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The use of conservation agriculture (SWC-soil and water conservation) technologies is now becoming more and more necessary. For the soils in arid ecosystems, the problem of irrigation deficiencies has always been relevant, and clean fresh water is always insufficient to irrigate these agricultural lands. This paper provides a brief historical overview of the use of mineralized water sources in agriculture and their impacts on soils and plants ( Triticum aestivum L.). The experiment involving wheat cultivation in saline soils irrigated with mineralized water was set for 3 years. The main chemical and physical-chemical properties of the agro-transformed solonchaks and mineralized water sources were investigated. According to the contents of mobile forms of N, P, and K, the soils were poorly supplied; after a series of irrigation phases, they remained the same. There were signs of the growth of mobile phosphorus in the variants where mineralized water sources were applied. Our results showed that under conditions of irrigation with water sources with mineralization rates of up to 2.8-3.5 g/L, the wheat yield increased by 1.5 c/ha compared to the control. The use of mineralized water for irrigation purposes will reduce the use of clean river water.

Chernevaya taiga in West Siberia is a unique environment, with gigantism of grasses and shrubs. Exceptionally high productivity of plants is determined by the synergistic interaction of various factors, with a special role belonging to microorganisms colonizing the plant roots. This research explored whether agricultural plants can recruit specific microorganisms from within virgin Chernevaya Umbrisol and thus increase their productivity. Radish and wheat plants were grown on the Umbrisol (T1) and control Retisol of Scotch pine forest stand (T3) soils in the phytotron, and then a bacterial community analysis of the rhizosphere was performed using high-throughput sequencing of the 16S rRNA genes. In laboratory experiments, the plant physiological parameters were significantly higher when growing on the Umbrisol as compared to the Retisol. Bacterial diversity in T1 soil was considerably higher than in the control sample, and the principal coordinate analysis demonstrated apparent differences in the bacterial communities associated with the plants. Agricultural plants growing in the T1 soil form specific prokaryotic communities, with dominant genera Chthoniobacter, Pseudomonas, Burkholderia, and Massilia. These communities also include less abundant but essential for plant growth nitrifiers Cand. Nitrosocosmius and Nitrospira, and representatives of Proteobacteria, Bacilli, and Actinobacteria, known to be gibberellin-producers.

The article provides an analysis of the cenopopulation and tissues element composition of the medicinal caper plant Capparis spinosa L. distributed on Calcisols formed on eroded alluvial-proluvial gravel textured rocks in the south of the Fergana Valley (Uzbekistan, Central Asia). The predominance of immature plants in the cenopopulation was detected in the Arsif hills massive, and quantitative indicators of micronutrients in the vegetative and generative organs of C. spinosa L. were determined. The study of biomorphological characteristics of the plant during the growing season (April-October) was carried out in the identified 10 observational experimental field populations. The cenopopulation dynamics and plant development patterns of Capparis spinosa L. were characterized for environmental conditions of south Uzbekistan for the first time. Soil, plant element analysis was performed by neutron-activation method. In this case, the samples were irradiated in a nuclear reactor with a neutron flux of 5 × 10 13 neutrons/cm 2 s, and their quantities were determined in accordance with the half-life of chemical elements. It has also been compared with research materials conducted by world scientists on the importance and pharmacological properties of botanicals in medicine and the food industry, as well as their botanical characteristics. The plant can serve to conserve soil resources, as it prevents water and wind erosion of dense clay soils in the dry subtropical climate of Central Fergana and could be considered an effective agent of destroyed soils remediation. The development of this plant will contribute to the diversification of agriculture in Uzbekistan (Central Asia) and the development of the food industry and pharmacology.

Background and Aims: In the roots of most vascular plants, the growth zone is small, the meristem and the elongation zone are sharply separated, and only meristematic cells divide. This statement is based almost entirely on studies with soil-rooted plants. Whether aerial roots of structurally dependent (=epiphytic/hemiepiphytic) species differ is virtually unexplored., Methods: Growth of aerial roots in 20 structurally dependent plant species from eight families was studied ex situ . In 12 species, we studied the anatomical structure and distribution of cortex cell lengths and rhizoderm in the growth zone., Key Results: All the studied aerial roots had an open apical meristem, and mitoses were not restricted to the meristem. In contrast to belowground roots, relative growth rate did not strongly increase upon transition to the elongation zone, while elongating growth was often prolonged. Still, the relative growth rate was lower than in belowground roots in soil, and in different species, it did not change considerably compared to each other., Conclusions: A distinct elongation zone with rapid cell growth was missing in the studied aerial roots. Rather, there was a growth zone in which division, growth, and differentiation co-occurred. We observed a generally low relative growth rate in aerial roots and a surprisingly similar initial growth pattern in spite of the diversity in taxonomy and ecology, which resembled initial cellular growth in leaves, stems, and fleshy dicotyledonous fruit., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Eskov, Viktorova, Abakumov and Zotz.)

