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Fossil fuels, land use, and agriculture are the three major sources contributing to the rise in atmospheric greenhouse gases (GHGs). Agricultural activities including the production of rice, animal raising, and aquaculture directly contribute to GHG emissions. Approximately one fourth of all GHG emissions are attributable to agricultural operations primarily as a result of unsustainable farming practices. The GHG emissions from agriculture include carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4). However, measurements of GHGs are laborious, expensive, and technically challenging but are crucial to select the most appropriate and feasible system. Since it is difficult to find a comprehensive overview of the variety of techniques, including latest technologies, in one article, this review aims to provide details of available methodologies, their benefits and drawbacks, with a focus on those that have been extensively tested in various ecosystems and regions. This paper is a purely methodological one which, on purpose, tried to familiarize the reader with the vast range of different developments. Our analysis is not exhaustive and is not intended to be a systematic review. The article summarizes that micrometeorological approaches are suitable for measurement from broader footprints, whereas chamber techniques measuring gases from point sources, are more appropriate for high spatio-temporal resolutions in diverse ecosystems. Stable isotope techniques are the most accurate methods and allow a process-specific quantification of GHGs but require sophisticated equipment.

With the extensive application of wood-based panels in the home decor industry, determining formaldehyde release form wood-based panels (FRWBP) is crucial for ensuring environmental air quality and human health. This article addresses the issues of insufficient monitoring of the testing stages for FRWBP and the difficulty in tracing the operation records of operator during determining FRWBP by the chamber method. It proposes a system for monitoring and analyzing the testing stages of FRWBP based on electrical monitoring. The system employs non-invasive sensing technology that does not interfere with normal testing process to collect real-time electrical usage data from the devices. The data is uploaded to an industrial computer for storage and processing. Statistical features of the electrical time series data are extracted using a sliding window approach and optimized with Principal Component Analysis (PCA). Subsequently, the binary tree support vector machine algorithm (BTSVM) optimized by k-means clustering algorithm is used to identify the detection states of the wood-based panels. Experimental results show that the system can achieve traceability of the formaldehyde detection stage records of artificial boards, and the designed algorithm model can also effectively identify the detection status of wood-based panels. The system and methods proposed in this paper have significant prospects for implementation in monitoring and traceability management within the testing industry.

A mass decline of Picea abies (hereinafter – spruce), often associated with outbreaks of Ips typographus, is one of the main reasons for the reduction of spruce forests. In turn, dry and fallen trees can be both stock and source of greenhouse gases at various stages of decomposition. In our study, using an unmanned aerial vehicle, we evaluated the dynamics of spruce decline in two forest types in the southwest of the Valdai Upland (Central Forest State Nature Reserve, Russia), namely Sphagnum-bilberry forests and nemoral spruce forests. It was found that the rate of decline in Sphagnum-bilberry spruce forest was much higher than in nemoral spruce forest. By the fourth year after a windfall on 0.13 km2, 913 spruce individuals had withered in Sphagnum-bilberry forest and 66 ones in the nemoral spruce forest. Based on direct measurements of greenhouse gas fluxes by chamber method on dead trunks and coarse woody debris, it was found that in relative values the highest amount of CO2 is emitted by coarse woody debris of the decay classes 3–4 (800–1800 mg CO2 × m-2 × h-1). Deadwood and coarse woody debris from the first decay classes are assumed to be a source of CH4 (0.0008–0.0070 mg CO2 × m-2 × h-1), and from classes 3–5 they are a stock (from -0.0070 mg CO2 × m-2 × h-1 to -0.0009 mg CO2 × m-2 × h-1). When converted to the total surface areas of deadwood and coarse woody debris of the study sites, it was found that coarse woody debris of the decay classes 3–5 (2.3–13.6 kg CO2 × h-1) made the highest contribution to the integral CO2 emission, and deadwood (67 mg CH4 × h-1) made the highest contribution to the CH4 emission. Significant differences in greenhouse gas fluxes were found both between deadwood and decay classes of coarse woody debris, and between fluxes from deadwood and coarse woody debris of individual decay classes in various forest types. The results have shown the importance of considering deadwood and all available decay classes of coarse woody debris when estimating greenhouse gas fluxes from dead timber and the contribution of debris to the carbon cycle in forest ecosystems.

