Mass Fraction Of Organic Matter Research Articles

Оценка химического состава сапропелей различных месторождений

Complex chemical composition and wide mining opportunities determine the use of sapropels and sapropel-based products in various sectors of national economy. The fullest potential of sapropel is revealed in agriculture, where it is used as fertilizer, a component of soils, raw materials for humic preparations production etc. The aim was to study the sapropels’ suitability for the production of humic fertilizers. Using validated methods we analyze chemical composition of sapropel sediments from 4 freshwater lakes located within the latitudinal section of 53–56° N in the temperate climate. Microbiological parameters of all studied samples are within the normal range. Dry matter content in the range of 46.1–51.3% corresponds to the normative indicators. The mass fraction of organic matter varies in the range of 31.8–39.9% DM. This allows classifying all samples as organo-clay, and determines the possibility of their use for soils of light granulometric composition. The relatively high content of humic (18.3–22.9% DM) and fulvic acids (3.7–6.4% DM) makes it possible to use the studied sapropel samples for the manufacture of humic preparations (especially, a sapropel sample of the lake Chervonoe, Belarus). Low P and K content (0.24–0.36% DM and 0.32–0.42% DM, respectively) can negatively affect the efficiency of fertilizers from these sapropel species; this can be avoided by mixing sapropel with manure or enrichment with mineral fertilizers. Indicators of heavy metal (Cu, Mn, Zn, Co, Pb and Cd) content in all studied samples meet the safety requirements. Samples from deeper layers of the Rusaki Lake (Altai Territory) and the Beloe Lake (Novosibirsk Region) refer to the 1st class of suitability, the rest (according to a number of indicators) – to the 2nd class. The content of trace elements in the studied sapropels is within the established norms and makes it possible to use them for replenishing the deficit of trace elements in soils. In general, all the studied samples can be used as environmentally friendly organomineral fertilizers, as well as production of humic preparations to increase in the biological and energy capacity of agrocenoses and to reproduce the soil fertility.

Evaluating the effect of organic matter contained in shale on hydraulic fracturing of infill-well

Organic matter which is scattered uniformly in shale can respond to the applied stress and result in the variation of stress field. However, the effects of organic matter content in organic-rich shale on stress interference have not been well considered during developing infill-wells. A fully coupled numerical model is proposed in this paper to consider the whole flow spectrum of shale gas and investigate the effect of organic matter content on stress variation and fracture propagation in infill-well. Through simulating the production and fracturing process with only one set of code, some conclusions can be drawn that the alteration angle of the maximum horizontal principal stress increases and then decreases with the production time. Furthermore, the shrinkage of organic matter enlarges the alteration angle and the magnitude of the maximum horizontal principal stress. Certainly, the optimal fracturing effect in the infill-wells vary due to the different mass fraction of organic matter. This study not only helps to understand the effect of mass fraction of organic matter on stress variation and fracture propagation, but also provides theoretical support for increasing production from shale gas reservoirs.

Soil microbiocoenosis in the agricultural environment as a dynamic system: primary results of the assessment of changes

Soil biota is characterized by high structural, taxonomic and functional diversity and determines the leading trends in the process of soil formation, while the microorganisms content in the soil varies widely depending on its chemical composition, humidity, temperature, pH and other properties. On the other hand, the soil microbiome has a significant impact on soil fertility, participating in the conversion of nutrients inaccessible to plants into usable forms. Soil microbiota can promote or inhibit plant growth. The purpose of this work is to conduct a comparative analysis of the leading representatives of the microbiome for soil samples from the territory of the model field of the peasant (farm) economy Tsirulev E.P. (Privolzhsky District of the Samara Region). Soil sampling was carried out in accordance with the methods of sampling and sample preparation for chemical, bacteriological, helminthological analysis. For comparison, 15 samples were taken from the same points of the field in different years 2019 and 2020. Soil suspensions were prepared according to the serial dilution method. Sowing dilutions was carried out on potato-glucose agar. Microorganisms were identified by microscopic method. The test result was calculated separately for fungi and bacteria. The ratio of fungi and bacteria in % to their total number was determined by calculating the number (N) of microorganisms present in the sample. Chemical analysis of soil samples was carried out according to the following parameters: water pH, salt pH, mass fraction of organic matter, mobile potassium and mobile phosphorus, exchangeable calcium and exchangeable magnesium. Laboratory study of soil samples taken on a model field from the territory of a peasant (farm) economy Tsirulev E.P. showed a fairly stable level of water and salt pH values, moderate variability in the content of organic matter, mobile potassium, magnesium and calcium, with a high heterogeneity of the spatial distribution of mobile phosphorus in the soil. Identification of the presence and abundance in soil samples of typical representatives of soil microbiocoenosis (12 broad-spectrum phytopathogens and 2 phytopathogen antagonists) made it possible to detect microorganisms: common in this soil environment in both years of research (causative agents of phomosis, yellow mucous bacteriosis); found for samples of one year in the minimum number of samples, not detected in another year (causative agent of verticillium, gray mold) or significantly increased their presence (causative agents of rhizoctoniosis, anthracnose, cladosporiosis). The presence in a significant proportion of soil samples, from 20 to 5080% of the samples, was noted for a significant group of objects (Alternaria, Fusarium, Aspergillus, Penicillium, Rhisopus), in both years of research, the presence of the phytopathogen antagonist Trichoderma was detected in all samples. The question of the connection between the revealed changes in the composition of the soil microbiome and the species of plants that were cultivated in this field during a given growing season requires additional data to be clarified, which we will do in subsequent years. Nevertheless, the primary data obtained confirm the existing ideas about the lability of soil microbiocoenosis as a dynamic system that changes its state in response to the impact of abiotic (temperature, humidity) and biotic factors.

