Articoli di riviste: "Production de CH4"

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Chen, Chung-Nan, Tzu-Tai Lee e Bi Yu. "19. Improving the Prediction of Methane Production Determined by in Vitro Gas Production Technique for Ruminants". Annals of Animal Science 16, n. 2 (1 aprile 2016): 565–84. http://dx.doi.org/10.1515/aoas-2015-0078.

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Abstract Twelve feedstuffs (cereals, fibrous byproducts, protein-rich byproducts and forages) were determined for methane (CH4) production by the in vitro gas production technique (IVGPT) and were correlated with their chemical compositions to predict enteric CH4 originating from these feedstuffs in ruminants. Corn, soybean hull, soybean meal and corn silage generated the highest CH4 production from their respective categories. The average CH4 production of fibrous byproducts (44.6 ml/g DM incubated) was significantly higher than that of cereals (40.3 ml/g DM incubated), forages (33.3 ml/g DM incubated) and protein-rich byproducts (31.0 ml/g DM incubated) after the 48-h incubation (P≤0.05). The highest average total volatile fatty acid (VFA) concentration was determined in cereals (53.6 mM). The acetate to propionate ratio was significantly lower in cereals when compared with other categories of feedstuff (P≤0.05). The correlation analysis showed that in vitro true digestibility (IVTD) positively correlated with the CH4 production in all four categories of feedstuffs (P≤0.05). The neutral detergent fiber (NDF) and acid detergent fiber (ADF) content positively correlated with CH4 production in every category of feedstuffs except cereals. The starch content negatively correlated with CH4 production for fibrous and protein-rich byproducts (P≤0.05), but it positively correlated with CH4 production for forages (P≤0.05). The CH4 production was predicted more accurately by the equations proposed for each category (R2=0.944, 0.876, 0.942 and 0.915 for cereals, fibrous and protein-rich byproducts and forages, respectively) than for the unclassified feedstuffs (R2=0.715). In conclusion, the contribution of individual chemical composition to CH4 production differed depending on the category of feedstuffs. The precision of CH4 prediction could be substantially improved by classifying feedstuffs into categories according to their chemical composition, and selecting the appropriate predictors for each category. Information about the CH4 output of these feedstuffs will be useful in formulating low CH4-producing diets for ruminants.

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SAUVANT, D., S. GIGER-REVERDIN, A. SERMENT e L. BROUDISCOU. "Influences des régimes et de leur fermentation dans le rumen sur la production de méthane par les ruminants". INRAE Productions Animales 24, n. 5 (8 dicembre 2011): 433–46. http://dx.doi.org/10.20870/productions-animales.2011.24.5.3276.

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Ce travail s'appuie sur l'étude de plusieurs bases de données en vue d'extraire des modèles de prévision de la production de CH4 enfonction des régimes et des fermentations ruminales. La méthanogenèse est décrite en relation avec les principaux principes de la stoechiométrieet de la thermodynamique des fermentations ruminales. Il apparaît en particulier une relation étroite entre la productionde CH4 et le rapport des acides acétique/propionique du jus de rumen (Ac/Pr). Les variations du profil des AGV et de la productionde CH4 traduisent des phénomènes d'adaptation des microorganismes du rumen à la quantité d'énergie disponible. Au sein desdifférents critères alimentaires de prévision de la production de CH4, la teneur en matière organique digestible (MOD) est intéressante: elle est globalement bien liée à la MO fermentescible du rumen, donc au CH4 produit, et à la valeur énergétique des aliments.Cependant, le rapport CH4/MOD varie également en fonction de certains facteurs de variation qui modifient aussi le rapport Ac/Prdans le rumen : le niveau alimentaire, la qualité du fourrage, la teneur en concentré du régime et l'apport de matières grasses.Une dernière partie du texte est consacrée à l'étude de modèles plus mécanistes qui s'appuient sur les principes de stoechiométrie desAGV, ces modèles constituant une étape vers une modélisation intégrative de l'ensemble des phénomènes digestifs et fermentaires durumen.

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Setyanto, P., Rosenani A.B., A. K. Makarim, Che Fauziah I., A. Bidin e Suharsih Suharsih. "SOIL CONTROLLING FACTORS OF METHANE GAS PRODUCTION FROM FLOODED RICE FIELDS IN PATI DISTRICT, CENTRAL JAVA". Indonesian Journal of Agricultural Science 3, n. 1 (25 ottobre 2016): 1. http://dx.doi.org/10.21082/ijas.v3n1.2002.1-11.

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Atmospheric methane (CH4) is recognized as one of the most important greenhouse gases. Methane, with some 15-30 times greater infrared-absorbing capability than CO2 on a mass basis, may account for 20% of anticipated global warming. Soils are one of the key factors, which play an important role in CH4 production and emission. However, data on CH4 emission from different soil types and the characteristics affecting CH4 production are lacking when compared to data on agronomic practices. This study was conducted to investigate the potential of CH4 production of selected soils in Java, and determine the limiting factors of CH4 production. The results showed that addition of 1% glucose to the soils led to an increase in CH4 production by more than twelve fold compared to no glucose addition. The CH4 production potential ranged between 3.21 and 112.30 mg CH4 kg-1 soil. The lowest CH4 production potential occurred in brown-grayish Grumosol, while the highest was in dark-gray Grumosol. Chemical and physical properties of the soils have great influence on CH4 production. Stepwise multiple regression analysis of CH4 production and soil characteristics showed that pH and the contents of Fe2O3, MnO2, SO4, and silt in the soil strongly influenced CH4 production. Results of this study can be used for further development of a model on CH4 emission from rice fields.

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Setyanto, P., Rosenani A.B., A. K. Makarim, Che Fauziah I., A. Bidin e Suharsih Suharsih. "SOIL CONTROLLING FACTORS OF METHANE GAS PRODUCTION FROM FLOODED RICE FIELDS IN PATI DISTRICT, CENTRAL JAVA". Indonesian Journal of Agricultural Science 3, n. 1 (25 ottobre 2016): 1. http://dx.doi.org/10.21082/ijas.v3n1.2002.p1-11.

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Abstract (sommario):

Atmospheric methane (CH4) is recognized as one of the most important greenhouse gases. Methane, with some 15-30 times greater infrared-absorbing capability than CO2 on a mass basis, may account for 20% of anticipated global warming. Soils are one of the key factors, which play an important role in CH4 production and emission. However, data on CH4 emission from different soil types and the characteristics affecting CH4 production are lacking when compared to data on agronomic practices. This study was conducted to investigate the potential of CH4 production of selected soils in Java, and determine the limiting factors of CH4 production. The results showed that addition of 1% glucose to the soils led to an increase in CH4 production by more than twelve fold compared to no glucose addition. The CH4 production potential ranged between 3.21 and 112.30 mg CH4 kg-1 soil. The lowest CH4 production potential occurred in brown-grayish Grumosol, while the highest was in dark-gray Grumosol. Chemical and physical properties of the soils have great influence on CH4 production. Stepwise multiple regression analysis of CH4 production and soil characteristics showed that pH and the contents of Fe2O3, MnO2, SO4, and silt in the soil strongly influenced CH4 production. Results of this study can be used for further development of a model on CH4 emission from rice fields.

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Tenorio, Sandy E., e Laura Farías. "Picoplanktonic methane production in eutrophic surface waters". Biogeosciences 21, n. 8 (25 aprile 2024): 2029–50. http://dx.doi.org/10.5194/bg-21-2029-2024.

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Abstract. Over the past decade, extensive research has delved into the methane (CH4) paradox, which involves aerobic CH4 production. We present noteworthy observations of CH4 oversaturation within the surface layer of the central Chile upwelling zone (36° S, 73° W) over two consecutive seasonal cycles (2018–2021). Complementing these observations, CH4 cycling experiments were conducted, utilizing distinct plankton fractions (encompassing the natural planktonic community, fractions < 150, < 3 and < 0.2 µm), in different productivity periods of phytoplanktonic production and composition throughout the year. Our findings underscore the pivotal role of picoplankton (< 3 µm) in CH4 production on the ocean surface, contrasting with the limited contribution of larger microorganisms (< 150 µm). Notably, incubations with methylated substrates, such as methylphosphonic acid (MPn) and trimethylamine (TMA), induce heightened CH4 production within the picoplanktonic fraction. This phenomenon is consistently observed during both upwelling (austral spring–summer) and non-upwelling (winter) seasons, with significance in the latter period, when Synechococcus sp. exhibits notably high relative abundance. Long-term microcosm experiments highlight the crucial roles played by heterotrophic bacteria and cyanobacteria in methylotrophic methanogenesis. This process enhances CH4 production, facilitated by the recycling of dissolved organic carbon (DOC). Picoplankton emerges as a pivotal factor influencing the recycling of methylated substrates, and it is responsible for maintaining CH4 supersaturation. These findings provide valuable insights into the biogeochemical processes driving CH4 dynamics, particularly in highly productive upwelling areas.

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Schroll, Moritz, Katharina Lenhart, Thomas Bender, Piet Hötten, Alexander Rudolph, Sven Sörensen e Frank Keppler. "Fungal Methane Production Controlled by Oxygen Levels and Temperature". Methane 3, n. 2 (19 aprile 2024): 257–75. http://dx.doi.org/10.3390/methane3020015.

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Saprotrophic fungi, key players in global carbon cycling, have been identified as methane (CH4) sources not yet accounted for in the global CH4 budget. This study, for the first time, explores the influence of oxygen (O2) and temperature on CH4 production by two fungi, Laetiporus sulphureus and Pleurotus sapidus. To explore the relationship between these parameters and fungal CH4 formation, we examined CH4 formation under varying O2 levels (0 to 98%) and temperatures (17, 27, and 40 °C) during fungal growth on pine wood, beech wood, and grass under sterile conditions. Our findings show that fungal CH4 formation strongly depends on O2 levels. Methane formation was highest when O2 levels exceeded 5%, whilst no CH4 formation was observed after complete O2 consumption. Reintroducing O2 immediately resumed fungal CH4 production. Methane formation normalized to O2 consumption (CH4_norm) showed a different pattern. L. sulphureus showed higher CH4_norm rates with higher O2 levels, whereas P. sapidus showed elevated rates between 0 and 5%. Temperature also significantly influenced CH4 and CH4_norm rates, with the highest production at 27 °C, and comparatively lower rates at 17 and 40 °C. These findings demonstrate the importance of O2 levels and temperature in fungal CH4 emissions, which are essential for refining CH4 source predictions.

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Zheng, Jianqiu, Taniya RoyChowdhury, Ziming Yang, Baohua Gu, Stan D. Wullschleger e David E. Graham. "Impacts of temperature and soil characteristics on methane production and oxidation in Arctic tundra". Biogeosciences 15, n. 21 (8 novembre 2018): 6621–35. http://dx.doi.org/10.5194/bg-15-6621-2018.

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Abstract. Rapid warming of Arctic ecosystems accelerates microbial decomposition of soil organic matter and leads to increased production of carbon dioxide (CO2) and methane (CH4). CH4 oxidation potentially mitigates CH4 emissions from permafrost regions, but it is still highly uncertain whether soils in high-latitude ecosystems will function as a net source or sink for CH4 in response to rising temperature and associated hydrological changes. We investigated CH4 production and oxidation potential in permafrost-affected soils from degraded ice-wedge polygons on the Barrow Environmental Observatory, Utqiaġvik (Barrow), Alaska, USA. Frozen soil cores from flat and high-centered polygons were sectioned into organic, transitional, and permafrost layers, and incubated at −2, +4 and +8 ∘C to determine potential CH4 production and oxidation rates. Significant CH4 production was only observed from the suboxic transition layer and permafrost of flat-centered polygon soil. These two soil sections also exhibited highest CH4 oxidation potentials. Organic soils from relatively dry surface layers had the lowest CH4 oxidation potential compared to saturated transition layer and permafrost, contradicting our original assumptions. Low methanogenesis rates are due to low overall microbial activities measured as total anaerobic respiration and the competing iron-reduction process. Our results suggest that CH4 oxidation could offset CH4 production and limit surface CH4 emissions, in response to elevated temperature, and thus must be considered in model predictions of net CH4 fluxes in Arctic polygonal tundra. Future changes in temperature and soil saturation conditions are likely to divert electron flow to alternative electron acceptors and significantly alter CH4 production, which should also be considered in CH4 models.

