Humus Forms Research Articles

Balance model of humus state of arable chernozems of the Western Siberia

The results of model simulation of the humus state of arable soils in the Western Siberia based on long-term stationary studies and agrochemical monitoring of agricultural lands are presented. The following were studied: leached chernozem; podzolized chernozem; meadow-chernozem and dark gray forest soils. It was found that the nature of the root system formation depends on the biological characteristics of crops and cultivation conditions (the level of mineral nutrition, moisture). The mass of crop-root residues, as well as straw, is in close correlation with the yield of grain crops. Based on the actual data, regression equations were obtained with a high degree of reliability of the calculated data (approximation coefficient from R2= 0.84 to R2 = 0.93). Using the balance model of humus formation, it was found that the podzolized chernozem and dark gray forest soil were the least resistant to the anthropogenic factor. As a result of prolonged agricultural activity (52 years), humus losses in them amounted to 28 and 37 t/ha, which corresponded to annual losses of 0.54 and 0.71 t/ha. Leached arable chernozems lost 24 t/ha of humus, which corresponded to annual losses of 0.46 t/ha. In the course of the study, it was revealed that the arable land of the Western Siberia has a stable negative balance of humus state, which requires optimization of the farming system in the region.

The Functions of Potential Intermediates and Fungal Communities Involved in the Humus Formation of Different Materials at the Thermophilic Phase

The Functions of Potential Intermediates and Fungal Communities Involved in the Humus Formation of Different Materials at the Thermophilic Phase

EFFECT OF «MICROORGANIC» ORGANIC FERTILIZER ON WINTER WHEAT PRODUCTIVITY

The results of researches of technological process, chemical-biological indicators of organic fertilizer "Microorganic", obtained as a result of processing of secondary raw materials by the method of accelerated biological fermentation, are given. On the basis of experimental and industrial researches it is established that technological process of aerobic fermentation on open sites should be maintained within the following limits: humidity - the optimal level of 50-60% (permissible - 45-70%); temperature 50-55oC (permissible 40-60oC); oxygen concentration - more than 10% (permissible not less than 5%); density - 650 kg / m2 (550-750 kg / m2 is admissible). The obtained organic fertilizers "Microorganic" contained 1.5-2.3% nitrogen, 0.8-1.4% phosphorus, 1.2-1.8% potassium, the pH was 6.5-7.5. They are environmentally friendly, do not contain similar weed seeds, pathogens. The positive effect of fertilizer on agrophysical, agrochemical and microbiological properties of soil has been established. With the introduction of "Microorganic" increased microbiological activity of the soil as a test indicator of the positive effect of fertilizer, on average by 30% compared to the control (unfertilized soil with this type of organic fertilizer). At the same time, the content of soil copyitrophs (ammonifiers, microorganisms that decompose nitrogen - free compounds and the enzymatic, biochemical activity of the soil, the process of humus formation and the tendency to accumulate it in the soil increased especially). . A characteristic indicator of the activation of the microflora under the influence of these organic fertilizers is the increase in CO2 emissions, which is the result of accelerated accelerated decomposition of soil organic compounds (including humus). The average content of nutrients in the soil increased on average: for mineral nitrogen - by 10-15%, mobile phosphorus - by 10-30%, metabolic potassium - by 5-20%. The microbial potential of the organic fertilizer "Microorganic" contributed to the increase of biological activity of the soil, which led to increased access of biophilic elements to the root systems of plants, ensuring the formation of high yields. The highest yield of winter wheat variety "Tsentilivka", on average for three years, was on the option where organic fertilizers "Microorganic" were applied at a dose of 5 t / ha + N50P50K50 and was 8.81 t / ha, which is 4.75 t / ha more compared to the control Economic analysis obtained. The results of the study showed in this case and the highest economic indicators of cultivation with a level of profitability of 151.7%

