Share Of Biomass Research Articles

Warming Increases Ecological Niche of Leymus chinensis but Is Detrimental to Species Diversity in Inner Mongolia Temperate Grasslands

Dominant species are crucial in regulating the structure and productivity of plant communities. Adaptation strategies to climate change vary among the dominant species of different life types. However, the responses of the ecological niches of dominant species to warming and precipitation in semi-arid grasslands and their impacts on community structure and function are unknown. This study involved conducting a long-term experimental simulation of warming and increased precipitation on grasslands in Inner Mongolia and studying population dynamics, ecological niches, and their responses to the structure and function of the community species of two dominant plants, L. chinensis (perennial rhizome grass) and S. krylovii (perennial clumped grass). The results show that the niche width of L. chinensis increased and S. krylovii decreased under warming and increased precipitation conditions. The overlap of L. chinensis and S. krylovii decreased under the same conditions. The niche widths of L. chinensis and S. krylovii were 1.22 for the control (C), 1.19 and 1.04 under warming (W) conditions, 1.27 and 0.97 under warming plus precipitation (WP) conditions, and 1.27 and 1.24 under the conditions of precipitation addition (P). The niche overlap of L. chinensis and S. krylovii were 0.72 in C, 0.69 in W, 0.68 in WP, and 0.82 in P. The biomass share and importance value of L. chinensis increased, and those of S. krylovii decreased in response to warming and precipitation. The effects of warming on species diversity and community stability are primarily influenced by the effects on the niche breadth of S. krylovii. Combined with our previous study, L. chinensis will offer more resources in communities in warmer and wetter steppe climates in the future. However, this is not conducive to community diversity.

Мегабентос западного прибрежья архипелага Новая Земля в приловах донного трала

As a part of a marine expedition on the R/V «Dalnye Zelentsy» along the western coast of the Novaya Zemlya archipelago, an assessment of megabenthic species diversity and biomass in bycatch of trawl was carried out in August 2023 specimens of 29 taxa belonging to 6 phyla were identified during the survey. The highest species diversity (20 species) was recorded in the northern coastal area of the Novaya Zemlya archipelago, where the dominant forms in terms of biomass were sea urchins Strongylocentrotus pallidus – 237.1 kg/km2. A tendency for a 5-fold decrease in megabenthos species diversity and a decrease in the average biomass of organisms – from 17.2 to 0.47 kg/km2 was detected with transition from north to south. The association of sea urchins S. pallidus and brittle stars Gorgonocephalus sp. (84 % biomass share of representatives in bycatch) is identified in the north of the study area, which is replaced by the association of sea urchins S. pallidus and crustaceans Chionoecetes opilio (74.6 %) when moving to the south. According to the results of the RDA analysis, the effects of trawl fishing and type of water mass have the greatest impact on species diversity and biomass of megabenthic organisms. Trawling intensity, type of water mass, and sediment characteristics explain 75 % of the observed variability in these biological parameters.

Improving dual cover crop mixtures to increase shoot biomass production and weed suppression potential

IntroductionCover crop services depend on biomass production and species composition of the cover crop stand. In this study, we investigated the interactions in shoot biomass of dual cover crop mixtures and their competitiveness to suppress weeds before winter under different growing conditions.MethodsA field experiment was performed on sandy loam soil in Triesdorf, Germany, for two consecutive years. The cover crop species white mustard (Sinapis alba L.), oil radish (Raphanus sativus var. oleiformis L.), phacelia (Phacelia tanacetifolia J.), Egyptian clover (Trifolium alexandrinum L.), common vetch (Vicia sativa L.), field pea (Pisum sativum L.), and field bean (Vicia faba L.) were grown in pure stands or dual mixtures. Cover crops were sown in August, and shoot biomass was harvested at the end of the vegetation period. Cover crop shoot biomass was dried, and the share of each species and the sown test weed (Brassica napus L.) were determined.ResultsThe share of shoot biomass of a cover crop species in dual-species mixtures was closely related to its shoot biomass in its pure stand. In both years, mustard and phacelia showed similar interactions in shoot biomass production when growing with a second species. Regarding competitiveness against weeds, cruciferous species outperformed other cover crop species and could suppress weeds even if they were mixed with a less competitive partner. Weed suppression of mixtures with phacelia depended on the second component in the mixture and was more effective in a dry season. Legume species, especially Egyptian clover and common vetch could not suppress weeds in a pure stand.DiscussionOur results show that species with high weed suppression potential as single stands retain this ability in dual cover crop mixtures, regardless of the suppression potential of the second species that completes the mixture.

