Maksim L. Burdukovskii

Dark-humus podbels of Primorsky region are characterized predominantly by elevated or high content of mobile potassium forms. The potassium regime of postagrogenic soils of the region has not been studied so far. The aim of this work is to study the dynamics of the content of mobile potassium forms and their stocks in abandoned and arable dark-humus podbels of the southern Primorsky region. The study was carried out on abandoned lands aged 15, 20, 35, and 80 years; as a control, samples from modern arable land were used. It was established that at the early stage of postagrogenic development in the upper horizon of agro-dark-humus podbels, there occurs an increase in the content of mobile potassium. After 20-35 years following the withdrawal of soil from agricultural use, a pronounced decrease of mobile potassium is observed in the humus horizon; the stocks significantly decrease throughout the profile as a whole. By the 80th year, a partial stabilization of the potassium regime is observed, however, the upper stratum remains poorer than arable land. The results have applied significance for the assessment of the fertility potential of abandoned lands and for planning their possible involvement in agricultural use.

The structure, composition, and specificity of accumulation of trace elements by rounded nodules in gleyic soddy brown-podzolic soils (Gleyic Luvisol (Manganiferric)) of nature reserves and a national park in the south of the Far East have been studied by advanced analytical methods and noninvasive techniques. The nodules are characterized by pronounced differentiation into external (brown and ocher-brown, Fe-enriched, and dense) and internal (dark brown, Mn-enriched, and loose) zones. According to the distribution of Mn compounds in the internal zone, two types of nodules are identified: with an undifferentiated internal zone and with a core (cores). The cores contain C-enriched microzones, which are centers of Fe and Mn precipitation. The stages of coprecipitation of Fe and Mn and the stages with predominant precipitation of one of the elements are identified in the nodules. The nodules consist of a complex of minerals inherited from soils, as well as of nodule-specific minerals (goethite, feroxyhyte, and birnessite). The Fe content in the nodules is, on average, four times higher than that in the soil, the Mn content is 21.9 times higher, and the C content is 3.6 times higher. The most intensive accumulation in nodules is typical for Pb (EF = 5.53–12.14), which is determined by the joint participation of C- and Mn-containing compounds in its binding. Nickel (EF 0.89–5.81) and Cr (EF 1.22–2.60) are less actively accumulated; and the accumulation of V (EF 0.85–1.88) and Sr (EF 0.58–1.43) is weak. The phases accumulating Ni, Cr, V, and Sr are represented by nodules containing Fe and C. Zinc does not accumulate in the nodules. A comparison of the concentrations of water-soluble forms of trace elements reflects a decrease in the mobility of Cr, Pb, Ni, V, and Sr in nodules as compared to soils.

