Methane Emission Intensity Research Articles

Whole cottonseed supplementation improves performance and reduces methane emission intensity of grazing beef steers

<h2>ABSTRACT</h2> The objective of this experiment was to determine the effect of level of whole cottonseed (WCS) supplementation on ADG and enteric CH₄ emissions of steers grazing tallgrass prairie in the summer. Steers (n = 18; initial BW=316 ± 23 kg) were trained for 3 wk to use a portable, automated head-chamber system (GreenFeed; C-Lock Inc., Rapid City, SD). Steers were then offered from 0 to 2.9 kg/d (as fed) WCS in individual feeders for 43 d. Body weight was measured weekly before feeding. Total fat concentration of the diet (supplement + forage) at the greatest supplement intake was estimated to be 8.3% of DM. Body weight gain increased linearly as supplement intake increased (<i>P</i> = 0.01). Because of inadequate use of the automated head-chamber system by steers at the 0-kg WCS level, this level was excluded from further analysis. In supplemented steers, there was a tendency (<i>P</i> = 0.1) for a quadratic relationship between CH₄ emissions (g/animal per d) and supplement intake, with minimum CH₄ at 2.0 kg of supplement (WCS + bait) per day. Emission intensity (g of CH₄/kg of BW gain) also responded quadratically (<i>P</i> < 0.004) and was minimized at approximately 2.2 kg of supplement intake per day. The results of this experiment suggest that if WCS supplementation is used to mitigate CH₄ emission intensity in stocker cattle grazing tallgrass prairie in the early summer, a dose near 2 kg/d is suggested.

Effects of grass silage quality and level of feed intake on enteric methane production in lactating dairy cows.

The objective of this study was to determine the effect of level of feed intake and quality of ryegrass silage as well as their interaction on enteric methane (CH) emission from dairy cows. In a randomized block design, 56 lactating dairy cows received a diet of grass silage, corn silage, and a compound feed meal (70:10:20 on DM basis). Treatments consisted of 4 grass silage qualities prepared from grass harvested from leafy through late heading stage, and offered to dairy cows at 96 ± 2.4 (mean ± SEM) days in milk (namely, high intake) and 217 ± 2.4 d in milk (namely, low intake). Grass silage CP content varied between 124 and 286 g/kg of DM, and NDF content between 365 and 546 g/kg of DM. After 12 d of adaptation, enteric CH production of cows was measured in open-circuit climate-controlled respiration chambers for 5 d. No interaction between DMI and grass quality on CH emission, or on milk production, diet digestibility, and energy, and N retention was found ( ≥ 0.17). Cows had a greater DMI (16.6 vs. 15.5 kg/d; SEM 0.46) and greater fat- and protein-corrected milk (FPCM) yield (29.9 vs. 25.4 kg/d; SEM 1.24) at high than low intake (both ≤ 0.001). Apparent total-tract nutrient digestibility was not affected ( ≥ 0.08) by DMI level. Total enteric CH production (346 ± 10.9 g/d) was not affected ( = 0.15) by DMI level. A small, significant ( = 0.025) decrease at high compared with low intake occurred for CH yield (21.8 ± 0.59 g/kg of DMI; -4%). Methane emission intensity (12.8 ± 0.56 g/kg of FPCM; -12%) was considerably smaller ( ≤ 0.001) at high intake as a result of greater milk yields realized in early lactation. As grass quality decreased from leafy through late heading stage, FPCM yield and apparent total-tract OM digestibility declined (-12%; ≤ 0.015), whereas total CH production (+13%), CH yield (+21%), and CH emission intensity (+28%) increased ( ≤ 0.001). Our results suggest that improving grass silage quality by cutting grass at an earlier stage considerably reduces enteric CH emissions from dairy cows, independent of DMI. In contrast, losses of N in manure increased for the earlier cut grass silage treatments. The small increase in DMI at high intake was associated with a small to moderate reduction in CH emission per unit of DMI and GE intake. This study confirmed that enteric CH emissions from dairy cows at distinct levels of feed intake depend on the nutritive value and chemical composition of the grass silage.