Combined effects of herbicides and insecticides reduce biomass of sensitive aquatic invertebrates

The structure and biomass of aquatic invertebrate communities play a crucial role in the matter dynamics of streams. However, biomass is rarely quantified in ecological assessments of streams, and little is known about the environmental and anthropogenic factors that influence it. In this study, we aimed to identify environmental factors that are associated with invertebrate structure and biomass through a monitoring of 25 streams across Germany. We identified invertebrates, assigned them to taxonomic and trait-based groups, and quantified biomass using image-based analysis. We found that insecticide pressure generally reduced the abundance of insecticide-vulnerable populations (R2 = 0.43 applying SPEARpesticides indicator), but not invertebrate biomass. In contrast, herbicide pressure reduced the biomass of several biomass aggregations. Especially, insecticide-sensitive populations, that were directly (algae feeder, R2 = 0.39) or indirectly (predators, R2 = 0.29) dependent on algae, were affected. This indicated a combined effect of possible food shortage due to herbicides and direct insecticide pressure. Specifically, all streams with increased herbicide pressure showed a reduced overall biomass share of Trichoptera from 43 % to 3 % and those of Ephemeroptera from 20 % to 3 % compared to streams grouped by low herbicide pressure. In contrast, insecticide-insensitive Gastropoda increased from 10 % to 45 %, and non-vulnerable leaf-shredding Crustacea increased from 10 % to 22 %. In summary, our results indicate that at the community level, the direct effects of insecticides and the indirect, food-mediated effects of herbicides exert a combined effect on the biomass of sensitive insect groups, thus disrupting food chains at ecosystem level.

Carbon storage in a dry Miombo woodland area in Tanzania

A persistent need exists, both politically and academically, for knowledge on carbon storage and sequestration potentials of forest ecosystems and their contributions to the global carbon balance. This study assessed carbon stocks of a 6 065 ha dry Miombo woodland site in Iringa Rural district, Tanzania. The carbon stock for each of the six pools: trees, shrubs, deadwood, herbaceous vegetation (grass and herbs), surface litter and soil were estimated. Assuming a 50% carbon share of biomass, the results showed that the aboveground carbon stocks were: 24.71 Mg C ha−1 for trees; 10.88 Mg C ha−1 for shrubs; 0.54 Mg C ha−1 for deadwood; 0.58 Mg C ha−1 for herbaceous vegetation; and 2.47 Mg C ha−1 for surface litter. Soil carbon was estimated separately for two depth ranges: 0–15 cm and 15–30 cm below the surface. These soil strata contributed 21.24 Mg C ha−1 and 8.22 Mg C ha−1 respectively. The total carbon (C) stock of the six pools was 68.64 Mg C ha−1. Considering the vast area covered by dry Miombo woodlands in Tanzania and in 10 other countries in south-eastern Africa, the carbon stock of these ecosystems is clearly tremendous, underscoring the importance of conserving them.

