Northwest Russia Research Articles

Contribution of microbial activity and vegetation cover to the spatial distribution of soil respiration in mountains.

The patterns of change in bioclimatic conditions determine the vegetation cover and soil properties along the altitudinal gradient. Together, these factors control the spatial variability of soil respiration (RS) in mountainous areas. The underlying mechanisms, which are poorly understood, shape the resulting surface CO2 flux in these ecosystems. We aimed to investigate the spatial variability of RS and its drivers on the northeastern slope of the Northwest Caucasus Mountains, Russia (1,260-2,480 m a.s.l.), in mixed, fir, and deciduous forests, as well as subalpine and alpine meadows. RS was measured simultaneously in each ecosystem at 12 randomly distributed points using the closed static chamber technique. After the measurements, topsoil samples (0-10 cm) were collected under each chamber (n = 60). Several soil physicochemical, microbial, and vegetation indices were assessed as potential drivers of RS. We tested two hypotheses: (i) the spatial variability of RS is higher in forests than in grasslands; and (ii) the spatial variability of RS in forests is mainly due to soil microbial activity, whereas in grasslands, it is mainly due to vegetation characteristics. Unexpectedly, RS variability was lower in forests than in grasslands, ranging from 1.3-6.5 versus 3.4-12.7 μmol CO2 m-1 s-1, respectively. Spatial variability of RS in forests was related to microbial functioning through chitinase activity (50% explained variance), whereas in grasslands it was related to vegetation structure, namely graminoid abundance (27% explained variance). Apparently, the chitinase dependence of RS variability in forests may be related to soil N limitation. This was confirmed by low N content and high C:N ratio compared to grassland soils. The greater sensitivity of grassland RS to vegetation structure may be related to the essential root C allocation for some grasses. Thus, the first hypothesis concerning the higher spatial variability of RS in forests than in grasslands was not confirmed, whereas the second hypothesis concerning the crucial role of soil microorganisms in forests and vegetation in grasslands as drivers of RS spatial variability was confirmed.

Влияние реконструктивной рубки в лиственно-еловом древостое на корневую конкуренцию пород

The predominance of mixed forest stands in a productive forest fund, which is located in the middle taiga subzone of Northwest Russia, determines the relevance of an investigation of the growth and development characteristics of the trees. In secondary stands, created by an extensive human consumption of primary spruce stands, spruce trees are generally presented in a minor quantity. The recovery of their dominance is an urgent economic and ecological issue. Despite the unity of approaches concerning the maintenance of deciduous-spruce forests, the research characteristics on the structure of the root systems differ considerably along with age and geographical position. This article investigates a root system competition between spruce and deciduous species in a 70-year-old blueberry-type forest that was 100 thinning by a reconstructive cutting 35 years ago. The mass of fine roots and their distribution in the upper solid layers were examined by the method of soil monoliths in the mixed stands with different proportions of spruce. The numerical characteristics of the stands were determined by the results of a regular complete enumeration on the trail plots. Besides, the tree diameters were measured around the circular plots, which were made for the collection of the monoliths. The records were made on the dynamics of changes in forest floor thickness and vegetation. The relationship between the underground and elevated parts of the stands was explored. It was shown that the roots of spruce can occupy the same ecological niche as the roots of deciduous species. A correlation analysis revealed a statistically significant relationship between the mass of fine spruce roots and the competitive influence of deciduous species, the proportion of spruce in the stand, and its current volume increment. There was a significant difference in spruce root mass under joint growth with birch and aspen. Therefore, it was concluded that this phenomenon has a complex nature. Namely, the mass of the spruce roots has a direct dependency on their closeness to the maternal trees in combination with the spatial heterogeneity of the organic soil layers. The gained findings are important for the regulation of the composition and structure of the mixed deciduous-spruce stands for growing sustainable stands with a high economic value. For citation: Karpechko A.Yu., Sinkevich S.M. Influence of Reconstructive Cutting in Deciduous-Spruce Stands on Root Competition of Species. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 99–112. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-99-112