Surface mining operations are accompanied by serious disturbance of natural ecosystems. The rationale for a reclamation method is based on both agrochemical and biological properties of the dumped rocks. For this reason, the investigation of primary succession and soil-formation processes at the dumps gains significant importance. The article is aimed to examine the characteristics of natural reclamation of the soil and vegetation cover in the dumps of the Pavlovsk coal field, which are different in composition and relief, and establish the relevance of the dump rocks for biological reclamation. The investigations were carried out on the territory of the Pavlovsk coal mine (Mikhailovsky district, Primorskiy Krai). At the North Depression section (44°05'39.5"N 132°04'47.3"E), two dumps were investigated – the 8-year-old dump is characterized by the conical form, with the slope of 25° (See Fig. 1A), while the 15-year-old dump has a terrace in the middle section of the slope (See Fig. 1B). These dumps are formed by loamy rocks, with the ratio of its slopes being 12-15°. At the East Depression section (44°05'24.3"N 132°05'08.9"E), the 16-year dump with smoother slopes (up to 12°) formed by clay was investigated. To examine the characteristics of colonization by vegetation, the line transects were formed from the bases of dumps to their tops. The stages of succession of plants were identified according to Voronov (1973). The organic carbon (Corg.) was determined using the Tyurin method. The granulometric composition of rocks was determined according to Kachinsky. The content of active (mobile) forms of phosphorus and potassium was determined using the methods by Kirsanov and Maslova, respectively. The current and exchangeable acidities of soils were examined using potentiometry. The classification of soils of the technogenic landscapes by Kurachev (2002) and WRB (2022) was used. As part of this study, we revealed fragmentary vegetation cover at the 8-year-old dump of the North Depression section. Within the limits of the built transect, 11 species of plants belonging to 8 families were detected. The dump slopes were subjected to water erosion. The rocks of dump had рНН2О = 4.3-4.4, low content of active forms of phosphorus and potassium (See Table 3). Pedogenic accumulation of Corg. was not observed at this dump. The development of the vegetation cover was at the pioneer stage. The Initial Embryozems (Spolic Technosols (Loamic)) were formed. On the 15-year dump, 31 species of plants belonging to 12 families were detected. In the eluvial position, a minimum number of plant species were found (See Table 2). The rocks were weakly affected by the soil formation processes, had рНН2О = 4.7, low content of phosphorus and high of potassium, while that of carbon reached 2.5% at the expense of carbon-bearing inclusions (See Table 3). The development of vegetation cover was at the pioneer stage on the Initial Embryozems (Spolic Technosols (Loamic)). In the transit positions of the dump, the complex plant cluster (with large phytomass reserves) was formed. The active colonization by vegetation resulted in formation of sod horizon with the content of Сorg. up to 1.1%, where the Sod Embryozems (Spolic Technosols (Suprafolic, Loamic)) were formed. The environment reaction of the upper horizons changed toward neutral (рНН2О = 6.2). The content of active phosphorus was low, while that of active potassium was abundant. The role of woody vegetation increased in the accumulative position (terrace). This is a stage of closed phytocenosis with active soil-forming processes. Soils had рНН2О = 6.3 in the 0-5 cm layer, while the content of Corg. increased to 3.35%, and those of phosphorus and potassium reached high and very high values, respectively. The Humus-accumulative Embriozems (Spolic Technosols (Humic, Loamic)) were formed. At the 16-year-old clayey dump of the East section, the vegetation cover is very heterogeneous due to active erosion. In such areas, the vegetation cover development was at the pioneer stage and the soil cover was at the initial stage (Spolic Technosols (Clayic)). At the most overgrown sections of dump, the projective cover reached 80% (See Fig. 2). Within the limits of the built transect, 23 species of vascular plants were found (See Table 4). This is a stage of complex plant cluster, when the litter horizon and Organic-accumulative Embryozemes (Spolic Technosols (Protofolic, Clayic)) were formed on soil surface. The rocks of dump had рНН2О = 5.9-6.3, low content of Corg. very low of phosphorus, and very high of potassium. In this study, we found that the families of Asteraceae and Poaceae were the most abundant in the projective cover and number of species at the investigated dumps. The highest Jaccard similarity coefficient of vegetation species composition was relevant for older dumps. During the first ten years, the dumps of loamy composition, with slope of 25°, were scarcely colonized by vegetation due to strong erosion processes. The vegetation cover development was at the pioneer stage and the soil cover was at the initial stage (Spolic Technosols (Loamic)). With more favorable relief features, the full tree layer was already formed by the 15th year after dumping and Humus-accumulative Embryozems (Spolic Technosols (Humic, Loamic)) were developed. At the same time, Sod Embryozems (Spolic Technosols (Suprafolic, Loamic)) were formed on the slopes. The development of vegetation at the clayey 16-year-old dump remained at the stage of complex plant clusters. On this dump Organic-accumulative Embryozems (Spolic Technosols (Protofolic, Clayic)) were formed. The phytocenoses in the clayey dumps of the East section were formed in the meadow type. At the dumps formed by lighter rocks, the survival ability of woody species of plants was higher. One of the basic constraining factors of developing the stable phytocenoses at the dumps was the processes of...

Changes in the structural–aggregate state, acidity, and carbon stocks of dark-humus podbels (Luvic Albic Mollic Planosols (Epiloamic, Endoclayic, Aric)) during their postagrogenic development under unmanaged fallow were studied at the experimental station of the A.K. Chaika Federal Scientific Center of Agricultural Biotechnology of the Far East. Restoration of the aggregate state of the soil after its removal from agricultural use took place: the content of agronomically valuable aggregates increased and their weighted average diameter decreased in the former arable layer. In the course of vegetation restoration, soils were acidified. The most pronounced drop in pH took place in the 20-yr-old fallow soil with the appearance of woody plants. The content and stocks of carbon in the fallow soils tended to increase during the entire studied postagrogenic period. Carbon stocks in a layer of 0–25 cm reached their maximum by the 85th yr of the postagrogenic succession. However, the difference between carbon stocks in a layer of 0–50 cm in the 20- and 85-yr-old fallow soils was statistically insignificant. Bulk density of the plow layer in the cultivated soil reached 0.88 g/cm³. In the fallow soils, bulk density of the upper horizon varied within 0.67–0.79 g/cm³.

