Humus Accumulation Research Articles

Independent and combined effects of antibiotic stress and EM microbial agent on the nitrogen and humus transformation and bacterial community successions during the chicken manure composting

This study aimed to investigate the independent and combined effects of antibiotic and EM microbial agent on the nitrogen and humus (HS) transformations as well as the bacterial community successions during the chicken manure and rice husk composting. EM microbial agent accelerated the oxytetracycline (OTC) degradation, but slowed down the norfloxacin (NOR) degradation. OTC inhibited the TN retention and promoted the HS accumulation, both NOR and EM microbial agent inhibited the TN retention and HS accumulation, while EM microbial agent showed an antagonistic effect on TN immobilization with antibiotics and reduced the impacts of antibiotics on HS. Obvious bacterial community successions occurred. Firmicutes were related to HS transformation, while Firmicutes, Actinobacteriota and Proteobacteria were associated with nitrogen conversion. NOR promoted the transformations of NH4+-N to NO3—-N and FA to HA. The findings provided theoretical data for the recycle of antibiotic-contaminated manure and the efficient production of high-quality compost.

Кількісна діагностика дискусійних за генезисом ґрунтів надзаплавних річкових терас Лівобережного Лісостепу

Goal. To improve the diagnostics of soils of debatable genesis to determine their ecological and genetic status using a set of morphological criteria and quantitative parameters. Methods. A set of methods was used, which contained a description of the soil profile by morphological and genetic features, as well as a set of quantitative relative coefficients of humus accumulation and the ratio of calcium and magnesium exchange cations. Results. It was determined that a significant share of the land fund of pine and single-forest terraces were podzolic soils. Soils formed by different combinations of sod process with podzolization and hydromorphism were also found. A complex method of diagnosing polygenetic soils of floodplain terraces of low hypsometric level by parameters of such indicators as profile thickness, coefficient of relative accumulation of humus, coefficient of profile accumulation of humus, and regression coefficient of organoprofile was developed. Gradations of the specified criteria for identification of soils of debatable genesis were developed as well as gradations of the relation of exchange cations of calcium to magnesium for soils of floodplain terraces as a diagnostic criterion. Conclusions. Complex diagnostics of soils, in particular of debatable genesis, based on the morphological and genetic structure of soil profile, application of gradations of humus accumulation parameters in soils according to KVAG, KPNG, KRO, and ratio of calcium and magnesium metabolism were developed.

Functional and taxonomic changes in the domain Bacteria in response to phytomelioration of saline soils

The article presents the results of a five-year study of plant-microbe interactions in a small medium sodium solonetz. The research was carried out in the Barabinsk lowland of Siberia, where Bromus inermis was cultivated for 33 years in the fodder crop rotation. Its phytomelioration effect was reflected in soil desalinization which was proved by decrease of EC in 0-20 cm layer by 11.3 times, decrease of its oligotrophy by 6.3 times, replenishment of solonetz nitrogen fund and intensification of microbiological processes of humus accumulation. The taxonomic structure of microbiome under the crop rotation impact with B. inermis altered towards increasing the representation of genera from alpha-, beta- and delta-proteobacteria classes, functionally associated with the improvement of soil fertility, Gemmatimonadetes as a dryness indicator and reducing the Acidobacteria groups Gp4 and Gp6, associated with the pH control.

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.