Characteristics of the Low Molecular Weight Metabolome of Potamogeton Natans L. (Potamogetonaceae) from Lakes of Different Trophic State (Karelian Isthmus, Northwest Russia)

The qualitative and quantitative component composition of low molecular weight volatile organic compounds (VOCs) of the essential oil of the floating-leaf pondweed (Potamogeton natans L., Potamogetonaceae family) growing in various lakes of the Karelian Isthmus (North-West of the Russian Federation) in the fruiting stage was investigated in detail for the first time by gas chromatography-mass spectrometry. The low molecular weight metabolome (LMWM) of P. natans contained 138 components, 128 of which were identified. VOCs belonging to esters, alcohols, and various functional groups dominated the LMWM of floating leaf pondweed from mesotrophic and eutrophic lakes. A significant similarity was found between the component composition of VOCs of floating leaf pondweed from mesotrophic and eutrophic lakes. Many of the substances found in the LMWM of P. natans can be attributed to biologically active compounds. This opens up prospects for the use of this plant (particularly manool and ecdysteroids from its LMWM) for various economic applications as a valuable natural raw material. Due to the characteristic of the floating leaf pondweed's substantial resistance of its LMWM to the factor of the trophic status of the lakes, it is feasible to use it as an ecological indicator of significant disruptions in aquatic environments.

The nothingness myth

Abstract This article analyzes the concept of “nothingness” as a part of human- resource relations in pre- and post-industrial landscapes. It addresses nothingness as a part of mythological narratives in Kvartsitnyi settlement in northwestern Russia. Kvartsitnyi was built in the 1970s near the new quartzitic sandstone quarry and was initially viewed as a modern settlement attracting workers from all around the country. However, in the early 2000s, the quarry went bankrupt and closed. The pre-industrial landscape of Kvartsitnyi is often viewed in the interviews as empty, and the quarry's closure recreated this symbolic “nothingness.” These narratives resemble mythological creation stories when a new world appears from nothing but is destroyed as a result of human mistakes. The article discusses the cosmogonic myth of Kvartsitnyi within the larger context of Soviet and post-Soviet myth-making.

Floristic research at the Forest Research Institute of the Karelian Research Centre RAS: traditions of studying the species diversity of plants and fungi

Employees of the Forest Research Institute (FRI) KarRC RAS have contributed greatly to the study of the biodiversity of vascular plants, aphyllophoroid, sac and basidial fungi and lichens of the Republic of Karelia. Studies of vascular plants and various groups of fungi have been carried out since the FRI foundation in 1957 and are continuing successfully at present, with new tasks being set and the geographic range of interests expanding to cover the entire Northwest Russia. The lichenofloristic research component appeared at FRI later (in 1985) and is also developing. Prominent scientists such as V. I. Krutov, M. L. Ramenskaya, and V. I. Shubin, Doctors of Biological Sciences who worked at the FRI, made a huge contribution to the study of the biodiversity of Karelia, Eastern Fennoscandia, and the forest zone of European Russia as a whole. The role of these scientists and their students or successors is great not only in advancing the knowledge of the species diversity of Karelia and adjacent regions, but also in treating various issues of nature protection and sustainable use of natural resources, especially forest resources. The Institute’s employees have played a leading role in building the system of protected areas (PAs) in Karelia, especially considering that the republic’s first PA, Kivach Strict Nature Reserve, used to be a FRI unit for quite long. Botanists and mycologists from FRI participated in compiling the inventory of the flora and mycobiota and in preparing scientific substantiation papers for many planned PAs. Research continues in the PAs after their designation. Employees of the FRI prepared the first (unofficial) edition of the regional Red Data Book and then participated as leading authors in the preparation of three official editions of the Red Data Book. At present, many direct students (postgraduates) or successors of the pioneers in the study of the species diversity of vascular plants and fungi V. I. Krutov, M. L. Ramenskaya, and V. I. Shubin continue to work productively at the Institute.