A comparison of policies to reduce the methane emission intensity of smallholder dairy production in India

Within the dairy sector, the effects of climate change are particularly diverse as cows are affected by, and a significant contributor to climate change. With a burgeoning body of work indicating the importance of livestock’s contribution to climate change (via Greenhouse Gas (GHG) emissions), the dairy sector will increasingly be targeted for emission reduction. Yet, gaps in knowledge remain as to the effectiveness of interventions in achieving emission reductions. The investigation examines two high-profile Indian policies to evaluate their effectiveness in reducing the methane emission intensity of milk production in Odisha, India. Selected policies included the installation of smallscale anaerobic digesters and the control of Foot and Mouth Disease (FMD). The interventions were evaluated at the cow level informed by data collected from 115 smallholder dairy producers in Puri (n = 31) and Khurda (n = 84) districts in Odisha, India. The installation of an anaerobic digester was found to increase methane emission intensity by 4.41–5.01%. Control of FMD reduced methane emission intensity by 3.68–12.95% depending on the infection scenario considered. The findings highlight the importance of contextually relevant and multi-sectoral approaches to mitigation as the increase in methane emission intensity following anaerobic digester installation represents movement of emissions from the energy sector into the dairy sector where mitigation is inherently more complex. Thus, the long-term usefulness of anaerobic digester installation as a mitigation strategy is limited.

Development of nitrogen and methane losses in the first eight weeks of lactation in Holstein cows subjected to deficiency of utilisable crude protein under restrictive feeding conditions

ABSTRACTLow-protein diets are increasingly being used in dairy cow nutrition to minimise noxious nitrogen (N) emissions. However, at parturition, the lower milk yield at that time may mask deficiency in dietary utilisable crude protein (uCP; equivalent to metabolisable protein). Under restrictive feeding conditions, farmers would limit the feed allowance to match the lower measured milk yield, thereby exacerbating the deficiency. The consequences for N emission intensity per kg milk yield and methane emissions are unknown. In this study, two diets were fed to nine Holstein cows each from parturition onwards. One diet was complete and the other was calculated as 20% deficient in uCP. Feed allowance was always oriented towards the measured milk yield. In each of the first eight lactation weeks, intake and excretion were measured for 5 d. On the last 2 d of this period, methane emission was measured in respiration chambers. The statistical model included treatment, week and interaction as effects. The real levels of uCP and energy supply across the 8 weeks were 33% and 15% below requirements, respectively, in the Deficient cows. In addition, the Deficient cows consumed 18% less dry matter (caused by substantial refusals in week 1, where energy supply was according to requirements) and produced 25% less milk (26 vs. 34 kg/d). Cows in both groups used dietary N with similar efficiency for milk protein synthesis and excreted similar proportions of the N ingested via urine and faeces. This resulted in both treatments having similar N emission intensities per kg milk N and similar urinary N as a proportion of total excreta N, suggesting a similar potential for gaseous N emissions from the manure per kg of milk. The Deficient cows emitted 22% less methane overall but had similar methane yield and emission intensity to the Controls. In conclusion, a reduction in crude protein intake immediately after parturition does not reduce N emission per unit of milk when associated with uCP deficiency.

Model-based analysis of CO2 revalorization for di-methyl ether synthesis driven by solar catalytic reforming

The application of solar energy is investigated for the synthesis of di-methyl ether (DME) in a solar irradiated dry methane reformer (DMR). Solar radiations are concentrated onto a receiver and distributed to the reaction zone to provide necessary energy for syngas (CO and H2) generation. In order to maintain a H2/CO molar ratio of ‘1’, as required in DME synthesis, the produced syngas is processed via two alternative routes: solar reformer coupled in parallel with a non-solar reformer (SoR-NSoR) and solar reformer integrated with a water-gas shift reactor (SoR-WGS). It is found that steam methane reforming (SMR) is the most suitable methodology when coupled with a solar reformer due to high H2 content in the SMR syngas. Further performance analysis is conducted by simulating three days of operation under different insolation levels (high, medium and low irradiations). The simulation results showed that the SoR-WGS configuration produces the highest improvements of 18.7%, 32.2% and 20% in terms of methane, energy and CO2 emission intensity respectively. This enhanced process performance originates from the exothermic nature of the WGS process which helps in controlling the overall syngas composition, whereas the SoR-NSoR requires fossil based thermal energy to drive the NSoR process to similar control targets. This promising improvement of all metrics in SoR-WGS may stimulate in-depth techno-economic feasibility of this unique solar integration for DME and other synthetic fuels production.