Pellets from mixtures of short rotation coppice with forest-derived biomass: Production costs and energy intensity

The demand for feedstock for pellet production is growing, with a consequent increase in the cost of their purchase and the cost of production. The objective of this study was to determine the cost and energy intensity of pellet production from forest biomass (Scots pine, silver birch) and short rotation coppice – SRC (black locust, poplar and willow) and their mixtures. The lowest cost (339.7 € Mg−1) and energy input (1448 kWh Mg−1) for pellet production were determined for Scots pine. The cost of pellet production from poplar and willow was higher by 5–6% compared with Scots pine pellet. The energy input for pellet production from willow, black locust and poplar was higher by 48.1%, 50.4% and 53.2%, respectively. The feedstock purchase cost (50.3–57.8%) and energy input for drying them (74.6–82.6%) accounted for the largest portion. Increasing the share of SRC biomass from 25% through 50%–75% relative to Scots pine and silver birch biomass resulted in a cost and energy intensity increase and decrease in the energy efficiency of pellet production. Three pellet types: produced from Scots pine and those with an addition of 25% of willow or poplar made up one cluster.

Fundamental but underrepresented: root carbon stocks in African montane forests

African montane forests harbor some of the greatest biodiversity worldwide, with high levels of species endemism. However, the loss of these forests through fragmentation, deforestation and climate change has been rapidly increasing in recent years. Montane forests in Africa are more susceptible to changes in climate than their lowland counterparts, yet their ecological value is still underrepresented. These montane forests have recently been highlighted as a major aboveground carbon (C) stock. The estimated 149.4 Mg C ha−1 from aboveground live trees surpasses estimates from the Intergovernmental Panel on Climate Change for these endangered forests, and exceeds reported values for neotropical montane and lowland forests by up to 70%. Despite the tremendous implications of these findings, coordinated and available research on the C storage potential of the other share of African montane forest biomass, that is in tree roots, is largely missing. Broadly estimated from the allometry of aboveground C stocks and from root:shoot ratios in lowland forests, more than 60 Mg C ha−1 can be stored in African montane forest roots, about 40% more than previously determined. While this broad estimation points at the potential importance of root C stocks in African montane forests, it also unveils a far-reaching knowledge gap. Here, we advocate for a more quantitative representation of the root C stock from dominant forest tree species of African tropical montane forests and ultimately for a better grasp on tree C stocks from this endangered ecosystem.

Effect of warming on ground vegetation in Carpathian Norway spruce stands, exemplified by European blueberry (Vaccinium myrtillus L.) nutrient stoichiometry

Despite its small share of total forest biomass, ground vegetation plays an important role in biogeochemical cycles, being able to modify carbon (C) and nutrients fluxes. Global climate warming may affect plant nutrient uptake and the carbon:nitrogen:phosphorus (C:N:P) stoichiometry, the release of nutrients from the soil and soil organic matter, as well as significantly influence the tree stand nutrient supply. In this context, the response of Norway spruce (Picea abies (L.) H.Karst) stands' ground vegetation to warming is uncertain. An open-top chamber soil-warming simulation, lasting two growing seasons, was conducted in a spruce forest. At the end of each of the two growing seasons, before leaf senescence, European blueberry (Vaccinium myrtillus L.) aboveground biomass (leaves and stems) and mineral topsoil samples were collected from the plots. The C, N, P, micronutrient, and macronutrient concentrations were estimated in the samples. Warming caused significant decreases in C, N, and P in the soil. Warming also decreased the C:P and N:P stoichiometric ratios in the soil and increased the C:P ratio in plant stems. Significant increase in foliar C and decrease in foliar P in warmed plots were observed. The most evident effect was reduction of N and P in the soil, which directly affected the plant C:P and soil N:P stoichiometry. Our results show that warming has caused a significant decrease in the content of some nutrients in the aboveground plant tissues of blueberries. Given that N is a limiting factor of ecosystems productivity, its reduction in the soil caused by warming may be a serious threat to proper nutrient uptake and cause disruption of biogeochemical cycles. The decrease in nutrient content in aboveground tissues due to warming can result in disruptions to physiological processes.