Humus formation in soils of the Lena River Delta

The aim of the study. Nowadays close attention is paid to polar soils due to the expected landscape transformation rate under the predicted climate crisis. Intensive degradation of permafrost and the release of nutrients from their frozen state can lead to an increase in the emission of greenhouse gases into the atmosphere, as well as the loss of landscapes. The aim of the study was to investigate the peculiarities of organic residues formation and humification degree as well as humus structure and functioning in soil the Lena River Delta. 
 Location and time of the study. The study was conducted on the Samoylov and Sardach Islands in the Lena River Delta (Yakutia, Russia). Field studies were performed during the summer of 2019. 
 Objects and methodology. Soils of the Lena River Delta from the Samoylov Island (flooded area) and Sardakh (non-flooded zone), i.e. Subaquatic Fluvisol (Arenic) and Histic Cryosol (Siltic) were the objects of the study, respectively. To examine the features of humification chemical-analytical, sedimentation, micromorphological methods were used, as well as CP/MAS 13C-NMR spectroscopy. 
 Main results. The data obtained indicate a high diversity of soils and soil formation conditions in the Lena River Delta. Under non-flooded conditions Histic Cryosol (Siltic) were formed in the flooded parts of the Samoylov Island, Subaquatic Fluvisol (Arenic) were formed. These soils play an important role in the global carbon cycle, accumulation, transformation and deposition of condensed high- and low molecular mass organic compounds in the composition of soils and permafrost. The main soil micromorphology features were identified. In the young landscapes the soil microstructure was represented by poorly sorted sand with a circular type of optical orientation of the soil plasma (which indicated the influence of the river), as well as vertically oriented micas (muscovite/biotite). Soils influenced by the floodplain process were characterized by the presence of coarse amorphous humus. Due to the long-term effect of the freezing/thawing processes on the permafrost-affected soils the biogenic aggregates were formed. In such organo-mineral microaggregates humus is fixed in the composition of mineral components consisting of particles of quartz, micas and Mn-Fe nodules and is in a stable state (physical stabilization of humus). To analyze the molecular composition the 13C NMR spectroscopy method was used. According to 13C NMR spectroscopy data, up to 37% of aromatic structural fragments accumulated in soils, which indicates the process of condensation of molecules in humic acids, thus showing a relatively high level of humus stabilization in the soils of the Lena River delta. From the data obtained, three main groups of chemical structural fragments that accumulate in the delta soils can be distinguished, such as C,H - alkyls ((CH2)n/CH/C and CH3), aromatic compounds (C–C/C–H, C–O) and the OCH group (OCH/OCq). In the studied humic preparations aliphatic structural fragments of HAs (63–64%) predominated, which indicated a deficiency of lignin and lignin-like compounds in the composition of humification precursors. The predominance of aliphatic structures is typical of humic substances formed under reduction conditions, including the aqueous humic substances, as well as in soils, the precursors of humification of which are typical tundra vegetation (mosses and lichens) with a predominance of carbohydrates (up to 80%). A significant amount of aromatic fragments accumulated in the delta in the alluvial soils of the first terrace of the river (flooded zone). This is apparently due to the formation of vascular plants in the flooded areas of the Lena River Delta. The chemical composition of vascular plants includes components such as tannins, flavonoids and lignin (arenas). Thus in the samples formed under vascular plants with a lignin content of about 30%, an increase in signals in the range of 110-160 ppm were observed. Aromatic and carboxyl fragments in the structure of HA were formed during the transformation of lignin, which leads to the resistance of HAs to biodegradation.
 Conclusion. Under the floodplain condition humus is represented by coarse amorphous forms, whereas without the influence of flooding humus is fixed in mineral microaggregates. Specific humic acids composition in the studied regions is determined by bioclimatic conditions, cryogenic processes and the composition of humification precursors. High abundance of aromatic structures in humus substances suggests relatively stable humus status (most likely due to the putative condensation of humic acids) in the Lena River Delta during the study period.