Prioritizing climate-smart livestock technologies in rural Tanzania: A minimum data approach

Crop-livestock production systems play an important role in the livelihoods of many rural communities in sub-Saharan Africa (SSA) but are vulnerable to the adverse impacts of climate change. Understanding which farming options will give the highest return on investment in light of climate change is critical information for decision-making. While there is continued investment in testing adaptation options using on-farm experiments, simulation models remain important tools for ‘ex-ante’ assessments of the impacts of proposed climate-smart agricultural technologies (CSA). This study used the Ruminant model and the Trade-offs Analysis model for Multi-Dimensional Impact Assessment (TOA-MD) to assess how improved livestock management options affect the three pillars of CSA: increased productivity, improved food security, and reduced greenhouse gas (GHG) emissions. Our sample was stratified into: 1) households with local cow breeds (n=28); 2) households with improved dairy cow breeds (n=70); and 3) households without dairy cows (n=66). Results showed that the predicted adoption rates for improved livestock feeding among households with improved dairy cows (stratum 2) were likely to be higher compared to households with only local cows (stratum 1). Both households with local cows and those with improved cows had increased income and food security. However, overall poverty reduction was only modest for households with local cows. Expected methane emissions intensity declined with adoption of improved livestock feeding strategies both in stratum 1 and stratum 2, and greater impacts were observed when households in stratum 2 received an additional improved cow breed. Providing a cow to households that were not keeping cows showed substantial economic gains. Additional research is, however, needed to understand why those farms currently do not have cows, which may determine if the predicted adoption rates are feasible.

Daily methane emissions and emission intensity of grazing beef cattle genetically divergent for residual feed intake

As daily methane production (DMP; g CH4/day) is strongly correlated with dry matter intake (DMI), the breeding of cattle that require less feed to achieve a desired rate of average daily gain (ADG) by selection for a low residual feed intake (RFI) can be expected to reduce DMP and also emission intensity (EI; g CH4/kg ADG). An experiment was conducted to compare DMP and EI of Angus cattle genetically divergent for RFI and 400-day weight (400dWT). In a 6-week grazing study, 64 yearling-age cattle (30 steers, 34 heifers) were grazed on temperate pastures, with heifers and steers grazing separate paddocks. Liveweight (LW) was monitored weekly and DMP of individual cattle was measured by a GreenFeed emission monitoring unit in each paddock. Thirty-nine of the possible 64 animals had emission data recorded for 15 or more days, and only data for these animals were analysed. For these cattle, regression against their mid-parent estimated breeding value (EBV) for post-weaning RFI (RFI-EBV) showed that a lower RFI-EBV was associated with higher LW at the start of experiment. Predicted dry matter intake (pDMI), predicted DMP (pDMP) and measured DMP (mDMP) were all negatively correlated with RFI-EBV (P &lt; 0.05), whereas ADG, EI, predicted CH4 yield (pMY; g CH4/kg DMI) were not correlated with RFI-EBV (P &gt; 0.1). Daily CH4 production was positively correlated with animal LW and ADG (P &lt; 0.05). The associations between ADG and its dependent traits EI and pMY and predicted feed conversion ratio (kg pDMI/kg ADG) were strongly negative (r = –0.82, –0.57 and –0.85, P &lt; 0.001) implying that faster daily growth by cattle was accompanied by lower EI, MY and feed conversion ratio. These results show that cattle genetically divergent for RFI do not necessarily differ in ADG, EI or pMY on pasture and that, if heavier, cattle with lower RFI-EBV can actually have higher DMP while grazing moderate quality pastures.