The impact of the share of waste lignocellulosic biomass from apple orchards on the susceptibility to drilling of produced particleboards

The impact of the share of waste lignocellulosic biomass from apple orchards on the susceptibility to drilling of produced particle boards. Every year, care cuts are carried out in the orchards, which result in a significant amount of waste. This waste is a valuable source of lignocellulosic material for particleboards production. As part of this study, the influence of the share of waste apple wood on the susceptibility to drilling of particleboards was investigated. Three-layer particle boards with share of lignocellulosic waste biomass from apple orchards (0%, 25%, 50% and 75%) and density level at 650 kg/m3and 550 kg/m3 were made. The particleboards were examined for the axial force and torque that occurs during drilling. The highest value of the axial force during drilling was notice for particleboard without apple wood and a density of 650 kg/m3. While the lowest axial force during drilling was recorded for particleboard with 50% share of apple wood and density of 550 kg/m3. The obtained results allow to conclude that density of the produced particleboards and the share of apple wood waste have a statistically significant effect on the axial force during drilling. While the share of apple wood do not statistically affect the torque during drilling. In the case of the pressing unit pressure used in the particleboards production process, no statistically significant influence on the axial force and torque during drilling was found.

Assessing rural households’ biomass consumption patterns in three Upazilas in Khulna district of Bangladesh

In developing countries, rural households instinctively burn huge amounts of biomass fuel, which has become a concern at present. In this study, an attempt has been made to assess the consumption pattern of biomass fuel in relation to socio-economic factors in rural households in the three upazilas (subdistricts) in Khulna district of Bangladesh. The consumption pattern of biomass fuel was assessed by multistage random sampling techniques with a semi-structured questionnaire. The study revealed that households incorporate a variety of fuel sources, of which 97% use various types of biomass fuel, e.g., firewood, leaves and twigs, coconut shell and coir, crop residues, cow dung, etc. The average monthly household biomass fuel consumption was 193 kg, with a monthly expenditure of 5.86 USD. The largest share of biomass fuel was derived from firewood, which amounted to 105 kg per month. The middle income group and Kacha (clay) type households consume more biomass than other types of households. The major sources of biomass fuel were found in their home gardens and agricultural lands. These biomass fuels are mainly used for domestic cooking, and most of the households in the study area used general stoves. Among commonly available species, ten firewood species were identified as the most preferred by the majority of households in the study area. Insights from our research may be utilized to promote accessibility to clean energy for households in Bangladesh and other countries alike.

TO THE BIOLOGY OF INVASIVE SPECIES OF IМРАТIЕNS GLАNDULIFЕRА RОYLЕ. (BALSAMINACEAE) IN BASHKORTOSTAN REPUBLIC

Morphometric parameters and population characteristics of the invasive species Impatiens glandulifera in the Southern Ural Range (Republic of Bashkortostan) are analyzed. Twenty four localities of invasion in 20 districts of the Cis-Urals were examined. The density of the species in communities is 18-79 individuals per 1 m2; its biomass ranges from 1 to 9 kg/m2. The biomass share of the species reaches from 49.7 to 99.0%, i.e. this species dominates in all localities. It is established that the maximum values of morphometric parameters are characteristic of populations growing in conditions more favorable in terms of moisture availability and richness of soils, with a slight anthropogenic impact. Minimal ones are observed under conditions of a stronger anthropogenic impact (recreational load, trampling, landfills). The good adaptation of the species to different growing conditions in new habitats and the competitive advantages of I. glandulifera over local plant species were noted. There is a high probability of further settlement of the species in slightly disturbed, as well as in natural habitats along the shores of the reservoirs of the republic.

A sustainable use of biomass for electrical energy harvesting using distributed generation systems

Pakistan has been facing an electricity shortage since the year 2005, which is negatively affecting the country's agricultural, industrial, and services sectors growth. In this study, Low Emissions Analysis Platform (LEAP®) software was used for forecasting energy mix of Pakistan for the period of 2022–2050 under the baseline and transformation scenarios. Baseline scenario emphasizes to enhance the share of hydro while transformation scenario emphasizes to enhance the share of biomass in total energy mix of Pakistan. Transformation scenario is recommended because hydro plants will retire in future and delay in construction of new hydro plants is noticed due to limited budget. In this regard, electrical energy is harvested using biomass based distributed power generation (BBDPG) for the sustainable economic development of Pakistan. The aggregate capacity of biomass is used which includes agriculture residue, forest residue, municipal waste, and animal waste. The results of this study show that the share of hydro at around 54.09% (614.14 TWh) is dominated over other renewable sources in the baseline scenario, whereas, in transformation scenario the share of biomass at around 33.3% (378 TWh) is dominated over other renewable sources till 2050. Pakistan could generate a total of 1135.20 TWh energy units in 2050, which would be enough to meet the future energy demand of 966.05 TWh by 2050.