System of Diagnostic Indicators for Low-Productive and Degraded Soils to Assess Their Suitability for Afforestation

Purpose. The identification of soil indicators for assessing the forest growth potential of soils for the possibility of afforestation. Methods. The indicators were chosen among the soil parameters most often used to assess fertility: reserves and thickness of forest litters, morphological characteristics of soils, particle size distribution, acidity, humus and various forms of NPK content, composition and content of exchangeable cations. The research was carried out in natural medieval forests according to the methods generally accepted in forest inventory, typology, soil science, analytical work - according to classical agrochemical and standardized methods. Results. The article gives an analysis of the problem of forestry typological evaluation of low-output and degraded soils (sandy, with shortened profile, salted, eroded), which were withdrawn from agricultural usage. The actual and theoretical material on the basis of which the range of issues related to the evaluation of forest land use in different natural zones is generalized, was collected and analyzed. On the main categories of low-productive lands in different natural zones of the flat part of Ukraine temporary trial areas were laid, where soil and typological investigation were conducted. The soil indicators and parameters of forest productivity of low productivity and degraded soils are determined, on the basis of which the classification of soils based on the degree of their suitable for afforestation has been developed. The suitability of soils for afforestation were evaluated in three categories: suitable for afforestation, limitedly suitable and unsuitable suitable for afforestation. Conclusions. The experience of afforestation of low-productive and degraded soils is generalized and a system of diagnostic indicators for their forest typological evaluation on zonal and morphological basis is proposed, and an information analysis on the problem of assessing the suitability for afforestation of low-productive lands (saline, stony, sandy) that are derived from agricultural circulation is provided. The suitability of soils for afforestation is described by a system of soil indicators, in particular, their particle size distribution, humus content, common and mobile forms of NPK, and exchangeable cations. However, among these indicators, one can single out informative indicators of the level of productivity of forest lands - mineralogical (chemical) and granulometric composition of soils. At the same time, it has been proved that the granulometric composition of the soil determines such important characteristics as the content of exchange bases, common forms of phosphorus, potassium, and humus.

ФОРМИРОВАНИЕ МИКРОЭЛЕМЕНТНОГО СОСТАВА ТЁМНО-СЕРЫХ ЛЕСНЫХ ПОЧВ СТАВРОПОЛЬСКОЙ ВОЗВЫШЕННОСТИ

The article discusses the main regularities of the formation of the microelement composition of the dark gray forest soils of the Stavropol Hill. It has been established that the microelement composition of soils is formed under special conditions of the course of soil-forming processes: with a periodically flushed type of water regime, an oxidizing environment in the soil profile, the influx of organic residues with a high content of bases, and the predominance of humic acids in the humus composition. The development of a system of soil compounds of microelements occurs against the background of humus formation, humus accumulation, clay formation, weakened carbonate leaching to the lower part of the soil profile, partial loessage, illuviation. In the soil profile of dark gray forest soils, several geochemical barriers are formed, on which microelements are fixed: biogeochemical, alkaline, and sorption. The main phases-carriers of microelements in dark gray forest soils are organomineral complexes, secondary aluminosilicates of the montmorillonite group. The role of ferruginous minerals in fixing trace elements is weakened due to the low intensity of oxidogenesis processes.

Detecting Organic Materials in Fly Ash using Chromatographic Method

Abstract: Fly ash, a byproduct of coal-fired power plants, is entirely inorganic and inert, making it unfit for life. In Korba, fly ash is deposited in dykes, which are open embankments. The quest for organic compounds was critical because the humus formation is a revolution in fly ash, and just it will be capable of supporting life forms. This was conducted in the dykes to verify the organic materials source in fly ash, namely, whether they are originated from coal, furnace start-up oil, or animals and plants that grew in the area. Thin layer chromatography and ascending paper chromatography in a liquid medium were used as the method.

Research of tools for monitoring changes in natural and anthropogenic-transformed ecosystems

Decarbonization issues are one of the main strategic directions of modern environmental development today. New technologies of agricultural use of soils are used to fix carbon in the soil in the form of humus, which ultimately helps to reduce the greenhouse effect and actively affects the amount of carbon entering the atmosphere. The use of open data of remote sensing of the Earth from space (further - RSE) together with the data of satellite monitoring of the Normalized Difference Vegetation Index (NDVI) can allow us to obtain new methods of carbonation analysis. In this paper, we consider the possibilities of such use of standard NDVI data together with a more accurate definition of specific boundaries of agricultural fields in order to increase the accuracy of research results. This article shows the results of processing data and images obtained using open crop monitoring data. The proposed technology is proposed by us as an additional tool for monitoring changes in the ecosystems of the regions.