Study of the Distribution of Rare-Earth Elements and Strontium in Apatite from Rocks of the Vuoriyarvi Carbonatite Complex by Total-Reflection X-Ray Fluorescence Spectrometry (TXRF): First Results and Prospects

Abstract —We have studied the trace element composition of apatite from several varieties of carbonatites and associated apatite ores of the Vuoriyarvi alkaline-ultrabasic carbonatite complex (Kola region, northwestern Russia), which hosts several commercial deposits of apatite–magnetite and pyrochlore ores and large-scale unexplored rare-earth mineral occurrences. The composition of apatite was analyzed by total-reflection X-ray fluorescence spectrometry (hereafter, TXRF). Verification of the obtained results was carried out by ICP-MS analysis of weighed portions of apatite monomineral samples. It is shown that during the evolution of the Vuoriyarvi carbonatites and associated apatite–magnetite ores, the contents of Sr and rare-earth elements (REE) and the degree of REE fractionation in apatite synchronously increased. The obtained TXRF data on the composition of apatite in the carbonatite complex demonstrate the efficiency of TXRF and its high potential in both applied and fundamental research concerned with apatite of various geologic objects.

Isolation basin stratigraphy and Holocene relative sea-level change on the Barents Sea coast at Teriberka, Kola Peninsula, northwestern Russia

The paper presents isolation basin stratigraphy in bottom sediments from nine lakes in the Teriberka area on the Kola Peninsula, northwestern Russia. Isolation contacts in these basins, identified from lithological and diatom analysis, were used together with 25 radiocarbon dates, to construct a relative sea-level (RSL) curve for the Holocene. Records of marine water re-influx were found in the sediment sequence from one lake, located at c. 17 m a.s.l. The re-influx of marine water seems to be caused by the mid-Holocene (Tapes) transgression and tsunami event. The RSL curve indicates several phases in the postglacial evolution of the Kola coast. An early phase of rapid sea-level fall of c. 32 m around 11,500 cal yr BP, at a rate of c. 40 mm per year, corresponds to glacio-isostatically induced emergence following deglaciation at the Younger Dryas and beginning of the Holocene. In the time interval between c. 11,000 and 7600 cal yr BP, either a stillstand or a slight rise in relative sea level, cresting at about 21 m a.s.l., is suggested in the Teriberka area. This is followed, after c. 7300 cal yr BP to the present day, by a slow glacioisostatic emergence with an average rate of about 2–3 mm per year.

Population structure and genetic diversity of Fusarium graminearum from southwestern Russia and the Russian Far East as compared with northern Europe and North America

ABSTRACT Genetic variation at variable number tandem repeat (VNTR) markers was used to assess population structure and diversity among 296 Fusarium graminearum isolates from northern Europe (Finland, northwestern Russia, and Norway), southern Europe (southwestern and western Russia), and Asia (Siberia and the Russian Far East). We identified at least two highly differentiated and geographically structured genetic populations (E1 and E2) in Eurasia (ΦPT = 0.35). Isolates from northern Europe were almost exclusively from the E1 population (95.6%) and had the 3ADON (3-acetyldeoxynivalenol) trichothecene genotype (97.3%). In contrast, all isolates from southern Europe were from the E2 population and 94.4% had the 15ADON (15-acetyldeoxynivalenol) genotype. The E2 population also predominated in the Asian sampling locations (92.7%) where 3ADON and 15ADON genotypes occurred at nearly equal frequencies. Southern European isolates were more closely related to those from Asia (ΦPT = 0.06) than to geographically closer populations from northern Europe (ΦPT ≥ 0.31). Northern European populations also harbored substantially less genetic diversity (Ne ≤ 2.1) than populations in southern Europe or Asia (Ne ≥ 3.4), indicative of a selective sweep or recent introduction and subsequent range expansion in northern Europe. Bayesian analyses incorporating previously described genetic populations from North America (NA1 and NA2) surprisingly identified NA2 and E2 as a single genetic population, consistent with hypotheses of a recent Eurasian origin for NA2. Additionally, more than 10% of the isolates from Asia and southern Europe were assigned to the NA1 population, indicating recent introductions of NA1 into parts of Eurasia. Collectively, these results demonstrate that there are at least three genetic populations of F. graminearum in the Northern Hemisphere and indicate that population-level diversity in Eurasia and North America has been shaped by recent transcontinental introductions.