Мікробіологічна деструкція органічної речовини в агроценозах

Goal. To study the microbiological processes of straw transformation during introduction into agrocenoses of microorganisms — producers of cellulase enzyme complexes, which play an important role in the biodegradation of fresh organic matter. Methods. Field — to carry out field experiment, microbiological — to determine the quantity of cellulosolytic bacteria, biochemical — to determine the cellulase, peroxidase, and polyphenol oxidase activity of the soil, statistical — to identify differences between relevant indicators and assessment of the reliability of such differences. Results. In the conditions of a long-term field experiment on leached chornozem (short-term crop rotation: winter wheat — buckwheat — lupine), microbiological processes that occur during the mineralization of 4 t/ha of straw were studied. It was found that during the growing season buckwheat in the soil (the 1-st year after the introduction of winter wheat straw) and lupine (the 2-nd year after the introduction of organic residues) increased the number of cellulosolytic microorganisms. In buckwheat agrocenoses in the variant with Microbacterium sp. 6634 their quantity amounted to 25.6 million/g of soil with a value of 10.9 million/g of soil under control. The studied soil samples from lupine agrocenoses were also characterized by a significant number of cellulose-destructive microorganisms (17.7 million/g of soil under the action of Bacillus sp. 6658) compared to the control variant (9 million/g of soil). Under the action of bacterial destructors of organic matter, they observed increased enzymatic activity of soil (cellulase, peroxidase, and polyphenol oxidase). Cellulase activity at the use of Bacillus sp. 6658 and Pseudomonas sp. 6650 increased 1.5 times. Under the influence of microorganisms introduced into agrocenoses, an increase in the biochemical coefficient of humus accumulation according to Muromtsev’s methodology was observed. Conclusions. Introduction into the agrocenosis of bacteria — members of the genera Bacillus, Microbacterium, Pseudomonas promoted the development of leached chornozem microorganisms with cellulosolytic properties and increased cellulase, peroxidase, and polyphenol oxidase activity, which was a prerequisite for strengthening the mineralization of straw. The increase in the intensity of decomposition of fresh organic matter with the introduction of plant residues was confirmed by indicators of the biochemical coefficient of humus accumulation according to Muromtsev’s methodology. The studied bacteria are promising as bioagents of microbial preparations to optimize the processes of mineralization-immobilization using plant by-products.

Humus of the brown soils of the mountain pastures of Uzbekistan

The aim of the study: assessment of humus content and its distribution in the profile of brown soils of mountain pastures in Uzbekistan. Location and time of the study. Soil pits were cut in the Republic of Uzbekistan in seven agricultural regions, widely used in agriculture: Tashkent region, Bustonlik district; Jizzakh region, Zomin district; Samarkand region, Nurabad district; Navoi region, Nurata district; Kashkadarya region, Kitab district; Surkhandarya region, Sherabad district; Namangan region, Papal district. The study was carried out in 2019-2021. Methods. Field studies, sampling and sample preparation were carried out in accordance with the generally accepted methods: soil organic carbon content was measured by bichromate digestion, carbonate content was determined by acidimetric method and soil inorganic carbon content was calculated by subtracting from the total content of carbonates. Silty fractions were isolated by centrifugation. Humus differentiation into reserves and their estimation was carried out according to the method proposed by one of the authors. Main results. The studied brown soils of mountain pastures of Uzbekistan are characterized by loamy granulometric composition, with a clay fraction not exceeding 20%. The content of carbonates is low (2.5–9%), with the maximum amount in the carbonate horizon. Soils are slightly leached. The total humus content in the upper horizon varies from 1% to 6.6%. The dependence of soil humus content on the slope exposure was noted: the soils of the more humid northern and western slopes contain more humus than the southern and eastern ones. In addition, the humus content is significantly affected by erosion. To assess the nature of changes in the organic matter of the brown soils during their agricultural use, humus of the near, labile and potential reserves (as percentage of the total content) was isolated for the first time. It was revealed that humus of potential reserve prevails in soils (35.5-90%). Its vertical distribution is characterized by a sharp decrease in the sub-humus part, while the humus of the near and labile reserves is distributed evenly in the profile, without a pronounced dependence on external conditions and the degree of disturbance. The proportion of insoluble organic substances in the total humus content ranged from 0.39 to 86%, of sparingly soluble organic substances - from 3 to 100%. There is a relationship between the amount of sparingly soluble and insoluble organic matter in the upper horizon and the degree of soil erosion. Conclusion. The distribution of humus and its reserves in the brown soils of the mountain pastures of Uzbekistan is uneven and strongly affected by erosion. The loss of near and labile humus reserves leads to a decrease in the content of total humus. Further study of humus features, humus accumulation and restoration in brown soils is important for the development of recommendations for the rational use, anti-erosion protection and increasing the productivity of mountain pastures in Uzbekistan.