Biological implications of longevity in dairy cows: 2. Changes in methane emissions and efficiency with age

Previous studies indicated that absolute CH4 emissions and CH4 yield might increase and that milk production efficiency might decrease with age in cattle. Both would make strategies to increase longevity in dairy cattle less attractive. These aspects were experimentally determined in Brown Swiss cattle distributed continuously across a large age range. Thirty lactating dairy cows (876–3,648 d of age) received diets consisting of hay, corn silage, and grass pellets supplemented with 0 or 5kg of concentrate per day. Twelve heifers (199–778 d of age) received hay only. Cows and heifers were members of herds subjected to the 2 different feeding regimens (with or without concentrate) for the past 10 yr. Methane emissions were measured individually for 2 d in open-circuit respiration chambers, followed by quantifying individual feed intake and milk yield over 8 d. Additional data on digestibility, rumination time, and passage time of feed of all experimental animals were available. Regression analyses were applied to evaluate effects of age and feeding regimen. Body weight, milk yield, and the hay proportion of forage dry matter intake were considered as covariates. Methane emissions per unit of intake, body weight, and milk yield were significantly related to age. Their development in the cows with age was characterized by an increase to maximum at around 2,000 d of age, followed by a decline. This response was not accompanied by corresponding age-related changes in intake, chewing activity, digesta passage time, and digestibility of organic matter, which would have explained shifts in CH4. However, fiber digestibility showed a similar change with age as methane emissions, resulting in quite stable methane emissions per unit of digestible fiber. As expected, methane emissions intensity per unit of milk produced was greater by 8% without concentrate than with concentrate, but no difference was noted in the response to age when the animals were subjected to different feeding regimens. The efficiency of milk production was only marginally influenced by age and diet, and no different response was observed for age in the 2 dietary regimens. In conclusion, life cycle analyses of milk production systems focusing on longevity should consider changing methane yields with age in addition to the variation in environmental costs for replacements of culled cows.

&amp;lt;i&amp;gt;In Vitro&amp;lt;/i&amp;gt; Evaluation of the Antimethanogenic Potency and Effects on Fermentation of Individual and Combinations of Marine Macroalgae

Contribution of ruminants to total greenhouse gas emissions in Australia is approximately 10% and likely to increase with demand for livestock products, thus an efficient method of mitigation must be implemented. The red marine macroalgae Asparagopsis taxiformis reduces enteric methane production by up to 99% in vitro. Other macroalgae with less potent antimethanogenic properties may complement inclusion of Asparagopsis in livestock feeds. Adoption of environmental based changes in livestock systems must provide benefits to producers if change in management is to be adopted. This study used 72 h in vitro fermentations with rumen inoculum to characterize and rank seven species of macroalgae at low inclusion that previously demonstrated some degree of antimethanogenesis at higher inclusion concentration. The seven were assessed at 5% inclusion (OM basis) and in combination with Asparagopsis to evaluate beneficial effects on fermentation. When tested individually, improvements in volatile fatty acids were generally observed, however, minimal effect on gas production and no clear justification for a ranking order were demonstrated. When tested in combination with Asparagopsis, the effects on fermentation were dominated by presence of Asparagopsis at 2% and no further benefits demonstrated. Therefore, Asparagopsis remains the only macroalga inducing near elimination of methane in vitro and benefit of combinations with other macroalgae evaluated in this study was not demonstrated. However, combination with high protein macroalgae is proposed to provide productivity enhancement during seasonal lows in grass quality and thus reduce methane emissions intensity providing a stronger conduit for environmental responsibility while increasing productivity.

Effect of rice cultivars on yield-scaled methane emissions in a double rice field in South China