U–Pb geochronology of detrital zircon from the Ediacaran and Cambrian sedimentary successions of NE Estonia and Volyn region of Ukraine: Implications for the provenance and comparison with other areas within Baltica

Trends in detrital zircon age distribution patterns are used to constrain the paleotectonic and paleogeographic conditions during deposition of the late Ediacaran - Early Cambrian sedimentary successions in northwestern, western, and southwestern Baltica. Detrital zircons from three sandstone samples collected from a drill-core drilled in northeastern Estonia and four sandstone samples collected from three drill-cores located in the Volyn region of Ukraine were dated using the U-Pb LA-ICP-MS isotope technique. The resulting age patterns are compared with the published data for southwestern Ukraine and Moldova, eastern Poland, Belarus, and northwestern Russia to constrain the late Ediacaran - Early Cambrian evolution of the sedimentary basins developed on Baltica. All sedimentary basins from these areas of Baltica show a transition during that interval from a passive continental margin to collisional settings, which has been triggered by the pre-Schythides and Santacrusades orogenies along the south-southwestern and, to a lesser extent, by the Timanian Orogeny along the north-northeastern and eastern (in modern coordinates) margins of Baltica.

Morphological features of Late Ordovician (Sandbian) bryozoans from the basin of Khrevitsa River (north-western Russia) and description of a new species of the genus Prophyllodictya Gorjunova, 1987.

Some Sandbian (Late Ordovician) bryozoans are here described from the Leningrad region, north-western Russia. The studied association is represented by eight species including one new cryptostome bryozoan Prophyllodictya khrevitsa n. sp. We explore the colony morphology and evolutionary morphogenesis of Prophyllodictya Gorjunova, 1987 and discuss the morphological features of trepostome and cryptostome bryozoans from the Khrevitsa Formation. Finally, we classify protective structures in bryozoan colonies in three groups based on functional criteria: 1) structures to strengthen the colony, 2) structures to defend the colony against predators, and 3) structures to protect the polypide.

Structure, Growth and Histology of Gnathal Elements in Dunkleosteus (Arthrodira, Placodermi), with a Description of a New Species from the Famennian (Upper Devonian) of the Tver Region (North-Western Russia)

A new species of Dunkleosteus, D. tuderensis sp. nov., is named based on an infragnathal from the Famennian of the Tver Region, Russia. CT scanning of the holotype revealed two high-density bony constituents comparable in position and interrelations to components described for coccosteomorph arthrodires, supported by the presence of at least two clusters of large vascular canals marking separate arterial supplies. Coccosteomorph and dunkleosteid pachyosteomorphs exhibit similar growth patterns including labio-basal depositions of vascularized bone in the infragnathals and basally in the supragnathals. In contrast to coccosteomorphs, dunkleosteid reinforcement of the occlusal margins occurred via the formation of dense osteonal bone, in parallel with resorption forming extensive lingual fossae. Active bone remodeling proceeded without a complete reworking of the primary osteonal bone structure and the original arrangement of vascular canals. Due to inconsistent anatomical terminology in gnathal elements of dunkleosteid arthrodires, a revised terminology is suggested and new terms are introduced.

