Postpyrogenic Polycyclic Soils in the Forests of Yakutia and Transbaikal region

Periodical forest fires are typical natural events under the environmental and climatic conditions of central and southern Yakutia and Transbaikal region of Russia. Strong surface fires activate exogenous geomorphological processes. As a result, soils with polycyclic profiles are developed in the trans-accumulative landscape positions. These soils are specified by the presence of two–three buried humus horizons with abundant charcoal under the modern humus horizon. This indicates that these soils have been subjected to two–three cycles of zonal pedogenesis during their development. The buried pyrogenic humus horizons accumulate are enriched in humus; nitrogen; total and oxalate-extractable iron; exchangeable bases (Са⁺² and Mg⁺²); and the fractions of coarse silt, physical clay (<0.01 mm), and clay (<0.001 mm) particles in comparison with the neighboring mineral horizons of the soil profile. The humus of buried pyrogenic horizons is characterized by the increased content of humic acids, particularly, those bound with mobile sesquioxides (HA-1) and calcium (HA-2) and by certain changes in the type of humus.     

Amorphous clay materials of towada ando soils

Towada Ando soils consisted of five soils—Towada-a (1,000 years old), Towada-b (2,000 years old), Chuseri (4,000 years old), Nanbu (8,600 years old), and Ninokura soils (10,000 years Amorphous clay materials of these soils taken at different localities were studied by the combined use of selective dissolution and differential infrared spectroscopy, X-ray analysis, electron microscopy, etc.

The main clay minerals of Towada-a soils, present-day soils, were montmorillonite-vermic-ulite chloritic intergrades and opaline silica, or these minerals and allophane in the humus horizons, and allophane in the non-humus ones. Towada-b soils overlain by the Towada-a soils showed the clay mineralogical constituents similar to those of Towada-a soils. However, allophane was one of the main clay minerals in all the humus horizons as well as non-humus ones. The main clay minerals of Chuseri soils were allophane and layer silicates consisting chiefly of chloritic intergrades and chlorite in the humus horizons, and allophane in the non-humus ones. Opaline silica was present in minor amounts in the humus horizons of Chuseri soils, but nearly absent in Nanbu and Ninokura soils.

There were remarkable differences in the clay mineralogical composition of Nanbu and Ninokura soils with differences of their environmental conditions. Allophane and imogolite Were dominant in the clay fractions of both humus and non-humus horizons of very shallowly buried Nanbu soil which was subjected to the strong leaching process. Allophane was the main clay mineral of deeply buried Nanbu and Ninokura soils which showed the absence of notable accumulation of bases and silica. On the contrary, halloysite with a small amount of siliceous amorphous material appeared in very deeply buried Nanbu and Ninokura soils where bases and silica were distinctly accumulated. The amounts of halloysite in the clay fractions were larger in the humus horizons than non-humus ones, and in Ninokura soil than Nanbu soil.

Soil age, soil organic matter, and depositional overburden of tephras were observed to be conspicuous among various factors relating to the weathering of amorphous clay materials in Towada Ando soils.     

Morphology,Radiocarbon Age,and Genesis of Vertisols of the Eisk Peninsula (the Kuban–Azov Lowland)

Data on the morphology and radiocarbon ages of humus of dark vertic quasigley nonsaline clayey soils with alternating bowl-shaped (Pellic Vertisols (Humic, Stagnic)) and diapiric (Haplic Vertisols (Stagnic, Protocalcic)) structures are discussed, and the genetic concept for these soils is suggested. The studied soils develop on loesslike medium clay in the bottom of a large closed depression on the Eisk Peninsula in the lowest western part of the Kuban–Azov Lowland. The lateral and vertical distribution of humus in the studied gilgai catena displays a lateral transition of a relatively short humus profile of the accumulative type with a maximum near the surface and with a sharp increase in ¹⁴C dates of humus in the deeper layers within the diapiric structure to the extremely deep humus profile with a maximum at the depth of 40–80 cm, with similar mean residence time of carbon within this maximum, and with a three times slower increase in ¹⁴C dates of humus down the profile within the bowl-shaped structure. The development of the gilgai soil combination is specified by the joint action of the lateral–upward squeezing of the material of the lower horizons from the nodes with an increased horizontal stress toward the zones a decreased horizontal stress, local erosional loss of soil material from the microhighs and its accumulation in the adjacent microlows, leaching of carbonates from the humus horizons in the microlows, and the vertical and lateral ascending capillary migration of the soil solutions with precipitation of calcium carbonates in the soils of microhighs.     