Korea is currently developing country-specific emission factors to support the 2050 zero-carbon campaign. Dairy cattle represent one of the largest livestock industries in Korea, and the industry is estimated to continue increasing because of an increase in milk demand. However, country-specific emission factors for dairy cattle are currently only available for calculating methane (CH4) emissions from enteric fermentation. Two experiments were conducted to evaluate CH4 and nitrous oxide (N2O) fluxes from sawdust-bedded barn in dairy cow and steer, as well as dairy cattle manure composting lots. The greenhouse gas (GHG) fluxes were quantified using the open-chamber method and gas chromatography. CH4 fluxes from steer, dairy cow, and manure compost were 27.88 ± 5.84, 36.12 ± 10.85, and 259.44 ± 61.78 µg/head/s, respectively. N2O fluxes from steer, dairy cow, and manure compost were 14.04 ± 1.27, 4.11 ± 1.57, and 3.97 ± 1.08 µg/head/s, respectively. The result of this study can be used to construct country-specific data for GHG emissions from manure management. Thus, the application of mitigation strategies can be prioritized based on the GHG profile and targeted source.

The applicability of semiconductor methane sensors designed for detection of explosive concentrations of gases in rooms to the study of background methane contents in the atmosphere and its emissions from the surface of a water body is studied. An experimental prototype of the methane sensor is designed. To increase the accuracy of determining the methane content in air, the calibration procedure is suggested where the ambient humidity, temperature, and pressure are taken into account. Laboratory and field experiments show that TGS sensors are capable of detecting variations in the methane contents from 0.1 ppm and higher and can be mounted in floating chambers used to determine methane emissions from the water surface. The experimental setup is described; the results of calibration and selection of the best parametric model are presented. Recommendations for further development of the device are given. [ABSTRACT FROM AUTHOR]

The landscapes in the discontinuous permafrost area of Western Siberia are unique objects for assessing the direct and indirect impact of permafrost on greenhouse gas fluxes. The aim of this study was to identify the influence of permafrost on the CO2 emission at the landscape and local levels. The CO2 emission from the soil surface with the removed vegetation cover was measured by the closed chamber method, with simultaneous measurements of topsoil temperature and moisture and thawing depth in forest, palsa, and bog ecosystems in August 2022. The CO2 emissions from the soils of the forest ecosystems averaged 485 mg CO2 m−2 h−1 and was 3–3.5 times higher than those from the peat soils of the palsa mound and adjacent bog (on average, 150 mg CO2 m−2 h−1). The high CO2 emission in the forest was due to the mild soil temperature regime, high root biomass, and good water–air permeability of soils in the absence of permafrost. A considerable warming of bog soils, and the redistribution of CO2 between the elevated palsa and the bog depression with water flows above the permafrost table, equalized the values of CO2 emissions from the palsa and bog soils. Soil moisture was a significant factor of the spatial variability in the CO2 emission at all levels. The temperature affected the CO2 emission only at the sites with a shallow thawing depth. [ABSTRACT FROM AUTHOR]

Soil respiration is an important component of the global carbon cycle and is highly responsive to disturbances in the environment. Human impacts on the terrestrial ecosystem lead to changes in the environmental conditions, and following this, changes in soil respiration. Predicting soil respiration and its changes under future climatic and land-use conditions requires a clear understanding of the processes involved. The observation of CO2 fluxes was conducted at an urban grassland, where plants were removed and respiration from bare soil was measured. Nine soil respiration models were applied to describe the temperature dependence of heterotrophic soil respiration. Modified models were suggested, including a linear relationship of the temperature sensitivity and base respiration coefficients with soil temperature at various depths. We demonstrate that modification improves the simulated soil respiration. The exponential and logistic models with linear dependences on the model parameters from the soil temperatures were the best models describing soil respiration fluxes. Variability of the apparent temperature sensitivity coefficient (Q10) was demonstrated, depending on the model used. The Q10 value can be extremely high and does not reflect the actual relationships between soil respiration and temperature. Our findings have important implications for better understanding and accurately assessing the carbon cycling characteristics of terrestrial ecosystems in response to climate change in a temporal perspective. [ABSTRACT FROM AUTHOR]