Methods for restoring fertility and improving physical and mechanical properties of soils

Insufficient intake of organic matter into the soil, non-compliance with crop rotations result in the soil degradation. Only due to the use of mineral nutrition, it is impossible to maintain a high level of soil fertility. To compensate for the lack of humus, the most optimal is the use of green fertilizers. The costs of producing and applying cover crops are significantly less than the costs of using organic fertilizers. In terms of peasant farms conditions in the Tambov region, two types of crop rotations with the introduction of sideral crops are recommended. It is important to carry out grinding and embedding of sideral crops specifically so that it can provide optimal parameters for the decomposition of organic mass and promote humus formation. Currently, four processing techniques are used for harvesting and embedding sideral crops. The recommended scheme involves mowing and step-by-step grinding of the grass stand with a mower-shredder located in front of the tractor, followed by embedding in the soil with a disc harrow. The analysis shows that small producers segment has no affordable machines for high-quality grinding of sideral crops with low specific energy consumption. To ensure stems cutting with minimal specific energy consumption, a mower has been developed, which, due to the trough-shaped type of its body, forms plants tilted forward in a mass and then, they fall into the grinding zone with the angle of inclination of the stems in this mass close to the angle of body inclination. In the grinding zone, the plant stems are exposed to knives rotating in plane surfaces perpendicular to the longitudinal surface of the mower body. As a result of operational tests of the mower-shredder of sideral crops and crop residues, it was found that technological process of plants grinding is carried out steadily and with a quality that meets agrotechnological requirements.

Органическое вещество почв и техногенных поверхностных образований селитебных районов г. Перми

On the territory of the left-bank part of Perm, the urban pedocomplexes (UPC) were distinguished as a combination of soil and technogenic surface formations on the same soil-forming rocks within a certain functional zone. Within the UPC, formed on eluvial-deluvial loams and clays in the zone of multi-storey buildings, the surface horizons of soils and TSF (technogenic surface formations) were studied. A change in the zonal trend of humus formation in reclaimed soils was observed as an increase in the content of organic matter, as well as in a change in the type of humus to the humate side. The conservation of zonal features of humus formation in non-purposefully recultivated urban soils and TSF was noted. It manifests in a low or medium content of organic carbon, the formation of a humate-fulvate type of humus. Keywords: URBAN ECOLOGY, URBAN SOILS, URBAN PEDOCOMPLEX, HUMUS, HUMUS TYPE, SOIL PROPERTIES

Carbon Polygons and Carbon Offsets: Current State, Key Challenges and Pedological Aspects

Russia holds the largest store of carbon in soils, forests and permafrost grounds. Carbon, stored in a stabilized form, plays an important role in the balance of the global biogeochemical cycle and greenhouse gases. Thus, recalcitrance of soil organic matter to mineralization results in a decrease in current emissions of carbon dioxide into the atmosphere. At the same time, stabilization of organic matter in the form of humus due to organo–mineral interactions leads to the sequestration of carbon from the atmosphere into soils and biosediments. Thus, global carbon balance is essentially determined by soil cover state and stability. Currently, Russia is faced with a set of problems regarding carbon offsets and the carbon economy. One of the methods used to evaluate carbon stocks in ecosystems and verify offsets rates is carbon polygons, which are currently being organized, or are under organization, in various regions of Russia. This discussion addresses the current issues surrounding the methods and methodology of carbon polygons and their pedological organization and function.

Biological activity and humus state of soils in the near-adjacent part of the Selenga River

Peculiarities of humus formation and manifestation of biological activity of soils are revealed. The objects of research are grey forest nonpodzolized, alluvial meadow soils as arable land, meadow-marsh soils as hayfield. Humus condition of the studied soils is in satisfactory condition within each soil type. The current state of the humus fund of old-arable grey forest soils is characterized by low humus content and unsatisfactory composition, which is caused by the absence of fertility change. The productivity of meadow-marsh soils is high and considerably exceeds grey forest and alluvial meadow soils. The information obtained on biological activity, can be used in agricultural practice to assess soil productivity, as well as in environmental monitoring.