The history of Sámi nursing education and the path toward regulations on a national guideline for Sámi nursing education in Norway

The history of the Norwegianization policy against the Sámi, the Indigenous people of Sápmi, (northern Norway, Sweden, Finland and northwest Russia) was about colonization, assimilation and discrimination from 1930 until 1980. Many Sámi lost their mother tongue and were disconnected from their culture and traditional ways of living, which resulted in historical trauma. Taking this into consideration, a nursing program with specific Sámi content was implemented in northern Sápmi four times since 1995. This article elaborates our experiences with developing programs and new national guidelines in Sámi nursing in Sápmi. We encourage more tertiary education institutions in Sápmi to offer Sámi nursing programs with the above focus and recommend admission requirements that do not prolong the linguistic discrimination of Sámi students. Today, all Norwegian universities and colleges can draw up curricula for nursing programs with the particular aim of focusing on Sámi issues in nursing programs.

Occurrence and population status of the pond bat (Myotis dasycneme) in Northwest Russia

Abstract Pond bat Myotis dasycneme is distributed from Belgium to Eastern Siberia, between 44°–50° N and 60° N. The total population of M. dasycneme is probably declining, but supporting data are incomplete. The conservation status of the species is not yet completely assessed. Surveys of hibernacula and foraging sites have been carried out recently in Northwest Russia. Evidence of a recent increase in numbers of wintering bats have been recorded, a northwards expansion is supposed. However, the local pond bat is still under threat as its most significant population is concentrated in only one hibernaculum, which is not well protected.

Geoinduced currents on Karelian-Kola power line and finnish gas pipeline on september, 12–13 2017

Geomagnetic activity and occurrence of large values of geoinduced currents (GICs) during a moderate magnetic storm (SYM/H ∼ −65 nT) on September, 12–13 2017 have been studied. Two intense substorms (AL ∼600 nT and ∼1200 nT) were observed within the period of this magnetic storm. Amplification and motion of electrojets during substorms is known to be one of the important sources of GIC value increase in the auroral zone. The fine spatial temporal structure of westward electrojet has been analyzed using the latitudinal profiles of the IMAGE network and the equivalent currents of the MIRACLE system data. GICs activity were monitored by EURISGIC from Russian stations Vykhodnoy (VKH) and Revda (RVD) in the North-West of Russia (eurisgic.ru) and Mäntsälä station (MAN) in South Finland. The data from these stations are convenient to track GIC from ∼60° to ∼69° geographical latitudes. It has been shown that the increase in GIC amplitudes at different latitudes was associated with the poleward movement of the westward electrojet during the expansion phase of the substorm. Besides, it has been found that the source of the GICs at the recovery phase of the second substorm appeared to be a short pulse of Pc5 pulsations and the amplitudes of GICs were comparable with substorms one. It is also shown that the increase in GIC amplitude are in good agreement with the increase in the Wp- and IL-geomagnetic indices used for global and local control over the substorm appearance.

Bulimia symptoms and anger and aggression among adolescents

BackgroundPrevious research has indicated that anger and aggression may be elevated in adolescents with a bulimia nervosa (BN) diagnosis. However, as yet, little is known about whether bulimia symptoms are linked to anger and aggression in adolescents in the general population. To address this deficit this study aimed to explore the associations between a clinical level of bulimia symptoms (CLBS) and anger, anger rumination and aggression in community-based adolescents, and determine whether gender is important in this context.MethodsThis study was conducted on a representative sample of youth from northwestern Russia (n = 2613, age 13–17 years old, 59.5% female) using self-report scales. A proxy variable for a CLBS was created using the Eating Disorder Diagnostic Scale. Aggression, anger and anger rumination were assessed by the Trait Anger Scale of the State Trait Anger Expression Inventory, the Anger Rumination Scale, and scales created to assess physically and verbally aggressive behavior. Multivariate analysis of covariance was used to examine the associations between the study variables.ResultsA CLBS was more prevalent in girls than in boys (13.4% vs. 3.5%). The association with anger and aggression was stronger in both genders with a CLBS, compared to those adolescents without a CLBS. In the CLBS group, boys as compared to girls scored higher on verbal and physical aggression, anger rumination and social aggression. In both the CLBS and Non-CLBS groups higher anger and aggression scores were associated with increasing age.ConclusionsFindings suggest that aggression and anger rumination are elevated in adolescents with BN symptoms, and that the associations between anger, aggression and BN symptoms may be stronger in boys. As previous research has indicated that the presence of aggressive behaviors may affect the prognosis of BN and complicate management of the disorder, clinician screening for these behaviors in adolescents with BN symptoms may facilitate the provision of more effective treatment, especially among boys.