Haylands are the mildest option for the agricultural use of drained peatlands in terms of CO2 emissions. However, CO2 fluxes and their balance may depend on various conditions including the frequency of mowing and amount of phytomass removed. Based on field measurements of CO2 fluxes using the chamber method and monitoring of environmental factors conducted in 2018–2020 on hayland and fallow on drained peatland in central European Russia, a mathematical model of CO2 balance was built. Numerical experiments showed that mowing of hayland, irrespective of the intensity, did not lead to an increase in CO2 emissions compared to fallow. Fallow and hayland after single mowing had closely modelled net ecosystem exchange (NEE) values: 9.9 ± 2.4 and 8.5 ± 2.7 t C ha−1 season−1, respectively. Furthermore, a single mowing turned out 2.8 t ha−1 of hay (0.8 ± 0.1 t C ha−1), and 4.4 (1.4 ± 0.1) after double mowing. The modelled NEE after double mowing increased to 9.4 ± 2.9 t C ha−1 season−1. A single mowing session in early summer is recommended. Compared to other uses, e.g. arable land, mowing on hayland is a compromise between reducing CO2 emissions and gaining economic benefits from drained peatlands. [ABSTRACT FROM AUTHOR]

As the population grows, so does waste generation, which is a major concern, particularly in developing countries. Although composting and vermicomposting are environmentally friendly methods of managing organic waste, one of the major downsides is the release of greenhouse gases (GHGs). The most essential elements influencing GHG generation are aeration, C/N ratio, temperature, pH, bulking agent, and moisture content, all of which are thoroughly explained in this review. Vermicomposting emits less GHGs than composting in many cases mostly in reduction of methane (CH4) emissions; however, earthworms are also significant contributors to nitrous oxide (N2O) during vermicomposting, imposing the need to juxtapose both processes in context to GHGs emission (GHGsE). Effective GHGsE measuring methodologies allows for the calculation of emissions while also assisting in the identification of the critical elements relevant to GHGs emission reduction. Various methodology implemented for GHGs measurement and among them chamber method is the most common method used. Finally, the review also discussed the already existing mitigation measures as well as perspectives.

The landscapes in the discontinuous permafrost area of Western Siberia are unique objects for assessing the direct and indirect impact of permafrost on greenhouse gas fluxes. The aim of this study was to identify the influence of permafrost on the CO2 emission at the landscape and local levels. The CO2 emission from the soil surface with the removed vegetation cover was measured by the closed chamber method, with simultaneous measurements of topsoil temperature and moisture and thawing depth in forest, palsa, and bog ecosystems in August 2022. The CO2 emissions from the soils of the forest ecosystems averaged 485 mg CO2 m−2 h−1 and was 3–3.5 times higher than those from the peat soils of the palsa mound and adjacent bog (on average, 150 mg CO2 m−2 h−1). The high CO2 emission in the forest was due to the mild soil temperature regime, high root biomass, and good water–air permeability of soils in the absence of permafrost. A considerable warming of bog soils, and the redistribution of CO2 between the elevated palsa and the bog depression with water flows above the permafrost table, equalized the values of CO2 emissions from the palsa and bog soils. Soil moisture was a significant factor of the spatial variability in the CO2 emission at all levels. The temperature affected the CO2 emission only at the sites with a shallow thawing depth.

Ecosystem-based approaches to climate change mitigation involves the use of ecosystems carbon storage and sequestration services. For this purpose, comprehensive CO2 efflux (Reco) measurements of the wetland and terrestrial ecosystems were performed in the adjacent area of Bucharest, by applying two complementary methods using close chambers: dynamic by respiration chamber and static by injection kit. For the evaluation and comparison in time, the measurements were performed simultaneously with the two methods at relevant time intervals. The results of both practices have been inter-compared in the established plots. The aim of this paper is to highlight the values of Reco measured on days when extreme temperatures and precipitations were recorded. The data set from the selected days was statistically analyzed in comparison with the recorded measurements during the corresponding season. The results highlight the response of CO2 efflux in relation with daily meteorological parameters, for analyzing the ecosystems storage and carbon sequestration in the context of climate change. In addition, the analysis performed contributes to the uncertainty reduction for the independent use of the two methods as a monitoring tool for greenhouse gases exchanges between ecosystems and atmosphere. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of unmanned aerial vehicles for detailed mapping of ecosystems has become increasingly important in recent years. As one of the main terrestrial carbon reserves, peatland ecosystems are of the great interest in obtaining highly detailed orthophotoplans. At the same time, there is a lack of publications devoted to the total carbon dioxide fluxes in each type of bog microforms. This paper presents the results of our study, which aimed to develop methods for mapping peatland microlandscapes and for estimation of integral carbon dioxide fluxes between the peatland surface and the atmosphere. Based on a highly detailed orthophotoplan compiled using unmanned aerial vehicles, we assessed the areas of major microform groups (swamps, hollows, and ridges) in a bog located in the Central Forest State Nature Biosphere Reserve (European Russia). The classification accuracy ranged from 79% to 93%. The areas of ridges, hollows, and swamps were 0.16 km2, 0.32 km2, and 0.12 km2, respectively. To make an integral estimation of carbon dioxide fluxes, we used earlier data on carbon dioxide emissions (ecosystem respiration), uptake (gross ecosystem exchange), and balance (net ecosystem exchange) measured by soil chamber method on representative experimental plots of respective microform types. After recalculating fluxes to areas of microforms, the integral values for different classes in the summer seasons of 2014, 2016 and 2017 were 15–91 kg CO2 × h-1 for ecosystem respiration, 21–190 kg CO2 × h-1 for gross ecosystem exchange, and from -122 kg CO2 × h-1 to 41 kg CO2 × h-1 for net ecosystem exchange. The results of the study confirmed that highly detailed orthophotoplans, obtained with the use of unmanned aerial vehicles, make it possible to distinguish the boundaries of such bog microforms as swamps, hollows and ridges with a high accuracy, despite the presence of some errors in the classification. The study of the structural and functional organisation of the bog should be carried out with considering its seasonal and interannual dynamics as well as all microform types.