Trophic activity of amphibians as a factor influencing the state of ecosystems of the Dnipro River valley

The problems of disruption and transformation of natural ecosystems have reached a significant level and directly affect the state of human life: there is the existence of harmful insects, their resistance to chemical compounds, etc. Therefore, the functional significance of zoocenosis is manifested in various aspects: digging, excretory, trophic and other types of animal activity. The importance of the trophic activity of amphibians lies in their consumption of a significant number of harmful insect species. It is animals that act as consumers of various kinds in the conditions of natural ecosystems, take an active part in the movement of energy along trophic chains. The trophic activity of animals is also important in regulating the number of groups of invertebrates of different systematic groups, it is one of the factors that contributes to the maintenance of the system in a state of homeostasis and the speed of its recovery. Attention is also paid to regulating the number of invertebrates, as well as poisonous species among them, species that cause human diseases or are their carriers. Amphibians do not have a specific food specialization and are consumers of any available food. The food spectrum also expands as individuals grow and due to the consumption of larger prey. The main component of amphibian nutrition is insects, they make up about 75% of the diet. Phytophages on average make up 60–85% of the total weight of food in the food of amphibians. The coefficient of usefulness and the share of biomass of various pests in different types of amphibian floodplains range from 52 to 84. As a rule, the ratio of different food objects of amphibians corresponds to their ratio in individual parts of ecosystems. Thanks to the trophic activity of amphibians, the number of pests is regulated, which is important in floodplains of rivers, and the number of energy consumers of a higher level, such as birds and mammals, depends on the trophic activity of amphibians. This fact proves that amphibians are a necessary component of the food chains of terrestrial and aquatic ecosystems. The trophic activity of amphibians affects the stability and plasticity of ecosystems, species diversity of both zoocenosis and phytocenosis in terrestrial and aquatic systems, as well as on the boundaries between them.

Energy transition through bioelectricity in Pakistan: Implications for limiting global mean temperature below 1.5°C

AbstractClimate change threats demand unprecedented economic shifts around the world, including a fundamental transformation of the global energy system. An energy transition is underway in most regions, predominantly in the power sector. This research depicts the energy transition pathway for achieving 100% renewable energy systems through bioenergy in Pakistan. The growth rate of 20%, 30%, and 40% in biomass projects were considered for the study period 2023 to 2053 using the Low Emissions Analysis Platform (LEAP) software. It presents a technology‐rich, multi‐sectoral and cost‐optimal energy transition pathway for limiting global mean temperature below 1.5°C. The results revealed that Pakistan's electricity generation undergoes a rapidly evolving transition from predominantly fossil fuels 62.1% in 2023 to 81.3% renewables in 2053, and entirely zero CO2 emissions by 2060. Hydro source is costly, wind and solar sources are seasonal so biomass emerges as the major electricity supply source in a cost optimal energy transition of Pakistan. Share of biomass is increasing from a mere 0.81% in 2023 to around 9.44% by 2053 under the 20% growth rate, which then increase to 39.67% by 2053 under the 30% growth rate and further increases to 78.33% by 2053 under the 40% growth rate. Pakistan contributes 0.8% of the global carbon footprint, but we are among the 10 most climate‐stressed countries on the planet in 2023 so this study helps to reduce cumulative CO2 emissions from 151.63 million metric tons to 8.90 million metric tons from 2023 to 2053 across the power, heat, transport, and desalination sectors.

