts have been ranked according to their order of emissions and the relatively large emitters are termed as hotspots. A direct correlation between coal consumption and districts with high CO 2 emission was observed. CO 2 emission from the largest 10% emitters increased by 8.1% in 1995 with respect to 1990 and emissions from rest of the districts decreased over the same period, thereby indicating a skewed primary energy consumption pattern for the country. Livestock followed by rice cultivation were the dominant CH 4 emitting sources. The waste sector though a large CH 4 emitter in the developed countries, only contributed about 10% the total CH 4 emission from all sources as most of the waste generated in India is allowed to decompose aerobically. N 2O emissions from the use of nitrogen fertilizer were maximum in both the years (more than 60% of the total N 2O). High emission intensities, in terms of CO 2 equivalent, are in districts of Gangetic plains, delta areas, and the southern part of the country. These overlap with districts with large coal mines, mega power plants, intensive paddy cultivation and high fertilizer use. The study indicates that the 25 highest emitting districts account for more than 37% of all India CO 2 equivalent GHG emissions. Electric power generation has emerged as the dominant source of GHG emissions, followed by emissions from steel and cement plants. It is therefore suggested, to target for GHG mitigation, the 40 largest coal-based thermal plants, five largest steel plants and 15 largest cement plants in India as the first step. 相似文献
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