Formation of organic soil horizons during the initial pedogenesis in the taiga zone of the European Russian Northeast

Investigations were carried out in the European Russian Northeast (Komi Republic), -in the middle taiga subzone, in the (construction sand) quarry area. Formation of the soil profile within two decades after forest reclamation practices (Pinus sylvestris planting) was considered. Specifics of litter and humus horizons formation, processes of humus formation and accumulation on substrates of different granulometric composition were determined. It is shown that the rate of these processes is determined by the species composition and structure of the plant community. By the end of the second decade, up to 2.7 t·ha-1 of organic carbon accumulates in the humus-accumulative layer (0-20 cm) of sandy and sandy-loam soils, 6.3 t·ha-1 - in clay-loam soils, and 0.1 and 0.4 t·ha-1of nitrogen, respectively, accumulates there as well. The accumulation rate of Corg in the soil of the sandy and sandy-loam quarry reached 0.16, in the clay-loam quarry - 0.37 t·ha-1·year-1. The organic horizons of the forming soils demonstrate a decrease of the mass fraction of calcium, potassium, phosphorus and an increase in iron and aluminum down the profile.

Transformation of organic matter of Cisbaikal forest-steppe abandoned lands

For the first time, quantitative estimates of the carbon pools (plant residues, microbial biomass, and humus) that provide organic matter reserves in gray forest soils depending on the abandoned age are presented for the region. The pool of C-plant residues, which comprises only carbon reserves in the aboveground part of the herbaceous layer and litter fall, varied from 0.3 to 5.9 t·ha-1. Young fallows were observed to demonstrate the highest values. The increase in the age of the abandoned land was found to be accompanied by the decrease in carbon reserves in the plant pool. The microbial carbon pool (Cmic) varied from 2.1 t·ha-1 on young fallows to 5.2 t·ha-1 on long-term abandoned lands approaching the indicators identified for natural cenoses (6-8 t·ha-1). The largest value (25-72 t·ha-1) characterized the carbon pool in the humus, but no regular changes depending on the abandoned age were identified. The type of humus in the soils after abandonment, as well as in undisturbed soils, was fulvate-humate, and the degree of humification varied from “medium” to “very high”. This indicates the preservation of zonal features of humus formation of gray forest soils in the region during their postagrogenic development.

ПОКАЗАТЕЛИ ХЕМОДЕСТРУКЦИОННОГО ФРАКЦИОНИРОВАНИЯ ОРГАНИЧЕСКОГО ВЕЩЕСТВА ПОЧВ ПРИРОДНЫХ И АНТРОПОГЕННО ПРЕОБРАЗОВАННЫХ ЛАНДШАФТОВ ЮГА ПРИМОРЬЯ

The differences in the qualitative composition of organic matter in the soils of natural and anthropogenically transformed landscapes in the south of Primorye were established by the method of chemodestructive fractionation (CDF). The lowest indices of the easily oxidizable part (EOP) in the organic matter are typical for soils of technogenic landscapes (embryozems) with very low humus content due to low reserves of aboveground phytomass and the supply of fresh organic matter of plant origin. Embryozems are characterized by a low supply of humus with nitrogen. Higher EOP values are characteristic of soils of natural landscapes (burozems) with average humus content. In burozems, oxidative and eluvial processes are balanced by humus formation. In the soils of agrogenic landscapes (agro-dark-humus podbeles, agro-dark-humus gley soils) with low humus content, the proportion of EOP decreased and, at the same time, the proportion of the hardly oxidized part in the composition of soil organic matter increased. Some increase in EOP was recorded in agro-dark-humus gley soils with rump crops, which is associated with the intensification of the transformation processes of organic matter and the transition of organic matter from the difficult-to-oxidize to the easily oxidized part. Based on the data obtained on the qualitative composition of organic matter, the CDF method implies that in the soils of natural landscapes (burozems), the proportion of EOP exceeded that in comparison with soils of agrogenic (agro-dark-humus podbely, agro-dark-humus gley) and technogenic landscapes (em-briozems). This indicates differences in the conditions of soil formation and the ongoing oxidative and humus-forming processes.