Soil respiration is an important component of the global carbon cycle and is highly responsive to disturbances in the environment. Human impacts on the terrestrial ecosystem lead to changes in the environmental conditions, and following this, changes in soil respiration. Predicting soil respiration and its changes under future climatic and land-use conditions requires a clear understanding of the processes involved. The observation of CO2 fluxes was conducted at an urban grassland, where plants were removed and respiration from bare soil was measured. Nine soil respiration models were applied to describe the temperature dependence of heterotrophic soil respiration. Modified models were suggested, including a linear relationship of the temperature sensitivity and base respiration coefficients with soil temperature at various depths. We demonstrate that modification improves the simulated soil respiration. The exponential and logistic models with linear dependences on the model parameters from the soil temperatures were the best models describing soil respiration fluxes. Variability of the apparent temperature sensitivity coefficient (Q10) was demonstrated, depending on the model used. The Q10 value can be extremely high and does not reflect the actual relationships between soil respiration and temperature. Our findings have important implications for better understanding and accurately assessing the carbon cycling characteristics of terrestrial ecosystems in response to climate change in a temporal perspective.

Rainfed agriculture is one of the most common farming practices in the world and is vulnerable to global climate change. However, only limited studies have been conducted on rainfed agriculture, mainly using low-frequency manual techniques, which caused large uncertainties in estimating annual N2O emissions. In this study, we used a fully automated system to continuously measure soil N2O emissions for two years (April 2017 to March 2019) in a typical rainfed maize field in Northeast China. The annual N2O emissions were 2.8 kg N ha−1 in year 1 (April 2017 to March 2018) and 1.8 kg N ha−1 in year 2 (April 2018 to March 2019), accounting for 1.9 and 1.2% of the nitrogen fertilizer applied, respectively. The inter-annual variability was mainly due to different weather conditions encountered in years 1 and 2. A severe drought in year 1 reduced plant N uptake, leaving high mineral N in the soil, and the following moderate rainfalls promoted a large amount of N2O emissions. The seasonal pattern of N2O fluxes was mainly controlled by soil temperature and soil nitrate concentration. Both soil moisture and the molar ratio of NO/N2O indicate that N2O and NO were mainly derived from nitrification, resulting in a significant positive correlation between N2O and NO flux in the intra-rows (where nitrogen fertilizer was applied). Moreover, we observed that the N2O emissions during the freeze–thaw periods were negligible in this region for rainfed agriculture. Our long-term and high-resolution measurements of soil N2O emissions suggest that sampling between LST 9:00 and 10:00 is the best empirical sampling time for the intermittent manual measurements.