Creation of artificial forest plantations on a global scale is one of the ways to mitigate the negative effects of climate change on ecosystems, at the same time providing soil protection from erosion, regulation of the hydrological regime and carbon sequestration in soils of different natural and climatic zones. However, the change of the dominant plant community cause significant ecosystem changes, reflecting at the structure and functioning of the soil microbial complex as well. The shifts in prokaryotic community of the meadow soil resulting from the conversion of the native meadow (further grassland) phytocenosis to the artificial forest plantations was investigated with the use of NGS sequencing technology and metabarcoding approach-amplicon sequencing of V4 region of 16 S rRNA (performed on Illumina Miseq platform). The identified shifts in taxonomic structure and diversity may be the result of changes in the physic-chemical conditions of soils and, on the other hand, may serve as indicators of such changes. Cultivation of larch led to an increase in the diversity of the prokaryotic community and its stratification by depth. The acidifying effect of larch manifested itself in an increase in the proportion and diversity of acidobacteria, in the abundance of oligotrophic microorganisms of phyla Chloroflexi, Firmicutes, and a simultaneous comparative decrease in the bacteria of Verrucomicrobia phylum, alphaproteobacteria of or. Rhizobiales and Burkholderiales. The absence of clearly expressed dominants in the prokaryotic community, as well as a significant increase in alpha-diversity indices, compared with the control plot of native mountain-meadow soil under grassland vegetation, suggests a transitional nature of the soil ecosystem of artificial forest plantations., Competing Interests: The authors have declared that no competing interests exist.

Rendzic Leptosols are intrazonal soils formed on limestone bedrock. The specialty of these soils is that parent rock material is more influential in shaping soil characteristics than zonal factors such as climate, especially during soil formation. Unlike fast evolving Podzols due to their leaching regime, Leptosols do not undergo rapid development due to the nature of the limestone. Little is known how microbiome reflects this process, so we assessed microbiome composition of Rendzic Leptosols of different ages, arising from disruption and subsequent reclamation. The mountains and foothills that cover much of the Crimean Peninsula are ideal for this type of study, as the soils were formed on limestone and have been subjected to anthropogenic impacts through much of human history. Microbiomes of four soil sites forming a chronosequence, including different soil horizons, were studied using sequencing of 16S rRNA gene libraries and quantitative PCR. Dominant phyla for all soil sites were Actinobacteria, Proteobacteria, Acidobacteria, Bacteroidetes, Thaumarchaeota, Planctomycetes, Verrucomicrobia and Firmicutes. Alpha diversity was similar across sites and tended to be higher in topsoil. Beta diversity showed that microbiomes diverged according to the soil site and the soil horizon. The oldest and the youngest soils had the most similar microbiomes, which could have been caused by their geographic proximity. Oligotrophic bacteria from Chitinophagaceae, Blastocatellaceae and Rubrobacteriaceae dominated the microbiome of these soils. The microbiome of 700-year old soil was the most diverse. This soil was from the only study location with topsoil formed by plant litter, which provided additional nutrients and could have been the driving force of this differentiation. Consistent with this assumption, this soil was abundant in copiotrophic bacteria from Proteobacteria and Actinobacteria phyla. The microbiome of 50-year old Leptosol was more similar to the microbiome of benchmark soil than the microbiome of 700-year old soil, especially by weighted metrics. CCA analysis, in combination with PERMANOVA, linked differences in microbiomes to the joint change of all soil chemical parameters between soil horizons. Local factors, such as parent material and plant litter, more strongly influenced the microbiome composition in Rendzic Leptosols than soil age., Competing Interests: The authors declare there are no competing interests., (©2021 Kimeklis et al.)

