Humus Forms Research Articles

Урбостратоземы жилых многоэтажных районов г. Перми: формирование, трансформация и оценка экологического состояния

The processes of formation of technogenic urbostratozems on the basis of grounds self-overgrowing with ruderal vegetation are considered. The main physical and chemical properties of urbostratozems have been studied. The main soil-forming processes in urbostratozems - soddy process, humus formation and humus accumulation, as well as decarbonatization of surface horizons - occur with a combination of zonal and anthropogenic factors of soil formation. Phytotesting showed that urbostratozems generally have a satisfactory ecological state and provide better conditions for plants than zonal soddy-podzolic soils and grounds from which they are formed. Keywords: URBAN SOILS, SOIL FORMATION PROCESSES, PHYTOTESTING, URBOSTRATOZEMS

Hydrothermal pretreatment improves humification in co-composting of oil palm fronds and paper mill sludge

The co-composting of oil palm fronds and paper mill sludge may be economical and eco-friendly, yet the complex indigenous configuration of lignocellulose reduces the bioavailability of waste, resulting in the hindrance to the humification process. In this work, oil palm fronds after hydrothermal pretreatment were mixed with paper mill sludge for co-composting, and the effect of hydrothermal pretreatment on the humification process was explored using excitation-emission matrix-parallel factor analysis and 16S rDNA sequencing. The results showed that the duration of thermophilic phase was extended from 13 days to 17 days after hydrothermal pretreatment. During hydrothermal-pretreated composting, the consumption of protein-like substances and the production of humus-like substances increased by 24.7% and 33.9%, respectively, compared with those of control. The degradation of polysaccharide (decreased from 76.5 to 20.0 g/kg) was accelerated and the content of reducing sugar (ranged from 11.5 to 13.5 g/kg) was increased. The key microbial communities (including Bacillaceae, Sphingobacteriaceae, Streptosporangiaceae and Thermonosporaceae) showed obviously stronger activity. Correlation analysis showed that the production of reducing sugar and the activity of key microbial communities were reinforced, and both were favorable for the rapid synthesis of humus. Collectively, this work provides an overview of a regulatory mechanism underlying humus formation during the composting of lignocellulosic wastes.

Study on the Profile Distribution and Morphology of Soil Humic Substances in Karst Area of Zunyi City, China

Soil degradation in low soil humus content karst areas is a serious problem. Humus is composed of a series of polymer organic compounds, with no fixed form, therefore it is difficult to study, especially humin. In this study, 13C CP/MAS NMR was used to study the humic acids (HA), fulvic acids (FA), and humin (HM) components in the soil profiles of carbonate rocks and argillaceous rocks in the Northern Guizhou region. Through the vertical distribution of humus in soil, the transformation mechanism among functional groups of humus was studied. The content of HA and FA in the soil of Zunyi New Area was low, and the humification degree was low. FA was the main HA with simple molecules, which were directly related to the surface vegetation in the area. There may have been some genetic relationship between Aliphatic C and Aromatic C, Aliphatic C and Carboxyl C in the same group of humus. In the phylogenetic relationship of HA, FA, and HM, more transformations existed between HA and FA, and between HA and HM, while the transformations between FA and HM were very rare. This study provides an important scientific basis for the theory of the formation and transformation of soil humus in karst area.

The interplay between atmospheric deposition and soil dynamics of mercury in Swiss and Chinese boreal forests: A comparison study