Open gas emission sources, such as open dairy lot and manure stockpile, are still challenge to directly measure the gas emissions, due to their fully open nature and the relatively low flux of gas emission, particularly interfering by other emissions sources, such as barns and animals. The detection accuracy of the commonly used static-chamber method depends on the chamber configuration and the different external environment. Four key parameters were evaluated, including the disturbing fan, vent holes, surface wind speed of emission (0.0, 0.5, 1.0, 1.5, and 2.0 m/s) and deployment time (0 to 60 min) in the 300 mm (diameter) × 300 mm (height) (D300×H300) static chamber using nitrous oxide (N2O) as reference gas. The experiment was carried out in a wind tunnel to adjust the wind speed in order to simulate the real environment of open dairy lots. A calibration system was designed to generate a reference flux, and the accuracy of chamber performance was defined based on the difference between the reference fluxes and the calculated fluxes in the static chamber. The results showed that the deviation rates have the similar trends during the deployment time in the static chambers with different configurations. The flux of gas emission that measured by the static chamber was higher at the beginning of process, and then lower compared with that of the reference flux. The measurement accuracy of the static chamber reached the maximum when the deployment time was 50 min, where the deviation rate of the static chamber without the disturbing fan and vent was 1.02%－-20.06%, 12.29% －-47.92% without the disturbing fan and with the vent, -9.71%－-40.92% with the disturbing fan and without the vent, and 4.42%－-25.64% with the disturbing fan and vent. There was no significant difference in the deviation rates of the detected N2O emission fluxes under different wind speeds (P>0.05) using the static chamber with the disturbing fan and with/without vent, indicating these two types of chambers have better detection stability. However, the measurement accuracy of the D300 mm×H300 mm static chamber with the disturbing fan and vent was significantly higher than that with the fan and without vent (P<0.05). When the emission speed of surface wind was 0－2 m/s, the disturbing fan had no significant influence on the measurement accuracy of the static chamber (P>0.05), indicating the emission surface wind was affected by the Venturi effect through the vent. Both the deployment time and emission surface wind speed had significant negative correlation on the deviation rate of the static chambers (P<0.05). However, the correlation between the deployment time and emission surface wind speed was not obvious (P>0.05). This study recommends to use a D300 mm×H300 mm static chamber with the disturbing fan and vent to detect the N2O emission flux in an open gas emission system, such as dairy open lots without manure and emission sources with similar media, with the speed of emission surface wind less than 2 m/s, and the deployment time of 50 min. [ABSTRACT FROM AUTHOR]

The atmospheric corrosion resistance of metals can be reached by the formation of ultrathin protective films on their surface. Over recent years, a fundamentally new feasibility of the nanodimension films on metals capable of ensuring high atmospheric corrosion resistance of metals at least for the period of transportation and in-process storage of the metals was studied. The method of formation of such films by semivolatile nontoxic compounds capable of being adsorbed on metal surface from gas phase at increased temperature (chamber inhibitors) was proposed for this purpose. It is based on the use of such low-volatile organic inhibitors, which are prone to chemisorption on protected metal, and, as a consequence, can provide the stability of the adsorbed layers and long protection after-effect. It was shown by the complex of accelerated corrosion, electrochemical, and optical techniques that the treatment of zinc by vapors of low-volatile corrosion inhibitors at increased temperature and suitable compilation of the reagents results in the formation of the adsorption film with the effect of the long protection after-effect. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Machine Construction & Maintenance is the property of Institute for Sustainable Technologies - National Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The West Siberia Lowland (WSL) is one of the biggest wetland areas in high latitudes; however, measurements of gas fluxes from WSL floodplain wetlands were absent. During 2015–2016, we made first effort to estimate methane emission from floodplain using chamber method. Obtained fluxes varied greatly with medians from zero to 17.5 mgC·m−2·h−1. We found that observed heterogeneity could be addressed for further upscaling by grouping the flux observations using a set of environmental parameters: i) floodplain width (wide/narrow), ii) microtopography (elevated/depressed), iii) inundation during the measurements («wet»/«dry»). We found that several classes could be easily merged basing on CH4 emission rates: i) flux median from both «wet» and «dry» depressions of wide floodplains reached 4.21 mgC·m−2·h−1, ii) «wet» elevations within wide floodplains and all small «wet» floodplains had lower flux of 1.47 mgC·m−2·h−1, iii) «dry» elevations within wide floodplains and all small «dry» floodplains had the lowest median of 0.07 mgC·m−2·h−1. Besides the common factors which influence the methane fluxes, we also found extreme methane emission during ten days after main water subsiding in Ob' floodplain with further gradual decreasing of fluxes and dispersions. We suggested that methane release could be triggered by abrupt hydrostatic pressure decrease induced by water drawdown. [ABSTRACT FROM AUTHOR]