Rice cultivar is the most influential factor affecting methane emissions from double rice fields. A two-year field experiment was conducted at Huizhou, Guangdong province, South China, to identify from among nine cultivars those cultivars with high-yield potential and lower yield-scaled methane emissions (YSMEs). Methane emissions were measured using the static chamber – gas chromatograph method. Results indicate that the cultivars Qihuazhan (QH), Yexianzhan 8 (YX8) and Yue’erzhan (YE) provide higher rice grain yield (8.69%) with lower YSME (30.27%) compared to the other six cultivars (Yexianzhan 6, Yuejingsimiao, Hefengzhan, Huangsizhan, Huangruanzhan and Huangxiuzhan) (p < 0.05). In particular, QH has the highest yield potential (6777 kg ha−1) and lowest methane emission intensity (0.36 kg kg−1 yield) capacity. Methane emissions from the double rice field was found to be significantly (p < 0.05) and positively correlated with tiller number, culm biomass and soil organic matter, dissolved soil organic carbon and total carbon content, but negatively correlated (p < 0.05) with rice harvest index (HI), and root and panicle biomass, suggesting that organic source strength provides the substrate of methane production while the oxidation potential in the rhizosphere and the methane transport capacity of rice roots and culm dominate the emissions of methane from soil to the atmosphere. Multivariate decision regression tree (DRT) analysis showed a significant class difference between QH, YX8 and YE with the other six cultivars. These three cultivars are suitable for promotion of low carbon agriculture in South China. DRT analysis also successfully illustrated a potential way to identify rice varieties for low YSME by decisive parameters of tiller number (<15), HI (>0.43) and nitrogen assimilation of leaves (<40). These findings suggest that optimization of rice cultivars may represent an effective way to address both food demand and climate change concerns by improving rice yields while simultaneously minimizing the impact of climate change per unit yield.

Effect of technical cashew nut shell liquid on rumen methane emission and lactation performance of dairy cows

Technical-grade cashew nut shell liquid (TCNSL) is a by-product of the cashew nut industry in tropical countries, and is known to exhibit a wide range of biological activities, including inhibitory effect against gram-positive bacteria. This study was conducted to investigate the effects of TCNSL (73.3% cardanol, 16.4% cardol, and 3.0% methylcardol) on rumen methane emission, nutrient digestibility, dry matter intake, and milk yield and composition in dairy cows. Eight multiparous Holstein cows were used in a crossover design trial with two 21-d experimental periods. The diet was based on corn silage and alfalfa haylage and was formulated to meet or exceed the energy and metabolizable protein requirements of the cows. Treatments were control (no TCNSL supplementation) or 30g/cow per day of TCNSL. Rumen carbon dioxide emission was not affected by TCNSL. Treatment had no effect on methane emission (542 vs. 511±35.3g/cow per day, respectively) and methane emission intensity (15.0 vs. 13.9±0.58g/kg of energy-corrected milk, respectively) and tended to decrease methane emission per kilogram of dry matter intake (20.2 vs. 18.6±1.04g/kg, respectively). Dry matter intake (average 26.9±1.00kg/d), milk yield (40.0±1.73kg/d), and milk composition were not different between treatments. The TCNSL had no effect on N losses in urine and feces and total-tract apparent digestibility of nutrients, except digestibility of neutral detergent fiber tended to be increased compared with the control. Plasma urea and glucose concentrations were not affected by TCNSL. Concentration of milk C18:0 tended to be decreased (17%) by TCNSL compared with the control. In this study, TCNSL did not alter absolute methane emission in the rumen, but tended to decrease it by 8% per kilogram of dry matter intake. The TCNSL had no effect on milk yield and composition in dairy cows.

The relevance of methane emissions from beef production and the challenges of the Argentinean beef production platform

The livestock sector faces the challenge to respond to the growing demand for animal protein from an expanding population while reducing environmental impact through GHG emissions. Globally about 2.836milliontons of CO2-eq were emitted by the beef production sector equivalent to 46,2kgCO2-eq per kg carcass weight (CW). From the 1.485million cattle head spread out over the world, 82% are on extensive grazing systems while only 18% are on high productive intensive systems. Among the top ten beef exporter countries, five are located in Latin America accounting a quarter of the global stock and two of them, Argentina and Uruguay, produce on temperate pastures under grazing systems. In Argentina, the livestock area was reduced in favor of increasing the grain cropping area, which took place in the last two decades. Production systems were intensified to maintain cattle stock. Cattle programs changed from 100% pasture to pasture supplemented with cereal grains and conserved forages, and confinement on grain feeding for fattening was incorporated. Due to land sharing competition with cash crops, no increment of cattle stock is expected therefore improving production efficiency appears as the only way to increase beef production while reducing methane emissions intensity. Beef produced on intensive grazing systems on supplemented pastures maintained organoleptic, nutritional and lipid profile than that of beef produced on pure grazing systems.