Taking advantage of the different histories of Hg deposition in Davos Seehornwald in E-Switzerland and Changbai Mountain in NE-China, the influence of atmospheric deposition on Hg soil dynamics in forest soil profiles was investigated. Today, Hg fluxes in bulk precipitation were similar, and soil profiles were generally sinks for atmospherically deposited Hg at both sites. Noticeably, a net release of 2.07 μg Hg m−2 yr−1 from the Bs horizon (Podzol) in Seehornwald was highlighted, where Hg concentration (up to 73.9 μg kg−1) and soil storage (100 mg m−3) peaked. Sequential extraction revealed that organic matter and crystalline Fe and Al hydr (oxide)-associated Hg decreased in the E horizon but increased in the Bs horizon as compared to the Ah horizon, demonstrating the coupling of Hg dynamics with the podzolisation process and accumulation of legacy Hg deposited last century in the Bs horizon. The mor humus in Seehornwald allowed Hg enrichment in the forest floor (182–269 μg kg−1). In Changbai Mountain, the Hg concentrations in the Cambisol surface layer with mull humus were markedly lower (<148 μg kg−1), but with much higher Hg soil storage (54–120 mg m−3) than in the Seehornwald forest floor (18–27 mg m−3). Thus, the vertical distribution pattern of Hg was influenced by humus form and soil type. The concentrations of Hg in soil porewater in Seehornwald (3.4–101 ng L−1) and in runoff of Changbai Mountain (1.26–5.62 ng L−1) were all low. Moreover, the pools of readily extractable Hg in the soils at both sites were all <2% of total Hg. Therefore, the potential of Hg release from the forest soil profile to the adjacent aquatic environment is currently low at both sites.

The functions of potential intermediates and fungal communities involved in the humus formation of different materials at the thermophilic phase

Humus is the final product of humus precursors (HPS) during the humification process, while the associated mechanisms of humus formation have not been clarified. Here, the HPS degradation intermediate and core fungal function for wheat straw and chicken manure compost (SCM), cow dung compost (CD), Chinese traditional medicine residue compost (CTM) and mushroom dreg and chicken manure compost (MCM) was investigated during the thermophilic phase. The results showed SCM and MCM were rich in proteins, lipids, cellulose, low-molecular-weight organic acids, while CD and CTM contained abundant carbohydrates, aliphatic compounds, easily biodegradable aromatic structures, and intermediates from the lignocellulose degradation. In particular, the HPS degrading intermediates including O-alkyl-C and aromatic C compounds were the critical factors, and Scedosporium, Hypsizygus and Remersonia were the core fungal genera for the humification. Furthermore, the potential fungal functional genes involved in carbohydrate and lignin degradation might be the key factors to drive the humification process.

Comparison between cold plasma, ultrasonication, and alkaline hydrogen peroxide pretreatments of garden waste to enhance humification in subsequent composting with kitchen waste: Performance and mechanisms

This study compared the performance and mechanisms of cold plasma, ultrasonication, and alkali-assisted hydrogen peroxide for garden waste pretreatment to advance humification in composting with kitchen waste. High-throughput sequencing integrated with Functional Annotation of Prokaryotic Taxa was used to relate bacterial dynamics to humification. Results show that all pretreatment techniques accelerated humification by 37.5% – 45.7% during composting in comparison to the control treatment. Ultrasonication and alkalization preferred to decompose lignocellulose to produce humus precursors in garden waste, thereby facilitating humus formation at the beginning of composting. By contrast, cold plasma was much faster and simpler than other pretreatment techniques to effectively disrupt the surface structure and reduce the crystallinity of garden waste to enrich functional bacteria for aerobic chemoheterotrophy, xylanolysis, cellulolysis, and ligninolysis during composting. As such, a more robust bacterial community was developed after cold plasma pretreatment to advance humification at the mature stage of composting.

Перспективи використання місцевих сировинних ресурсів у виробництві поліпшувачів ґрунту

Goal. To analyze the qualitative characteristics of local raw materials of different origins and assess the prospects of its rational use as a source of organic matter for the production of various types of improvers and secondary raw materials in Ukraine for the production of various types of soil improvers, Methods. Laboratory — for the study of agrochemical properties of the main types of local raw materials, conducted according to certified methods, followed by statistical data processing. Results. The agrochemical characteristics are given of fertilizing and reclamation materials of organic and mineral origin, which are considered as a source of nutrients and organic compounds, and can be used for the manufacture of soil improvers after the relevant technological solutions. Most of the analyzed materials are characterized by the significant potential for humus formation in soils. Conclusions. The solution of the ecological resource situation in Ukraine largely depends on the treatment of local raw materials, because it is the main factor in environmental pollution, it “frozen” a certain part of the resource and energy potential. This affects the balance of economic development of Ukraine in both environmental and resource terms. It is proved that with organic local raw materials the soil receives a complex of different chemical compositions, degree of stability, and reactivity of organic compounds, which cause significant reclamation potential of soil improvers. Involvement of local raw materials of different genesis in the production of soil improvers, the introduction of processing technologies to improve their reclamation properties, will allow obtaining a quality product balanced in terms of humus and nutrients.