Distribution of Zinc,Manganese, Copper,Cobalt, and Nickel in Andosols Profiles

The distribution of zinc, manganese, copper, cobalt, and nickel in Andosols was investigated. Sixty nine soil samples were collected from different horizons of an Andosols profile in Miyakonojo Basin in south Kyushu, Japan, The total contents of heavy metals were determined by digestion and four extraction solutions, 1 M NH₄Ac (ammonium acetate) pH 4.5, 0.1 M HCl, 0.01 M EDTA (ethylenediaminetetraacetic acid) pH 6.5, and 0.005 M DTPA (diethylenetri-aminepentaacetic acid) pH 7.3 were used to determine the contents of available Zn, Mn, Cu, Co, and Ni in Andosols in relation to the organic carbon content. The results of the extraction analysis showed that by the use of 0.1 M H Cl high value of extracted heavy metals in the upper layers of the humus horizons were obtained while EDTA extraction yielded a large amount of the above mentioned metals in the high humus horizons. The extractable heavy metals contents were high and these metals closely related to the organic carbon content mostly in the humus horizons in the profile. Where, biocycling process may play an important role in the concentration of heavy metals. Based on the study, it was found that the total content of Zn increased towards the C horizons or pumice layers in the soil profile. Such a trend was also found in the case of the Mn content. While the Cu content in the humus horizons was much higher in the upper part of each humus horizon. According to this study the distribution of heavy metals, Cu (organic matter complexes) in the Andosols profile was more stable than that of Zn (organic matter complexes) in soils. It was shown that Zn in the surface humus horizon was enriched but that some amount was leached under buried conditions. The same phenomenon was also observed in the distribution of Mn in the profile. The movement of Co and Ni in the soil profile was limited, as evidenced by the sharp reduction in the concentrations of these two metals in buried soils.

Hence, it is concluded that the distribution of Zn, Mn, Cu, Co, and Ni was considerably higher in the humus horizons of the Andosols profiles.     

Specificity of soil hydrolytically microbial complex under different moisture conditions

It has been established that soil moisture has a significant impact on the activity of chitinolytic microbial processes, rather than pectinolytic processes. The degradation of polysaccharides with an increase in soil moisture in microbial complex markedly increases the role of prokaryotic microorganisms, especially actinomycetes. For the first time, using the FISH method, the amount of detected phylogenetic composition of a metabolically active hydrolytic complex of humus horizons of grey forest and gley and weakly podzolic soil and humus has been estimated depending on the humidity. At optimum moisture, phylogenetic groups Actinobacteria and Firmicutes dominated in the chitinolytic process. An increase in the proportion of proteobacteria is observed with an increase in humidity. The role of gamma- and alphaproteobacteria and actino-bacteria is heightened with the drying of soil in the hydrolytic complex. A quantitative estimate of the rate of degradation of polysaccharides (pectin and chitin) in different types of soils at different levels of moisture is given. The dependence of the phylogenetic composition of an active microbial hydrolytic complex of humus horizons of grey forest and gley, weakly podzolic soils and humus on humidity is revealed.     

Assessing the humus status and CO<Subscript>2</Subscript> production in soils of anthropogenic and agrogenic landscapes in southern regions of the Russian Far East

The humus status and CO₂ production have been assessed in soils of natural and anthropogenic landscapes in southern regions of the Far East with different types of redox conditions. A higher production of CO₂ is typical of burozems and soddy-eluvial-metamorphic soils with oxidative and contrast redox conditions. These are soils with medium or high humus content, high potential humification capacity, and medium enrichment with catalase. A decrease in the content of humus in the plow horizons of soils in agrogenic landscapes is revealed compared to their natural analogues. The studied soils mainly have humus of the fulvate–humate type. The fractions strongly bound to the mineral soil component prevail in humic acids. In waterlogged mucky-humus gley soils, the anaerobic conditions hamper the biological activity and transformation of organic matter, which favors its accumulation. A low production of CO₂ is observed in soils with reducing conditions. To determine the differences between the CO₂ emission parameters in soils of agrogenic and natural landscapes, monitoring studies should be extended.     