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Heslop, J. K., K. M. Walter Anthony, A. Sepulveda-Jauregui, K. Martinez-Cruz, A. Bondurant, G. Grosse e M. C. Jones. "Thermokarst lake methanogenesis along a complete talik profile". Biogeosciences 12, n. 14 (24 luglio 2015): 4317–31. http://dx.doi.org/10.5194/bg-12-4317-2015.

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Abstract. Thermokarst (thaw) lakes emit methane (CH4) to the atmosphere formed from thawed permafrost organic matter (OM), but the relative magnitude of CH4 production in surface lake sediments vs. deeper thawed permafrost horizons is not well understood. We assessed anaerobic CH4 production potentials from various depths along a 590 cm long lake sediment core that captured the entire sediment package of the talik (thaw bulb) beneath the center of an interior Alaska thermokarst lake, Vault Lake, and the top 40 cm of thawing permafrost beneath the talik. We also studied the adjacent Vault Creek permafrost tunnel that extends through ice-rich yedoma permafrost soils surrounding the lake and into underlying gravel. Our results showed CH4 production potentials were highest in the organic-rich surface lake sediments, which were 151 cm thick (mean ± SD: 5.95 ± 1.67 μg C–CH4 g dw−1 d−1; 125.9 ± 36.2 μg C–CH4 g C−1org d−1). High CH4 production potentials were also observed in recently thawed permafrost (1.18 ± 0.61 μg C–CH4g dw−1 d−1; 59.60± 51.5 μg C–CH4 g C−1org d−1) at the bottom of the talik, but the narrow thicknesses (43 cm) of this horizon limited its overall contribution to total sediment column CH4 production in the core. Lower rates of CH4 production were observed in sediment horizons representing permafrost that has been thawing in the talik for a longer period of time. No CH4 production was observed in samples obtained from the permafrost tunnel, a non-lake environment. Our findings imply that CH4 production is highly variable in thermokarst lake systems and that both modern OM supplied to surface sediments and ancient OM supplied to both surface and deep lake sediments by in situ thaw and shore erosion of yedoma permafrost are important to lake CH4 production.

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Heslop, J. K., K. M. Walter Anthony, A. Sepulveda-Jauregui, K. Martinez-Cruz, A. Bondurant, G. Grosse e M. C. Jones. "Thermokarst-lake methanogenesis along a complete talik profile". Biogeosciences Discussions 12, n. 6 (24 marzo 2015): 4865–905. http://dx.doi.org/10.5194/bgd-12-4865-2015.

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Abstract. Thermokarst (thaw) lakes emit methane (CH4) to the atmosphere formed from thawed permafrost organic matter (OM), but the relative magnitude of CH4 production in surface lake sediments vs. deeper thawed permafrost horizons is not well understood. We assessed anaerobic CH4 production potentials from various depths along a 590 cm long lake sediment core that captured the entire sediment package of the talik (thaw bulb) beneath the center of an interior Alaska thermokarst lake, Vault Lake, and the top 40 cm of thawing permafrost beneath the talik. We also studied the adjacent Vault Creek permafrost tunnel that extends through ice-rich yedoma permafrost soils surrounding the lake and into underlying gravel. Our results showed CH4 production potentials were highest in the organic-rich surface lake sediments, which were 151 cm thick (mean ± SD 5.95 ± 1.67 μg C-CH4 g dw−1 d−1; 125.9± 36.2 μg C-CH4 g C−1org d−1). High CH4 production potentials were also observed in recently-thawed permafrost (1.18± 0.61 μg C-CH4g dw−1 d−1; 59.60± 51.5 μg C-CH4 g C−1org d−1) at the bottom of the talik, but the narrow thicknesses (43 cm) of this horizon limited its overall contribution to total sediment column CH4 production in the core. Lower rates of CH4 production were observed in sediment horizons representing permafrost that has been thawed in the talik for longer periods of time. No CH4 production was observed in samples obtained from the permafrost tunnel, a non-lake environment. Our findings imply that CH4 production is highly variable in thermokarst-lake systems and that both modern OM supplied to surface sediments and ancient OM supplied to both surface and deep lake sediments by in situ thaw as well as shore erosion of yedoma permafrost are important to lake CH4 production.

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Jentsch, W., B. Piatkowski, M. Schweigel e M. Derno. "Quantitative results for methane production of cattle in Germany". Archives Animal Breeding 52, n. 6 (10 ottobre 2009): 587–92. http://dx.doi.org/10.5194/aab-52-587-2009.

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Abstract. An extensive number of investigations on the energetic utilization efficiency of nutrients and feedstuffs by cattle were carried out in the former Oskar-Kellner-Institute (now the »Oskar Kellner« Research Unit of Nutritional Physiology at the Research Institute for the Biology of Farm Animals (FBN), Dummerstorf). The amounts of methane (CH4) that they produced were compiled and stratified with regard to various performances, dietary nutrient composition and nutrition levels. With increasing food intake and performance, an increase of CH4 emission per animal was observed. However, with increasing performance, a strong decrease of CH4 production per unit of product was determined. Altogether, the 12.74 million cattle in Germany produce 1.04 million tons of CH4 per year. This represents 1.25 % of the CH4 production of the 1.3 thousand million (UK)/billion (US) cattle in the world or 0.22 % of the total emission on the earth. As a greenhouse gas, CH4 from cattle worldwide and from cattle in Germany account for 3.5 % and 0.04 % of global warming, respectively. In addition, opportunities for a further reduction of enteric CH4 release are discussed.

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Klintzsch, Thomas, Gerald Langer, Gernot Nehrke, Anna Wieland, Katharina Lenhart e Frank Keppler. "Methane production by three widespread marine phytoplankton species: release rates, precursor compounds, and potential relevance for the environment". Biogeosciences 16, n. 20 (28 ottobre 2019): 4129–44. http://dx.doi.org/10.5194/bg-16-4129-2019.

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Abstract. Methane (CH4) production within the oceanic mixed layer is a widespread phenomenon, but the underlying mechanisms are still under debate. Marine algae might contribute to the observed CH4 oversaturation in oxic waters, but so far direct evidence for CH4 production by marine algae has only been provided for the coccolithophore Emiliania huxleyi. In the present study we investigated, next to E. huxleyi, other widespread haptophytes, i.e., Phaeocystis globosa and Chrysochromulina sp. We performed CH4 production and stable carbon isotope measurements and provide unambiguous evidence that all three investigated marine algae are involved in the production of CH4 under oxic conditions. Rates ranged from 1.9±0.6 to 3.1±0.4 µg of CH4 per gram of POC (particulate organic carbon) per day, with Chrysochromulina sp. and E. huxleyi showing the lowest and highest rates, respectively. Cellular CH4 production rates ranged from 16.8±6.5 (P. globosa) to 62.3±6.4 ag CH4 cell−1 d−1 (E. huxleyi; ag = 10−18 g). In cultures that were treated with 13C-labeled hydrogen carbonate, δ13CH4 values increased with incubation time, resulting from the conversion of 13C–hydrogen carbonate to 13CH4. The addition of 13C-labeled dimethyl sulfide, dimethyl sulfoxide, and methionine sulfoxide – known algal metabolites that are ubiquitous in marine surface layers – resulted in the occurrence of 13C-enriched CH4 in cultures of E. huxleyi, clearly indicating that methylated sulfur compounds are also precursors of CH4. By comparing the algal CH4 production rates from our laboratory experiments with results previously reported in two field studies of the Pacific Ocean and the Baltic Sea, we might conclude that algae-mediated CH4 release is contributing to CH4 oversaturation in oxic waters. Therefore, we propose that haptophyte mediated CH4 production could be a common and important process in marine surface waters.

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Yuan, Q., J. Pump e R. Conrad. "Straw application in paddy soil enhances methane production also from other carbon sources". Biogeosciences 11, n. 2 (22 gennaio 2014): 237–46. http://dx.doi.org/10.5194/bg-11-237-2014.

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Abstract. Flooded rice fields are an important source of the greenhouse gas methane. Methane is produced from rice straw (RS), soil organic matter (SOM), and rice root organic carbon (ROC). Addition of RS is widely used for ameliorating soil fertility. However, this practice provides additional substrate for CH4 production and results in increased CH4 emission. Here, we found that decomposing RS is not only a substrate of CH4 production, but in addition stimulates CH4 production from SOM and ROC. Apart from accelerating the creation of reduced conditions in the soil environment, RS decomposition resulted in enhancement of SOM-derived CH4 production. In particular, hydrogenotrophic methanogenesis from SOM-derived CO2 was stimulated, presumably by H2 released from RS decomposition. On the other hand, the enhancement of ROC-derived CH4 production after RS application was probably caused by the significant increase of the abundance of methanogenic Archaea in the RS treatment compared with the untreated control. Our results show that traditional management of rice residues exerts a positive feedback on CH4 production from rice fields, thus exacerbating its effect on the global CH4 budget.

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Flourie, B., P. Pellier, C. Florent, P. Marteau, P. Pochart e J. C. Rambaud. "Site and substrates for methane production in human colon". American Journal of Physiology-Gastrointestinal and Liver Physiology 260, n. 5 (1 maggio 1991): G752—G757. http://dx.doi.org/10.1152/ajpgi.1991.260.5.g752.

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On two occasions separated by seven days, 22 g mucin (hog gastric mucin) was infused into right and left colon of 12 healthy volunteers (6 CH4 producers and 6 non-producers) maintained on a controlled diet. In the six CH4 producers, excess volumes of H2 excreted in breath were 73.4 +/- 11.9 and 35.1 +/- 14.1 (SE) ml/8 h (P less than 0.05) in response to right and left colonic infusion of mucin, respectively; excess volumes of CH4 were, respectively, 6.7 +/- 1.7 and 38.9 +/- 11.1 ml/8 h (P less than 0.05). In the six CH4 nonproducers, excess volumes of H2 excreted in breath were 76.6 +/- 17.6 and 30.8 +/- 6.3 ml/8 h (P less than 0.02) in response to right and left colonic infusion of mucin, respectively; excess volumes of CH4 were, respectively, 0.0 +/- 0.0 and 0.1 +/- 0.1 ml/8 h (not significant). In a further experiment, 17 healthy volunteers (10 CH4 producers and 7 nonproducers) were given on 2 consecutive days an oral load and an enema of 10 g lactulose. In the 10 CH4 producers, excess volumes of H2 excreted in breath were 74.6 +/- 15.1 and 32.3 +/- 11.5 ml/6 h (P less than 0.001) in response to oral ingestion and lactulose enema, respectively; excess volumes of CH4 were, respectively, 7.7 +/- 3.0 and 38.2 +/- 7.2 ml/6 h (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

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Xu, Jiaxing, Derrick Y. F. Lai e Suvadip Neogi. "Effects of Land Use Types on CH4 and CO2 Production Potentials in Subtropical Wetland Soils". Water 12, n. 7 (28 giugno 2020): 1856. http://dx.doi.org/10.3390/w12071856.