Iodine distribution and volatilization in contrasting forms of forest humus during a laboratory incubation experiment

Radionuclides 129I (t1/2 = 15.7 × 106 years) and 131I (t1/2 = 8.02 days) are both introduced into the environment as a result of nuclear human activities. Environmental transfer pathways and fluxes between and within ecosystems are essential information for risk assessment. In forest ecosystems, humus degradation over time could result in re-mobilization and then downward migration and/or volatilization of intercepted 129I. In order to estimate the scale of these processes, humus (mull and moder forms) sampled under deciduous and coniferous forests were spiked with 125I− (t1/2 = 59.4 days), as a surrogate for 129I, in order to study the evolution of its water-soluble and organic fractions as well as the volatilization rate during humus degradation at laboratory scale. To our knowledge, this is the first time that interactions between iodine and contrasting forms of forest humus have been investigated. The evolution of native stable iodine (127I) pools in unspiked humus was also studied.The nature of the humus’ organic matter appears to be a factor that impacts on the proportions of water-soluble and organic fractions of iodine and on their evolution. Iodine-125 was mainly organically bound (fraction for mulls and moders: ∼54–59 and 41–49%, respectively) and no clear evolution was observed within the 4-month incubation period. A large decrease in 125I water-solubility occurred, being more marked for mull (from ∼14–32 to 3–7%) than for moder (from ∼21–37 to 7–19%) humus. By contrast, a significant fraction was not extractible (∼38–43%) and varied in inverse proportion to the water-soluble fraction, suggesting a stabilization of iodine in humus after wet deposit. The nature of the humus organic matter also impacted on 125I volatilization. Although of the same order of magnitude, the total volatilization of 125I was higher for moders (∼0.039–0.323%) than for mulls (∼0.015–0.023%) within the 4-month incubation period. Volatilization rates for mulls were correlated with the water-soluble fraction, implying that volatilization of 125I could occur from the humus solution. Our results showed that humus is thus a zone of iodine accumulation by association with organic matter and that potential losses by lixiviation are significantly more important compared to volatilization.

Evaluation of a Restoration Approach After One Century – Effects of Admixed European Beech on the Natural Regeneration Potential and Humus Condition in Spruce Stands

About 100 years ago, groups of European beech were reintroduced into Norway spruce stands in some parts of Germany as a restoration approach. The aim of this approach was to maintain or rehabilitate the ecological function of soil fertility and the regeneration option of beech for the next generation. The effect of beech groups on surrounding spruce stands was studied in the Ore Mountains by recording natural regeneration of beech and humus layer thickness and form. Point pattern statistics were used to analyse the spread of beech regeneration and to determine factors influencing its establishment. It was found that the density of regeneration decreases with increasing distance from the beech group. However, beech regeneration was found up to distances of 69 m. Furthermore, it becomes evident that PAR radiation (maximum regeneration densities at PAR values of 35 W/m2) and fencing (3.41 times higher regeneration density compared to unfenced areas) against deer have a positive influence on beech regeneration density. Ordered categorical models were used to model humus form and non-linear models were used to model humus layer thickness. It could be proven that the most bioactive humus forms and lowest humus layer thicknesses were found within the beech group. With increasing distance to the beech group, the total humus layer thickness and the proportion of mormoder in the spruce stand increased. The positive influence of the beech group on the humus composition extends to about 40 m from the centre of the beech group. Due to the former arrangement of the beech groups in the terrain, the effects can also extend to the spruce stands in between. The hypotheses on the restoration approach of reintroducing groups of beech into spruce stands formulated by foresters 100 years ago can thus be confirmed. For future restoration approaches of spruce stands, groupwise mixtures of beech should be established with a distance of 40–50 m.