Although Antarctica is considered one of the most pristine areas on Earth, an accelerating human presence in this remote continent, such as scientific operations and functioning of numerous scientific stations, logistics, and tourism activities, has increased the risks of environmental impacts in recent decades. During the 63rd Russian Antarctic expedition, 42 samples from topsoil horizons were collected from Larsemann Hills, Mirny station, and Fulmar Island, Eastern Antarctica. The purpose of this work was to analyze the accumulation levels 8 trace elements and to assess possible environmental risks associated with contamination of Antarctic soils. Various human activities have been found to be responsible for increase of metal levels in studied Antarctic environments. Our study also revealed a specific role of ornithogenic factor and moss cover in distribution of contaminants in severe conditions of Eastern Antarctica soils. Ornithogenic soils were characterized by higher rates of accumulation of some trace metals and metalloids (especially zinc and copper) compared with other investigated "pristine" sites without significantly visible traces of guano inputs. In general term, obtained geoaccumulation index for trace elements in all samples were under or slightly above the 0 level, indicating low to moderate pollution of the studied soils. Results of principal component analysis revealed the necessity for further detailed research on interactions of trace metals with soil organic matter for better understanding of their biogeochemistry in the Antarctic environment. Although most of contaminated sites were found in anthropogenically affected areas, accumulation of some elements in guano-derived and moss materials were associated with higher values for soil pollution indices in natural soils, as well.

This study is aimed at investigation of various potential contaminants (arsenic, mercury and polycyclic aromatic hydrocarbons) content in soils of different landscapes of Eastern Antarctica ice-free areas. Our data not only showed that intensive human impact might result in significant direct contamination of surrounding landforms, but also revealed a specific role of ornithogenic transport in distribution of contaminants. Analysis revealed that the contents of investigated elements were 0.100-8.055 mg kg -1 (arsenic), 0.025-0.027 mg kg -1 (mercury) in Larsemann Hills and 0.100-1.213 mg kg -1 (arsenic), 0.023-0.593 mg kg -1 (mercury) in vicinities of Mirny station and Fulmar Island. Accumulation of some elements in guano-derived and moss materials lead to higher values of other soil pollution indices at natural sites. Results of our study revealed the predominance of light molecular weight PAHs (fluorene and acenaphthylene) in studied soils. Results of our study are not completely in agreement with the idea of an practically uncontaminated Antarctic ecosystem which was previously reported for Eastern Antarctica ice-free areas. Various human activities carried out at local scale have been found to be responsible for increase of metal levels in studied Antarctic environments.

The Arctic marginal environment has been considered as far from industrial areas and low population. During June-July of 2016 "Russian High Latitude" expedition, 93 samples of soil genetic horizon from 25 soil profiles dug till frozen ground were sampled from 8 islands and 2 capes of the Russian Arctic without direct anthropogenic influences. Nine trace metals (Pb, Cd, Cu, Ni, Co, Zn, Fe, Mn and Hg) were measured and quantified by energy-dispersive X-ray analysis for elemental concentrations. Through analysis of divided soil groups (Haplothels, Turbels, Historthels), the factors of organic matter and cryoturbation had a significant influence on metals' distribution except for Fe and Mn. From summarized soil master horizons (O, A, B, C), Fe and Mn are abundant in all horizons suggesting as geochemical background values. Cu, Pb, Co and Ni are distributed specifically in different horizons with leaching and accumulation process, whereas Hg is evenly disturbed in all horizons. The correlation analysis reveals that distribution of most metals in present soils is highly depended on soil properties (pH, TOC, clay and silt). Li was selected as normalizing element for metals' concentrations from mineral layers to establish geochemical baseline concentrations. The concentrations of trace metals have been assessed by geoaccumulation index (I geo ) and enrichment factor, showing only Co and Zn are moderately polluted and slightly polluted, and Co, Cu, Zn and Pb are enriched in topsoil. Other indices as modified degree of contamination (mC degree ) and pollution load index (PLI), mC degree show moderate degree of pollution and PLI shows unpolluted to moderate pollution load. The ecological risk indices, e.g., ecological risk factor (E r ) and potential ecological risk index, show low ecological risk potential.