Influence of Texture on Humus Accumulation in Soils of Dry Steppes of Tuva

Influence of Texture on Humus Accumulation in Soils of Dry Steppes of Tuva

ЭФФЕКТИВНОСТЬ ИСПОЛЬЗОВАНИЯ ФОСФОГИПСА С ОРГАНИКОЙ ДЛЯ ПОЧВ КОМПЛЕКСНОГО ПОКРОВА ПРИ ОРОШЕНИИ

Purpose: to determine the impact of phosphogypsum rates in combination with organic matter on the properties of integrated cover soils, their productivity, and also to substantiate the economic feasibility of their application for chemical reclamation during irrigation. Materials and methods. The studies were carried out in the Martynovsky district Rostov region for 4 years on the integrated cover soils according to the scheme of the experiment, including the application of phosphogypsum (Ph) and organic matter (OM) at certain rates. The studies were carried out according to generally accepted methods. Results. It has been stated that the phosphogypsum application at 10 t/ha rate contributed to the southern chernozem desalination up to 3 % sodium from the total soil-absorbing complex and an calcium and magnesium increase to the optimal parameters for this soil. On the solonetz, the content of exchangeable sodium decreased to 9–8 % in the variants with 10 t/ha Ph rate. In the variant with 5 t/ha Ph rate, the process of soil salinization proceeded somewhat more slowly, which is associated with an insufficient ameliorant rate for the solonetz. The accumulation of humus to the greatest extent was observed in the variant 10 t/ha Ph + 40 t/ha OM. After 4 years, it amounted to 0.24 % on the southern chernozem, and 0.19 % on the solonetz. Both soils included in the complex decompacted, and in the better option, the southern chernozem density was 1.17 t/m³, and on the solonetz – 1.20 t/m³. The soil properties improvement contributed to the increase in productivity. By the 4th year of the aftereffect of ameliorants, it increased by 73–85 % on the southern chernozem and by 69–79 % on solonetz compared with the control. The average productivity for 4 years of research on the southern chernozem ranged from 7.18 (5 t/ha Ph + 40 t/ha OM) to 8.03 t grain units/ha (10 t/ha Ph + 40 t/ha OM), and in the control 4.82 t grain units/ha. On the solonetz, respectively, it increased from 6.03 to 6.93 t grain units/ha, in the control – 4.30 t grain units/ha. Conclusions: the application of phosphogypsum with organic matter provides both reclamative and economic effect on solonetz integrated cover soils.

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.

KOSTYCHEV-ORLOV EQUATION AND FIRST MATHEMATICAL MODELS OF HUMUS DYNAMICS

This work is a report written at the suggestion of the talented Soviet scientist V.V. Zeleneva in 1986-1987, when the author was a 4th year student at the Faculty of Soil Science, Moscow State University. M.V. Lomonosov.
 The report analyzes the equation proposed at the dawn of soil science by P.A. Kostychev for the maximum level of humus accumulation (and later modified by D.S. Orlov). It is shown that from the point of view of mathematics, the Kostychev equation is meaningless and has no solution at all. Improved by Orlov, it already has solutions, but it seems that it still cannot be effectively used. In this regard, various types of those mathematical models of humus dynamics are considered, which were used by specialists in soil science and ecology.

KOSTYCHEV-ORLOV EQUATION AND FIRST MATHEMATICAL MODELS OF HUMUS DYNAMICS

This work is a report written at the suggestion of the talented Soviet scientist V.V. Zeleneva in 1986-1987, when the author was a 4th year student at the Faculty of Soil Science, Moscow State University. M.V. Lomonosov.
 The report analyzes the equation proposed at the dawn of soil science by P.A. Kostychev for the maximum level of humus accumulation (and later modified by D.S. Orlov). It is shown that from the point of view of mathematics, the Kostychev equation is meaningless and has no solution at all. Improved by Orlov, it already has solutions, but it seems that it still cannot be effectively used. In this regard, various types of those mathematical models of humus dynamics are considered, which were used by specialists in soil science and ecology.

Influence of manure application method on gray forest soil fertility, crop yield and quality

The article presents the results of field experiments on deepening the arable horizon of gray forest medium loamy soil to increase its fertility through applying organic fertilizer under PY-3-35 layer plow to a depth of 2527 cm. Low mineralization of organic fertilizer during layer cultivation under oxygen deficiency conditions contributed to accumulation of humus in soil by 6.6 t/ha more than during conventional plowing, and by 7.5 t/ha - than during disking. It also improved water-physical and biological properties of soil: number of water-resistant aggregates increased by 4.6 and 5.3 %, soil density lowered by 0.03 and 0.04 g/cm3, number of earthworms increased by 3...6 individuals, expanded reproduction of fertility was provided, productivity of arable land increased by 7.0 and 6.7 % and crop quality increased compared to conventional plowing and disking, respectively. Deep manure incorporation extended life of organic fertilizer up to 5 years, while after conventional plowing and disking this process lasted only 2...3 years. It is not economically and environmentally beneficial, since frequent application requires a lot of fuel, and a large amount of harmful chemical compounds contained in combustion products is dumped into the environment.