Chemical properties and pedogenesis of yellowish/yellow brown forest soils in the submontane and mountain zones of Kyushu district,southwestern Japan

Abstract

This study aimed to clarify pedogenetic processes and classification of yellowish Brown Forest Soils according to the Classification of Forest Soils in Japan and the Yellow Brown Forest soils according to the Unified Soil Classification System of Japan in the warm and cool temperate forest of Kyushu district, Japan. In addition, the study aimed to clarify a problem with the Unified Soil Classification System of Japan. Thirty-six soil profiles of Brown Forest Soils, including 13 yellowish Brown Forest Soils and 15 Yellow Brown Forest soils, were compared with regard to their chemical properties and the relationship with climatic conditions was assessed. The yellowish Brown Forest Soils had thin A horizons, low pH and low levels of free oxides in the B horizons, and a low amount of silica and a high aluminum and iron to silica ratio. These features were related to the paleo reddish weathering. The immaturely developed A horizon of the yellowish Brown Forest Soils was caused by these weathered, low-activity substances. The Yellow Brown Forest soils had low levels of active iron oxides and a low activity ratio of free iron oxides compared with the Haplic Brown Forest soils in the same thermal climatic conditions. The activity ratio of free iron oxides was correlated to mean annual air temperature with the carbon stocks and with many other chemical properties. Accordingly, classification of Brown Forest Soils was clearer according to thermal climatic conditions. The activity ratio of free iron oxides can become an effective index that distinguishes Yellow Brown Forest soils under warm temperate lucidophyllous forest and Haplic Brown Forest soils under cool temperate broad-leaved deciduous forest with considerable vertical soil zonality.     

Assessment of agronomic homogeneity and compatibility of soils in the Vladimir Opolie region

Complexes of gray forest soils of different podzolization degrees with the participation of gray forest podzolized soils with the second humus horizon play a noticeable role in the soil cover patterns of Vladimir Opolie. The agronomic homogeneity and agronomic compatibility of gray forest soils in automorphic positions (“plakor” sites) were assessed on the test field of the Vladimir Agricultural Research Institute. The term “soil homogeneity” implies in our study the closeness of crop yield estimates (scores) for the soil polygons; the term “soil compatibility” implies the possibility to apply the same technologies in the same dates for different soil polygons within a field. To assess the agronomic homogeneity and compatibility of soils, the statistical analysis of the yields of test crop (oats) was performed, and the spatial distribution of the particular parameters of soil hydrothermic regime was studied. The analysis of crop yields showed their high variability: the gray forest soils on microhighs showed the minimal potential fertility, and the maximal fertility was typical of the soils with the second humus horizon in microlows. Soils also differed significantly in their hydrothermic regime, as the gray forest soils with the second humus horizon were heated and cooled slower than the background gray forest soils; their temperature had a stronger lag effect and displayed a narrower amplitude in seasonal fluctuations; and these soils were wetter during the first weeks (40 days) of the growing season. Being colder and wetter, the soils with the second humus horizons reached their physical ripeness later than the gray forest soils. Thus, the soil cover of the test plot in the automorphic position is heterogeneous; from the agronomic standpoint, its components are incompatible.     

Soil development on the Crimean Peninsula in the Late Holocene

The study of soils of different ages in different physiographic regions of the Crimean Peninsula made it possible to reveal the main regularities of pedogenesis in the Late Holocene (in the past 2800 years). With respect to the average rate of the development of soil humus horizons, the main types of soils in the studied region were arranged into the following sequence: southern chernozems and dark chestnut soils > mountainous forest brown soils > gravelly cinnamonic soils. In the newly formed soils, the accumulation of humus developed at a higher rate than the increase in the thickness of humus horizons. A sharp decrease in the rates of development of soil humus profiles and humus accumulation took place in the soils with the age of 1100-1200 years. The possibility for assessing the impact of climate changes on the pedogenetic process on the basis of instrumental meteorological data was shown. The potential centennial fluctuations of the climate in the Holocene determined the possibility of pulsating shifts of soil-geographic subzones within the steppe part of the Crimea with considerable changes in the rates of the development of soil humus horizons in comparison with those in the Late Holocene.     