Influence of Different Mining Damage Types on Soil Erodibility in Coal Mining Areas of Northern Shaanxi in the Middle Reaches of the Yellow River in China

The middle reaches of the Yellow River basin are not only rich in coal resources in China, but are also a typical experimental field for studying the law and mechanism of soil erosion caused by coal mining in the area. Grasping the differences in soil’s physical and chemical properties caused by different types of mining damage and then analyzing the differences in soil erosion is conducive to achieving ecological environmental protection and high-quality development in coal mining areas, thus improving soil and water conservation efficiency and saving costs. In this study, we took the typical loess subsidence slope of Ningtiaota mine field in the northern Shaanxi coal mining area as the research object, collected the soil samples at different slope positions, and measured the soil mechanical composition and organic matter mass fraction using an MS2000 laser particle size analyzer and a total organic carbon analyzer, respectively. Based on the EPIC model, the soil erodibility K value was further calculated, the spatial variation characteristics of the soil’s mechanical composition and organic matter mass fraction were analyzed, and the soil erosion effect under different mining damage types was interpreted. The results are as follows: ① The subsidence of loess slope and the development of mining ground fissures will reduce the clay mass fraction and increase the sand mass fraction in the shallow soil on the slope. The clay mass fraction of the whole slope will decrease by 4.50–30.30%, and the soil sand mass fraction will increase by 6.83–23.67%. The shallow soil at the top and middle of the slope has obvious sandy characteristics, and the amount of sandy soil in the crack area of the same slope is obviously higher than that in the non-crack area. Slope position is the main reason to control the shallow soil sand on the slope of loess subsidence in the northern Shaanxi coal mining area. ② The subsidence of loess slope and the development of mining ground fissures will lead to a decrease in organic matter mass fraction in shallow soil in different amounts. The decrease in organic matter mass fraction in the whole slope is 12.68–35.46%, and the decrease in organic matter mass fraction in shallow soil at the top and middle of the slope is significant, and the loss of organic matter in the crack area of the same slope is obviously higher than that in the non-crack area. The greater the width of the mining ground fissures and the smaller the horizontal distance from ground fissures, the more organic matter mass fraction in shallow soil will decrease. Mining ground fissures are the main factors when it comes to controlling the loss of organic matter in the shallow soil on the loess subsidence slope in northern Shaanxi coal mining area. ③ The negative correlation coefficients of shallow soil erodibility K value with the soil clay mass fraction and organic matter mass fraction all exceeded 0.6, a significant level, and there is a high degree of consistency in the change characteristics of the slope scale. The subsidence of the loess slope and the development of the mining ground fissures will have the effect of improving the erodibility of shallow soil in all parts of the slope. The erodibility of shallow soil at the top and middle of the slope increases significantly, and the erodibility of shallow soil in the crack area of the same slope is obviously higher than that in the non-crack area. The larger the width of the mining ground fissures and the smaller the horizontal distance from the ground fissures, the higher the erodibility of the surrounding shallow soil. After calculation, it was found that the maximum boundary of the mining ground fissures developed on the loess subsidence slope in northern Shaanxi coal mining area to improve the erodibility of the surrounding shallow soil was 115 cm, and the main action range was concentrated within 90 cm. These research results can provide a scientific basis for accurate prevention and control of the soil erosion effect of mining subsidence in loess coal mining in the area of northern Shaanxi, thus saving costs.