Rapid urbanization and economic growth has led to significant increase in municipal solid waste generation in India during the last few decades and its management has become a major issue because of poor waste management practices. Solid waste generated is deposited into open dumping sites with hardly any segregation and processing. Carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) are the major greenhouse gases that are released from the landfill sites due to the biodegradation of organic matter. In this present study, CH 4 and CO 2 emissions from a landfill in north-east India are estimated using a flux chamber during September, 2015 to August, 2016. The average emission rates of CH 4 and CO 2 are 68 and 92 mg/min/m 2 , respectively. The emissions are highest in the summer whilst being lowest in winter. The diurnal variation of emissions indicated that the emissions follow a trend similar to temperature in all the seasons. Correlation coefficients of CH 4 and temperature in summer, monsoon and winter are 0.99, 0.87 and 0.97, respectively. The measured CH 4 in this study is in the range of other studies around the world. Modified Triangular Method (MTM), IPCC model and the USEPA Landfill gas emissions model (LandGEM) were used to predict the CH 4 emissions during the study year. The consequent simulation results indicate that the MTM, LandGEM-Clean Air Act, LandGEM-Inventory and IPCC models predict 1.9, 3.3, 1.6 and 1.4 times of the measured CH 4 emission flux in this study. Assuming that this higher prediction of CH 4 levels observed in this study holds well for other landfills in this region, a new CH 4 emission inventory (Units: Tonnes/year), with a resolution of 0.1 0 × 0.1 0 has been developed. This study stresses the importance of biodegradable composition of waste and meteorology, and also points out the drawbacks of the widely used landfill emission models. [ABSTRACT FROM AUTHOR]

Despite broad information on greenhouse gas (GHG) emissions from the soil surface, only few studies have examined the depth related GHG concentration and production within the soil. We coupled chamber surface GHG flux measurements with analysis of subsurface GHG concentrations at five depths (0, 10, 30, 50 and 70 cm) using silicon tubes in a grassland and cropland soils in a semi-arid agro-pastoral ecotone over a full year. Grassland and cropland soils behaved as net CO 2 and N 2 O sources, but sinks of CH 4. CO 2 and N 2 O concentrations increased but CH 4 decreased with soil depth. Subsurface GHG fluxes calculated using Fick's law decreased with depth. The modeled GHG and measured surface fluxes agreed much better for CO 2 than N 2 O or CH 4. Spring-thaw and rainfall events triggered N 2 O pulses, CH 4 uptake peaks and CH 4 concentration drops. Annual emissions or uptake based on chamber method were 4820–7580 kg C ha−1 yr−1, 2.4–1.5 kg C ha−1 yr−1, and 0.13–0.14 kg N ha−1 yr−1 for CO 2 , CH 4 , and N 2 O across the grassland and cropland, respectively. Modeled annual accumulation of GHG fluxes dropped with depth, whereas the topsoil (0–20 cm) contributed about 65% for CO 2 , 68% for N 2 O and 72% for CH 4 of the total profile. The vertical distribution of GHG fluxes reflected those of soil organic carbon and root biomass. The grassland had higher annual CO 2 flux but lower CH 4 uptake than the cropland. Annual N 2 O fluxes were similar between the two ecosystems. • CO 2 and N 2 O concentrations increased but CH 4 decreased with soil depth. • Spring-thaw and rainfall events triggered N 2 O pulses, CH 4 uptake peaks. • More than 65% of the GHG efflux originated from the top 20 cm soil. • The vertical distribution of GHG fluxes reflected those of SOC and root biomass. [ABSTRACT FROM AUTHOR]

Measurements of greenhouse gas fluxes over many ecosystems have been made as part of the attempt to quantify global carbon and nitrogen cycles. In particular, annual flux observations are of great value for regional flux assessments, as well as model development and optimization. The chamber method is a popular approach for soil/ecosystem respiration and CH4 flux observations of terrestrial ecosystems. However, in situ flux chamber measurements are usually made with non-continuous sampling. To date, efficient methods for the application of such sporadic data to upscale temporally and obtain annual cumulative fluxes have not yet been determined. To address this issue, we tested the adequacy of non-continuous sampling using multi-source data aggregation. We collected 330 site-years monthly soil/ecosystem respiration and 154 site-years monthly CH4 flux data in China, all obtained using the chamber method. The data were randomly divided into a training group and verification group. Fluxes of all possible sampling months of a year, i.e., 4094 different month combinations were used to obtain the annual cumulative flux. The results showed a good linear relationship between the monthly flux and the annual cumulative flux. The flux obtained during the warm season from May to October generally played a more important role in annual flux estimations, as compared to other months. An independent verification analysis showed that the monthly flux of 1 to 4 months explained up to 67%, 89%, 94%, and 97% of the variability of the annual cumulative soil/ecosystem respiration and 92%, 99%, 99%, and 99% of the variability of the annual cumulative CH4 flux. This study supports the use of chamber-observed sporadic flux data, which remains the most commonly-used method for annual flux estimating. The flux estimation method used in this study can be used as a guide for designing sampling programs with the intention of estimating the annual cumulative flux.