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Changes in land use types can alter the soil and environmental characteristics of wetlands, which in turn influence the magnitude of greenhouse gas production by soil microbes. However, the effects of land use change on the production potential of methane (CH4) and carbon dioxide (CO2) in subtropical wetland soils and the underlying controls are still largely unknown. In this study, we examined the soil CH4 and CO2 production potentials under five different land use types (natural mangrove, Gei Wai water channel, Gei Wai forest, reedbed, and freshwater pond) and their relationships with soil physico-chemical properties in a subtropical wetland in Hong Kong using aerobic and anaerobic laboratory incubation experiments. Our results showed an overall decreasing trend of CH4 and CO2 production potentials down the soil profile at all sites, which could be attributed to a reduction in the concentrations of soil organic matter (SOM), total Kjeldahl nitrogen (TKN) and ammonium nitrogen (NH4+-N). Moreover, the soil CH4 and CO2 production potentials varied significantly in the surface soils among land use types, but were more similar across the sites in the deeper soils. The conversion of natural mangrove to other land use types significantly reduced both the aerobic and anaerobic CO2 production potentials in the top 10 cm soils, except for Gei Wai forest, which demonstrated significantly higher CO2 production rates (61.15–97.91 μg g−1 day−1). Meanwhile, the mean CH4 production potential in the surface soils of natural mangrove (0.05 μg g−1 d−1) was significantly lower than that in the Gei Wai forest and Gei Wai channel (0.26–0.27 μg g−1 day−1) but slightly higher than that in the freshwater pond and reedbed (0.00–0.02 μg g−1 day−1). The high soil CH4 and CO2 production potentials observed in the Gei Wai forest could be explained by the high soil concentrations of SOM, TKN and NH4+-N. On the other hand, the lower anaerobic CH4 and aerobic CO2 productions observed in the reedbed could be attributed to the lower concentrations of NH4+-N and available phosphorus. Our findings highlighted the significant impacts of land use types on the CH4 and CO2 production potentials of subtropical wetland soils, which had practical implications for wetland management for climate change mitigation.

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Behrouzi, Amir, Hailey Bolen, Francisco José de Novais, John A. Basarab, Edward bork e Carolyn J. Fitzsimmons. "PSVIII-19 Assessing methane and carbon dioxide production in beef cows across diverse foraging conditions". Journal of Animal Science 102, Supplement_3 (1 settembre 2024): 600–601. http://dx.doi.org/10.1093/jas/skae234.674.

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Abstract Beef cattle grazing across more than 40M ha of Canada’s grasslands is economically significant yet contributes to methane (CH4) emissions. Accurately measuring CH4 emissions across diverse environments presents substantial challenges. Our study investigated CH4 and carbon dioxide (CO2) production in 3-yr-old pregnant crossbred beef cows (n = 30) across different phases of the beef production cycle, including in drylot and while grazing on native rangeland, in Western Canada’s Aspen Parkland region using the GreenFeed Emissions Monitoring System (GEM). During the January to March drylot phase, enteric CH4 and CO2 production of the cows were monitored for 63 d in consort with feed efficiency testing while consuming a mixed oat-barley silage diet. Following this, cows were categorized into three distinct groups based on the standard deviation (SD) of CH4 yield [gּ kg−1 dry matter intake (DMI)]: Low (< 0.5 SD; n = 11), Medium (± 0.5 SD; n = 10), and High (> 0.5 SD; n = 9). Post-calving, cows and calves transitioned to native pastures for CH4 and carbon dioxide (CO2) assessment across three distinct foraging conditions: high-quality, high-quantity forage in summer (SUM; 50 d); moderate-quality, high-quantity forage in September (SEP; 22 d); and finally, low-quality, low-quantity forage in October (OCT; 22 d). We hypothesize that ranking cows based on their CH4 yield (gּ kg−1 DMI) in drylot settings may have the potential to reflect their CH4 production (g/d) during grazing conditions, even without feed intake data. Data were analyzed using the PROC MIXED procedure of SAS to examine CH4 production among cows categorized by their assigned ranking. Spot CH4 and CO2 measurements totaled 1,242, 1,145, and 1,205 for the SUM, SEP, and OCT, production phases, respectively. Average daily visits to GEM units were 1.4 ± 0.1, 1.84 ± 0.1, and 1.96 ± 0.1 for the corresponding phases. While High CH4-ranked cows had methane production similar to Low CH4-ranked cows (234.8 ± 8.2 vs. 235.0 ± 6.0 g/d, respectively), the Medium group had significantly greater methane production (260.5 ± 6.2 g/d; P = 0.008) than the Low and High CH4 groups. Furthermore, significant interactions were observed between CH4 ranking groups and CH4 production during the grazing phase (P = 0.035). Cows in the Medium CH4 group emitted greater amounts of CH4 compared with the High group in SUM (288.2 ± 9.3 vs. 247.0 ± 14.1 g/d) and to the Low group in SEP and OCT (276.5 ± 6.6 vs. 238.1 ± 6.3, and 216.7 ± 7.2 vs. 191.8 ± 7.5 g/d, respectively). In conclusion, the drylot CH4 ranking may hold promise in predicting outcomes for both Low and Medium CH4-ranked groups during grazing phases. However, High CH4-ranked cows had decreased methane production, likely influenced by grazing-induced changes in feed intake and individual feeding behaviors, prompting further exploration.

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Bradford, M. A., P. Ineson, P. A. Wookey e H. M. Lappin-Scott. "Role of CH4 oxidation, production and transport in forest soil CH4 flux". Soil Biology and Biochemistry 33, n. 12-13 (ottobre 2001): 1625–31. http://dx.doi.org/10.1016/s0038-0717(01)00078-5.

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17

Yuan, Q., J. Pump e R. Conrad. "Straw application in paddy soil enhances methane production also from other carbon sources". Biogeosciences Discussions 10, n. 8 (26 agosto 2013): 14169–93. http://dx.doi.org/10.5194/bgd-10-14169-2013.

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Abstract. Flooded rice fields are an important source of the greenhouse gas methane. Methane is produced from rice straw (RS), soil organic matter (SOM), and rice root organic carbon (ROC). Addition of RS is widely used for ameliorating soil fertility. However, this practice provides additional substrate for CH4 production and results in increased CH4 emission. Here, we found that decomposing RS is not only a substrate of CH4 production, but in addition stimulates CH4 production from SOM and ROC. Apart from accelerating the creation of reduced conditions in the soil environment, RS decomposition exerted a positive priming effect on SOM-derived CH4 production. In particular, hydrogenotrophic methanogenesis from SOM-derived CO2 was stimulated, presumably by H2 released from RS decomposition. On the other hand, the positive priming effect of RS on ROC-derived CH4 production was probably caused by the significant increase of the abundance of methanogenic archaea in the RS treatment compared with the untreated control. Our results show that traditional management of rice residues exerts a positive feedback on CH4 production from rice fields, thus exacerbating its effect on the global CH4 budget.

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18

McCaughey, W. P., K. Wittenberg e D. Corrigan. "Methane production by steers on pasture". Canadian Journal of Animal Science 77, n. 3 (1 settembre 1997): 519–24. http://dx.doi.org/10.4141/a96-137.

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Abstract (sommario):

In order to determine the quantity of methane (CH4) produced by steers on pasture, 16 steers with a mean weight of 356 ± 25 kg were randomly selected from a larger group of cattle (n = 48) to evaluate the effects of grazing management and monensin controlled release capsule (CRC) administration on ruminal CH4 production using the sulphur hexafluoride (SF6) tracer-gas technique. Pasture management treatments consisted of two grazing systems (continuous stocking or 10-paddock rotational stocking) at each of two stocking rates (low, 1.1 steer ha−1 or high, 2.2 steers ha−1) with two replications of each pasture treatment. Half of the animals on each pasture treatment were administered a monensin CRC delivering 270 mg d−1, and untreated animals served as controls. During the 140-d grazing season, one steer from each treatment-replicate combination was sampled to determine daily intake and CH4 production on four occasions. The chemical composition of diets differed between grazing management treatments and sampling periods. Voluntary intake and CH4 production, adjusted for differences in body weight, were unaffected by grazing management, sampling period or by monensin CRC administration and averaged 0.69 ± 0.1 L kg BW−1 d−1 across all grazing management treatments. The energy lost through eructation of CH4 averaged 4.5 ± 1.4% of gross energy intake. Key words: Methane, cattle, environment, digestion efficiency, pasture, forage

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19

Galyean, Michael L., e Kristin E. Hales. "Relationships between Dietary Chemical Components and Enteric Methane Production and Application to Diet Formulation in Beef Cattle". Methane 3, n. 1 (9 gennaio 2024): 1–11. http://dx.doi.org/10.3390/methane3010001.

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Abstract (sommario):

We used published data consisting of 263 treatment mean observations from beef cattle and dairy steers and heifers, in which CH4 was measured via chambers or head boxes, to evaluate relationships between enteric CH4 production and dry matter intake (DMI) and dietary components. Daily DMI was positively related (slope = 15.371, p < 0.001) to total daily production (g/d) of CH4 (r2 = 0.821). Among chemical components, dietary neutral detergent fiber (NDF) concentration was the most highly related (r2 = 0.696; slope = 0.2001; p < 0.001) to CH4 yield (g/kg of DMI), with strong relationships also noted for dietary starch:NDF ratio (r2 = 0.662; slope = −2.4587; p < 0.001), starch (r2 = 0.495; slope = −0.106; p < 0.001), and the proportion of metabolizable energy relative to gross energy (r2 = 0.561; slope = −23.663; p < 0.001). The slope (−0.5871) and intercept (22.2295) for the dietary ether extract vs. CH4 yield were significant (p < 0.001), but the relationship was highly variable (r2 = 0.150). For dietary crude protein concentration, the slope for CH4 yield was not significant (−0.0344; p < 0.381) with an r2 value near zero. Decreasing DMI by programming body weight gain or restricting feed intake could decrease CH4 production in confined cattle, but these approaches might negatively affect growth performance and product quality, potentially negating positive effects on CH4 production. Feeding higher-quality forages or using grazing management systems that decrease dietary NDF concentrations or substituting grain (starch) for forage should decrease both CH4 yield from enteric production and manure CH4 production via increased digestibility. Effects of feeding management and diet formulation strategies should be additive with other mitigation approaches such as feed additives, allowing the cattle industry to achieve maximal decreases in enteric CH4 production, while concurrently maintaining optimal beef production.

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20

Vizza, Carmella, William E. West, Stuart E. Jones, Julia A. Hart e Gary A. Lamberti. "Regulators of coastal wetland methane production and responses to simulated global change". Biogeosciences 14, n. 2 (26 gennaio 2017): 431–46. http://dx.doi.org/10.5194/bg-14-431-2017.

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Abstract (sommario):

Abstract. Wetlands are the largest natural source of methane (CH4) emissions to the atmosphere, which vary along salinity and productivity gradients. Global change has the potential to reshape these gradients and therefore alter future contributions of wetlands to the global CH4 budget. Our study examined CH4 production along a natural salinity gradient in fully inundated coastal Alaska wetlands. In the laboratory, we incubated natural sediments to compare CH4 production rates between non-tidal freshwater and tidal brackish wetlands, and quantified the abundances of methanogens and sulfate-reducing bacteria in these ecosystems. We also simulated seawater intrusion and enhanced organic matter availability, which we predicted would have contrasting effects on coastal wetland CH4 production. Tidal brackish wetlands produced less CH4 than non-tidal freshwater wetlands probably due to high sulfate availability and generally higher abundances of sulfate-reducing bacteria, whereas non-tidal freshwater wetlands had significantly greater methanogen abundances. Seawater addition experiments with freshwater sediments, however, did not reduce CH4 production, perhaps because the 14-day incubation period was too short to elicit a shift in microbial communities. In contrast, increased organic matter enhanced CH4 production in 75 % of the incubations, but this response depended on the macrophyte species added, with half of the species treatments having no significant effect. Our study suggests that CH4 production in coastal wetlands, and therefore their overall contribution to the global CH4 cycle, will be sensitive to increased organic matter availability and potentially seawater intrusion. To better predict future wetland contributions to the global CH4 budget, future studies and modeling efforts should investigate how multiple global change mechanisms will interact to impact CH4 dynamics.