Characteristics of Soil Erodibility in the Yinna Mountainous Area, Eastern Guangdong Province, China

Soil erodibility research is of theoretical and practical significance to the prediction and prevention of regional soil erosion. At present, the study on soil erodibility in the lateritic red soil area of eastern Guangdong province is relatively lacking. Taking the forest land soil of the Yinna mountainous area as the research object, the physical and chemical properties (organic matter mass fraction, texture, moisture, bulk density, pH, aggregate content) of soil samples at different altitudes were measured with field survey sampling and indoor analysis. Soil erodibility K values were simulated with different models (the EPIC model, the Torri model, and the Shirazi model) and the regional applicability of the K simulation models was discussed. The influence of soil properties on soil erodibility was analyzed. The results showed that: (1) K values in the Yinna mountainous area are between 0.0250 and 0.0331 t·hm2·h/MJ·mm·hm2, and the K value in the subsoil layer (20-40 cm) is higher than that of the topsoil layer (0-20 cm). These values decreased significantly with the increase of altitude. The soil in the study area belongs to low-medium to medium erodible soil types. (2) The three models have certain applicability in the Yinna mountainous area, but the simulation results still lack validation. (3) Soil particle size composition is the most important factor affecting the K value in the study area. As far as the topsoil is concerned, K values increase with the increase of clay and silt content and decrease with the increase of sand content and aggregate stability. Soil erodibility has no significant correlation with pH and bulk density and has no clear relationship with the content of soil organic carbon and soil moisture. The research results can provide basic data for regional soil and water conservation and the construction of K value databases of different soil types in China.

ВМІСТ МІНЕРАЛЬНИХ ЕЛЕМЕНТІВ У ПЛОДАХ LYCOPERSICON ESCULENTUM MILL. ЗА ВПЛИВУ РЕКУЛЬТИВАНТУ КОМПОЗИЦІЙНОГО TREVITAN

The article presents the results of research on the effect of the Trevitan® composite recultivator on the elemental composition and ratio of macroelements in the fruits of the F1 Talent edible hybrid tomato. Field experiments with edible tomato were carried out in the conditions of the Western Forest Steppe of Ukraine on meadow-chernozem medium loam soils in 2021. The soil of the experimental field was characterized by a neutral reaction (pH=7,12), a low content of mobile compounds of macronutrients, and of trace elements (Fe, Mn, Cu, Zn). In the studies, Trevitan® composite recultivator was used – a product of organic origin for rapid soil regeneration, processing of seeds and planting material of various agricultural crops, acceleration of plant growth and development. Trevitan® is a liquid with a pH=7.5-10.9 and a mass fraction of organic matter of 50-80 % on the dry substance of the preparation. Trevitan® was applied by autumn soil treatment before plowing, seed and plant treatment during the growing season. 
 The use of Trevitan® compound recultivator in the technology of growing the Talent hybrid tomato influenced the indicators of the content of macro- and microelements, mainly by increasing their content. The content of Nitrogen, Potassium and Magnesium in the fruits of experimental plants compared to the control increased by 21,0, 31,6 and 43,3%, respectively. The amount of nitrogen in the fruits did not exceed the permissible level, which is an important characteristic of the quality of the fruits. It has been established that the use of Trevitan® composite recultivator helps to improve the mineral composition and biological value of tomato fruits, to increase the content of Manganese, Copper, Zinc and Potassium in them, while optimizing nutrition in the soil-plant system.

Features of sewage sludge degradation being involved in biomethanogenesis

Recycling waste into biogas not only provides energy source material, but also reduces the concentration of organic matter in the recycled raw material. The paper studies energy potential and rate of sewage sludge digestion, once combined at municipal plants with chicken manure and sugar beet pulp. A laboratory biogas plant with batch reactors was used for trials. A specific yield of biogas from activated sludge was 597.97±154.75 ml/g OM, specific yield of methane – 9.93±3.16 ml/g OM. The rate of organic matter digestion was 19.31%. Adding broiler chicken manure and sugar beet pulp into the bioreactor had a positive effect on fermentation. The specific yield of biogas increased to 978.39±166.32, bagasse – up to 1089.12±195.26 ml/g OM. The specific yield of methane increased, respectively, to 44.75±12.9 and 16.24±8.16 ml/g OM. The organic matter degradation rate increased to 30.61%, bagasse – to 33.94%. Thus, chicken manure and sugar beet pulp added into the bioreactor increases the efficiency of sludge treated into biogas, which is most likely due to increased mass fraction of organic matter and normalized carbon-nitrogen ratio in the bioreactor.

