Grass Burning Research Articles

Annual extent of prescribed burning on moorland in Great Britain and overlap with ecosystem services

AbstractIn the UK uplands, prescribed burning of unenclosed heath, grass and blanket bog (‘moorland’) is used to support game shooting and grazing. Burning on moorland is contentious due to its impact on peat soils, hydrology and habitat condition. There is little information on spatial and temporal patterns of burning, the overlap with soil carbon and sensitive habitats and, importantly, whether these patterns are changing. This information is required to assess the sustainability of burning and the effectiveness of new legislation. We developed a method for semi‐automated detection of burning using satellite imagery – our best performing model has a balanced accuracy of 84.9%. We identified annual burn areas in Great Britain in five burning seasons from 2017/18 to 2021/22 of 8333 to 20 974 ha (average 15 250 ha year−1). Annual extent in England in 2021/22 was 73% lower than the average of the four previous seasons. Burning was identified over carbon‐rich soils (mean 5150 ha or 34% by area of all burning annually) and on steep slopes – 915 ha across the five seasons (1.3%), contravening guidance. Burning (>1 ha) was recorded in 14% of UK protected areas (PAs) and, within these, the percentage area of moorland burned varied from 2 to 31%. In England in some years, the percentage area of moorland burned inside PAs was higher than outside, while this was not the case in Scotland. Burning in sensitive alpine habitats totalled 158 ha across the five seasons. The reduction in burned area in England in 2021/22 could relate to England‐specific legislation, introduced in May 2021, to prohibit burning on deep peat in PAs. This suggests that regulation can be effective. However, the continued overlap with sensitive features suggests that burning falls short of sustainable practices. Our method will enable repeatable re‐assessment of burning extents and overlap with ecosystem services.

Source Apportionment and Health Risk of Some Organic Contaminants in Water and Suspended Particulate Matter from Imo River, Nigeria

The objective of this study was to provide the source identification and assessment of potential health associated with some organic contaminant detected in water and suspended particle matter (SPM) from the Imo River, Nigeria using gas chromatography with a flame ionization detector (GC/FID) after 1:1 ratio solvent mixture (n-hexane and dichloromethane) extraction. The findings on SPM revealed the values; pH (5.42±0.097-5.567±0.057), conductivity (74.58±5.390-87.6±0.9 uS/cm), and total organic carbon (TOC) (3.626±0.366-6.143±0.176), and surface water; pH (6.077±0.049-6.46±0.52), conductivity (49.03±1.430- 58.12±0.553 uS/cm). The total concentrations of both low and high molecular PAHs in SPM recorded at stations1-3 were 4.384 mg/kg, 16.87 mg/kg, and (22.69 mg/kg); surface water 2.329 mg/L, 7.428 mg/L and 6.657 mg/L. The source apportionment of PAHs in SPM and surface water via molecular diagnostic ratios identified both petrogenic source (crude oil, petroleum spillages, and seepages) and pyrogenic sources (combustion of grass, wood, coal, and gas flaring). A further analysis with Principal Component Analysis (PCA) revealed two principal components, with 65.568% for component 1 and 34.432% for component 2 for SPM, and 62.80% for principal components and 37.2% for principal component 2 for surface water. The correlation analysis of PAHs affirmed common sources such as petrogenic and pyrogenic origins. The toxic equivalent factor of total benzo(a)pyrene for 6 ∑PAHs in SPM was recorded as 3.693 mg/kg, 1.605 mg/kg, and 0.453 mg/kg; surface water was recorded as 0.823 mg/L, 1.858 mg/L, and 0.353 mg/L, while the mutagenic equivalency quantities of SPM were recorded as 3.693mg/kg, 1.146 mg/kg, and 0.316 mg/kg; surface water 0.739 mg/L, 0.938, and 0.577 for stations 1-3. The effect of carcinogenic PAHs in SPM was higher in adults than in children, with regards to ILCR analysis. Users of Imo Rivers should be guided on the exposure of SPM and surface water since the toxic, mutagenic, and cancer risk levels of the river are above the permissible limit in some stations.