Microbial biomass carbon in the profiles of forest soils of the southern taiga zone

In the mineral horizons of the soils under different southern taiga forests (oak, archangel spruce, and aspen in the Kaluzhskie Zaseki Reserve of Kaluga region and the green moss spruce and spruce-broadleaved forests of the Zvenigorod Biological Station of Moscow State University in Moscow region), the carbon content in the microbial biomass (C_mic), the rate of the basal respiration (BR), and the specific microbial respiration (qCO₂= BR/C_mic) were determined. The C_mic content was measured using the method of substrate-induced respiration (SIR). In the upper humus horizons of the soils, the C_mic content amounted to 762–2545 μg/g and the BR ranged from 1.59 to 7.55 μg CO₂-C/g per h. The values of these parameters essentially decreased down the soil profiles. The portion of C_mic in the organic carbon of the humus horizons of the forest soils was 4.4 to 13.2%. The qCO₂values increased with the depth in the soils of the Biological Station and did not change in the soils of the Reserve. The pool of C_mic and C_org and the microbial production of CO₂ (BR) within the forest soil profiles are presented.     

Properties of soils in Southern Sikhote-Alin using the example of the Ussuri Reserve

The physical and physicochemical parameters of soils in the Ussuri Reserve presenting the typical soils of the Southern Sikhote-Alin were determined for the first time with consideration for the composition and structure of the soil cover. The soils in the surface horizons had loamy and clay loamy texture. It could vary depending on the overlain soil processes. All the soils were characterized by the minimum base saturation and an increase in the actual acidity down the profile. The organic matter was characterized by an abrupt decrease down the profile and the high mobility of the humus substances. The fractional-group humus composition was analyzed, and the humus status of the soils was characterized. The burozems were regarded as background soils, while a humus-illuvial podburs were referred to the rare ones. Recommendations were developed for the organization of soil monitoring with key test plots in different ecological conditions as examples.     

Humus Horizons of Soils in Urban Ecosystems

The origin, structure, composition, and properties of soil humus horizons in functional zones of St. Petersburg have been studied. The radiocarbon age of organic matter in the humus horizons varies from 500 to 2700 years, which attests to the natural origin of humus. The structure of microbiomes in the humus horizons of soils under different plant communities has its specific features. The taxonomic structure of microbial communities at the phylum level reflects both genetic features of natural soils and the impact of anthropogenic factors, including alkalization typical of the studied urban soils. Tomographic studies have shown that the transporting system of humus horizons is less developed in the anthropogenically transformed soils in comparison with the natural soils. It can be supposed that the intensity of water and gas exchange in the anthropogenic soils is much lower than that in the natural soils. The fractional and group composition of humus in the urban soils is specified by the long-term pedogenesis, on one hand, and by the impact of metabolic products of the city and the factors of soil formation in the megalopolis, on the other hand. Bulk density of the humus horizon in the urban soils is higher than that in the natural soils; the portion of overcompacted humus horizons in the urban soils reaches 44%. Humus horizons of the lawns along highways are most contaminated with heavy metals: Pb, Zn, and Cu. There are no definite regularities in the distribution of major nutrients (NPK) in the humus horizons of anthropogenic soils.     

Morphometric profiles of pore space in loamy soils of the forest and steppe zones of European Russia