For wood-based panels, is possible to apply two different testing methodologies for formaldehyde emissions (gas analysis (GA) method and chamber method), respectively, regulated by UNI EN717-2:1996 and UNI EN717-1:2004; the analysis procedures have many differences, with regard to the equipment, the dimensions of samples and the testing environment parameters (temperature and relative humidity). The aim was to identify the most reliable method, by evaluating the technical results obtained, as well as by making a supporting statistical analysis aimed at the definition of the agreement degree between the two methodologies. In detail, we individuated the nine most used wood-based panels by a kitchens producer and we performed two different types of analysis: the GA method and chamber method. As properly described in this paper, the chamber method has a higher reliability due to the more realistic environmental testing conditions; moreover, we have demonstrated a low correlation between the two methodologies. [ABSTRACT FROM PUBLISHER]

Plants affect CH emissions from wetlands by providing routes for CH ventilation from the soil and its re-oxidation, the outcome depending on the vertical distribution of the plant ventilating structures as related to water level. This study investigated the effect of elevated hummocks on CH emissions in a temperate wetland dominated by a hummock-forming sedge, Carex acuta L. Comparative measurements of CH fluxes from paired plots with or without hummocks revealed a prevailing positive difference interpreted as plant-mediated fluxes. All types of CH fluxes responded positively to water level with a hysteresis related to its recent dynamics. Seasonal medians of CH emissions from the ecosystem, based on fluxes from both types of plots, were 15.09 and 0.11 mg m day in the wet year 2012 and the dry year 2014, respectively. This relatively low magnitude of CH emissions, compared to values from similar habitats within the same range of water levels, is ascribed to the presence of hummocks. At water levels near the soil surface, hummocks extend above the water table and serve as aerobic micro-habitats in which plant structures avoid anaerobic stress and CH produced in the bulk soil and vented via deep roots can be re-oxidized. [ABSTRACT FROM AUTHOR]

Although most studies find temperature, soil moisture and water table to be important environmental factors that affect peatland carbon dynamics, the role of vegetation communities has been investigated less. Therefore, this study investigates whether peatland ecosystems produce heterogeneous CO fluxes due to differences in vegetation community. In addition, the study also examines which major environmental factors influence this vegetation. To achieve the aims of this study, four sites with different vegetation communities were established in a semi-natural peatland ecosystem in Poland. CO flux measurements were carried out using a closed dynamic chamber system. Measurement campaigns were carried out from April until December 2008, every 2-3 weeks. Measured ecosystem respiration (Reco) and net ecosystem exchange (NEE) rates showed daily and seasonal variation at all investigated sites. Reco presented a strong dependence on soil temperature at the 5 cm depth, while NEE showed a strong dependence on solar radiation. The mean temperature sensitivity (Q) for the four sites ranged between 3.17 and 8.3. The highest NEE and Reco values were obtained at the site represented by Caricetum elatae and the lowest NEE and Reco at the site represented by Calamagrostietum neglectae. [ABSTRACT FROM AUTHOR]

Land-use change in tropical peatland potentially results in a large amount of carbon dioxide (CO 2 ) emissions owing to drainage, which lowers groundwater level (GWL) and consequently enhances oxidative peat decomposition. However, field information on carbon balance is lacking for rubber plantations, which are expanding into Indonesia's peatlands. To assess soil CO 2 emissions from an eight-year-old rubber plantation established on peat after compaction, soil CO 2 efflux was measured monthly using a closed chamber system from December 2014 to December 2015, in which a strong El Niño event occurred, and consequently GWL lowered deeply. Total soil respiration (SR) and oxidative peat decomposition (PD) were separately quantified by trenching. In addition, peat surface elevation was measured to determine annual subsidence along with GWL. With GWL, SR showed a negative logarithmic relationship ( p < 0.01), whereas PD showed a strong negative linearity ( p < 0.001). Using the significant relationships, annual SR and PD were calculated from hourly GWL data to be 3293 ± 1039 and 1408 ± 214 g C m − 2 yr − 1 (mean ± 1 standard deviation), respectively. PD accounted for 43% of SR on an annual basis. SR showed no significant difference between near and far positions from rubber trees ( p > 0.05). Peat surface elevation varied seasonally in almost parallel with GWL. After correcting for GWL difference, annual total subsidence was determined at 5.64 ± 3.20 and 5.96 ± 0.43 cm yr − 1 outside and inside the trenching, respectively. Annual subsidence only through peat oxidation that was calculated from the annual PD, peat bulk density and peat carbon content was 1.50 cm yr − 1 . As a result, oxidative peat decomposition accounted for 25% of total subsidence (5.96 cm yr − 1 ) on average on an annual basis. The contribution of peat oxidation was lower than those of previous studies probably because of compaction through land preparation. [ABSTRACT FROM AUTHOR]