Neutral saccharides and hemicellulose over two urban sites in Indo-Gangetic Plain and Central Europe during winter

Saccharides are ubiquitous organic compounds that are omnipresent in nature and are considered tracers of aerosol sources. Saccharides and hemicellulose were analyzed in the aerosols of two polluted regions (Allahabad, India and Sosnowiec, Poland). The chemical compositions of the compounds and their abundances were significantly different at the two sites. Levoglucosan was the most dominant saccharide present at both sites. Galactosan, anhydroglucofuranose, mannosan, glucose, arabitol, D-pinitol, sucrose, and trehalose were found in Allahabad samples in high abundance but were significantly lower than levoglucosan. Mannosan, galactosan, arabinose, glycerol, and sucrose were significant compounds in Sosnowiec after dominating levoglucosan. The major sources of saccharides present in the Allahabad aerosols are hardwood and agricultural waste-burning emissions, whereas those at Sosnowiec are attributed to the burning of softwood (mainly gymnosperm trees), pine needles, or sporadically grass during the winter. Further, the chemical characteristics of hemicellulose remnants present in ambient aerosol at the Indian and European sites were analyzed and discussed. At both locations, hemicellulose was found using methanolysis of the filter samples; however, its state of preservation was poor. We believe that the primary sources of hemicellulose remnants are incomplete wood burning, crop straw, grass burning, or plant debris. Relatively poor preservation is associated with partial hemicellulose degradation when exposed to elevated temperatures or due to the oxidation and microbial degradation of plant fragments.

A Burning Grass and Removing Root Immunoregulatory Strategy Toward Chronic Wounds Therapy by MnO2 Nanoparticle Incorporated Hyaluronic Acid Hydrogel

AbstractComplex immune microenvironment of diabetic wound possesses polarization misalignment of macrophages and excessive inflammatory response, which prolong the healing process. Consequently, developing hydrogel dressings with immunoregulatory ability shows huge potential in clinical management of diabetic wound. Nevertheless, recent immunoregulatory strategies are mainly focusing on switching the proinflammatory M1‐type to anti‐inflammatory M2‐type macrophages by using high‐cost dressings composed of cytokines and cells. Considering the hyperpolarized M1 macrophages of diabetic wounds as wild grass of wasteland, a burning grass and removing root immunoregulatory strategy toward wound healing is developed based on dopamine‐manganese dioxide nanoparticle incorporated high molecular weight hyaluronic acid (HHA) hydrogel. The self‐healing and injectable hydrogel is formed by boronate ester bonds between the HHA grafted with phenylboronic acid and polyvinyl alcohol. Notably, in vitro and vivo results confirm that the HHA components can burn the grass by switching M1 to M2 in the inflammatory microenvironment while the dopamine‐manganese dioxide nanoparticles can remove the root by relieving M1 polarization through eliminating reactive oxygen species. The comprehensive immunoregulation ability enables the hydrogel as effective therapeutic that improves wound healing, and shows reliable potential in clinical dressings for the management of diabetic wounds.

The Effect of Heating on Properties of Sandy Soils

Although burning grass and crop residues is prohibited in many countries, farmers perceive it as a quick and inexpensive way to eliminate unwanted biomass. The aim of this study was to estimate the impact of heating temperature (simulation of biomass burning) on the studied properties (soil organic carbon (SOC) content, pH(H2O), water drop penetration time, WDPT, and contact angle, CA) of acidic sandy soils. Soil samples were taken from the experimental sites S1, S2, and S3 at Studienka village in the Borská nížina lowland (southwestern Slovakia). Experimental site S1 was arable land, experimental site S2 was arable land abandoned for approximately 10 years, and experimental site S3 was arable land abandoned for approximately 30 years with scattered Scots pine (Pinus sylvestris L.) trees. It was found that all the soil properties studied were strongly affected by heating. A drop in SOC was observed in all the soils for the heating temperature between 20 and 600 °C. Due to the incomplete combustion of SOC, a small (0.1–0.7%) SOC content was recorded even in soils heated to between 600 and 900 °C. An increase in pH(H2O) was observed in all the soils for the heating temperature higher than 300 °C. Soil from the experimental site S1 was wettable (WDPT < 5 s) for all of the heating temperatures. WDPT vs. heating temperature relationships for the soils from the experimental sites S2 and S3 were more complex. After a decrease in the heating temperature of 50 °C, an increase in WDPT for the heating temperature between 50 °C and 300 °C (for S3 soil) and 350 °C (for S2 soil) was registered. Finally, the WDPT dramatically dropped to 0 for the heating temperature of 350 °C (for S3 soil) and 400 °C (for S2 soil). CA started to decrease at 300 °C in all the soils and dropped to 0° for all the soils at 800 °C. CA > 0° measured in soils for the heating temperature between 400 and 800 °C, as a consequence of the small SOC contents due to the incomplete combustion of SOC, is a novelty of this study which demonstrates that CA is more sensitive to the changes in subcritical water repellency than WDPT.