ДИНАМИКА ЗАПАСОВ ГУМУСА И ПРОГНОЗ УГЛЕРОДСЕКВЕСТИРУЮЩЕГО ПОТЕНЦИАЛА ЗОНАЛЬНЫХ ПОЧВ РЕСПУБЛИКИ ТАТАРСТАН

The article analyzes the results of statistical processing of morphometric and agrochemical indicators of zonal soils of the Republic of Tatarstan based on the accumulated information of large-scale soil studies. The boundaries of genetic horizons are examined, the content of humus and its reserves within the limits of heavy loamy and clay varieties of arable soil subtypes is estimated. Arithmetic averages allow us to generalize the humus content in soils. So, in the series of sod-podzolic soils – light gray forest-gray forest – dark gray forest-podzolic chernozems – leached chernozems-typical soils in a layer of 0-30 cm on average contains 2,20; 2,58; 3,76; 4,76; 6,8; 7,6; 7,2 % humus. The observed patterns of humus accumulation in soils are also preserved in the distribution of its reserves – 85; 97; 140; 162; 233; 257; 240 tons per he-1. It is proposed to characterize the general population along the boundaries of typical values that fit into the 50% confidence interval to assess the overall range of spatial variability of humus indicators. The upper limit of the typicity will correspond to the greatest accumulation of humus with a combination of local features of soil formation factors and can serve as a guide for predicting carbon sequestration in the soils of this region. Accordingly, the carbon-sequestering potential of sod-podzolic soil and typical chernozem is-20 tons per he-1, light gray forest soil-22 tons per he-1, gray forest soil and leached chernozem-27 tons per he-1, the highest values in dark gray forest soil are more than 30 tons per he-1

Ways to improve biogeneity, assimilation potential and fertility of soil cover of the urban landscapes of Sumgait city

Aim . The aim of the research was to identify the possibility of increasing the content of humus in the soil cover of the city of Sumgait using biologics, including those containing cellulose‐decomposing microorganisms, in a controlled manner. Material and Methods . In the process of conducting laboratory experiments, we took soil samples with the introduction of various modifications of organic substances of plant origin and with the simultaneous introduction of biologics. As biopreparations, we used cultures of cellulose‐decomposing microorganisms isolated from soils, excess activated sludge and the Fermi‐Start biopreparation, both individually and in the form of compositions. Total carbon content was carried out according to the Tyurin method. The total number of microorganisms was determined by generally accepted methods. Enzyme activity was determined by the F. Kh. Khaziev method. Results . It was revealed that the use of biopreparations – the association of cellulose‐decomposing bacteria, excess activated sludge and Fermi‐Start stimulated an increase in the number of cellulose‐decomposing bacteria (3‐10 times) and the accumulation of total carbon and humus in the soil by 20‐55%. Conclusion . The use of biological preparations and the introduction of cellulose‐containing materials into the soil, provided that optimum moisture is maintained, ensures in a short period of time – 6 months ‐ a significant increase of humus in the gray‐brown soil content.

Soils of the Darkhitui catena in the southern Vitim Plateau and their micromorphological features

Soils of the Darkhitui catena in the south of the Vitim Plateau on a northern slope and the foothill plain were studied. Skeletic Folic Cryosols (Nechic) are formed on watersheds under larch forests on eluvium of mafic rocks. Soils have high humus content in a thin humus horizon and a significant content of clay. Folic Phaeozems (Colluvic, Tonguic) are developed on a gentle slope under a forb-birch forest on colluvium. The most prominent features of these soils are as follows: high content of humus and fine material, impregnation by carbonates, and iron films on ped faces. Luvic Chernozems (Tonguic) are developed in the foothills under steppe meadows on lacustrine sediments. These soils are characterized by redistribution of fine fractions along the profile and significant humus accumulation favored by permafrost moisture content.

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.