ЗАКОНОМЕРНОСТИ ФОРМИРОВАНИЯ МИКРОЭЛЕМЕНТНОГО СОСТАВА ПОЧВ ПОД ГОРНО-ЛУГОВОЙ РАСТИТЕЛЬНОСТЬЮ БОЛЬШОГО КАВКАЗА

Report. The purpose of the work is to identify the features of the formation of the microelement composition of soils under the mountain meadow vegetation of the Greater Caucasus based on the analysis of literary materials and the results of our own field research. Methods. The study of the microelement composition of soils under subalpine and alpine vegetation was carried out on the territory of the Teberdinsky State Biosphere Reserve. Traditional methods of soil-geochemical studies were used with the laying of soil sections, the selection of soil samples and their analysis for the content of four trace elements (Zn, Cu, Pb and Cd). Determination of trace elements was carried out by voltammetric and atomic absorption methods. The humus content was determined by the Tyurin method with wet salting, the pH of the water extract was determined potentiometrically. Statistical processing of the obtained data was performed in the Statistica 10 program. The microelement composition of soil-forming rocks was compared with the clarks of chemical elements in the upper part of the continental crust; the microelement composition of mountain-meadow soils was compared with the clarks of the soils of the world. The radial distribution of trace elements in the soil profile was analyzed. The qualitative trace element composition of soils was characterized as a sequence of decreasing the content of trace elements in the humus horizon. Results. It is established that the microelement composition of soils under the mountain-meadow vegetation of the Western Caucasus is formed under specific conditions that affect the course of soil processes. High solar insolation, low temperatures, intensive humidification throughout the year affects the features of the processes of humification, the formation of clay minerals in the soil and other products of intra-soil weathering. The predominance of acid hydrolysis processes leads to the predominant accumulation of aluminosilicates, Fe hydroxides, chelated organomineral complexes in the soil profile, which play a leading role in the binding of trace elements. The microelement composition of mountain-meadow soils under subalpine vegetation is formed with more intensive processes of humus formation and oglinivaniya. These soils are characterized by a more pronounced biogenic accumulation of Cu and Zn in the humus horizon, the illuvial nature of the Cd distribution is more pronounced. The microelement composicomposition of mountain-meadow soils under alpine and rock-scree vegetation is formed against the background of relatively weakened processes of humus formation, humus accumulation and oglinivaniya. This affects the lower intensity of biogenic accumulation of trace elements, their leaching into the lower part of the profile. Conclusions. The main regularities of the formation of the microelement composition of mountain-meadow soils are determined by the special conditions in which these soils develop. The fixation of trace elements in mountain-meadow soils occurs mainly on aluminosilicates, Fe, Mn hydroxides and chelated organomineral complexes, which largely form the silty fraction. The movement of silty particles along the soil profile leads to the redistribution of trace elements associated with them. The granulometric composition, which is an indicator of the content of the silty fraction and its distribution along the soil profile, is of great importance when characterizing the microelement composition of mountain meadow soils. The established regularities of the formation of the microelement composition of mountain-meadow soils allow us to determine the main directions of economic activity that will contribute to the preservation of their ecological state. This is, first of all, the rational use of pasture resources of mountain meadows with the introduction of a system of alternating mowing, changing the main pastures with spare ones during the year for their restoration. An important component should be monitoring changes in the trace element composition of mountain meadow soils, which will allow timely response to changes and make adjustments to the structure of the use of these soils.