The impact of the share of waste lignocellulosic biomass from apple orchards on the susceptibility to drilling of produced particleboards

The impact of the share of waste lignocellulosic biomass from apple orchards on the susceptibility to drilling of produced particle boards. Every year, care cuts are carried out in the orchards, which result in a significantamount of waste. This waste is a valuable source of lignocellulosic material for particleboards production. As part of this study, the influence of the share of waste apple wood on the susceptibility to drilling of particleboards was investigated. Three-layer particle boards with share of lignocellulosic waste biomass from apple orchards (0%, 25%, 50% and 75%) and density level at 650 kg/m3and 550 kg/m3 were made. The particleboards were examined for the axial force and torque that occurs during drilling. The highest value of the axial force during drilling was notice for particleboard without apple wood and a density of 650 kg/m3. While the lowest axial force during drilling was recorded for particleboard with 50% share of apple wood and density of 550 kg/m3. The obtained results allow to conclude that density of the produced particleboards and the share of apple wood waste have a statistically significant effect on the axial force during drilling. While the share of apple wood do not statistically affect the torque during drilling. In the case of the pressing unit pressure used in the particleboards production process, no statistically significant influence on the axial force and torque during drilling was found

Techno-economic assessment of biomass and coal co-fueled chemical looping combustion unit integrated with supercritical CO2 cycle and Organic Rankine cycle

This study evaluates the effect of co-combustion of woody biomass and coal on the techno-economic performance of a 300 MWth in-situ gasification chemical looping combustion power plant. The circulating fluidized bed reactor system was designed and a modified macroscopic model was applied to predict the fuel conversion and the CO2 capture efficiency. The supercritical CO2 cycle and the Organic Rankine cycle were integrated with the heat sources for power generation. The results showed that increasing biomass share in the input thermal power, in addition to enhancing the CO2 capture efficiency, improves the coal conversion. Moreover, negative CO2 emissions are achieved as the biomass share exceeds 50 MWth. The net electrical efficiency of the plant is about 43.89% and grows slightly for higher biomass shares. For biomass share of 150 MWth, the CO2 capture efficiency increases from 79.27% to 90.87%. Also, the levelized cost of electricity (LCOE) rises by 15.9%–108.262 $/MWh due to higher biomass price. Despite this increased fuel cost, the LCOE is still lower than that value for the coal-fired power plant with conventional CO2 capture technology. Biomass utilization becomes more cost-effective than coal if the carbon tax is above 30 $/tCO2.

High-Temperature Corrosion of Flame-Sprayed Power Boiler Components with Nickel Alloy Powders

The development trends in the energy sector clearly indicate an increase in the share of biomass and alternative fuels fed for combustion in power boilers, which results in the imposition of many unfavourable factors and a demanding working environment. During the operation of the energy system, this means a sharp increase in corrosion of the gas-tight pipe walls and coils by the destructive action of chlorine and sulphur. Implementing advanced surface protection in addition to the selection of materials of better quality and resistance to difficult working conditions would significantly reduce their wear by high temperature corrosion. Thermally sprayed coatings offer a great opportunity to protect machine components and energy systems against corrosion, erosion, impact load and abrasive wear. This article presents the test results of high-temperature corrosion resistance of coatings made with Ni-Cr-B-Si and Ni-B-Si alloy powders on a boiler steel substrate. Samples with sprayed coatings were exposed to an atmosphere with a composition of N2 + 9% O2 + 0.08% SO2 + 0.15% HCl at 800 °C for 250, 500, 750 and 1000 h. Tests results of coatings made of Ni-Cr-B-Si alloys subjected to the influence of a corrosive environment showed the formation of a layer of scale on the surface, composed mainly of Cr2O3 oxide, which was a passive layer, reducing the rate of corrosion. Coatings sprayed with Ni-B-Si alloys showed significantly lower corrosion resistance. It was found that the developed technology of subsonic flame spraying with powders of the Ni-Cr-B-Si type allows the production of coatings compliant with the requirements of the energy industry, which allows their use as anti-corrosion protection on boiler elements intended for waste disposal and biomass combustion.