Climate change and broadacre livestock production across southern Australia. 3. Adaptation options via livestock genetic improvement

Climate change is predicted to reduce the productivity of the broadacre livestock industries across southern Australia; to date there has been no formal evaluation of the potential of genetic improvement in cattle or sheep to ameliorate the impacts of changing climates. We used the GRAZPLAN simulation models to assess selection of five traits of sheep and cattle as adaptation options under the SRES A2 global change scenario. Analysis of the breeding strategies was carried out for 25 representative locations, five livestock enterprises and three future years (2030, 2050, 2070). Uncertainty in future climates was taken into account by considering projected climates from four global circulation models. For three sheep enterprises, breeding for greater fleece growth (at constant body size) was predicted to produce the greatest improvements in forage conversion efficiency, and so it was the most effective genetic adaptation option. For beef cow and steer enterprises, breeding for larger body size was most effective; for beef cows, however, this conclusion relied on per-animal costs (including provision of bulls) remaining stable as body size increases. Increased conception rates proved to be less effective but potentially viable as an adaptation in beef cow and crossbred ewe enterprises. In the southern Australian environments that were analysed, our modelling suggests that breeding for tolerance to heat stress is unlikely to improve the performance of livestock production systems even at 2070. Genetic improvement of livestock was able to recover much less of the impact of climate change on profitability at drier locations where the need for adaptation is likely to be greatest. Combinations of feedbase and livestock genetic adaptations are likely to complement one another as the former alter the amount of forage that can be consumed, while the latter affect the efficiency with which consumed forage is converted to animal products. Climate change impacts on pasture production across southern Australia are likely to have only small effects on methane emissions intensity, as are a range of candidate genetic and feedbase adaptations to climate change; methane emissions per hectare in future climates will therefore be driven mainly by changes in livestock numbers due to alterations in pasture productivity.

Investigation of parameterization effect on the methane flux estimation from the regional climate model of the main geophysical observatory for the territory of Russia

An effect is studied of parameterization method of the methane flux from the wetlands of Siberia on the results of model estimates carried out using the one-dimensional model of heat transfer in the soils. The results of computations of the regional climate model of the Main Geophysical Laboratory are used as the input data of this model. The computation estimates of seasonal methane flux variations at certain observation points are compared with the measured values of the methane flux. It is shown that the optimal choice of methane flux parameterization at the use of the grid climate model data as the forcing should correspond to the conditions of prevailing subgrid natural complex of one or another type of wetlands. A spatial distribution of methane emission intensity under conditions of the present-day climate and at the end of the 21st century is obtained. The analysis revealed that the methane fluxes in Western Siberia will increase by 1.5–2.5 times by the end of the 21st century.

Potential effects of animal management and genetic improvement on enteric methane emissions, emissions intensity and productivity of sheep enterprises at Cowra, Australia

The efficacy of technologies to reduce enteric CH4 emissions from ruminants are typically evaluated on individual animals with little consideration of enterprise scale impacts. While impacts of the many rumen manipulations being studied are hard to anticipate, there is adequate information to assess impacts of farm management changes and potential animal genetic changes on whole farm productivity and enteric CH4 emissions. Seven common sheep production systems grazing an annual pasture in central New South Wales, Australia, were modelled using GrassGro® (version 3.1.2). A range of animal management and animal genetic strategies were examined for their impact on total enteric emissions, emission intensity (i.e., kg CO2 equivalent/kg live weight (LW) of animal sold) and profit. Within enterprises, mitigation options were compared at their respective sustainable economic optimum stocking rate as it was assumed that farmers would seek to achieve the highest sustainable profit achievable from a finite land resource. Management options considered were choice of lambing time, mating ewes for the first time as lambs rather than yearlings, and feeding lambs to reduce time to slaughter. The potential for using selective animal breeding was also tested, with sheep physiological parameters being altered in GrassGro® to represent genetic improvement in fecundity, LW gain, residual feed intake and CH4 yield. In general, the management choices delivering lowest emission intensity were also the most profitable within sustainability constraints. Mating maiden ewes as lambs was only effective in reducing enterprise emissions intensity in self-replacing flocks (i.e., no purchased replacements). When stocking rates were at the sustainable economic optimum, choice of enterprise or management had little influence on total enteric emissions from the enterprise. If decisions are guided solely by economics, farmers are likely to continue with similar levels of production (and emissions) until a price on enteric CH4 emissions makes the sheep enterprise unprofitable, or an alternative more profitable enterprise than sheep grazing emerges. Improving animal genetics for residual feed intake or CH4 yield offers opportunity to reduce enterprise emissions, but industry progress toward higher genetic merit for these traits is expected to be slow due to relatively low heritability and competing economic imperatives for progress in other traits.This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