Trauma, sexuality, and identity in The Lover by Marguerite Duras and Burning Grass on The Field by Doan Minh Phuong

This paper examines the relationship between sexuality and trauma in two works, The Lover by Marguerite Duras and Burning Grass on The Field (Dot co ngay dong, in Vietnamese) by Doan Minh Phuong. Using trauma studies as a critical perspective to compare the two works, we focus on the relationship between sexuality and trauma, analyse the construction of identity of traumatized characters, and clarify the role of sexuality in such a process. Juxtaposing a newly released Vietnamese literary work, Burning Grass on The Field next to the well-known novel The Lover is also expected to reveal more meaning for the seemingly asymmetrical works. This can be seen as our effort to blur the division between the so-called classics and the other, contributing partly to decolonizing human literature.

Compositions and Sources of Organic Aerosol in PM2.5 in Nanjing in China

Organic aerosols are harmful to the environment because of their impact on air quality and visibility. They have serious effects not only on living beings and ecosystems because of their biological toxicity, but they also have an indirect effect on regional climate change as cloud condensation nuclei and radiation force. Many measures have been applied to decrease air pollution. Although the air quality has greatly improved, the standard of the World Health Organization (WHO) is far from being met at present. In this study, fine particulates were collected in Nanjing throughout 2019, and high-performance liquid chromatography–electrospray ion–mass spectrometry/mass spectrometry (HPLC-ESI-MS/MS) was carried out to determine 14 organic acids, 10 nitrated phenols, 1 aldehyde, and 1 ketone in aerosol samples. In this study, we further determined the changes in the pollutants in Nanjing in recent years compared to previous studies and characterized more kinds of species in the air. We found that different kinds of nitrated phenols showed similar trends of being abundant in winter and substituted in spring, autumn, and summer. 4-Nitrophenol was the most abundant species (2.83 ng m−3) among the nitrated phenols. p-Coumaric acid presented the highest level in summer with an average concentration of 1.55 ng m−3, indicating that grass burning was significant in summer, possibly due to wheat stalk and perennial ryegrass burning. The positive matrix fraction (PMF) model was applied to identify the sources of aerosols in Nanjing, including coal burning, grass burning, softwood burning, hardwood burning, anthropogenic secondary organic aerosols (SOAs), and biogenic SOAs. Coal burning and softwood burning contributed much more to the total determined species with values of 20.3% and 18.2%, respectively. Anthropogenic SOAs contributed 17.1%, and hardwood burning contributed 16.7%. The contribution of biogenic SOAs was 15%, and the grass-burning source contribution was the lowest, with 12.6%. With consideration of the large contribution from anthropogenic combustion activities, more strict measures are required to reduce emission pollutants in the future.