Novel Genetic Lineages of Rickettsia helvetica Associated with Ixodes apronophorus and Ixodes trianguliceps Ticks.

Ixodes apronophorus is an insufficiently studied nidicolous tick species. For the first time, the prevalence and genetic diversity of Rickettsia spp. in Ixodes apronophorus, Ixodes persulcatus, and Ixodes trianguliceps ticks from their sympatric habitats in Western Siberia were investigated. Rickettsia helvetica was first identified in I. apronophorus with a prevalence exceeding 60%. "Candidatus Rickettsia tarasevichiae" dominated in I. persulcatus, whereas I. trianguliceps were infected with "Candidatus Rickettsia uralica", R. helvetica, and "Ca. R. tarasevichiae". For larvae collected from small mammals, a strong association was observed between tick species and rickettsiae species/sequence variants, indicating that co-feeding transmission in studied habitats is absent or its impact is insignificant. Phylogenetic analysis of all available R. helvetica sequences demonstrated the presence of four distinct genetic lineages. Most sequences from I. apronophorus belong to the unique lineage III, and single sequences cluster into the lineage I alongside sequences from European I. ricinus and Siberian I. persulcatus. Rickettsia helvetica sequences from I. trianguliceps, along with sequences from I. persulcatus from northwestern Russia, form lineage II. Other known R. helvetica sequences from I. persulcatus from the Far East group into the lineage IV. The obtained results demonstrated the high genetic variability of R. helvetica.

Using DNA markers to reconstruct the lifetime morphology of barley grains from carbonized cereal crop remains unearthed at Usvyaty Settlement

Research on taxonomic and genetic diversity of cultivated plants provides valuable data that help to clarify how the flora of cultivated plants was formed in a particular region. Paleogenetics, a discipline that developed at the intersection of molecular biology, archeology and genetics, helps to explore plant origin and changes in plant genotype during evolution. By the 12th century, the economy of medieval Northern Russia was based on a developed farming culture. Tracing the origin of its constituent agricultural traditions is an important fundamental task. The objective of this work was to study and identify the species affiliation of carbonized fossil remains of plants that grew in the Russian Northwest in the 12th century using morphological and molecular genetic methods. The results of the morphological analysis of grain fossils showed that most of the unearthed plant material was barley. Other cereals, such as wheat, rye and oat, were also observed. Molecular genetic studies helped to clarify the species affiliation of partially destroyed grains and reconstruct their lifetime morphology.

Tolerance of Rare-Earth Elements in Extremophile Fungus Umbelopsis isabellina from Polar Loparite Ore Tailings in Northwestern Russia

In this study, extremophile fungal species isolated from pure loparite-containing sands and their tolerance/resistance to the lanthanides Ce and Nd were investigated. The loparite-containing sands were collected at the tailing dumps of an enterprise developing a unique polar deposit of niobium, tantalum and rare-earth elements (REEs) of the cerium group: the Lovozersky Mining and Processing Plant (MPP), located in the center of the Kola Peninsula (northwestern Russia). From the 15 fungal species found at the site, one of the most dominant isolates was identified by molecular analysis as the zygomycete fungus Umbelopsis isabellina (GenBank accession no. OQ165236). Fungal tolerance/resistance was evaluated using different concentrations of CeCl3 and NdCl3. Umbelopsis isabellina exhibited a higher degree of tolerance/resistance to cerium and neodymium than did the other dominant isolates (Aspergillus niveoglaucus, Geomyces vinaceus and Penicillium simplicissimum). The fungus began to be inhibited only after being exposed to 100 mg L-1 of NdCl3. The toxic effects of Ce were not observed in fungus growth until it was subjected to 500 mg∙L-1 of CeCl3. Moreover, only U. isabellina started to grow after extreme treatment with 1000 mg∙L-1 of CeCl3 one month after inoculation. This work indicates, for the first time, the potential of Umbelopsis isabellina to remove REEs from the loparite ore tailings, making it a suitable candidate for the development of bioleaching methods.