Methane emissions from a dairy feedlot during the fall and winter seasons in Northern China

Accurately determining methane emission factors of dairy herd in China is imperative because of China’s large population of dairy cattle. An inverse dispersion technique in conjunction with open-path lasers was used to quantify methane emissions from a dairy feedlot during the fall and winter seasons in 2009–2010. The methane emissions had a significant diurnal pattern during both periods with three emission peaks corresponding to the feeding schedule. A 10% greater emission rate in the fall season was obtained most likely by the higher methane emission from manure during that period. An annual methane emission rate of 109 ± 6.7 kg CH 4 yr −1 characterized with a methane emission intensity of 32.3 ± 1.59 L CH 4 L −1 of milk and a methane conversion factor ( Y m) of 7.3 ± 0.38% for mature cattle was obtained, indicating the high methane emission intensity and low milk productivity in Northern China.

Diurnal and Seasonal Patterns of Methane Emissions from a Dairy Operation in North China Plain

In China, dairy cattle managed in collective feedlots contribute about 30% of the milk production and are believed to be an important contributor to national methane emissions. Methane emissions from a collective dairy feedlot in North China Plain (NCP) were measured during the winter, spring, summer, and fall seasons with open-path lasers in combination with an inverse dispersion technique. Methane emissions from the selected dairy feedlot were characterized by an apparent diurnal pattern with three peaks corresponding to the schedule of feeding activities. On a per capita basis, daily methane emission rates of these four seasons were 0.28, 0.32, 0.33, and 0.30 kg head−1 d−1, respectively. In summary, annual methane emission rate was 112.4 kg head−1 yr−1associated with methane emission intensity of 32.65 L CH4L−1of milk and potential methane conversion factor Ymof 6.66% of gross energy intake for mature dairy cows in North China Plain.

Methane emission from the oligotrophic bog massif in the Northwestern Russia

Results of measuring methane emissions from the Lammin-Suo oligotrophic bog massif are considered. It is shown that emission intensity depends on the methane transport from the active layer of the peat bed. The highest emission intensity is observed in the sedge-sphagnum microlandscape and over swampy hollows of the hummock-ridge complex. It is found that the methane flux intensity approaches zero when the wetland level drops by 30–35 cm from the bog surface. Spatial methane emission variability is estimated within dominating bog landscapes. The methane emission reaches its maximum values (207%) in microlandscapes with oriented microrelief (hummock-ridge complex); in the central bog (sphagnum-suffrutescent-cottongrass landscape afforested with pine), it reaches its lowest level (76%). A model of methane emissions from bogs is developed. The model has been verified from the observational data. The comparison of model calculations with experimental data is indicative of their good agreement, which makes it possible to use the model in different calculations and assessments of the influence of natural factors on the methane emission intensity.

Global Warming and the Neglected Greenhouse Gas: A Cross-National Study of the Social Causes of Methane Emissions Intensity, 1995

The human dimensions of greenhouse gas emissions and global warming attract considerable attention in macrosociology. However, cross-national analyses generally neglect greenhouse gases other than carbon dioxide. The current study addresses this paucity through the testing of theoretically derived models for the social structural causes of the second largest anthropogenic contributor to global warming: methane emissions intensity. The cross-national analyses consider the effects of particular economic activities and their social organization as well as other domestic conditions and the environmental commitment of nation states. Results suggest that both the intensity and social organization of production in different sectors contribute to methane emissions per capita. In particular, the production of beef and veal, oil and natural gas, and biomass energy all positively affect methane emissions intensity. Evidence indicates that while the level of economic development and foreign direct investment in the manufacturing and petroleum sectors increases emissions, the level of state environmentalism has the opposite effect. These findings illustrate the necessity for social scientists to take more nuanced approaches when studying human-caused environmental degradation.