The Effect of CaO on the CO and NOx Emission Characteristics of Fast-Growing Grass Combustion

Fast-growing grass is a biomass material with characteristics such as high temperature and drought resistance; rapid growth and development; and repeated germination and cutting. Therefore, it is a popular biomass fuel. It is required that the pollutants produced during the biomass combustion process are appropriately controlled. For this purpose, our study analyses the influence of combustion temperature and calcium oxide (CaO) on the nitrogen oxides (NOx) and carbon monoxide (CO) emission characteristics of fast-growing grass combustion using the biomass combustion flue gas analysis and testing platform. The results of our analysis revealed that CaO additive can simultaneously reduce the peak and total NOx emissions at 750 °C. Particularly, 5% CaO demonstrated a significant control effect on the NOx emission from the fast-growing grass combustion process, with a peak and total emissions reduction of 47.05% and 56.81%, respectively. In addition, with an increase in temperature, the CO emission curve attains a second peak higher than the first peak, and the peak and total emissions show a decreasing trend.

Human activity and demographics drive the fire regime in a highly developed European boreal region

Organization of successful wildfire prevention and suppression require detailed information on ignition causes, size distributions and relations to weather. From a large and highly detailed dataset of Swedish wildfire incidents (n = 124 000) we assess temporal, geographical and human-related patterns over a 25-year-period (1996–2020). We find strong positive correlations between population density and wildfire occurrence, primarily caused by a wide spectrum of human activities. However, fires >10 ha mostly occurred in sparsely populated regions and were more often ignited by lightning or heavy machinery. Further, large fires had a history of long response times and insufficient mop-up, in turn intimately linked to low population density. We detect no trend over the 25-year-period in either fire weather, number of ignitions or burned area, but a dramatic decline in wildfire caused by children's play as well as by springtime burning of dead grass, a traditional fire use in rural areas. Our results indicate that irrespective of climate change, societal changes such as rural depopulation and cultural shifts are imminently important for the future fire regime in this intensely managed part of the boreal, and may warrant more attention worldwide.

Fauna of the Light Harriers of the Samara Region: Population Dynamics due to Changes in Environmental Conditions

The article characterizes the fauna of light harriers (Circus cyaneus(Linnaeus, 1766), Circus macrourus(S. G. Gmelin, 1771), Circus pygargus (Linnaeus, 1758)) living in open and near-water spaces of the territory of the Samara Region. The dynamics of the number of light harriers and the reasons provoking significant fluctuations in the number of harriers are analyzed in detail. The boundaries of the breeding ranges of light harriers within the European part of Russia, the Middle Volga region and the real nesting zones on the territory of the Samara Region are discussed. The sections to which light harriers especially gravitate during reproduction are given, nevertheless visiting the entire area occupied by the region. Analyzing data from publications and oral reports of ornithologists on avifauna of the Samara region, the authors extrapolate a picture of the dynamics of the ‘squeezing’ of light harriers from the natural environment. The paper provides information on changes in the number of each species of light harriers in recent years. Among the most important factors limiting the number of light harriers, the following are noted: plowing of steppe areas; destruction of the habitat of birds; unauthorized, spontaneous burning of dry grass in the floodplains of small rivers in the spring; scattering of poisoned baits in order to exterminate rodents; poaching; the effect of the ‘anxiety factor’ in the breeding season; instability of the food supply.

Levels, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons in vegetable bases of northwest China.

Dietary consumption of contaminated vegetables is the main route of human exposure to polycyclic aromatic hydrocarbons (PAHs). However, there is a lack of research on PAHs in vegetables from northwest China. In this study, the concentrations, sources, and risk assessment of PAHs in the soil and vegetables of Urumqi, an urbanized city in Xinjiang, China, were investigated. The total concentrations of 16 PAHs in soil and vegetable samples ranged 10.58-77.20 and 93.7-1071.8ng/g, with average values of 2.86 and 242.76ng/g, respectively. Among vegetable samples, the concentrations were in the order: leafy vegetables (299.08ng/g) > fruits (192.65ng/g) > vegetable roots (152.05ng/g). The source apportionment of PAHs was identified using positive matrix factorization. The primary sources of PAHs in soil samples are oil spills, traffic emissions, coal combustion, and coke combustion. The main sources of PAHs in vegetable samples are oil spills and burning of grass, wood, coal, and coke. In soil samples, the ecological risk caused by PAHs is at a safe level, and the incremental lifetime cancer risks (ILCRs) of ingestion exposure exceed 1.0 × 10-6, which will pose potential risks to human body. The ILCRs of vegetable samples revealed that all groups had potential risks from onion and cabbage consumption (ILCRs > 1.0 × 10-6). In particular, adult women had a higher risk of cancer (ILCRs > 1.0 × 10-4). These results emphasize the importance of combating PAHs pollution in vegetable bases.