Humipedon dynamics in lowland Amazonian forests: are there Amphi humus forms even in tropical rain forests?

Understanding humipedon dynamics is crucial to capture forest ecological processes. However, studies disentangling humipedon dynamics in tropical forests are scarce. The humipedon structure classification is important because it shows how forest ecosystems interact and react with (a)biotic factors. Here, we used the humus morpho-functional approach to investigate how soil texture and reduced impact-logging affect forest humipedon structure and dynamics in the eastern Amazon. We used a morpho-functional classification of humus forms as the foundation to visualize, classify, and code 133 soil profiles in two contrasting soil textures and different post-logging practices, to identify litter leaching, fragmentation, and humification processes coupled with soil aggregation and root dynamics. The classification of humus forms resulted in the identification of three humus systems: Mull, Moder and Amphi. Sandy and clayey textures differ statistically (χ2 = 51.83; p < 0.001), with sandy texture predominating in Moder system, while clayey texture exhibits Amphi or Mull systems. Sandy textures presented a weak soil aggregation, but strong association with root (rhiOF) and humification (OH) horizons, leading to a clear transition between organic and mineral pools. In contrast, clayey textures show a strong carbon storage and soil aggregation. The humipedon horizons differ significantly (p = 0.009; stress = 0.1142 and R2 = 0.987) and their dynamics clearly evolve towards an opposite direction. The classification framework introduced here supports environmental management by promoting speed and viability in diagnosing forest ecosystem soils towards forest protection or use in the landscape, and specific climate mitigation goals both in local and regional planning.

Формирование микроэлементного состава черноземов обыкновенных Центрального Предкавказья

The article discusses the features of the formation of the microelement composition of various genera of ordinary chernozems in the Central Caucasian Region. Their development takes place in peculiar conditions: mild temperate continental climate, non-leaching water regime, carbonate soil-forming rocks, forb-grass vegetation. Depending on the nature of the soil-forming rocks, ordinary and carbonate chernozems (on loess-like loams), solonetzic (on eluvium-deluvium of Maikop clays), and residual-carbonate chernozems (on eluvium of limestone and sandstone) are formed. The main soil-forming processes that determine the development of a system of soil compounds of microelements are humus formation and humus accumulation, claying, accumulation of Ca carbonates, and very weak ferruginization. The distribution of most of the microelements under consideration (Pb, Cu, Zn) in the soil profile is determined, first of all, by the processes of biogenic accumulation in the composition of low-mobility organic-mineral complexes with humic acids. The severity of the sorption geochemical barrier is weakened due to the uniform distribution of the clay fraction along the soil profile. In addition to the binding of microelements to the organic matter of soils, they are intensively fixed in the composition of carbonates. This leads to a decrease in the migration mobility of microelements in the soil profile and their inaccessibility to plants. The features of the formation of the microelement composition of ordinary chernozems in the Central Caucasian Region vary depending on the specifics of soil-forming deposits. In the case of soil occurrence on salt-bearing clay deposits, the solonetz process plays a decisive role, in the case of occur-rence of dense rocks on the eluvium, the proximity of carbonate deposits, and in the case of occurrence on loess-like loams, their increased porosity and water permeability.