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21

Saenab, Andi, Komang G. Wiryawan, Y. Retnani e Elizabeth Wina. "Synergistic Effect of Biofat and Biochar of Cashew Nutshell on Mitigate Methane in the Rumen". Jurnal Ilmu Ternak dan Veteriner 25, n. 3 (2 settembre 2020): 139. http://dx.doi.org/10.14334/jitv.v25i3.2475.

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Abstract (sommario):

The study aimed to evaluate the effectiveness of a combination of biofat with biochar or biosmoke (bioindustrial products of cashew nut shells) at the best level as feed additive in reducing methane production and improving in vitro rumen fermentation. This experiment had two series of combination and each used a randomized block design with 6 treatments and 4 replications. A series of biofat (BF) and biochar (BC) combination were added each to substrate as followed BFBC1 = 0: 100%; BFBC2 = 25:75%; BFBC3 = 50:50%; BFBC4 = 75:25%; BFBC5 = 100: 0%. While, a series of biofat (BF) and biosmoke (BS) combination as followed BFBS1 = 0: 100%; BFBS2 = 25:75%; BFBS3 = 50:50%; BFBS4 = 75:25%; BFBS5 = 100: 0%. Both series used a control treatment which contained only substrate. The in vitro experiment was repeated 4 times and each treatment was done in duplicates. The measured variables were: total gas and CH4 productions, dry matter, organic matter, NDF degradability, NH3 and partial VFA concentrations. The results showed that the combination of biofat and biochar levels resulted in a significant decrease (P<0.01) of CH4 production in the rumen. CH4 production was 88.50% (BFBC1), 63.15% (BFBC2), 61.50% (BFBC3), 58.16% (BFBC4) and 73.93% (BFBC5) compared to control treatment (100% CH4 production). The combination caused higher NH3 at BFBC4 and significantly higher propionate and total VFA in the rumen than control. Dry matter degradation values increased by a combination level biofat and biochar (BFBC4 and BFBC5), but these results were the same as control. Addition of combination of biofat and biosmoke caused a significant decrease (P<0.01) of CH4 production in the rumen. CH4 production was 71.98% (BFBS1), 65.57% (BFBS2), 64.81% (BFBS3),60.21% (BFBS4) dan 80.72 (BFBS5) compared to control treatment (100% CH4 production). At BFBS4 level, NH3 production, DMD and OMD values were lower than control. In conclusion, the best combination producing synergistic effect as feed additive to reduce methane and increase ammonia in the in vitro rumen was combination of biofat and biochar (BFBC4=75: 25%) or biofat with biosmoke (BFBS4= 75: 25%).

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22

Chang, Kuang-Yu, William J. Riley, Patrick M. Crill, Robert F. Grant e Scott R. Saleska. "Hysteretic temperature sensitivity of wetland CH4 fluxes explained by substrate availability and microbial activity". Biogeosciences 17, n. 22 (27 novembre 2020): 5849–60. http://dx.doi.org/10.5194/bg-17-5849-2020.

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Abstract (sommario):

Abstract. Methane (CH4) emissions from wetlands are likely increasing and important in global climate change assessments. However, contemporary terrestrial biogeochemical model predictions of CH4 emissions are very uncertain, at least in part due to prescribed temperature sensitivity of CH4 production and emission. While statistically consistent apparent CH4 emission temperature dependencies have been inferred from meta-analyses across microbial to ecosystem scales, year-round ecosystem-scale observations have contradicted that finding. Here, we show that apparent CH4 emission temperature dependencies inferred from year-round chamber measurements exhibit substantial intra-seasonal variability, suggesting that using static temperature relations to predict CH4 emissions is mechanistically flawed. Our model results indicate that such intra-seasonal variability is driven by substrate-mediated microbial and abiotic interactions: seasonal cycles in substrate availability favors CH4 production later in the season, leading to hysteretic temperature sensitivity of CH4 production and emission. Our findings demonstrate the uncertainty of inferring CH4 emission or production rates from temperature alone and highlight the need to represent microbial and abiotic interactions in wetland biogeochemical models.

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23

Ellis, Jennifer L., Héctor Alaiz-Moretón, Alberto Navarro-Villa, Emma J. McGeough, Peter Purcell, Christopher D. Powell, Padraig O’Kiely, James France e Secundino López. "Application of Meta-Analysis and Machine Learning Methods to the Prediction of Methane Production from In Vitro Mixed Ruminal Micro-Organism Fermentation". Animals 10, n. 4 (21 aprile 2020): 720. http://dx.doi.org/10.3390/ani10040720.

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Abstract (sommario):

In vitro gas production systems are utilized to screen feed ingredients for inclusion in ruminant diets. However, not all in vitro systems are set up to measure methane (CH4) production, nor do all publications report in vitro CH4. Therefore, the objective of this study was to develop models to predict in vitro CH4 production from total gas and volatile fatty acid (VFA) production data and to identify the major drivers of CH4 production in these systems. Meta-analysis and machine learning (ML) methodologies were applied to a database of 354 data points from 11 studies to predict CH4 production from total gas production, apparent DM digestibility (DMD), final pH, feed type (forage or concentrate), and acetate, propionate, butyrate and valerate production. Model evaluation was performed on an internal dataset of 107 data points. Meta-analysis results indicate that equations containing DMD, total VFA production, propionate, feed type and valerate resulted in best predictability of CH4 on the internal evaluation dataset. The ML models far exceeded the predictability achieved using meta-analysis, but further evaluation on an external database would be required to assess generalization ability on unrelated data. Between the ML methodologies assessed, artificial neural networks and support vector regression resulted in very similar predictability, but differed in fitting, as assessed by behaviour analysis. The models developed can be utilized to estimate CH4 emissions in vitro.

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24

Zhang, G. B., Y. Ji, J. Ma, G. Liu, H. Xu e K. Yagi. "Pathway of CH4 production, fraction of CH4 oxidized, and 13C isotope fractionation in a straw incorporated rice field". Biogeosciences Discussions 9, n. 10 (15 ottobre 2012): 14175–215. http://dx.doi.org/10.5194/bgd-9-14175-2012.

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Abstract (sommario):

Abstract. Straw incorporation generally increases CH4 emission from rice fields, but its effects on the mechanism of CH4 emission, especially on the pathway of CH4 production and the fraction of CH4 oxidized are not well known. To investigate the methanogenic pathway, the fraction of CH4 oxidized as well as the stable carbon isotope fractionation during the oxidation and transport of CH4 as affected by straw incorporation, production and oxidation of CH4 in paddy soil and rice roots and δ13C-values of produced CH4 and CO2, and emitted CH4 were observed in incubation and field experiments. Straw incorporation significantly enhanced CH4 production potentials of the paddy soil and rice roots. However, it increased the relative contribution of acetate to total CH4 production (Fac) in the paddy soil by ~ 10–30%, but decreased Fac-value of the rice roots by ~ 5–20%. Compared with rice roots, paddy soil was more important in acetoclastic methanogenesis, with Fac-value being 6–30% higher. Straw incorporation highly decreased the fraction of CH4 oxidized (Fox) by 41–71%, probably attributed to the fact that it increased CH4 oxidation potential whereas CH4 production potential was increased to a larger extent. There was little CH4 formed during aerobic incubation, and the produced CH4 was more 13C-enriched relative to that of anaerobic incubation. Assuming δ13C-values of CH4 aerobically produced in paddy soil to be the δ13C-values of residual CH4 after being oxidized, Fox-value still appeared to be 45–68% lower when straw was incorporated. Oxidation fractionation factor (αox) was higher with straw incorporation (1.033) than without straw incorporation (1.025). The δ13C-values of CH4 emitted after cutting of the plants (−50–−43‰) were more positive than those of before (−58–−55‰), suggesting a transport fractionation factor (&varepsilon;transport) was −8.0‰ with straw incorporation and −12.0‰ without straw incorporation. Reasons for this difference may be related to the decrease in growth of the rice crop as a result of straw incorporation. The experiment shows that straw incorporation increases the contribution of acetate to total methanogenesis in paddy soil but decreases it on rice roots, and it significantly decreases the fraction of CH4 oxidized in the field, and expands oxidation fractionation while reducing transport fractionation.

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25

Xia, Zhizeng, Jian Hou, Xuewu Wang, Xiaodong Dai e Mingtao Liu. "Cyclic methane hydrate production stimulated with CO2 and N2". Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 76 (2021): 14. http://dx.doi.org/10.2516/ogst/2020097.

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Abstract (sommario):

The cyclic methane hydrate production method was proposed with CO2 and N2 mixture stimulation. The cyclic production model was established based on actual hydrate reservoir parameters, accordingly, the production characteristics were analyzed, and a sensitivity analysis was conducted. The results show the following: (1) The depressurization mechanism is dominant in the cyclic production. CH4 production and CH4 hydrate dissociation can be greatly enhanced because the cyclic process can effectively reduce the partial pressure of CH4 (gas phase). However, there is a limited effect for CO2 storage. (2) Heat supply is essential for continuous hydrate dissociation. The CH4 hydrate dissociation degree is the highest in the near-wellbore area; in addition, the fluid porosity and effective permeability are significantly improved, and the reservoir temperature is obviously decreased. (3) The initial CH4 hydrate saturation, absolute permeability, intrinsic CO2 hydrate formation kinetic constant, injection time and production time can significantly influence the production performance of the natural gas hydrate reservoir.

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26

Susilawati, Helena Lina, Anicetus Wihardjaka, Nurhasan Nurhasan e Prihasto Setyanto. "Potensi Bahan Alami dalam Menekan Produksi CH4 dan N2O dari Tanah Sawah". Jurnal Ilmu Pertanian Indonesia 26, n. 4 (27 ottobre 2021): 499–510. http://dx.doi.org/10.18343/jipi.26.4.499.

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Abstract (sommario):

Low nitrogen efficiency is one of the sources of greenhouse gas (GHG) emissions from rice fields. Methane (CH4) and nitrous oxide (N2O) emissions could be controlled by nitrification inhibitors (NI). However, NI that has been commercialized is expensive. Therefore, some natural materials should be developed as NI that is low cost, easy to use, low N2O and CH4, and eco-friendly. The objective of this study was to observe the effect of natural NI on the production potential of CH4 and N2O from paddy soil. The experiment in the laboratory was arranged in a factorial design (2 × 7 × 3 replication). The first factor was soil types (inceptisols and vertisols), and the second factor was natural NI (control, Cocos nucifera, Camellia sinensis, Coffea robusta, Curcuma domestica, Ageratum conyzoides). The results showed that the average CH4 production from the natural NI in the inceptisols and vertisols ranged 0,014-1,710 mg CH4 g soil-1 and 0,002-0,337 mg CH4 g soil-1, respectively. Application of natural NI reduced 32-69% CH4 production compare to control. Redox potential affected CH4 production. The chemical compound of the natural NI affected CH4 production in the soil. The application of coffee waste, coconut husk, tea waste, and Ageratum conyzoides reduced 60,71; 54,61; 64,83 dan 64,16% of N2O production in Inceptisols compare to control, respectively. Application of natural NI could contribute to save the environment because it decreased GHG production in paddy soil. Keywords: greenhouse gas, inceptisols, incubation experiment, natural nitrification inhibitors, vertisols

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27

Long, Nathan S., Jarret A. Proctor, Jason K. Smith, Juan M. Piñeiro, Ryan C. Foster, Vinícius N. Gouvêa, Bobbie L. Castleberry et al. "99 Dietary Inclusion of a High-Anthocyanin Corn Cob Meal into Feedlot Rations Reducesin Vitro Methane Emissions". Journal of Animal Science 101, Supplement_1 (1 maggio 2023): 71–73. http://dx.doi.org/10.1093/jas/skad068.085.