Structural and functional organization of ant communities in secondary meadow ecosystems

Introduction. Due to a significant biomass and diverse ecological niches, ants (Formicidae, Hymenoptera) are crucial in establishing the structure and functioning of the co-adaptive species complexes, i.e. myrmecocomplexes, to which they belong. The majority of ant species, which build their nests with visible anthills, create humpy micro-relief changing the habitats of numerous plant and animal species. The number of active ant families and the number of their nests indicate the functional power of every species in an ant community. According to the dynamics of nest numbers, it is possible to analyze the changes in the ecosystem as a whole. Materials and methods. The research territory is located in the SE suburb of Lviv on the edge of Davydiv and Holohory ridges. It includes two former agricultural sites: fallow arable land and fallow grazing land. The material was collected by the method of ant exclusion with its following conservation, laboratory analysis and determination. Anthill mapping was conducted on 200 sq. m sites. Results and discussion. The results suggest that the more structured a habitat is, the higher ant species diversity is observed: seven species were found in the fallow grazing land (Formica pratensis – dominant, F. cunicularia – subdominant, Tetramorium caespitum, Lasius niger, L. flavus, Myrmica rubra, Solenopsis fugax – all are influents). It is typical of the three influent species (L. flavus, T. caespitum, M. rubra) to distribute within the territory of a dominant’s foraging area. However, the influent ant species avoid contacting each other. The less structured habitat (fallow arable land) is presented by only two of the most adaptive species, which are in high numbers (L. niger – 95 % of the site nests, and L. flavus – only 5 % of them). Conclusions. Thus, each ant community is a system of „dominant–subdominant–influent” species, which is under permanent transformation due to anthropogenic habitat changes; only well-adapted species can stay in the community under the influence of the mentioned changes. The research on the spatial distribution of ant nests testifies to the prospects and need for the mapping method used to establish the type and level of previous anthropogenic impact on the ecosystem (grazing, ploughing, grass burning, etc.).

PLEISTOCENE PALYNOLOGY OF EAST JAVA

This study is a part of geological investigation on Pleistocene sediment in East Java in order to evaluate hydrocarbon potential within this sediment of this area. The area of study is located in the on-shore East Java (Figure 1). It is financially supported by the oil company as this is commercial work done by LEMIGAS Exploration Department. Therefore, data used in this paper will be incompletely presented as they are confidential. The name of the studied wells and their precise locations are hided in this paper. Data used in this study derives from three wells namely R, S and T. Three different disciplines are applied in this study including palynology, micropaleontology and nannoplankton analyses which are useful for crosschecking purposes. Apparently, the integration of these analyses gains accurate interpretation of stratigraphy and depositional environment. The area of study is in East Java Basin which can be classified as a classical back-arc basin. During Pleistocene, the area of study was marked by regional uplift and the cessation of open marine sedimentation (LEMIGAS, 2005). Therefore Pleistocene age was dominated by non-marine deposition. Generally, this type of sediment is separated from the underlying layer by an unconformity (LEMIGAS, 2005). Most Pleistocene sediment consists of volcanoclastic as a result of volcanic activity which related to uplifting period. It is possible that volcanic activity was responsible for the burning of grass as indicated by the occurrence of charred Gramineae cuticles. The previous investigations on Pleistocene sediment showed the domination of grass pollen of Monoporites annulatus which suggested the expansion of dry climate during Pleistocene glacial maxima. The pollen diagram from Lombok Ridge produced by van der Kaas (1991a) proves the domination of Gramineae pollen during Pleistocene (Figure 2). The period of dry climate (glacial climate) is characterised by abundant Gramineae pollen, whilst the period of wetter climate (interglacial climate) is indicated by an increase of coastal and mangrove palynomorphs, but greatly reduced frequencies of Graminaae pollen (Morley, 2000). In addition, Rahardjo et al. (1994) referred to the high abundance of Monoporites annulatus to propose Pleistocene pollen zone of M. annulatus (Figure 3).