Potato (Solanum tuberosum L.) Plant Shoot and Root Changes under Abiotic Stresses-Yield Response.

During the growing season, potato plants are often exposed to soil drought, frequently accompanied by heat stress, which results in crop losses. In our experiment, the impact of these stresses, both separately and simultaneously, on the above-ground, on the root, and on the tuber mass was assessed. Four potato cultivars were tested. In vitro plants were planted in plastic tubes. Four treatments were used: control-optimal irrigation and temperature (22/18 °C), drought stress, high temperature stress (38/25 °C), and drought and high temperature stresses combined. The stresses were applied for two weeks during the tuberization phase. Both stresses caused changes in plant morphology. Drought stress had a greater impact on these changes than high temperatures. The biggest changes, however, took place when both stresses were applied simultaneously. Under all stresses, a decrease in tuber yield was found. The largest decrease was recorded in the case of applying both stresses simultaneously, while the smallest one was in the case of high temperature stress in relation to a control condition. Among the morphological parameters studied, the mass of the root system and its share in the entire biomass of the plant had the greatest impact on the decrease in yield. This mainly concerned drought stress.

Experimental investigation of 40 kW[formula omitted] methane-assisted and self-sustained pulverized biomass flames

This paper presents an assessment of the effects of methane assistance on pulverized biomass swirl flames specifically regarding flow fields and flame structure. Experiments are carried out using a pilot-scale down-fired cylindrical combustion chamber equipped with a swirl burner and biomass/methane fuel mixtures. Studied conditions have an identical thermal output of 40 kW, with the thermal output share of methane gradually decreasing from 50% to 0% while the biomass share (walnut shells) increased from 50% to 100% (self-sustained condition). A detailed flow field characterization of the respective flames is conducted by in-flame, two-dimensional laser Doppler velocimetry measurements. These measurements are complemented by narrow-band flame imaging conducted at two different wavelengths (OH* and CH* radical band heads). Results show that the methane flames have a significant influence on the ignition and the determination of the flame flow field structure, including higher peak and overall velocities, as well as major changes in the ratio of tangential over axial velocity component. Further on, flame attachment of the self-sustained flame can be permanently achieved by the initial, short-term assistance of a methane flame with comparatively low thermal output. These observations are analysed and discussed, where higher measured velocities and overall changes in the flame structure between the self-sustained and the methane-assisted flames are attributed to important local expansion and momentum changes of the combustion gases introduced by the combustion of methane.

Consequences of Grazing Cessation for Soil Environment and Vegetation in a Subalpine Grassland Ecosystem.

Areas covered by seminatural grasslands have been in constant decline for decades in Europe. This trend is particularly strong for mountain territories, where such traditional agricultural practices as cattle grazing are no longer economically feasible. This study was conducted in the subalpine pasture of Cinte Tesino (TN, Italy), where local farmers have applied the following different management strategies: shorter and longer grazing durations during the season and a complete abandonment for the last 15 years. We aimed to study how these different management strategies impact the functioning and diversity of vegetation and the chemical and biological characteristics of the soil. Species richness was higher in plots subjected to longer grazing with a prevalence of D. caespitosa in terms of biomass share. A decline in species richness in abandoned plots was accompanied by an increase in the share of other graminoids in collected biomass. A concomitant increase in leaf N concentration and light availability in grazed plots resulted in higher photosynthetic efficiency in some species, as revealed by the δ13C of plant tissues. Soils under grazing were characterised by a higher concentration of total and extractable N, almost doubled microbial biomass C and increased extracellular enzymes activity, evidencing nutrient cycling mobilization. While the microbial pool was characterised by lower mineralization rates, C was lost from the soil with 15 years of abandonment. The longer grazing season demonstrated to be the most beneficial, promoting species richness, C accumulation and better soil microbial functioning. A change in soil pH from strongly acidic to moderately acidic with longer grazing is likely one of the important factors adding to the success in the functioning of primary producers and decomposers in this site.