The microbial mechanisms of enhanced humification by inoculation with Phanerochaete chrysosporium and Trichoderma longibrachiatum during biogas residues composting

This study investigated effects of composite microbes (CMs) (Phanerochaete chrysosporium and Trichoderma longibrachiatum) on humification during co-composting of biogas residue, spent mushroom substrate and rice straw. Results showed that CMs inoculation elevated degradation ratios of cellulose, hemicellulose and lignin by 7.86%, 8.87% and 6.45%, and contents of humus and humic acid were correspondingly promoted by 15.5% and 23.6%, respectively. Relative abundances of bacteria associated with refractory macromolecules degradation (Flavobacterium, Anseongella and Actinomadura) and cellulolytic fungi (Hypocreales_Incertae_sedis, Hypocreaceae and Psathyrellaceae) were raised by CMs addition. Redundancy analysis demonstrated a positive correlation between microbial communities and temperature, fulvic acid and lignocellulose contents. Moreover, CMs inoculation promoted pathways of xenobiotics biodegradation and metabolism, and biosynthesis of other secondary metabolites, which was closely associated with lignocellulose degradation and humus formation. These results suggested that biological inoculation could enhance composting efficiency and improve compost quality, benefiting biogas residues composting.

Concept of natural restoration process of the petrophyte ecosystem on the surface of the tailing dumps in the limestone quarry "Lafarge Ciment" (Moldova) S.A.

The process of natural restoration of the petrophyte ecosystem consists of the following stages: formation of tailing dumps, initiation and restoration of biodiversity on the surface of tailings dumps, solification (formation of new soil) on the surface of dumps, accumulation of nutrients (nitrogen, phosphorus, K2O) and humus formation in the layers of newly formed soil on the surface of tailings dumps depending on their age. The stages are established experimentally by studying the dynamics: the development of the number of plant species on the surface of the dumps, the degree of evolution of regosols in the chronological sequence, the results of increasing the nutrient content and humus formation depending on the age of the studied tailing dumps. The regularity has been demonstrated regarding the process of soil formation on the surface of tailings dumps, which represents the succession and mutual interaction of the natural processes of initiation and development of plant biological diversity on the surface of dumps, solification (new soil formation), nutrient accumulation and humus formation in soils, which take place simultaneously without human intervention and ensures the process of natural formation of the petrophyte ecosystem.

Structural and Functional Composition of Humic Acids Isolated from Soils of Natural and Urbanized Territories of the European Far North and the Arctic

The structural and functional composition of humic acids in natural and urbanized areas of the European Far North and the Arctic has been studied using modern physical and chemical research methods. It is shown that the content of fulvic acids for most of the studied soils is higher than humic acids; in soils, the process of humus formation is humate (replantozem, pelozem and humus-peat soil), humate-fulvate (turf soil, culturozem and urbanozem) and fulvate type (gleezem and lithozem); macromolecules of humic acids and himatomelanic acids of the studied soils are predominantly aliphatic in nature, with a high proportion of aromatic fragments, and FA have an aromatic structure. In addition, humus acids of natural soils located in more Northern regions are characterized by a high content of oxygen-containing functional groups compared to humus acids preparations of natural soils located to the South (turf and peat)

Polyarenes Distribution in the Soil-Plant System of Reindeer Pastures in the Polar Urals

Humic substances of soils consist of various organic compounds, including polycyclic aromatic hydrocarbons (PAHs). Soil as a fairly stable medium allows the correct use of polyarenes as markers of the humus formation process. Monitoring of the accumulation of PAHs as resistant organic toxicants is also necessary due to their carcinogenic and mutagenic properties. Natural plant resources serve as the feed base of northern reindeer husbandry. In this study, high-performance liquid chromatography in a gradient mode and gas chromatography-mass spectrometry methods were used to estimate the content of PAHs in mountain tundra and meadows of the Polar Urals (Russia). The accumulation of polyarenes in soils on carbonate rocks of the Bolshoi Paipudynsky ridge occurs mainly in the process of soil formation and largely depends on factors such as productivity of plant communities, the composition of standing biomass, the site’s position in relief, the granulometric composition of soils, cryogenesis process and pyrogenesis. According to the set of polyarenes, their number, and ratio, the studied objects were classified into separate groups by discriminant analysis. The most typical representatives of pedogenic origin are naphthalene and phenanthrene. The accumulation features of dibenz[a,h]anthracene and benz[b]-, benz[k]fluoranthene, benz[ghi]perylene, and benz[a]perylene are shown. In mountain tundra landscapes, the characteristics of PAHs can be used to diagnose the intensity and direction of soil formation processes in general and humification in particular.