Pleistocene Palynology Of East Java

This study is a part of geological investigation on Pleistocene sediment in East Java in order to evaluate hydrocarbon potential within this sediment of this area. The area of study is located in the on-shore East Java (Figure 1). It is financially supported by the oil company as this is commercial work done by LEMIGAS Exploration Department. Therefore, data used in this paper will be incompletely presented as they are confidential. The name of the studied wells and their precise locations are hided in this paper. Data used in this study derives from three wells namely R, S and T. Three different disciplines are applied in this study including palynology, micropaleontology and nannoplankton analyses which are useful for crosschecking purposes. Apparently, the integration of these analyses gains accurate interpretation of stratigraphy and depositional environment. The area of study is in East Java Basin which can be classified as a classical back-arc basin. During Pleistocene, the area of study was marked by regional uplift and the cessation of open marine sedimentation (LEMIGAS, 2005). Therefore Pleistocene age was dominated by non-marine deposition. Generally, this type of sediment is separated from the underlying layer by an unconformity (LEMIGAS, 2005). Most Pleistocene sediment consists of volcanoclastic as a result of volcanic activity which related to uplifting period. It is possible that volcanic activity was responsible for the burning of grass as indicated by the occurrence of charred Gramineae cuticles.

Evaluation of assumptions made by Hygroscopic Tandem Differential Mobility Analyzer inversion routines

The Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA) measures the hygroscopicity of atmospheric particles, and many atmospheric processes that change this hygroscopicity also change the atmospheric size distribution. Two assumptions made during H-TDMA inversion create spurious hygroscopic trends as a function of the changing inlet size distribution. These two assumptions—that the particles exiting the first Differential Mobility Analyzer (DMA1) are singly charged and that the inlet size distribution has a slope of zero (flat)— generate Multi-Charge Dispersion (MCD) bias and Slope bias, respectively. First, we use a model, named TAO, to show that the inlet size distribution could theoretically change the measured ammonium sulfate hygroscopicity by 10%–20% as a function of diameter or experimental time with no change in relative humidity. Secondly, we show experimentally that aerosol emitted from the flaming combustion of grass creates MCD bias. In this experiment, we measure the CPC response of the first three charges and invert these responses using a new routine named Junior. Junior's inversion of each charge shows that one growth factor distribution describes all measured diameters (no growth dependence on diameter). As in the modeling study above, previous publications of this aerosol system, using traditional inversion assumptions, report a decrease in hygroscopicity as DMA1 diameter increases. Unlike traditional inversions, Junior's inversion does not assume the particles are singly charged nor does it make the flat inlet size distribution assumption. Instead, both the inlet size distribution and each charge's CPC response are measured quantities. Thus, the discrepancy between our inversion results and previous publications is likely due to the traditional inversion routine assumptions. This underscores the importance for accounting for Slope and MCD bias during inversions. Experimental results should be carefully analyzed when reporting hygroscopic trends with respect to diameter or experimental time when using the traditional inversion assumptions.

ВІДНОВЛЕННЯ ДЕГРАДОВАНИХ МІСЬКИХ ВОДНО-БОЛОТНИХ УГІДЬ (НА ПРИКЛАДІ СОВСЬКИХ СТАВКІВ У КИЄВІ)