Soil fertility of Pinus massoniana forests under different near-natural management measures

Objective The research aims to study the effects of different near-natural management measures on soil fertility under Pinus massoniana forests. Method In Kaiyang near-natural management project area of Guiyang City, the near-natural selective cutting, near-natural thinning, near-natural tending, and the control group were selected to comprehensively evaluate the impact of different management measures on soil fertility under P. massoniana forests. Result The mass fractions of organic matter, soil total nitrogen, alkali-hydrolyzed nitrogen, total potassium, total phosphorus, available phosphorus, urease, alkaline phosphatase in near-natural selective cutting were higher than those of the control group, showing an up-going trend. The mass fractions of organic matter, total nitrogen, alkali-hydrolyzed nitrogen, total potassium, total phosphorus, and available phosphorus were significantly different(P＜0.05). The mass fraction of soil organic matter, total nitrogen, alkali-hydrolyzed nitrogen, total potassium, available potassium, total phosphorus, available phosphorus, and sucrose in near-natural thinning was higher than that in the control group, showing an increasing trend, among which the mass fraction of total nitrogen, alkali-hydrolyzed nitrogen, total potassium, available potassium, total phosphorus and available phosphorus had significant differences (P＜0.05), but the mass fraction of urease showed a decreasing trend. The mass fraction of alkali-hydrolyzed nitrogen, total potassium, available phosphorus and urease in near-natural tending showed a decreasing trend, among which the difference between alkali-hydrolyzed nitrogen and total potassium was significant (P＜0.05), and the mass fraction of sucrose showed an increasing trend. The comprehensive evaluation scores of soil fertility in the P. massoniana stands with near-natural thinning and selective cutting were significantly different from those of the control group (P＜0.05), but the difference in tending was not significant (P＞0.05). The effect of different near-natural management measures on soil physical indexes was not significant (P＞0.05). Conclusion Near-natural thinning and selective cutting can significantly promote soil fertility of P. massoniana forests, which is of great significance for maintenance and improvement of soil fertility of P. massoniana forests. The effect of near-natural tending on forest stands is not significant. The near-natural management theory plays an important role in improving forest soil fertility and sustainable forest management in Guiyang. [Ch, 1 fig. 6 tab. 19 ref.]

Aerosol Hygroscopicity during the Haze Red-Alert Period in December 2016 at a Rural Site of the North China Plain

A humidification system was deployed to measure aerosol hygroscopicity at a rural site of the North China Plain during the haze red-alert period 17–22 December 2016. The aerosol scattering coefficients under dry [relative humidity (RH) < 30%] and wet (RH in the range of 40%–85%) conditions were simultaneously measured at wavelengths of 450, 550, and 700 nm. It is found that the aerosol scattering coefficient and backscattering coefficient increased by only 29% and 10%, respectively when RH went up from 40% to 80%, while the hemispheric backscatter fraction went down by 14%, implying that the aerosol hygroscopicity represented by the aerosol scattering enhancement factor f(RH) is relatively low and RH exerted little effects on the aerosol light scattering in this case. The scattering enhancement factors do not show significant differences at the three wavelengths, only with an approximate 2% variation, suggesting that the aerosol hygroscopicity is independent of the wavelength. Aerosol hygroscopicity is highly dependent on the aerosol chemical composition. When there is a large mass fraction of inorganics and a small mass fraction of organic matter, f(RH) reaches a high value. The fraction of NO3– was strongly correlated with the aerosol scattering coefficient at RH = 80%, which suggests that NO3– played an important role in aerosol hygroscopic growth during the heavy pollution period.

Assessing the impact of anthropogenic pollution on isoprene-derived secondary organic aerosol formation in PM2.5 collected from the Birmingham, Alabama, ground site during the 2013 Southern Oxidant and Aerosol Study.