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Abstract (sommario):

Abstract Methane (CH4) is a greenhouse gas associated with global warming that is released as a byproduct of rumen fermentation. Two experiments were conducted to determine if dietary inclusion of a novel high anthocyanin (Hi-A) containing corn cob meal [CCM; 4.99 mg anthocyanin×g-1 of dry matter (DM)] influences in vitro CH4 emissions relative to a conventional CCM (CNV; 0.04 mg anthocyanin×g-1 of DM). High-roughage starter (experiment 1) and low-roughage finisher (experiment 2) diets were formulated to contain 20% and0% total CCM (DM-basis), respectively. Treatments were based on the proportion of Hi-A to CNV CCM within each diet and consisted of 0% (0A), 25% (25A), 50% (50A), 75% (75A), and 100% Hi-A (100A) CCM. In experiments 1 and 2, ruminal fluid was collected from 4 cannulated steers offered traditional feedlot starter or finisher diets, respectively. Filter bags (F57; ANKOM; Macedon, NY) were loaded with 0.5 g of substrate and 2 bags per ANKOM RF system were incubated in buffer and rumen fluid for 48 h at 39°C. Cumulative gas production was recorded at 10-min intervals. The concentration of CH4 as a proportion of total gas production (%CH4) was measured using gas chromatography after 48 h. Total gas production was fit to the Ørskov model to determine asymptotic and fractional rates of gas production. In experiment 1, there was a cubic relationship between total gas production and Hi-A CCM inclusion for the intercept, asymptote, and fractional gas production rate (P ≤ 0.04). There was also a cubic relationship between %CH4 and Hi-A CCM inclusion (P = 0.04), where 50A had the largest reduction relative to 0A at -19.6% (P = 0.05). Total CH4 production (mL CH4×g DM-1) also exhibited a cubic relationship with Hi-A-CCM inclusion (P = 0.03), where 100A produced 20% less CH4 than 0A. In experiment 2, there was a cubic relationship between total gas production and Hi-A CCM inclusion for the intercept and asymptote (P ≤ 0.02) of the Ørskov model; however, fractional gas production rate expressed a quadratic relationship (P < 0.01). Furthermore, a cubic relationship existed between %CH4 and Hi-A CCM inclusion, where 100A had the largest reduction relative to 0A (17.4%; P = 0.03). Lastly, there was a tendency for a cubic relationship between Hi-A CCM inclusion and total CH4 production (P = 0.06); however, 100A reduced total CH4 production by 22% relative to 0A (P = 0.01). Collectively, the greatest level of Hi-A CCM inclusion reduced total CH4 production relative to 0A in both starter and finisher diets. These results indicate that dietary inclusion of anthocyanins through CCM decreased CH4 emissions in vitro. Further research is needed to determine if anthocyanins from Hi-A CCM are effective at mitigating CH4 emissions in vivo.

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Kilian, Levi R. "146 Effect of Sire on Methane Production". Journal of Animal Science 101, Supplement_3 (6 novembre 2023): 33. http://dx.doi.org/10.1093/jas/skad281.040.

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Abstract (sommario):

Abstract The objective of this study was to determine if sires have a significant effect on methane (CH4) production in a feedlot setting. To reduce the emission of greenhouse gases from cattle, evaluating variables that are easy to manage and change becomes important for a solution. If sires influence methane production, selection can be used to reduce methane production in cattle as sire differences are indicative of a genetic influence. The data used in this study were obtained from Colorado State University (CSU), with animals from John E. Rouse Beef Improvement Center. Animals with methane data were included in this analysis if sire parentage was known. After filtering, there were 68 Angus cattle, with 56 sires and 12 heifers included in the study. A linear model fitting sire and pen to methane was used. RStudio was used for the general linear model, and significance values were generated. Individual CH4 emissions were collected using GreenFeed free-stall systems (C-Lock) in each of the four pens at the CSU Agricultural Research Development and Education Center facility in Fort Collins, CO. Methane emissions were measured over a 52-day period. The average animal age at the start of the period was 241± 15.76 days. After all collections were completed, the mean CH4 mass flow was 180.4 g/day with a median of 181.4 g/day. The minimum was 107.5 g/day with a maximum of 247.0 g/day. There were sex differences (P < 0.05) for (CH4) emission rate. Primary to this study, sires had a significant effect on (CH4) emission rates (P < 0.05). The range of sire means for methane production was considerable with the 1st and 3rd quartiles of 157.8 g/day and 209.6 g/day. In these data, sires significantly influenced the (CH4) emission rates of their progeny, and we believe selection could be used to reduce overall (CH4) emissions. With these results, however, additional analyses to fully understand if there truly is a genetic component to (CH4) production could be undertaken once additional data has been collected. These future studies need to consider the relationships between methane production and other traits such as average daily gain, dry matter intake, and weight as selection needs to occur while considering a system-wide perspective.

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Zhang, G. B., Y. Ji, J. Ma, H. Xu e Z. C. Cai. "Case study on effects of water management and rice straw incorporation in rice fields on production, oxidation, and emission of methane during fallow and following rice seasons". Soil Research 49, n. 3 (2011): 238. http://dx.doi.org/10.1071/sr10117.

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Abstract (sommario):

To investigate production, oxidation, and emission of methane (CH4) in rice fields during the fallow and following rice seasons as affected by water management and rice straw incorporation in the fallow season, field and incubation experiments were carried out from November 2007 to November 2008. Four treatments, i.e. two water managements (flooded and drained) and two rates of rice straw application (0 and 4.8 t/ha), were laid out in a randomised block design. Results show that obvious CH4 production occurred in flooded fields in the late fallow season; consequently, fallow CH4 emission contributed 9.6–33.1% to the annual total emission. However, emission mainly occurred during the rice season. During the rice season, the mean CH4 production potential in flooded fields was 2.6–3.8 times that in drained fields, making the total CH4 emission 2.1–2.5 times that in drained fields. Rice straw incorporated in flooded fields significantly increased production and emission of CH4 during both the fallow and the following rice seasons (P < 0.05), but in drained fields, no significant effect was observed (P > 0.05). There was no significant difference in mean CH4 oxidation potential between the treatments (P > 0.05), indicating that water management and rice straw incorporation in the fallow season have little influence on CH4 oxidation during the fallow and following rice seasons. Based on the findings, water management and rice straw incorporation in the fallow season significantly affected CH4 emission during the fallow and the following rice seasons by influencing CH4 production rather than CH4 oxidation in fields.

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30

Liu, D. Y., W. X. Ding, Z. J. Jia e Z. C. Cai. "Relation between methanogenic archaea and methane production potential in selected natural wetland ecosystems across China". Biogeosciences 8, n. 2 (14 febbraio 2011): 329–38. http://dx.doi.org/10.5194/bg-8-329-2011.

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Abstract (sommario):

Abstract. Methane (CH4) emissions from natural wetland ecosystems exhibit large spatial variability at regional, national, and global levels related to temperature, water table, plant type and methanogenic archaea etc. To understand the underlying factors that induce spatial differences in CH4 emissions, and the relationship between the population of methanogenic archaea and CH4 production potential in natural wetlands around China, we measured the CH4 production potential and the abundance of methanogenic archaea in vertical soil profiles sampled from the Poyang wetland in the subtropical zone, the Hongze wetland in the warm temperate zone, the Sanjiang marsh in the cold temperate zone, and the Ruoergai peatland in the Qinghai-Tibetan Plateau in the alpine climate zone. The top soil layer had the highest population of methanogens (1.07–8.29 × 109 cells g−1 soil) in all wetlands except the Ruoergai peatland and exhibited the maximum CH4 production potential measured at the mean in situ summer temperature. There is a significant logarithmic correlation between the abundance of methanogenic archaea and the soil organic carbon (R2 = 0.72, P < 0.001, n = 13) and between the abundance of methanogenic archaea and the total nitrogen concentrations (R2 = 0.76, P < 0.001, n = 13) in wetland soils. This indicates that the amount of soil organic carbon may affect the population of methanogens in wetland ecosystems. While the CH4 production potential is not significantly related to methanogen population (R2 = 0.01, P > 0.05, n = 13), it is related to the dissolved organic carbon concentration (R2 = 0.31, P = 0.05, n = 13). This suggests that the methanogen population might be not an effective index for predicting the CH4 production in wetland ecosystems. The CH4 production rate of the top soil layer increases with increasing latitude, from 273.64 μg CH4 kg−1 soil d−1 in the Poyang wetland to 664.59 μg CH4 kg−1 soil d−1 in the Carex lasiocarpa marsh of the Sanjiang Plain. We conclude that CH4 production potential in the freshwater wetlands of Eastern China is mainly affected by the supply of methanogenic substrates rather than temperature; in contrast, low summer temperatures at high elevations in the Ruoergai peatland of the Qinghai–Tibetan Plateau result in the presence of dominant species of methanogens with low CH4 production potential, which in turn suppresses CH4 production.

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31

Morana, Cédric, Steven Bouillon, Vimac Nolla-Ardèvol, Fleur A. E. Roland, William Okello, Jean-Pierre Descy, Angela Nankabirwa, Erina Nabafu, Dirk Springael e Alberto V. Borges. "Methane paradox in tropical lakes? Sedimentary fluxes rather than pelagic production in oxic conditions sustain methanotrophy and emissions to the atmosphere". Biogeosciences 17, n. 20 (29 ottobre 2020): 5209–21. http://dx.doi.org/10.5194/bg-17-5209-2020.

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Abstract (sommario):

Abstract. Despite growing evidence that methane (CH4) formation could also occur in well-oxygenated surface fresh waters, its significance at the ecosystem scale is uncertain. Empirical models based on data gathered at high latitude predict that the contribution of oxic CH4 increases with lake size and should represent the majority of CH4 emissions in large lakes. However, such predictive models could not directly apply to tropical lakes, which differ from their temperate counterparts in some fundamental characteristics, such as year-round elevated water temperature. We conducted stable-isotope tracer experiments, which revealed that oxic CH4 production is closely related to phytoplankton metabolism and is a common feature in five contrasting African lakes. Nevertheless, methanotrophic activity in surface waters and CH4 emissions to the atmosphere were predominantly fuelled by CH4 generated in sediments and physically transported to the surface. Indeed, CH4 bubble dissolution flux and diffusive benthic CH4 flux were several orders of magnitude higher than CH4 production in surface waters. Microbial CH4 consumption dramatically decreased with increasing sunlight intensity, suggesting that the freshwater “CH4 paradox” might be also partly explained by photo-inhibition of CH4 oxidizers in the illuminated zone. Sunlight appeared as an overlooked but important factor determining the CH4 dynamics in surface waters, directly affecting its production by photoautotrophs and consumption by methanotrophs.

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32

Korkiakoski, Mika, Tiia Määttä, Krista Peltoniemi, Timo Penttilä e Annalea Lohila. "Excess soil moisture and fresh carbon input are prerequisites for methane production in podzolic soil". Biogeosciences 19, n. 7 (13 aprile 2022): 2025–41. http://dx.doi.org/10.5194/bg-19-2025-2022.