The article is devoted to the problem of the preservation of urban wetlands as the most vulnerable valuable ecosystems in the conditions of rapid urbanization, which need to be protected. It researches the current state of the Sovky tract (and the lower cas­cade wetlands of the Sovski Ponds located within it) in the center of Kyiv. Despite the strong urban influence, the rich floristic and faunal diversity of the studied area has been revealed. The value of urban wetlands for Kyiv is determined by the vital ecosystem services provided to the local community. Such services include, first of all, regulation of the microclimate, moisture and nutrients distribution in the soil, habitats preservation for the rare species of animals and plants, regulation of the groundwater levels, pollution filtration, waste adsorption, oxygen produc­tion and carbon dioxide absorption, water quality improvement, mitigation of the climate change consequences, creation of the favourable conditions for recreation, etc. As a result of field surveys of the Sovky tract, the complete decline of the territory and the degradation of valuable wetlands have been indicated. We have investigated the main geoecological conflicts caused by littering of the territory with household and construction waste, persistent pollution of the water bodies caused by untreated sewage due to unauthorized intrusions of resi­dents into the household sewers, chemical and noise pollution from the road infrastructure, grass burning in spring, etc. The spatial localisation of all conflicts within the Sovky tract is shown on the relevant map. The negative consequences of the long-term unresolved conflicts for the functioning of the wetlands and the quality of the ecosystem services they provide have been identified. Given the perspective of development in the study area of the ecopark and a fairly general idea of the essence of this concept, we proposed to include wetlands of Sovky tract in the Nature Reserve Fund of Kyiv. According to the current legislation, this area meets all the criteria of the category “Regional Landscape Park” (RLP).The main purpose of preserving the unique urban wetlands is the protection of rare species of plants and animals and their natural habitats, which is possible only in the conditions provided for in the RLP reserved zone. In addition, granting the official status of a protected area will make it impossible to build and litter within unique urban wetlands in the future.

АССОРТИМЕНТ ГАЗОННЫХ ТРАВ И СОСТОЯНИЕ ГАЗОНОВ В ОБЪЕКТАХ ОЗЕЛЕНЕНИЯ Г. СТАВРОПОЛЯ

In 2019–2021, a study of the species composition and current state of ornamental lawns in two parks, a boulevard and ten public gardens in Stavropol was conducted to evaluate the range of lawns used, their current state and to determine the effectiveness of the management measures taken to improve the quality of lawn coverings. The collected database can be used to make effective economic decisions to optimize the range and increase the ecological and aesthetic value of landscaping objects. The longevity of a lawn depends on the selection of lawn formers adapted to the given soil and climate conditions, capable of producing a high-quality lawn for many years and on proper care. The survey found that lawn grasses of the first and second quality groups were mainly used to create lawn coverings – Poa pratensis L., Festuca rubra L., Lolium perenne L., with Trifolium repens L. subseeds. In most cases, grass mixtures were used to create lawns. Recently, a more drought-resistant species, Festuca arundinacea Schreb, has been used more often as a lawn-forming agent. Most of the surveyed grass stands were rated “satisfactory” and “good” lawn. Stationary irrigation systems have been installed in a number of new landscaping facilities; rolled lawns have been used more often. Among the factors of negative impact on non-irrigated lawns are long dry periods, which led to the burning of lawn grass up to II–IV points, in 2018 – more than 50 days, in 2019 – more than 40 days, in 2020 – more than 60 days. At the same time, they lost their decorative, environmental and sanitary functions. Another negative environmental factor was the shading of lawns by tree crowns, which leads to thinning of the herbage, loss of decorative effect and the formation of dead covers. Additional shading of the lawn grasses was provided by leaf litter which was not removed in time. Almost all lawns had weed species that increased in number with age (clogging 1–3 points, abundance r-3). As a rule, mowing lawns did not destroy perennial weeds, the renewal zones of which were below the cut-off level of the lawn mower. No insect and disease damage to plants was detected. Negative anthropogenic disturbances on the surveyed landscaping objects are trampling, laying trails, dog walking. Lawns are regularly seeded and repaired.

Concentration, source apportionment and potential carcinogenic risks of polycyclic aromatic hydrocarbons (PAHs) in roadside soils