Дан анализ проведенных в горных речных долинах южного Сихотэ-Алиня и Верхнеколымского нагорья систематических исследований крупных предпочтительных водопроводящих путей – залегающих на глубине до 1 м от поверхности подземных дрен склонового масштаба, в которых концентрируется основная часть склоновых вод. Приведены оценки стока и скорости движения воды в этих дренах – соответственно 0,041–7,36 л/с и 0,1–7,2 см/с, которые по величине близки к таковым в руслах рек первого порядка в периоды межени. Выявлена их приуроченность к реликтовым или активным каменным потокам. Выдвинута гипотеза, что наиболее крупные дрены масштаба склона могут определяться структурно-геологическими условиями, а именно разрывными нарушениями сублокального масштаба, оперяющими локальные разломы. На основе характера движения воды в дренах, с учетом результатов предшествующих исследований других авторов, предложен вариант их типизации, включающий три основные структурные группы: 1) главные проводники, имеющие длину порядка сотен и первых тысяч метров и ширину несколько метров; 2) домены фильтрационного потока длиной от 0,1 до первых десятков метров и шириной до 10 см, 3) пути матричного потока, характеризующиеся длиной намного менее 10 см и поперечными размерами менее 0,1 см. Детальное изучение строения склонового чехла и динамики склоновых водотоков позволит обосновать гипотезу о значительной роли малых разломов и связанных с ними активных или реликтовых каменных потоков в концентрации склонового стока. Это позволит глубже понять механизмы формирования паводков в реках, особенно в районах с резкими внутрисезонными колебаниями увлажнения, такими как районы Азии вблизи Тихоокеанского побережья. For the case of small valleys in South Sikhote-Alin Ridge and Verkhnekolymskoye Highlands (Pacific Russia, Northeast Asia), there is given an analysis of systematic observations of big preferential flow paths of slope-scale, – subsurface shallow (not deeper than 1 m) watercourses, in which the most water migrates fast. The watercourses occur most often within the bodies of relic or active stony stripes ("block streams"). In some of the studied watercourses, there were estimated discharges (0.041–7.36 l/s) and velocities (0.1–7.2 cm/s) that are quite comparable to the 1-order streamflow rates when low water periods. We suggest the biggest among such subsurface watercourses are to be controlled by geological structures of slope scale, namely sub-local fractures, which feather local fractures. Accounting for the results of relevant investigations by other authors and the water movement features revealed in the studied subsurface watercourses, we offer a variant of their division onto three main structural groups: 1) the main paths (conduits) with a length of hundreds to 1–2 thousand meters and width of several meters; 2) the filtration flow domains with a length of 0.1 meters to several dozen meters and width of up to 0.1 meters; and 3) the matrix flow paths with a length of much less 10 centimeters and width of less 0.1 centimeters. Detailed studies for talus texture and water regime of the hillside watercourses would make it possible to prove a hypothesis on the significant role of small faults (fractures) and related to them the active or relic block streams in the concentration of slope flow. It could allow a deeper understanding of the flood generation in river basins, especially in the areas where severe intra-annual moistening fluctuations as Pacific Asia.

Представлены результаты изучения структуры растительных сообществ и некоторых агрохимических свойств почв в ходе постагрогенной трансформации залежных экосистем. Работа проведена в Амурской области в Благовещенском районе на залежах 5-, 10- и 20-летнего возраста. В качестве контроля использовался рядом расположенный участок леса. Наиболее устойчивыми доминантами в залежных экосистемах являются вейниково-злаковые и полынные синузии. Запас общей фитомассы увеличивается по мере постагрогенного восстановления растительности. По уровню кислотности исследуемые почвы относятся к среднекислым. Значимой разницы в значениях рН солевой вытяжки между почвой разновозрастных залежей не выявлено. В 20-летних залежах отмечено увеличение содержания гумуса в верхнем пахотном слое на 17%, по сравнению с 5-летними. Содержание подвижных форм фосфора в почвах залежей «очень низкое», обеспеченность обменным калием снижается с увеличением возраста постагрогенного периода от «повышенных» до «средних» значений. Содержание гумуса, запасы углерода, подвижных форм фосфора и калия в верхней части профиля залежных почв существенно ниже, чем на...

The changes in the physical properties and carbon stocks of dark-humus podbels (Luvic Albic Mollic Planosols (Epiloamic, Endoclayic, Aric)) during long-term agricultural use and postagrogenic evolution were studied. Soil samples were taken in three trials: control (without fertilizers), high rates of mineral fertilizers, and mineral fertilizers + manure + lime (Chaika Experimental Field Station of the Federal Research Center for Agrobiotechnology of the Far East, Primorsky region) and in the abandoned fields (15, 20, and 35 years ago). It was shown that the long-term application of mineral fertilizers increases the soil bulk density. Application of organic and mineral fertilizers and lime had a positive effect on the bulk density and structural characteristics of soils. The abandonment of agricultural fields and the cessation of mechanical tillage resulted in the restoration of the natural soil structure. The content of agronomically valuable aggregates increased, while their mean weighted diameter decreased in the upper horizon of studied fallow soils. The carbon content and stock in the upper soil layer decreased in the first years of the conversion of arable fields to unmanaged fallow. The carbon stock in the upper 50-cm layer increased with time.

Гришин С.Ю., Перепелкина П.А., Бурдуковский М.Л.//2021

Impact of different fallow durations on soil aggregate structure and humus status parameters | Maksim Burdukovskii, Irina Kiseleva, Polina Perepelkina, Yuliya Kosheleva | Agricultural Journals