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Abstract (sommario):

Abstract. Boreal upland forests are generally considered methane (CH4) sinks due to the predominance of CH4 oxidizing bacteria over the methanogenic archaea. However, boreal upland forests can temporarily act as CH4 sources during wet seasons or years. From a landscape perspective and in annual terms, this source can be significant as weather conditions may cause flooding, which can last a considerable proportion of the active season and because often, the forest coverage within a typical boreal catchment is much higher than that of wetlands. Processes and conditions which change mineral soils from acting as a weak sink to a strong source are not well understood. We measured soil CH4 fluxes from 20 different points from regularly irrigated and control plots during two growing seasons. We also estimated potential CH4 production and oxidation rates in different soil layers and performed a laboratory experiment, where soil microcosms were subjected to different moisture levels and glucose addition simulating the fresh labile carbon (C) source from root exudates. The aim was to find the key controlling factors and conditions for boreal upland soil CH4 production. Probably due to long dry periods in both summers, we did not find occasions of CH4 production following the excess irrigation, with one exception in July 2019 with emission of 18 200 µg CH4 m−2 h−1. Otherwise, the soil was always a CH4 sink (median CH4 uptake rate of 260–290 and 150–170 µg CH4 m−2 h−1, in control and irrigated plots, respectively). The median soil CH4 uptake rates at the irrigated plot were 88 % and 50 % lower than at the control plot in 2018 and 2019, respectively. Potential CH4 production rates were highest in the organic layer (0.2–0.6 nmol CH4 g−1 d−1), but some production was also observed in the leaching layer, whereas in other soil layers, the rates were negligible. Potential CH4 oxidation rates varied mainly within 10–40 nmol CH4 g−1 d−1, except in deep soil and the organic layer in 2019, where potential oxidation rates were almost zero. The laboratory experiment revealed that high soil moisture alone does not turn upland forest soil into a CH4 source. However, a simple C source, e.g., substrates coming from root exudates with high moisture, switched the soil into a CH4 source. Our unique study provides new insights into the processes and controlling factors on CH4 production and oxidation, and the resulting net efflux that should be incorporated in process models describing global CH4 cycling.

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33

Praetzel, Leandra Stephanie Emilia, Nora Plenter, Sabrina Schilling, Marcel Schmiedeskamp, Gabriele Broll e Klaus-Holger Knorr. "Organic matter and sediment properties determine in-lake variability of sediment CO2 and CH4 production and emissions of a small and shallow lake". Biogeosciences 17, n. 20 (20 ottobre 2020): 5057–78. http://dx.doi.org/10.5194/bg-17-5057-2020.

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Abstract. Inland waters, particularly small and shallow lakes, are significant sources of carbon dioxide (CO2) and methane (CH4) to the atmosphere. However, the spatial in-lake heterogeneity of CO2 and CH4 production processes and their drivers in the sediment remain poorly studied. We measured potential CO2 and CH4 production in slurry incubations from 12 sites within the small and shallow crater lake Windsborn in Germany, as well as fluxes at the water–atmosphere interface of intact sediment core incubations from four sites. Production rates were highly variable and ranged from 7.2 to 38.5 µmol CO2 gC−1 d−1 and from 5.4 to 33.5 µmol CH4 gC−1 d−1. Fluxes ranged from 4.5 to 26.9 mmol CO2 m−2 d−1 and from 0 to 9.8 mmol CH4 m−2 d−1. Both CO2 and CH4 production rates and the CH4 fluxes exhibited a significant and negative correlation (p<0.05, ρ<−0.6) with a prevalence of recalcitrant organic matter (OM) compounds in the sediment as identified by Fourier-transformed infrared spectroscopy. The carbon / nitrogen ratio exhibited a significant negative correlation (p<0.01, ρ=-0.88) with CH4 fluxes but not with production rates or CO2 fluxes. The availability of inorganic (nitrate, sulfate, ferric iron) and organic (humic acids) electron acceptors failed to explain differences in CH4 production rates, assuming a competitive suppression, but observed non-methanogenic CO2 production could be explained up to 91 % by prevalent electron acceptors. We did not find clear relationships between OM quality, the thermodynamics of methanogenic pathways (acetoclastic vs. hydrogenotrophic) and electron-accepting capacity of the OM. Differences in CH4 fluxes were interestingly to a large part explained by grain size distribution (p<0.05, ρ=±0.65). Surprisingly though, sediment gas storage, potential production rates and water–atmosphere fluxes were decoupled from each other and did not show any correlations. Our results show that within a small lake, sediment CO2 and CH4 production shows significant spatial variability which is mainly driven by spatial differences in the degradability of the sediment OM. We highlight that studies on production rates and sediment quality need to be interpreted with care, though, in terms of deducing emission rates and patterns as approaches based on production rates only neglect physical sediment properties and production and oxidation processes in the water column as major controls on actual emissions.

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Goopy, J. P., D. L. Robinson, R. T. Woodgate, A. J. Donaldson, V. H. Oddy, P. E. Vercoe e R. S. Hegarty. "Estimates of repeatability and heritability of methane production in sheep using portable accumulation chambers". Animal Production Science 56, n. 1 (2016): 116. http://dx.doi.org/10.1071/an13370.

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This study was designed to screen a large number of sheep to identify individuals with high and low methane (CH4) production, and to estimate repeatability and heritability of CH4 emissions in sheep, utilising portable accumulation chambers (PAC) designed for in-field use. Mature ewes (n = 710) selected from a research flock with known sires had their CH4 production over 1 h measured in PAC [CH4 (g1h)]. Individuals with High (n = 103) or Low (n = 104) CH4 (g1h), adjusted for liveweight (LW), were selected and re-measured on three occasions 1–4 months later, at another site with more abundant and better quality pasture. Mean of the selected (207) ewes CH4 (g1h) emissions were ~50% higher than at the first measurement site (0.66 g vs 0.42 g). LW was a significant correlate of CH4 production (r = 0.47). Correlations between CH4 (g1h) for the three PAC measurements at Site 2, before adjusting for LW ranged from 0.44 to 0.55. After adjusting for the effect of LW, repeatability was 0.33 at the first and 0.43 at the second site. The correlation between estimates of an animal’s emissions at the first and second sites, adjusted for LW, was 0.24. Initial CH4 production of the selected High group was 32% greater than the Low group (P < 0.0001). On re-measurement there was still a significant difference (9–15%, P < 0.006) between Low and High groups. The initial estimate of heritability of CH4 (g1h), based on variation between the ewes’ sires (0.13), was not maintained across the two sites. This may be due to genotype × environment interactions. We postulate that aspects of rumen physiology, which modulate CH4 production, could be expressed differently in different nutritional environments. Our results indicate that field use of PAC to screen sheep populations for CH4 production is both robust and repeatable. However, further investigations are required into the relationship between CH4 output of individual animals in PAC compared with the more controlled conditions in respiration chambers.

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35

Scott, Brian, Andrew H. Baldwin e Stephanie A. Yarwood. "Quantification of potential methane emissions associated with organic matter amendments following oxic-soil inundation". Biogeosciences 19, n. 4 (23 febbraio 2022): 1151–64. http://dx.doi.org/10.5194/bg-19-1151-2022.

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Abstract. Methane (CH4) emissions are a potent contributor to global warming, and wetlands can be a significant CH4 source. In a microcosm study, we evaluated how the practice of amending soils with organic matter as part of wetland restoration projects may affect CH4 production potential. Organic amendments including hay, manure, biosolids, composted yard waste, and wood mulch were evaluated at three different levels. Using 1 L glass microcosms, we measured the production of biogenic gases over 60 d in two soils designated by texture: a sandy loam (SL) and a sandy clay loam (SCL). Fresh organic amendments increased CH4 production, leading to potentially higher global warming potential and wetland C loss, and CH4 production was more pronounced in SL. We observed biogenic gas production in two sequential steady-state phases: Phase 1 produced some CH4 but was mostly carbon dioxide (CO2), followed by Phase 2, 2 to 6 weeks later, with higher total gas and nearly equal amounts of CH4 and CO2. If this is generally true in soils, it may be appropriate to report CH4 emissions in the context of inundation duration. The CH4 from the SCL soil ranged from 0.003–0.8 cm3kg-1d-1 in Phase 1 to 0.75–28 cm3kg-1d-1 in Phase 2 and from SL range from 0.03–16 cm3kg-1d-1 in Phase 1 to 1.8–64 cm3kg-1d-1 in Phase 2. Adding fresh organic matter (e.g., hay) increased concentrations of ferrous iron (Fe2+), whereas in some cases composted organic matter decreased both Fe2+ concentrations and CH4 production. Methanogenesis normally increases following the depletion of reducible Fe; however, we observed instances where this was not the case, suggesting other biogeochemical mechanisms contributed to the shift in gas production.

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36

Lima, Danilo Montalvão, Adibe Luiz Abdalla Filho, Paulo de Mello Tavares Lima, Gabriel Zanuto Sakita, Tairon Pannunzio Dias e. Silva, Concepta McManus, Adibe Luiz Abdalla e Helder Louvandini. "Morphological characteristics, nutritive quality, and methane production of tropical grasses in Brazil". Pesquisa Agropecuária Brasileira 53, n. 3 (marzo 2018): 323–31. http://dx.doi.org/10.1590/s0100-204x2018000300007.

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Abstract: The objective of this work was to evaluate three tropical forage species for their in vitro methane (CH4) production and organic matter degradability, in order to determine the relationships between forage grass nutritive quality and CH4 production. Guinea grass (Megathyrsus maximus), palisade grass (Urochloa brizantha), and signal grass (Urochloa decumbens) were evaluated. Palisade grass showed the highest organic matter, neutral detergent fiber, acid detergent fiber, lignin, and lower-crude protein content. Signal grass had the highest values for hemicellulose and neutral detergent fiber-nitrogen, and the lowest-cellulose content. Guinea grass and signal grass showed a higher-total gas production than palisade grass. Besides, Guinea grass showed an increased CH4 production, and palisade grass showed lower value for truly degraded organic matter, and reduced partitioning factor, in comparison to signal grass. An increased CH4 production was observed in cases of lower hemicellulose and paratitioning factor. The nutritive value and CH4 production of forages may be employed as parameters, aiming at the sustainability of ruminant production.

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37

Deng, Jia, Qi Zhang, Jiujiu He, Guangjie Zhao, Fuquan Song e Hongqing Song. "Effects of competitive adsorption on production capacity during CO₂ displacement of CH₄ in shale". Physics of Fluids 34, n. 11 (novembre 2022): 116104. http://dx.doi.org/10.1063/5.0122802.

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During CO2 displacement of CH4 in shale, competitive adsorption results in reduced pore space used for gas flow in shale, which is closely associated with the production capacity of shale-gas reservoirs. Thus, the present work investigates the effects of CO2–CH4 competitive adsorption on production capacity. Herein, a slit–pore model is developed in terms of gas storage (CO2 and CH4) and graphene pores using molecular dynamics and implemented via large-scale atomic/molecular massively parallel simulator. The effects of CO2 injection pressure, temperature, and velocity and of pore size on CO2–CH4 displacement and competitive adsorption properties are simulated and examined. Hence, the displacement efficiency of CH4 and the adsorption layer thickness of the CO2–CH4 binary mixture are determined. Moreover, based on a basic seepage model of planar linear flooding, the effect of CO2–CH4 competitive adsorption on production capacity is analytically investigated. Results demonstrate that the production capacity with consideration of adsorption layer thickness is less than that without consideration of adsorption layer thickness, illustrating that CO2–CH4 competitive adsorption behaviors are closely connected with permeability, flow rate, and production capacity of shale-gas reservoirs, especially for shale-gas reservoirs containing large numbers of pores and slits.

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38

Tatsumi, Kenichi. "Effect of Surface Methane Controls on Ozone Concentration and Rice Yield in Asia". Atmosphere 14, n. 10 (13 ottobre 2023): 1558. http://dx.doi.org/10.3390/atmos14101558.

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Surface methane (CH4) is a significant precursor of tropospheric ozone (O3), a greenhouse gas that detrimentally impacts crops by suppressing their physiological processes, such as photosynthesis. This relationship implies that CH4 emissions can indirectly harm crops by increasing troposphere O3 concentrations. While this topic is important, few studies have specifically examined the combined effects of CH4 and CH4-induced O3 on rice yield and production. Utilizing the GEOS-Chem model, we assessed the potential reduction in rice yield and production in Asia against a 50% reduction in anthropogenic CH4 emissions relative to the 2010 base year. Based on O3 exposure metrics, the results revealed an average relative yield loss of 9.5% and a rice production loss of 45,121 kilotons (Kt) based on AOT40. Regions such as the India-Gangetic Plain and the Yellow River basin were particularly affected. This study determined that substantial reductions in CH4 concentrations can prevent significant rice production losses. Specifically, curbing CH4 emissions in the Beijing-Tianjin-Hebei region could significantly diminish the detrimental effects of O3 on rice yields in China, Korea, and Japan. In summary, decreasing CH4 emissions is a viable strategy to mitigate O3-induced reductions in rice yield and production in Asia.