Biological indicators in the environmental monitoring of gray forest soil of agrosystems

The objective was to monitor the biological indicators to assess the ecological sustainability of gray forest soil, due to the different level of agrotechnical burden on agricultural landscapes. During 10 years of research (2011-2020) the number of bacteria using various forms of nitrogen was continuously decreasing on the background of mineral intensification. The total average pool of active microflora on organomineral and mineral backgrounds in moulboard plowing was 20.1 and 16.1 million CFU g-1 of soil, respectively, during the period of observations. In non-moldboard plowing, the same average pool was 18.8 and 15.9 million CFU g-1. The minimum pool was maintained on a high-intensity mineral background in moldboard plowing, amounting to 14.5 million CFU g-1 of soil. The decrease in the total bacterial number in the soil of mineral backgrounds indicates a deterioration in their ecological stability. The calculated ecological and trophic indices indicate less ecologically stable low-intensity mineral background in moldboard plowing. This variant showed relatively low values of humus accumulation coefficients (Ch = 0.39) and transformation of organic residues into soil organic matter (Ct = 5.4) established at the highest mineralization coefficient (Cm = 1.57). In this soil, mineralization of organic matter prevails, which reduces its fertility and environmental sustainability. On this background, the activity of the studied enzymes was lower than in other variants and in the soil deposits. A set of micromycetes has shown to grow on mineral intensification backgrounds, especially on a high-intensity mineral background, where moldboard plowing was used as the main treatment. The lowest phytotoxicity was noted on a high-intensity organic-mineral intensification background –21.4%. Both microbiological and biochemical parameters represents an informative diagnostic feature of the ecological state of agrolandscapes. They ensure an objective assessment of the efficiency and degree of agrotechnical burden, predicting a decrease in environmental sustainability on mineral intensification backgrounds.

Temporal dynamics of mixed litter humification in an alpine treeline ecotone

Loss of plant diversity affects mountain ecosystem properties and processes, yet few studies have focused on the impact of plant function type deficiency on mixed litter humification. To fill this knowledge gap, we conducted a 1279-day litterbag decomposition experiment with six plant functional types of foliar litter to determine the temporal dynamic characteristics of mixed litter humification in a coniferous forest (CF) and an alpine shrubland (AS). The results indicated that the humus concentrations, the net accumulations and their relative mixed effects (RME) of most types were higher in CF than those in AS at 146 days, and humus net accumulations fell to approximately -80% of the initial level within 1279 days. The RME of the total humus and humic acid concentrations exhibited a general change from synergistic to antagonistic effects over time, but the mixing of single plant functional type impeded the formation of fulvic acid due to consistently exhibited antagonistic effects. Ultimately, correlation analysis indicated that environmental factors (temperature, snow depth and freeze-thaw cycles) significantly hindered litter humification in the early stage, while some initial quality factors drove this process at a longer scale. Among these aspects, the concentrations of zinc, copper and iron, as well as acid-unhydrolyzable residue (AUR):nitrogen and AUR:phosphorous, stimulated humus accumulation, while water-soluble extractables, potassium, magnesium and aluminium hampered it. Deficiencies in a single plant functional type and vegetation type variations affected litter humification at the alpine treeline, which will further affect soil carbon sequestration, which is of great significance for understanding the material circulation of alpine ecosystems.

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.

Interrelation of climatic factors of soil formation with the formation of chemical and physical-chemical properties of soil cover in agricultural landscapes of the Central Chernozem Region of Russia

Aim. To assess the interrelations of chemical and physical-chemical parameters of soil cover properties with climatic factors of soil formation in agricultural landscapes of the Central Chernozem Region (CCR) of Russia.Materials and Methods. The research was carried out using a systemic analysis of the complex of agroclimatic and soil parameters. Soil properties were assessed by the weighted average characteristics of arable soils for the areas of the Central Chernozem Region. Hydrothermal conditions were taken into account by rainfall, temperature and the amount of active temperatures for the period 1960-2000.Results. Estimated excess of annual precipitation (440-640 mm) over evaporation (407-500 mm) in the average annual cycle ensures the formation of total runoff and soil washability in the amount of 40-150 and 17-104 mm. This determines soil acidity (pHKCL, R2 = 0.36...0.73). Optimal conditions of humus accumulation are formed when the humidity factor is 0.8-0.9. Mesorelief is a factor of spatial heterogeneity of the total soil composition with which 85% of physical-chemical properties and up to 70% of nutrient availability are associated.Conclusion. The differences in the hydration of the territories both at the scale of the CCR and local levels determine the intensity of geochemical runoff, the oxidation-reduction regime and total chemical soil composition which constitute the basis of heterogeneity in the content of organic matter, acidic-base and other properties.