In the southeastern US, substantial emissions of isoprene from deciduous trees undergo atmospheric oxidation to form secondary organic aerosol (SOA) that contributes to fine particulate matter (PM2.5). Laboratory studies have revealed that anthropogenic pollutants, such as sulfur dioxide (SO2), oxides of nitrogen (NOx), and aerosol acidity, can enhance SOA formation from the hydroxyl radical (OH)-initiated oxidation of isoprene; however, the mechanisms by which specific pollutants enhance isoprene SOA in ambient PM2.5 remain unclear. As one aspect of an investigation to examine how anthropogenic pollutants influence isoprene-derived SOA formation, high-volume PM2.5 filter samples were collected at the Birmingham, Alabama (BHM), ground site during the 2013 Southern Oxidant and Aerosol Study (SOAS). Sample extracts were analyzed by gas chromatography-electron ionization-mass spectrometry (GC/EI-MS) with prior trimethylsilylation and ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS) to identify known isoprene SOA tracers. Tracers quantified using both surrogate and authentic standards were compared with collocated gas- and particle-phase data as well as meteorological data provided by the Southeastern Aerosol Research and Characterization (SEARCH) network to assess the impact of anthropogenic pollution on isoprene-derived SOA formation. Results of this study reveal that isoprene-derived SOA tracers contribute a substantial mass fraction of organic matter (OM) (~ 7 to ~ 20 %). Isoprene-derived SOA tracers correlated with sulfate () (r2 = 0.34, n = 117) but not with NOx. Moderate correlations between methacrylic acid epoxide and hydroxymethyl-methyl-α-lactone (together abbreviated MAE/HMML)-derived SOA tracers with nitrate radical production (P[NO3]) (r2 = 0.57, n = 40) were observed during nighttime, suggesting a potential role of the NO3 radical in forming this SOA type. However, the nighttime correlation of these tracers with nitrogen dioxide (NO2) (r2 = 0.26, n = 40) was weaker. Ozone (O3) correlated strongly with MAE/HMML-derived tracers (r2 = 0.72, n = 30) and moderately with 2-methyltetrols (r2 = 0.34, n = 15) during daytime only, suggesting that a fraction of SOA formation could occur from isoprene ozonolysis in urban areas. No correlation was observed between aerosol pH and isoprene-derived SOA. Lack of correlation between aerosol acidity and isoprene-derived SOA is consistent with the observation that acidity is not a limiting factor for isoprene SOA formation at the BHM site as aerosols were acidic enough to promote multiphase chemistry of isoprene-derived epoxides throughout the duration of the study. All in all, these results confirm previous studies suggesting that anthropogenic pollutants enhance isoprene-derived SOA formation.

Enhancement of the natural organic matter removal from drinking water by nanofiltration

Finnish surface waters are abundant in natural organic matter. Natural organic matter can be removed from drinking water in a water treatment process by coagulation and filtration. The standard treatment operations are not able to remove the smallest molar mass fraction of organic matter and the intermediate molar mass matter is only partly removed. The removal of residual natural organic matter from drinking water by nanofiltration was evalueted in this study. Three different nanofiltration membranes were compared in filtering six pre‐treated surface waters. The total organic carbon content of the feed waters varied from 2.0 to 4.2 mg 1‐1. Other water quality parameters measured were conductivity, alkalinity, hardness, UV‐absorbance, SUVA, E2/E3 value and molecular size distribution by high‐performance size‐exclusion chromatography. The natural organic matter removal efficiencies of the membranes were good and varied between 100% and 49%, and between 85% and 47% according to molecular size distribution and total organic carbon measurements, respectively. Removal of different molecular size fractions varied from 100% to 56%, 100% to 54% and 88% to 19%, regarding high molar mass, intermediate molar mass and low molar mass organic matter, respectively. The Desal‐5 DL membrane produced the highest natural organic matter removals.

Gas-particle partitioning of semivolatile organic compounds (SOCs) on mixtures of aerosols in a smog chamber.

The partitioning behavior of a set of diverse SOCs on two and three component mixtures of aerosols from different sources was studied using smog chamber experimental data. A set of SOCs of different compound types was introduced into a system containing a mixture of aerosols from two or more sources. Gas and particle samples were taken using a filter-filter-denuder sampling system, and a partitioning coefficient Kp was estimated using Kp = Cp/(CgTSP). Particle size distributions were measured using a differential mobility analyzer and a light scattering detector. Gas and particle samples were analyzed using GCMS. The aerosol composition in the chamber was tracked chemically using a combination of signature compounds and the organic matter mass fraction (f(om)) of the individual aerosol sources. The physical nature of the aerosol mixture in the chamber was determined using particle size distributions, and an aggregate Kp was estimated from theoretically calculated Kp on the individual sources. Model fits for Kp showed that when the mixture involved primary sources of aerosol, the aggregate Kp of the mixture could be successfully modeled as an external mixture of the Kp on the individual aerosols. There were significant differences observed for some SOCs between modeling the system as an external and as an internal mixture. However, when one of the aerosol sources was secondary, the aggregate model Kp required incorporation of the secondary aerosol products on the preexisting aerosol for adequate model fits. Modeling such a system as an external mixture grossly overpredicted the Kp of alkanes in the mixture. Indirect evidence of heterogeneous, acid-catalyzed reactions in the particle phase was also seen, leading to a significant increase in the polarity of the resulting aerosol mix and a resulting decrease in the observed Kp of alkanes in the chamber. The model was partly consistent with this decrease but could not completely explain the reduction in Kp because of insufficient knowledge of the secondary organic aerosol composition.