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Liu, D., W. Ding, Z. Jia e Z. Cai. "Influence of niche differentiation on the abundance of methanogenic archaea and methane production potential in natural wetland ecosystems across China". Biogeosciences Discussions 7, n. 5 (20 ottobre 2010): 7629–55. http://dx.doi.org/10.5194/bgd-7-7629-2010.

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Abstract. Methane (CH4) emissions from natural wetland ecosystems exhibit large spatial variability. To understand the underlying factors that induce differences in CH4 emissions from natural wetlands around China, we measured the CH4 production potential and the abundance of methanogenic archaea in vertical profile soils sampled from the Poyang wetland in the subtropical zone, the Hongze wetland in the warm temperate zone, the Sanjiang marsh in the cold temperate zone, and the Ruoergai peatland in the Qinghai-Tibetan Plateau. The top soil layer had the highest population of methanogens (1.07−8.29×109 cells g−1 soil) in all wetlands except the Ruoergai peatland and exhibited the maximum CH4 production potential measured at the mean in situ summer temperature. There is a significant logarithmic correlation between the abundance of methanogenic archaea and the soil organic carbon (R2=0.718, P<0.001, n=13) and between the abundance of methanogenic archaea and the total nitrogen concentrations (R2=0.758, P<0.001, n=13) in wetland soils. This indicates that the amount of soil organic carbon may affect the population of methanogens in wetland ecosystems. While the CH4 production potential is not significantly related to methanogen population (R2=0.011, P>0.05, n=13), it is related to the dissolved organic carbon concentration (R2=0.305, P=0.05, n=13). This suggests that the methanogen population is not an effective index for predicting the CH4 production in wetland ecosystems. The CH4 production rate of the top soil layer increases with increasing latitude, from 274 μg CH4 kg−1 soil d−1 in the Poyang wetland to 665 μg CH4 kg−1 soil d−1 in the Carex lasiocarpa marsh of the Sanjiang Plain. The CH4 production potential in the freshwater wetlands of Eastern China is affected by the supply of methanogenic substrates rather than by temperature, whereas the supply of substrates was mainly affected by the position and stability of the wetland water table. In contrast, low summer temperatures at high elevations in the Ruoergai peatland of the Qinghai-Tibetan Plateau result in the presence of dominant species of methanogens with low CH4 production potential rather than the reduction of the supply of methanogenic substrates, which in turn suppresses CH4 production.

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40

Guinguina, Abdulai, Maria Hayes, Fredrik Gröndahl e Sophie Julie Krizsan. "Potential of the Red Macroalga Bonnemaisonia hamifera in Reducing Methane Emissions from Ruminants". Animals 13, n. 18 (15 settembre 2023): 2925. http://dx.doi.org/10.3390/ani13182925.

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Researchers have been exploring seaweeds to reduce methane (CH4) emissions from livestock. This study aimed to investigate the potential of a red macroalga, B. hamifera, as an alternative to mitigate CH4 emissions. B. hamifera, harvested from the west coast of Sweden, was used in an in vitro experiment using a fully automated gas production system. The experiment was a randomized complete block design consisting of a 48 h incubation that included a control (grass silage) and B. hamifera inclusions at 2.5%, 5.0%, and 7.5% of grass silage OM mixed with buffered rumen fluid. Predicted in vivo CH4 production and total gas production were estimated by applying a set of models to the gas production data and in vitro fermentation characteristics were evaluated. The results demonstrated that the inclusion of B. hamifera reduced (p = 0.01) predicted in vivo CH4 and total gas productions, and total gas production linearly decreased (p = 0.03) with inclusion of B. hamifera. The molar proportion of propionate increased (p = 0.03) while isovalerate decreased (p = 0.04) with inclusion of B. hamifera. Chemical analyses revealed that B. hamifera had moderate concentrations of polyphenols. The iodine content was low, and there was no detectable bromoform, suggesting quality advantages over Asparagopsis taxiformis. Additionally, B. hamifera exhibited antioxidant activity similar to Resveratrol. The findings of this study indicated that B. hamifera harvested from temperate waters of Sweden possesses capacity to mitigate CH4 in vitro.

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41

Sato, Yoshiaki, Kento Tominaga, Hirotatsu Aoki, Masayuki Murayama, Kazato Oishi, Hiroyuki Hirooka, Takashi Yoshida e Hajime Kumagai. "Calcium salts of long-chain fatty acids from linseed oil decrease methane production by altering the rumen microbiome in vitro". PLOS ONE 15, n. 11 (10 novembre 2020): e0242158. http://dx.doi.org/10.1371/journal.pone.0242158.

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Calcium salts of long-chain fatty acids (CSFA) from linseed oil have the potential to reduce methane (CH4) production from ruminants; however, there is little information on the effect of supplementary CSFA on rumen microbiome as well as CH4 production. The aim of the present study was to evaluate the effects of supplementary CSFA on ruminal fermentation, digestibility, CH4 production, and rumen microbiome in vitro. We compared five treatments: three CSFA concentrations—0% (CON), 2.25% (FAL) and 4.50% (FAH) on a dry matter (DM) basis—15 mM of fumarate (FUM), and 20 mg/kg DM of monensin (MON). The results showed that the proportions of propionate in FAL, FAH, FUM, and MON were increased, compared with CON (P < 0.05). Although DM and neutral detergent fiber expressed exclusive of residual ash (NDFom) digestibility decreased in FAL and FAH compared to those in CON (P < 0.05), DM digestibility-adjusted CH4 production in FAL and FAH was reduced by 38.2% and 63.0%, respectively, compared with that in CON (P < 0.05). The genera Ruminobacter, Succinivibrio, Succiniclasticum, Streptococcus, Selenomonas.1, and Megasphaera, which are related to propionate production, were increased (P < 0.05), while Methanobrevibacter and protozoa counts, which are associated with CH4 production, were decreased in FAH, compared with CON (P < 0.05). The results suggested that the inclusion of CSFA significantly changed the rumen microbiome, leading to the acceleration of propionate production and the reduction of CH4 production. In conclusion, although further in vivo study is needed to evaluate the reduction effect on rumen CH4 production, CSFA may be a promising candidate for reduction of CH4 emission from ruminants.

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42

Lachquer, Farah, e Jamil Toyir. "Mechanistic Study and Active Sites Investigation of Hydrogen Production from Methane and H2O Steady-State and Transient Reactivity with Ir/GDC Catalyst". Hydrogen 5, n. 4 (17 novembre 2024): 882–900. http://dx.doi.org/10.3390/hydrogen5040046.

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Catalytic activity, mechanisms, and active sites were determined for methane steam reforming (MSR) over gadolinium-doped ceria (GDC) supported iridium (0.1 wt%) prepared by impregnation of GDC with iridium acetylacetonate. Isothermal steady-state rate measurements followed by micro-gas chromatography analysis were performed at 660 and 760 °C over Ir/GDC samples pretreated in N2 or H2 at 900 °C. Transient responses to CH4 or H2O step changes in isothermal conditions were carried out at 750 °C over Ir/GDC pretreated in He or H2 using online quadrupole mass spectrometry. In the proposed mechanism, Ir/GDC proceeds through a dual-type active site associating, as follows: (i) Ir metallic particles surface as active sites for the cracking of CH4 into reactive C species, and (ii) reducible (Ce4+) sites at GDC surface responsible for a redox mechanism involving Ce4+/Ce3+ sites, being reduced by reaction with reactive C into CO (or CO2) depending on the oxidation state of GDC and re-oxidized by H2O. Full reduction of reducible oxygen species is possible with CH4 after He treatment, whereas only 80% is reached in CH4 after H2 treatment.

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Kalamaras, Sotirios D., Georgios Vitoulis, Maria Lida Christou, Themistoklis Sfetsas, Spiridon Tziakas, Vassilios Fragos, Petros Samaras e Thomas A. Kotsopoulos. "The Effect of Ammonia Toxicity on Methane Production of a Full-Scale Biogas Plant—An Estimation Method". Energies 14, n. 16 (16 agosto 2021): 5031. http://dx.doi.org/10.3390/en14165031.

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Abstract (sommario):

Ammonia accumulation in biogas plants reactors is becoming more frequently encountered, resulting in reduced methane (CH4) production. Ammonia toxicity occurs when N-rich substrates represent a significant part of the biogas plant’s feedstock. The aim of this study was to develop an estimation method for the effect of ammonia toxicity on the CH4 production of biogas plants. Two periods where a biogas plant operated at 3200 mg·L−1 (1st period) and 4400 mg·L−1 (2nd period) of ammonium nitrogen (NH4+–N) were examined. Biomethane potentials (BMPs) of the individual substrates collected during these periods and of the mixture of substrates with the weight ratio used by the biogas plant under different ammonia levels (2000–5200 mg·L−1 NH4+–N) were determined. CH4 production calculated from the substrates’ BMPs and the quantities used of each substrate by the biogas plant was compared with actual CH4 production on-site. Biogas plant’s CH4 production was 9.9% lower in the 1st and 20.3% in the 2nd period in comparison with the BMP calculated CH4 production, of which 3% and 14% was due to ammonia toxicity, respectively. BMPs of the mixtures showed that the actual CH4 reduction rate of the biogas plant could be approximately estimated by the ammonia concentrations levels.

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44

Lee, Jaesung, Rajaraman Bharanidharan, Junseok Oh, Seyun Im, Sang Yeob Kim, Namal Ranaweera, Kyoung Hoon Kim e Myunggi Baik. "PSXI-17 Comparison of enteric methane production between the respiration chamber and the CO2 method in Holstein heifers". Journal of Animal Science 102, Supplement_3 (1 settembre 2024): 760–61. http://dx.doi.org/10.1093/jas/skae234.858.

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Abstract The objective of this study was to validate the carbon dioxide (CO2) method (CO2T) in comparison with the respiration chamber (RC) method for the measurement of enteric methane (CH4) emission. The study was conducted over 108 d with Holstein heifers [n = 10; initial body weight (BW) = 178 kg; and age, 7.7 mo). The study consisted of 3 consecutive measurement periods and each period consisted of 21 d of feed adaptation followed by 15 d of CH4 measurement using the CO2T (3 d) and the RC method (12 d). The 55% timothy hay and 45% concentrate were fed twice daily at 1.2% to 1.5% of BW on an as-fed basis. The CO2T was used for 3 d during the morning and afternoon feeding. For the CO2T, CH4 and CO2 concentrations of exhaled breath from each animal were continuously analyzed by gas analyzers and recorded every 10 sec for 10 min per animal. The CH4:CO2 ratio of the data were calculated and multiplied by daily CO2 production of each animal to determine daily CH4 production. Right after the CO2T measurement, CH4 emission was measured using the RC method by the difference between the inlet and outlet CH4 concentration of the RC. Statistical analyses were performed using the software R version 4.0.4. Differences in dry matter intake (DMI), CH4 production, and CH4 yield between the two methods were tested using the Wilcoxon signed-rank test. DMI was not different between the RC method and the CO2T measurements. The CH4 production (L/d, L/kg BW0.75) and yield (L/kg DMI) determined by two methods were similar (127 vs 120 L/d, 2.05 vs 2.16 L/kg BW0.75, and 23.5 vs 21.6 L/kg DMI for RC vs CO2T, respectively). There was a positive relationship between DMI (kg/d) and CH4 production (L/d) for both of the RC method (R2 = 0.46, P < 0.05) and the CO2T (R2 = 0.72, P < 0.01). Linear regression analysis of CH4 production (L/d) between the RC method and the CO2T showed a moderate positive relationship (R2 = 0.52, P < 0.05). Pearson correlation analyses showed a strong relationship between the RC method and the CO2T for CH4 production (L/d; R2 = 0.72, P < 0.05). In conclusion, the CH4 production of Holstein heifers estimated by the CO2T did not differ from that measured by the RC method, and method agreement indices showed moderate positive correlations. The CO2 method could be used as one of the alternative CH4 measurement techniques comparable to the respiration chamber method.