Numerous studies of terrestrial orchids have demonstrated widespread partial mycoheterotrophy, particularly the possibility of obtaining organic matter from surrounding trees through a common fungal network. Fungi are also widespread in epiphytic orchid roots, but there have been no attempts to determine if epiphytes accept organic matter from the living stems of their phorophytes. We hypothesise that such transfer does not exist because epiphytes and phorophytes harbour different fungal communities. To test this hypothesis, we tagged three short Randia sp. trees with 13 C-enriched CO 2 and examined 13 C transfer from the phorophyte into the epiphytic orchids Grosourdya appendiculata, Dendrobium oligophyllum and Gastrochilus sp. in Cat Tien National Park, (South Vietnam, Cat Tien National Park, plot size approx. 1 ha). The coincidence of fungal sequences in the orchid roots and in the branches on which they grew was also examined. We did not detect 13 C label moving from phorophytes to epiphytes. Using Illumina sequencing, 162 fungal operational taxonomic units (OTUs) were detected. The fungal communities were significantly different between the roots of epiphytes and branches of phorophytes, although no strict fungal specificity at the species level was found in either epiphytes or phorophytes.

Antarctica is considered as one of the most pristine areas on Earth. However, increasing intensity of human presence on the sixth continent (scientific operations, functioning of the numerous scientific stations, tourism activities) makes it crucial to investigate the level of environmental pollution within the vulnerable ecosystem of Antarctica. Soils play a significant role in processes of accumulation, mobilization, redistribution of chemical elements within landscapes, and ecosystems. The aim of this work was to analyze the levels of 17 polycyclic aromatic hydrocarbons and eight trace elements in soils of King George and Ardley islands, Western Antarctica. Moreover, our work was aimed to determine the trends and reasons of anthropogenic pollution of Antarctic soils and characterization of accumulation levels of trace elements and PAHs. Results showed the predominance of light PAHs in all studied sites. The content of benzo(a)pyrene does not exceed the threshold concentration (adopted by different national environmental legislation systems). At the same time, the content of benzo(a)pyrene, which is a marker of anthropogenic contamination, is relatively low or equal to 0 in soils of reference landscapes. Cu and Zn were found as most abundant elements in all studied soils. The highest lead concentration content has been described in soil from Bellingshausen station. In general term, obtained Igeo values for trace elements in all samples were under or slightly above the 0 level, indicating low to moderate pollution of the studied soils. This study also contributes new data on trace element accumulation in soils strongly influenced by ornithogenic factor. Principal component analysis allowed to estimate the probable sources of specific trace metals and their relationship with soil variables. Ornithogenic factor has been also revealed as a driver for some trace element accumulation especially in breeding penguin colonies. High contents of organic matter in ornithogenic habitats could increase trace metal mobility, environmental risks for surrounding terrestrial environments should be considered.

Forty soil and lichen samples and sixteen soil horizon samples were collected in the mining and surrounding areas of the Yamal-Nenets autonomous region (Russian Arctic). The positive matrix factorization (PMF) model was used for the source identification of PAHs. The results of the source identification showed that the mining activity was the major source of PAHs in the area, and that the mining influenced the surrounding natural area. The 5+6-ring PAHs were most abundant in the mining area. The lichen/soil (L/S) results showed that 2+3-ring and 4-ring PAHs could be transported by air and accumulated more in lichens than in the soil, while 5+6-ring PAHs accumulated more in the soil. Strong relationships between the quotient of soil/lichen (Q SL ) and Log K OA and Log P L and between the quotient of lichen/histic horizon soil and K OW were observed. In addition, hydrogeological conditions influenced the downward transport of PAHs. Particularly surprising is the discovery of the high levels of 5 + 6 rings in the permafrost table (the bottom of the active layer). One hypothesis is given that the global climate change may lead to further depth of active layer so that PAHs may migrate to the deeper permafrost. In the impact area of mining activities, the soil inventory for 5+6-ring PAHs was estimated at 0.14 ± 0.017 tons on average., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The simultaneous effects of biochar on soil organic matter (SOM, C4) and sweet potato (SP) residue ( Ipomoea batatas , C3) mineralization were studied over 180 days via 13 C and 14 C isotopic label partitioning. Upon concomitant SP residue addition, biochar mineralization decreased by 11% of the total added biochar-C. Compared to positive priming effects induced by biochar amendment alone on SOM (0.46 mg C g -1 soil) at 180 days, amendment solely with SP residues induced significantly larger effects (1.5 mg C g -1 soil). Combination biochar and SP residue addition reduced SOM mineralization by 20.5% and increased SP residue mineralization by 10.1%. Biochar addition caused preferential uptake of SP residues over SOM by microbes. Thus, the lower priming effects on SOM and CO 2 emission induced by biochar amendment with or without SP residues compared to that from SP residue addition alone may result in crop residues being partly pyrolyzed to biochar in the cropland.