PAHs are organic pollutants that have carcinogenic and mutagenic impacts on human health and are a subject of great concern. The soil-bound polycyclic aromatic hydrocarbons (PAHs) in the urban areas can be very lethal to human health. The concentrations, sources, and possible cancer risks of 15 PAHs were analysed by collecting roadside soil samples in Lucknow, India. The range of ∑15PAHs was found to be 478.94 ng/g to 8164.07 ng/g with a mean concentration of 3748.23 ng/g. The highest contribution (32.5%) was found to be from four-ring PAHs, followed by six-ring (24.5%) and five-ring (16.7%) PAHs. The source apportionment through diagnostic ratios ANT/(ANT + PHE) against FL-2/(FL-2+PYR) highlighted the dominance of petroleum, wood, coal, and grass combustion as sources of PAHs in the study area. Source apportionment was also done through positive matrix factorization, confirming the dominance of ‘vehicular emissions’ (49%), followed by ‘coal and biomass combustion’ (∼39%), and ‘leakages, volatilization and petroleum combustion’ (∼12%) as potential sources. The results from lifetime cancer risks (ILCR) varied in the range of 7.5 × 10−4 and 1.3 × 10 × −2 illustrating ‘high cancer risk’. The total cancer risk susceptibility of children was found to be 31% more than that of adults. The highest risk associated with toxic equivalent concentration (TEQ) was found at site S8 highlighting the impact of the presence of an international airport, and huge traffic load. The present study will prove to be useful for information related to human exposure to PAHs content in soil in the study area and as baseline study for policy makers, stakeholders, and researchers.

Long‐term (64 years) annual burning lessened soil organic carbon and nitrogen content in a humid subtropical grassland

Burning has commonly been used to increase forage production and nutrients cycling in grasslands. However, its long-term effects on soil organic carbon (SOC) and nitrogen (N) pools within the aggregates and the relation between aggregates-associated SOC and soil CO2 emissions need further appraisal. This study evaluated the effects of 64years of annual burning on SOC and N dynamics compared to annual mowing and undisturbed treatments in a grassland experiment established in 1950. Soils were sampled from four depths representing the upper 30cm layer and fractionated into macroaggregates, microaggregates and silt+clay fractions. The macroaggregates were further fractionated into three occluded fractions. The SOC in the bulk soil and aggregates were correlated to soil CO2 effluxes measured under field conditions. Compared to the undisturbed treatment, annual burning decreased aggregates stability, SOC and N in the upper 30cm layer by 8%, 5% and 12%, respectively. Grassland mowing induced greater aggregates stability than burning only in the upper 5cm. Burning also decreased SOC in the large macroaggregates (e.g., 0-5cm) compared to mowing and the undisturbed grasslands but proportionally increased the microaggregates and their associated SOC. Soil N associated with aggregates decreased largely following grassland burning, for example, by 8.8-fold in the microaggregates within the large macroaggregates at 20-30cm compared to the undisturbed grassland. Burning also increased soil CO2 emissions by 33 and 16% compared to undisturbed and mowing, respectively. The combustion of fresh C and soil organic matter by fire is likely responsible for the low soil aggregation, high SOC and N losses under burned grassland. These results suggested a direct link between grass burning and SOC losses, a key component for escalating climate change severity. Therefore, less frequent burning or a rotation of burning and mowing should be investigated for sustainable grasslands management.

Ecological risk and sources of metals in open‐burned grasses in Guinea Savanna of Nigeria

AbstractHeavy metals in particulate emissions released into the atmosphere from open burning of grasses pose considerable danger to human health and environment. This study investigated the ecological risks and sources of heavy metals from burned grass emissions. Particulates resulting from laboratory‐simulated open burning of 40 species of grasses common in Nigeria were analyzed for heavy metals using energy‐dispersive X‐ray fluorescence (EDXRF). Highest metal concentrations were observed in Digitaria nuda for Cr, Cu, Rb, Zr, and Ni at 105, 35, 95, 70, and 40 mg/kg dry weight, respectively. The pollution assessment with enrichment factor, geo‐accumulation index, and contamination factor showed that Panicum repens and Sorghum bicolor were heavily contaminated with Pb. Pearson correlation analysis indicated strong positive relationship between Cu, Ni, Rb, Cr, and Zr, implying a same pollution source. Principal component analysis was used to identify possible pollutant sources, and 36.29% of the total variance was observed in factor 1. High loading of Cu (0.987), Ni (0.987), Rb (0.986), Cr (0.984), and Zr (0.839) were contributed by metal industries and crustal origin. This study revealed the extent of environmental pollution by heavy metals during open burning of grasses particularly from anthropogenic sources.