Effect of Fertiliser on Changes in Labile and Water-Soluble Forms of Humus in Short-Term Rotations

Mobile (labile and water-soluble) forms of humus are one of the basic components of effective soil fertility and a precondition for high productivity of crop rotations. As a result of fermentation, these forms of humus are mineralised and take part in plant nutrition, and some of them, being included in mobilisation processes, transition into stable humus substances. Therefore, it is important to investigate agrotechnological factors for managing their dynamics and redistribution in the soil environment during the growing season of agricultural crops. The purpose of the study: to investigate the effect of complex application of mineral and organic (conventional and alternative) fertilisers on the change of water-soluble and labile forms of humus during the growing season of agricultural crops grown in short-term rotations. The following research methods were used in this study: field, laboratory-analytical, computational-comparative, mathematicalstatistical. Higher level of labile accumulation (359.59 mg kg-1 of soil) and water-soluble (11.69 mg kg-1 of soil) humus forms under winter wheat crops occur when the predecessor of the crop in the crop rotation is meadow clover. The application of N60P90K90 specifically for winter wheat and 40 t/ha of manure in the conventional fertilisation system of grain-grass crop rotation contributes to the formation of 529.07 and 20.20 mg kg-1 of soil of the organic substances under study. The application of N120P100K100 and 40 t/ha of manure for corn for grain yields 567.42 and 22.55 mg kg-1 of soil, and N90P90K90 and 40 t/ha of manure for potatoes yields 543.66 and 21.75 mg kg-1 of mobile compounds humus. The obtained research results can serve as a basis for the development of highly efficient environmentally friendly farming systems and can be used for further scientific research on the development of ways and directions for managing humus-forming processes in the soil environment

ОЦЕНКА ЗАПАСОВ ОРГАНИЧЕСКОГО УГЛЕРОДА В ПОЧВЕННОМ ПОКРОВЕ ОСТРОВНЫХ ЭКОСИСТЕМ КУЙБЫШЕВСКОГО ВОДОХРАНИЛИЩА

Assessment of organic carbon stocks in soils and other components of ecosystems are becoming increasingly important as a necessary reference point for a reliable determination of the amount of greenhouse gas removals at country scale. The gradual tightening of carbon balance requirements dictates the urgency of the problem under consideration. The aim of the work was to assess the stocks of organic carbon in the soils of the islands of the Kazan region of the variable backwater of the Kuibyshev reservoir in the 0–20 cm layer, and also to determine which type of soils makes the greatest contribution to the sequestration of carbon. The reserves of organic carbon in the soils of the islands of the Kuibyshev water reservoir were determined in the area from the Zelenodolsk – Nizhnie Vyazovye bridge (55°49’27.1 «N; 48°31’05.6″E) to the islands in front of the Teteyevo village (55°24’11.8 «N; 49°07’59.6» E). Surveys of the islands’ soil cover and selection of the soil samples were carried out in 2018-2019. The calculation of the organic carbon content was carried out for the 0–20 cm layer. The calculations took into account the total carbon content in the organogenic, organic-mineral and mineral horizons. It was found that the highest carbon content in the upper soil layer was observed in the profile of marsh-podzolic soils – 51.7 t / ha. The lowest organic carbon content was noted in sod-alluvial soils (12.0 t / ha) and artificial sandy deposits (3.8 t / ha). Carbon stocks in soil profiles and proportion of carbon in organogenic horizons increased with increasing of hydromorphic properties in the following row: 1) sod-podzolic soil &lt; marsh-podzolic soil; 2) light gray forest soil &lt; gray forest gley soil; 3) sod-alluvial soil &lt; alluvial meadow-marsh soil &lt; marsh-alluvial soil. The total reserves of organic carbon in the islands’ soils were calculated taking into account the areas occupied by individual soil contours. The total stock of organic carbon in the 0–20 cm layer of the studied area of the water reservoir was 49,190.9 tons. About 83 % of the total stock of organic carbon stored in the form of humus of accumulative mineral horizons and only 17 % in the organogenic and organic-mineral horizons. It was shown that alluvial meadow-marsh (23,125.9 t) and sod-podzolic soils (8,957.5 t), occupying the largest areas on the territory of the islands, make the largest contribution to the organic carbon reserves. An interesting point is that on the islands of floodplain origin, a greater contribution to the total humus reserves was made by soils with pronounced hydromorphic properties – alluvial meadow-marsh soils and alluvial meadow soils. On the islands of terrace origin, the bulk of carbon was concentrated in automorphic soils. A possible reason is the features of the islands’ relief of different origins. Reasonable data on the rate of organic carbon accumulation were obtained only for alluvial marsh soils, the organogenic horizon of which was formed after the creation of the reservoir – 390 kg / ha annually. Flooded soils are the most promising reservoirs for organic carbon deposition from greenhouse gases. Thanks to the research carried out using accurate GPS referencing of soil profiles, the islands’ soils are becoming a very valuable object for monitoring the rate of organic carbon accumulation, the volume of absorption of greenhouse gases and the increase in total organic carbon stocks.