In this study, the formaldehyde emission (FE) from different types of particleboard, medium density fiberboard (MDF), and plywood products supplied from a commercial plant in the Czech Republic were evaluated by gas analysis (EN 717-2) and European small chamber (EN 717-1) methods. The significant effects of manufacturing variables (board type and thickness) as well as different types of formaldehyde-based resins on FE measured by gas analysis were obtained. When the E1 type adhesives were employed, a wide variation in the quantity of free formaldehyde was observed among the three product types. The FE values of plywood samples measured by gas analysis were lower than those of the particleboard and MDF samples. The correlation between the two methods for the particleboard and MDF were good (R2 = 0.82 and 0.76, respectively) and however for plywood (R2 = 0.52) it was not convincing. FE specifi ed in EN 717-2 was comparable with the EN 717-1 values for the same board type and thickness as well as the resin type and below the E1-emission class.

Korea is currently developing country-specific emission factors to support the 2050 zero-carbon campaign. Dairy cattle represent one of the largest livestock industries in Korea, and the industry is estimated to continue increasing because of an increase in milk demand. However, country-specific emission factors for dairy cattle are currently only available for calculating methane (CH 4 ) emissions from enteric fermentation. Two experiments were conducted to evaluate CH 4 and nitrous oxide (N 2 O) fluxes from sawdust-bedded barn in dairy cow and steer, as well as dairy cattle manure composting lots. The greenhouse gas (GHG) fluxes were quantified using the open-chamber method and gas chromatography. CH 4 fluxes from steer, dairy cow, and manure compost were 27.88 ± 5.84, 36.12 ± 10.85, and 259.44 ± 61.78 µg/head/s, respectively. N 2 O fluxes from steer, dairy cow, and manure compost were 14.04 ± 1.27, 4.11 ± 1.57, and 3.97 ± 1.08 µg/head/s, respectively. The result of this study can be used to construct country-specific data for GHG emissions from manure management. Thus, the application of mitigation strategies can be prioritized based on the GHG profile and targeted source., Competing Interests: No potential conflict of interest relevant to this article was reported., (© Copyright 2023 Korean Society of Animal Science and Technology.)

Agricultural activities are co-responsible for the emission of the most important greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Development of methodologies to improve monitoring techniques for N2O are still needful. The LIFE+IPNOA project aims to improve the emissions monitoring of nitrous oxide from agricultural soils and to identify the agricultural practices that can limit N2O production. In order to achieve this objective, both a mobile and a stationary instrument were developed and validated. Several experimental field trials were set up in two different sites investigating the most representative crops of Tuscany (Central Italy), namely durum wheat, maize, sunflower, tomato and faba bean. The field trials were realized in order to test the effect on N2O emissions of key factors: tillage intensity, nitrogen fertiliser rate and irrigation. The field trial on durum wheat was set up in 2013 to test the effect of tillage intensity (minimum and conventional tillage) and nitrogen fertilisation rate (0, 110, 170 kg N ha-1) on soil N2O flux. Monitoring was carried out using the IPNOA mobile prototype. Preliminary results on N2O emissions for the durum wheat growing season showed that mean daily N2O fluxes ranged from –0.13 to 6.43 mg m-2 day-1 and cumulative N2O-N emissions over the period ranged from 827 to 2340 g N2O-N ha-1. Tillage did not affect N2O flux while increasing nitrogen fertilisation rate resulted to significantly increase N2O emissions. The IPNOA mobile prototype performed well during this first year of monitoring, allowing to catch both very low fluxes and peaks on N2O emissions after nitrogen supply, showing a good suitability to the field conditions.