A computer-based image analysis of vertically oriented thin sections was applied to study changes in the shape and orientation of fine soil macropores (d = 0.2−2.0 mm) in the profiles of soddy-podzolic soils and typical (migrational-mycelial) chernozems. Generalization of the obtained morphometric data was based on the theory of mereology, a scientific discipline studying the structure (part-whole relationships) of classified objects. As a first approximation, generalized data characterized archetypes of morphometric porespace profiles of the studied soils. The archetype of the pore-space profile of the soddy-podzolic soil consists of four components (meronyms) corresponding to the humus-accumulative, eluvial, textural (clay-illuvial), and transitional to the parent material (BC) horizons. Sharp boundaries between the upper horizons specify sharp changes in the studied meronomic indices of the shape and orientation of soil pores. The pore-space profile of the migrational-mycelial chernozem consists of two major components: specific pores in the granular dark-humus (AU) horizon and complex pore space of the BCA and BCca horizons that are poorly differentiated with respect to the shape and orientation of their fine macropores despite clear genetic differences between these horizons. Pore-space patterns in the lower (transitional to the parent material) horizons of the studied soils are characterized by the high degree of similarity (>75%). Pore-space patterns in the upper horizons of the studied soils are different; the level of their similarity does not exceed 24–41.5%. The results obtained in this study hold promise in the use of morphometric characteristics of the pore space in separate genetic soil horizons as meronyms composing archetypes of the pore-space profiles of different soils. Such archetypes may be used for diagnostic purposes as reference pore-space profiles of the particular types of soils.     

Variation of four phosphorus properties in woodland soils

Variation in total, organic and available-P contents and phosphatase activity of P-deficient soils of some English Lake District woodlands of differing vegetative composition were examined in relation to individual woodlands, two depths in the soil profile, mull, moder and mor humus types, and different times of the year. Depth in the soil profile was a more important source of variation in the P properties than different woodlands. Soils in individual woodlands differed in their degree of variability in the four P properties. Available P contents and phosphatase activities were more variable than total and organic P contents. Available-P and organic-P contents and phosphatase activity showed seasonal variation. Seasonal variation in available-P was almost as great as differences in available-P between woodlands. Total and organic-P contents showed similar patterns of variation with respect to individual woodlands, humus type and soil depth. Differences in degree of variation within woodlands and differences in degree and pattern of variation of the four P-properties may need to be taken into account in soil sampling programmes of studies comparing soils under differing vegetation regimes.Different interpretations of the variation in the soil-P properties were obtained by expressing the data respectively in terms of soil weight (g^?1 soil) or soil volume (cm^?1 soil), due to marked variation in bulk-densities of the woodland soils. It is suggested that where soils vary in bulk-density, soil data should be expressed in terms of soil volume.The P-deficiency of the woodland soils is probably associated with the relatively low total P content per unit volume of soil and the high proportion of it which is organically bound.     

The effects of agricultural use on the structure and physical properties of three soil types

This investigation was carried out to determine the influence of the use of soils on their morphological structure and properties. Three soil types (i.e. Haplic Phaeozem derived from loess, Orthic Luvisol derived from loess and Orthic Luvisol derived from sandy loam) were involved. In each soil unit, profiles lying at a small distance from one another were taken for detailed examination. The main difference between the soils within each unit was the use to which they were put. The following soils were selected for evaluation: (A) soil from natural forest habitat; (B) soil cultivated in farms with a very low level of mechanisation; (C) soil cultivated in farms which had been completely mechanised for many years; (D) soil used for many years in a vegetable garden, similar to hortisol.

In the selected profiles the morphological features, soil structure in all genetic horizons, granulometric composition, humus content, pH, density, air and water capacity and air permeability were analysed.

It was found that the transition from forest soil management to agricultural use leads not only to the formation of an arable-humus horizon and to changes in structure but also to changes of the physico-chemical properties of soils. Soils under agricultural use manifest a lower level of acidification than forest soils, as well as a different distribution of organic matter. In all agricultural soils, increased compaction of humus horizons was observed, compared with the corresponding horizons of forest soils, as well as changes in other physical features. The use of heavy machines over many years in field operations results in increased density of the soil and deterioration of soil structure. This effect is greater in soils with low colloids and organic matter contents.     

Chemodestructive fractionation of soil organic matter

The method of chemodestructive fractionation is suggested to assess the composition of soil organic matter. This method is based on determination of the resilience of soil organic matter components and/or different parts of organic compounds to the impact of oxidizing agents. For this purpose, a series of solutions with similar concentration of the oxidant (K₂Cr₂O₇), but with linearly increasing oxidative capacity was prepared. Chemodestructive fractionation showed that the portion of easily oxidizable (labile) organic matter in humus horizons of different soil types depends on the conditions of soil formation. It was maximal in hydromorphic soils of the taiga zone and minimal in automorphic soils of the dry steppe zone. The portion of easily oxidizable organic matter in arable soils increased with an increase in the rate of organic fertilizers application. The long-lasting agricultural use of soils and burying of the humus horizons within the upper one-meter layer resulted in the decreasing content of easily oxidizable organic matter. It was found that the portion of easily oxidizable organic matter decreases by the mid-summer or fall in comparison with the spring or early summer period.     