ЭКОЛОГИЧЕСКОЕ СОСТОЯНИЕ ЛУГОВО-ЧЕРНОЗЕМНОЙ ПОЧВЫ ПРИ ДЛИТЕЛЬНОМ ОРОШЕНИИ

The research was carried out on an irrigated stationary crop rotation of the Federal State Budgetary Scientific Institution “Omsk Agrarian Research Center” in the southern forest-steppe of Western Siberia. The aim of the research was to establish the direction and intensity of mobilization biological processes in case of long-term irrigation, their quantitative characteristics, as well as possible adverse changes of biological (ecological) properties of meadow – black soil. The microbial community performs the function of maintaining soil homeostasis, therefore it quickly responds to habitat changes. The intensity of soil mineralization and humus formation processes was determined by a combination of fertilization and irrigation factors. It was found that immobilization processes prevailed in the soil under crops. The highest coefficient of organic matter transformation, i.e. transformation increase of plant residues into organic matter, was noted when introducing nitrogen-phosphorus fertilizers for barley crops. Application of mineral fertilizers promoted an increase of the number of the defined microorganisms, enhanced cellulose decomposition in the soil, potential capacity of soils to accumulate nitrate and enzyme activity, which ultimately increased the yield of cultivated crops. The yield of perennial grasses on a fertilized background was at the control level due to loss of legumes (goat’s rue) and predominance of bluegrass species (awnless brome). A strong correlation was obtained between the intensity of cellulose decomposition in the soil, nitrification capacity and crop yields (r = 0.67 ± 0.28 and 0.91 ± 0.16, respectively). Long-term irrigation of meadow-black soil did not have a negative impact on its ecological state, and usage of intensive cultivation technology of crops in crop rotation stimulated an increase of soil microorganisms and their activity.

Pathway analysis of the biodegradation of lignin by Brevibacillus thermoruber

With increased interest in the biodegradation of lignin, there is a pressing need to evaluate the feasibility of using microorganisms for lignin degradation. A novel Bacillus strain was separated from compost and identified as Brevibacillus thermoruber. B. thermoruber showed excellent performance in lignin degradation and degraded 81.97% of lignin after 7 d, which was similar to the lignin degradation rate of fungi. The biodegradation of lignin G and H monomers mainly proceeded via the β-ketoadipate pathway at 37 °C. At 55 °C, the degradation product of lignin S monomer was mainly a benzoic acid substance, indicating that the lignin was degraded via the benzoic acid pathway. The degradation products of lignin are important precursors for humus formation in compost. The results of this study provide new insights into the biodegradation pathway of lignin in different stages of composting.

Forecrop Influence on Humus Formation under Novgorod Region Conditions

In the article, the data on the study of the forecrop influence on the spring wheat yield and humus formation in grain-fallow and grain-row crop rotations under the conditions of the D. P. Pavlyuk peasant farm household (PFH) of the Novgorod region is provided. It has been found that the yield of spring wheat and the accumulation of plant residues and humus in the soil in the crop rotation system is greatly influenced by the forecrop. Thus, as a result of the studies carried out to explore the influence of the forecrop on the yield and humus formation, it has been found that the forecrop has a great influence on the yield of grain and the accumulation of plant residues and humus in the soil in the crop rotation system. In grain-row crop rotation, spring wheat, sown after potato, demonstrated the highest grain yield (about 5.5 tonnes per hectare) and provided the output of root and crop residues of more than 6 tonnes per hectare. This led to the maximum formation of humus in the soil (about a tonne per hectare). In the grain-fallow crop rotation, the cultivation of wheat after pure fallow provided a grain yield per unit area of about 4.5 tonnes per hectare. Furthermore, 0.74 tonnes of humus were produced in the crop rotation system for the formation of the yield of the following crops. Repeated sowing of wheat provided a low grain yield of the spring grain crop. Permanent sowing of wheat formed the least amount of plant residues and humus. The humus formation was only 0.54–0.59 tonnes per hectare. This confirms the unreasonableness of using permanent sowing of wheat.

Biological factor of humus reproduction in conditions of the steppe zone of the Southern Urals

The paper considers a biological factor affecting the reproduction of humus and the maintenance of soil fertility in a region with unstable moisture. In the steppe zone of the Southern Urals, the humus formation process is affected by the amount of plant (stubble-root) residues entering the soil, which suggests the possibility of reducing the mineral fertilizers use. The purpose of the experiment was to determine the affecting of a set of field crops in crop rotations on the input of organic matter into the soil of the southern chernozem. The paper studies three variants of the experiment with different types of fallow. An increase of humus in the soil by 0.17% (in the percentage) was found in the crop rotation with fallow occupied by the summer sowing of Sudanese grass in comparison with grain-fallow with weed-free fallow. On average over 10 years, the largest volume of organic matter entered the soil during the cultivation of winter rye in a crop rotation with weed free-fallow (11.87 tons per 1 ha).