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Zhang, G. B., Y. Ji, J. Ma, G. Liu, H. Xu e K. Yagi. "Pathway of CH4 production, fraction of CH4 oxidized, and 13C isotope fractionation in a straw-incorporated rice field". Biogeosciences 10, n. 5 (22 maggio 2013): 3375–89. http://dx.doi.org/10.5194/bg-10-3375-2013.

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Abstract. Straw incorporation generally increases CH4 emission from rice fields, but its effects on the mechanism of CH4 emission, especially on the pathway of CH4 production and the fraction of CH4 oxidized, are not well known. To investigate the methanogenic pathway, the fraction of CH4 oxidized as well as the stable carbon isotope fractionation during the oxidation and transport of CH4 as affected by straw incorporation, observations were conducted of production and oxidation of CH4 in paddy soil and rice roots and δ13C-values of produced CH4 and CO2, and emitted CH4 in incubation and field experiments. Straw incorporation significantly enhanced CH4 production potentials of the paddy soil and rice roots. However, it increased the relative contribution of acetate to total CH4 production (Fac) in the paddy soil by ∼10–30%, but decreased Fac-value of the rice roots by ∼5–20%. Compared with rice roots, paddy soil was more important in acetoclastic methanogenesis, with Fac-value being 6–30% higher. Straw incorporation highly decreased the fraction of CH4 oxidized (Fox) by 41–71%, probably attributed to the fact that it increased CH4 oxidation potential whereas CH4 production potential was increased to a larger extent. There was little CH4 formed during aerobic incubation, and the produced CH4 was more 13C-enriched relative to that of anaerobic incubation. Assuming δ13C-values of CH4 aerobically produced in paddy soil to be the δ13C-values of residual CH4 after being oxidized, (Fox-value still appeared to be 45–68% lower when straw was incorporated. Oxidation fractionation factor (αox) was higher with straw incorporation (1.033) than without straw incorporation (1.025). The δ13C-values of CH4 emitted after cutting of the plants (−50 to −43‰) were more positive than those of before (−58 to −55‰), suggesting a transport fractionation factor (&varepsilon;transport) was −8.0‰ with straw incorporation and −12.0‰ without straw incorporation. Causes of this difference may be related to the diffusion process in transport as affected by growth of rice plants and pressure in the rhizosphere. The experiment shows that straw incorporation increases the contribution of acetate to total methanogenesis in paddy soil but decreases it on rice roots, and it significantly decreases the fraction of CH4 oxidized in the field and expands oxidation fractionation while reducing transport fractionation.

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Prathap, Pragna, Surinder Singh Chauhan, Brian J. Leury, Jeremy James Cottrell e Frank Rowland Dunshea. "Towards Sustainable Livestock Production: Estimation of Methane Emissions and Dietary Interventions for Mitigation". Sustainability 13, n. 11 (28 maggio 2021): 6081. http://dx.doi.org/10.3390/su13116081.

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Abstract (sommario):

The increasing need for sustainable livestock production demands more research in the field of greenhouse gas (GHG), particularly methane (CH4), measurement and mitigation. Dietary interventions, management, and biotechnological strategies to reduce the environmental impacts and economic implications of enteric CH4 emissions are needed. While the use of biotechnological interventions and management strategies can be challenging on a routine basis, feed additive supplementation appears to be the most researched, developed, and ready to use strategy to mitigate enteric CH4 emissions. This paper discusses various recently developed feeding strategies to reduce enteric CH4 emissions in livestock. Additionally, the manuscript reviews various technologies developed for CH4 estimation since the accurate and reliable estimation of CH4 emissions can be a limiting step in the development and adoption of any mitigation strategy.

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Robles-Jimenez, Lizbeth E., Navid Ghavipanje, Ashley Ulloa, Ali Rivero, Pablo Gallardo e Manuel Gonzalez Ronquillo. "Sub-Antarctic Macroalgae as Feed Ingredients for Sustainable Ruminant Production: In Vitro Total Gas and Methane Production". Methane 3, n. 3 (27 agosto 2024): 456–65. http://dx.doi.org/10.3390/methane3030026.

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The sustainable meeting of the global quest for ruminant intensification dictates the need to identify alternative, eco-friendly, and safe feed ingredients. In this sense, macroalgae offer a new paradigm in sustainable ruminant feed supply. This study aimed to investigate the potential of sub-Antarctic macroalgae, including Lessonia flavicans, Macrocystis pyrifera, Gigartina skottbergii, and Ulva Lactuca, regarding their chemical composition, in vitro gas production, and CH4 production. A completely randomized design consisted of a 96 h (h) incubation that included four different species and a control (alfalfa hay) with buffered rumen fluid. In vitro total gas, fermentation characteristics, and CH4 production were evaluated. The highest and the lowest crude protein (CP) contents were for U. lactuca (185.9 g/kg) and G. skottsbergi (86 g/kg), respectively (p < 0.0001). All macroalage had lower levels of natural detergent fiber (NDF) and acid detergent fiber (ADF) compared to alfalfa hay (p < 0.0001). The highest potential of gas production (b) was for M. pyriphera (162.8 mL gas/g DM), followed by alfalfa (119.3 mL gas/g DM). However, G. skottsbergi and M. pyriphera showed the highest dry matter degradability at 96 h (68.49 and 67.62 mg/100 mg, respectively; p < 0.0001) and microbial crude protein (679.8 and 669.8 mg/g, respectively, p < 0.0001). All four tested algae produced lower amounts of methane compared to alfalfa hay (p < 0.0001). After 24 h of incubation, M. pyriphera, L. flavicons, G. skottsbergi, and U. lactuca reduced CH4 by 99.7%, 98.6%, 92.9%, and 79.8%, respectively, when compared with the control. Also, all tested algae had lower (p = 0.0001) CH4 production (ml CH4/g Dry matter degradability, DMD) than alfalfa hay. The current results suggest that M. pyriphera and L. flavicons are promising feed additives for ruminants with eco-friendly production and acceptable CP content and DMD that could effectively mitigate CH4 emissions. Overall, these findings suggest that macroalgae hold promise as a substitute feed source for sustaining ruminant production at the onset of global warming.

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48

Boontanon, N., S. Watanabe, T. Odate e N. Yoshida. "Methane production, consumption and its carbon isotope ratios in the Southern Ocean during the austral summer". Biogeosciences Discussions 7, n. 5 (29 settembre 2010): 7207–25. http://dx.doi.org/10.5194/bgd-7-7207-2010.

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Abstract. The distribution of dissolved CH4 in the Southern Ocean at 140° E was measured during the austral summer. Surface CH4 was supersaturated on average, and the calculated mean sea-air flux rate was 0.32 μmol m−2 d−1. The vertical distributions exhibited a CH4 maximum at approximately 125 m (ΔCH4, 2.94 nM) below the chlorophyll-rich layer, suggesting a relationship between CH4 production and plankton dynamics in this area. CH4 oxidation and ocean movement characteristics in the deep layer led to the enrichment and fluctuation of δ13CCH4. We estimated the influence of Southern Ocean CH4, a source of isotopically heavy CH4 to the atmosphere, on the global CH4 budget to be approximately 0.19 Gg d−1.

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49

Alvarado-Ramírez, Edwin Rafael, Aristide Maggiolino, Mona M. M. Y. Elghandour, Marco Antonio Rivas-Jacobo, Gilberto Ballesteros-Rodea, Pasquale De Palo e Abdelfattah Z. M. Salem. "Impact of Co-Ensiling of Maize with Moringa oleifera on the Production of Greenhouse Gases and the Characteristics of Fermentation in Ruminants". Animals 13, n. 4 (20 febbraio 2023): 764. http://dx.doi.org/10.3390/ani13040764.

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The objective of this experiment was to evaluate the impact of maize co-ensiling with increasing percentages of MOL forage on the kinetics of biogas, methane (CH4), carbon monoxide (CO) and hydrogen sulfide (H2S) production, as well as the characteristics of ruminal fermentation and CH4 conversion efficiency, using steers (STI) and sheep (SHI) as inoculum sources. With the STI, the inclusion of MOL reduced (linear: p ≤ 0.0199; quadratic: p ≤ 0.0267) biogas production (mL g−1 DM incubated and degraded), CH4 (mL g−1 DM degraded), CO (mL g−1 DM degraded), and H2S (mL g−1 DM incubated and degraded), without affecting (p > 0.05) the parameters (b = asymptotic gas, c = rate of gas production and Lag = initial delay time before gas production) of CH4 and H2S, and the proportion and production of CH4 per kg of dry matter (DM). In addition, with this inoculum, pH, and dry matter degradation (DMD) increased (linear: p ≤ 0.0060), and although short-chain fatty acids (SCFA) and metabolizable energy (ME) decreased (linear: p < 0.0001; quadratic: p ≤ 0.0015), this did not affect (p > 0.05) the CH4 conversion efficiency. Meanwhile, with the SHI, the inclusion of MOL only decreased (linear: p ≤ 0.0206; quadratic: p ≤ 0.0003) biogas per dry matter (DM) degraded and increased (linear: p ≤ 0.0293; quadratic: p ≤ 0.0325) biogas per DM incubated, as well as the production (mL g−1 DM incubated and degraded and g−1 kg DM) and proportion of CH4, and CO per DM incubated and degraded. In addition, it did not impact (p > 0.05) on the CH4 and H2S parameters, and in the H2S by DM incubated and degraded, and although it increased (linear: p ≤ 0.0292; quadratic: p ≤ 0.0325) the DMD, SCFA, and ME, it was inefficient (quadratic: p ≤ 0.0041) in CH4 conversion. It is concluded that regardless of the percentage of MOL, the STI presented the highest values in the production of biogas, CH4, H2S, DMD, SCFA, and ME, and the lowest pH, so it turned out to be the most efficient in CH4 conversion, while with the SHI only the highest production of CO and pH was obtained, and the lowest DMD, SCFA, and ME, so it was less efficient compared to STI.

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50

Sypniewski, Mateusz, Tomasz Strabel e Marcin Pszczola. "Genetic Variability of Methane Production and Concentration Measured in the Breath of Polish Holstein-Friesian Cattle". Animals 11, n. 11 (6 novembre 2021): 3175. http://dx.doi.org/10.3390/ani11113175.

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The genetic architecture of methane (CH4) production remains largely unknown. We aimed to estimate its heritability and to perform genome-wide association studies (GWAS) for the identification of candidate genes associated with two phenotypes: CH4 in parts per million/day (CH4 ppm/d) and CH4 in grams/day (CH4 g/d). We studied 483 Polish Holstein-Friesian cows kept on two commercial farms in Poland. Measurements of CH4 and carbon dioxide (CO2) concentrations exhaled by cows during milking were obtained using gas analyzers installed in the automated milking system on the farms. Genomic analyses were performed using a single-step BLUP approach. The percentage of genetic variance explained by SNPs was calculated for each SNP separately and then for the windows of neighbouring SNPs. The heritability of CH4 ppm/d ranged from 0 to 0.14, with an average of 0.085. The heritability of CH4 g/d ranged from 0.13 to 0.26, with an average of 0.22. The GWAS detected potential candidate SNPs on BTA 14 which explained ~0.9% of genetic variance for CH4 ppm/d and ~1% of genetic variance for CH4 g/d. All identified SNPs were located in the TRPS1 gene. We showed that methane traits are partially controlled by genes; however, the detected SNPs explained only a small part of genetic variation—implying that both CH4 ppm/d and CH4 g/d are highly polygenic traits.

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