不同植被类型紫色土腐殖质的剖面分布特征

[目的]研究龙川江流域6种不同植被类型对紫色土腐殖质(胡敏酸、富里酸、胡敏素)和土壤养分(总磷、速效磷、总氮、碱解氮)剖面分布特征的影响,为该地区保持土壤肥力提供科学依据。[方法]采用锯齿形布点法,采集紫色土表层至30 cm深度的3个土层紫色土样品,用3次4分法分离多余样品,并测定相应指标。[结果]总磷、速效磷、总氮、碱解氮的含量和腐殖质、胡敏素、胡敏酸、富里酸碳量随土壤深度的增加而减小,枯枝落叶层显著高于其他层(地下0—10,10—20,20—30 cm),不同植被类型土壤无显著差异。果园土壤腐殖质及其组成显著高于桉树林覆盖土壤,表现为果园落叶阔叶林暖温性针叶林针阔混交林灌丛桉树林。土壤腐殖质各组分之间均存在极显著正相关关系,腐殖质组成与土壤有机质、总磷、速效磷、总氮、碱解氮均存在显著正相关关系。[结论]果园和落叶阔叶林下土壤腐殖质及其组分显著高于其他植被类型土壤,腐殖质组分含量与土壤理化性质之间呈极显著正相关。     

Transformation of old-plowed gray forest soils under the influence of differently aged pine forests in the middle Angara River region

The long-term (55–85 years) influence of pine forests on old-plowed gray forest soils (in the middle Angara River basin) has been reflected in the character of the biological cycle and intensity of the biological processes. The population of actinomycetes decreased, and that of fungi increased, within the whole profiles of these soils. The soil profiles became more differentiated according to eluvial-illuvial types. The thickness of the humus (former plowed) horizons decreased. The thicker differently decomposed litter with the abundant fungal mycelium was formed. The most conservative were relic morphological characteristics: plow sole, humus tongues, and the illuvial-metamorphic horizon.     

Genesis,hydrology, and properties of soils in mesodepressions waterlogged by surface water in the northern Ryazan forest-steppe

On the interfluves and in small depressions of the Ryazan forest-steppe, under periodic stagnation of surface water, acid chernozem-like soils with a relatively thick humus horizon, podzolic horizons, and marble-colored gleyed B1 and B2 horizons are formed. The eluvial horizons of these soils contain Mn-Fe nodules, and dark humus coatings occur in the illuvial horizons. In the spring, the eluvial horizons of these soils are excessively moistened and gravitational water stagnates on the soil surface for 3–4 weeks. The formation of the acid light-colored eluvial horizons of the soils on leached rocks is related to gleying under the conditions of the stagnant-percolative regime. Their total thickness is 15–25 cm and more. According to the properties of their solid phase, these horizons are similar to the podzolic horizons of soddy-podzolic gleyed soils. These soils have not been represented in the classification systems of soils of the USSR and Russia. Based on the principles of the substantial-genetic classification, one of the authors of this article [9] referred this soil to gleyed podzolic chernozem-like soils, thus, considering it as an individual genetic soil type. The gleyed podzolic chernozem-like soils differ from the leached chernozems by their low productivity and difficulty of tillage. In humid and moderately moist years, the death of crops or a reduction in yield are probable because of the excess of moisture.     

Properties and functioning of arable soils of the paleocryogenic soil complex in the Vladimir opolie region

In agrolandscapes of the Vladimir opolie region, the ancient paleocryogenic microtopography is completely buried. However, the pattern of the paleocryogenic soil complex can be deduced from data on the humus content in the plow layer. Under conditions of a leveled surface microtopography, regular differences in the temperature and moisture of soils with different morphologies of their profile are observed; they are explained by the differences in the properties of particular genetic horizons. It is supposed that differences in the regimes of functioning of modern soils of the complex favor the preservation of the relict soilscape.