Effect of humification during hydrothermal treatment of Aquatic Wastes with inorganic acid

Taking aquatic processing waste as the main experimental object, to explore the effect of different treatment conditions on the humification process in the acid-hydrothermal reaction process, through the analysis of the hydrothermal process of pH value, organic matter and humus content, humification rate, and infrared spectrum analysis verification to speculate the formation mechanism of humus. The results show that hydrothermal treatment can promote the formation of humus to a certain extent. Under the working conditions of 195℃ and 80min, the humus content of aquatic wastes reaches 78.1% and the humification rate reaches 0.35. In addition, within a certain treatment intensity, the hydrothermal humification intensity will increase with the increase of reaction time and temperature. Under the same working conditions mentioned above, adding a certain amount of inorganic acid for hydrothermal treatment, the humus content is slightly higher than that of the group without acid. The humification rate reaches 0.45, which is 0.3 times higher than that of the group without acid. It shows that hydrothermal treatment can promote the formation of humus to a certain extent. Compared with prolonging the reaction time, the increase of temperature has a more obvious effect on the increase of humification rate.

Трансформація гумусових речовин дерново-підзолистого ґрунту за тривалого внесення добрив

The article reflects the results of a study of the regularities of the transformation of humic substances at different levels of structural organization during long-term fertilization against the background of liming of podzolic sandy loamy soil in a field experiment in Western Polissya of Ukraine. It was found that the low content of chemically active organic substances in the humus composition of podzolic soils, caused by the zonal features of humus formation, can be positively corrected by applying fertilizers. Long-term use of organic and mineral fertilizers intensifies the process of new formation of humic acids and the formation of their mobile forms – the ratio of Cha-1 / Cfa-1 is 0.28 in the control without fertilizers and 0.33–0.88 in the variants of fertilization against the background of liming. With an organo-mineral fertilizer system, the most favorable conditions are formed for the humification of organic substances however, the type of humus remained fulvate – the Cha / Cfa ratio is 0.93 in the control variant and 0.41 – against the background of liming. Also, the application of fertilizers had an effect on the redistribution of the polydispersity of humic acids, which was characterized by a decrease in the heterogeneity of the composition of hydrophobic molecular aggregates. In a wide range of 1800 cm-1 to 2500 cm-1, a change in the direction of the line of the integral spectrum of soil humic acids under the application of CaCO3 from left to right was found, which is associated with a change in molecular parameters. Based on the results of chromatographic analysis, it was established that the profiles of the molecular distribution of humic acids podzolic soil correspond to the humus substances class. The first fraction is characterized by the formation of ion associates of larger molecules of polar composition. The recovery of humic acids occurred mainly due to high-molecular structures, which is the most sensitive to the application of fertilizers.

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.