Carotenoids and carotenes in the fruits of <i>Cucurbita maxima, C. moschata</i> and i>C. pepo</i> under the conditions of Northwestern Russia

Cucurbits are among the most valuable vegetable crops widely used for food all over the world, being an important source of carotenoids and carotenes, biologically active substances with antioxidant and other types of activity. Their content largely depends on the Cucurbita species and varietal features. The Cucurbita collection of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) contains more than 3,000 accessions of five cultivated Cucurbita spp. and serves as the most important source of source material for developing new cultivars in order to expand the range of functional food products. The present research was aimed at studying the content of carotenoids and carotenes in the fruits of Cucurbita maxima Duch., C. pepo L. And C. moschata Duch. ex Poir. grown in Northwestern Russia, which is characterized by a short growing season and a low sum of active temperatures. The performed study revealed significant differences between the Cucurbita species and cultivars in terms of the content of carotenoids, total carotenes and β-carotene. In contrast to C. pepo, the accessions of C. maxima and C. Moschata were characterized by a wide range of variation of these characters. A statistically significant effect of the flesh and fruit skin color on the content of carotenoids, carotenes and β-carotene in them was observed (p < 0.001). The minimum amount of carotenoids, carotenes and β-carotene was found in the fruits with light yellow flesh, and the maximum in those with dark orange flesh. Cucurbit fruits with red skin accumulated more target compounds in contrast to the fruits with white skin. The identified Cucurbita accessions with high content of carotenes and carotenoids can be used as valuable source material for breeding cultivars with improved biochemical composition, which can broaden the range of functional food products when grown in the regions with unfavorable conditions for the production of this crop.

The spread of rhizoctoniosis in potato plantings in the conditions of the North-West of the Russian Federation with a heterogeneous content of nutrients in the soil

Rhizoctoniosis is one of the most common and harmful diseases of potatoes in the North-West of Russia. The degree of its manifestation depends on many factors, including the content of basic nutrients in the soil. In the Leningrad region the effect of prolonged application of organic and mineral fertilizers on the degree and nature of the manifestation of rhizoctoniosis was studied in potato variety Meteor in forage and field crop rotations. By the results of the detailed accounting carried out in 2022 including observation of all potato plantings (43406 in total) it was determined that rhizoctoniosis damage had random distribution character in field crop rotation and focal distribution in forage crop rotation. This conclusion was confirmed by respective coefficients of variation (79 and 87 %) and aggregation (1.0 and 1.5). Spatial heterogeneity of plants damaged by rhizoctoniosis was visualized on digital maps compiled with GIS AFI and Surfer 11 while grouping the data into elementary sections. There was sufficient influence of cultivation and fertilization of different levels on rhizoctoniosis spread. The influence of cultivation was weak and statistically significant only in forage crop rotation, where there was an increase of rhizoctoniosis damage of potato plants (by 1.7-2.5 times compared to low cultivated soil). Under mineral fertilizers application there was a decrease of rhizoctoniosis damage of potato plants both in field crop rotation (by 1.1-1.7 times compared to variant without fertilizers application), and in forage crop rotation (by 1.1-1.3 times). Complex influence of soil cultivation and fertilization of potato plantings caused a decrease of rhizoctoniosis damage of potato tubers by 1.9 and 2.0 times in field and forage crop rotations, respectively.