Assessment of health of soil in different climatic zones of European part of Russia depending on elemental composition

The fractional composition of dissolved organic matter and the chemical nature of humic and fulvic acids were studied in lysimetric waters from forest soils of different altitudinal zones in the Sikhote Alin Range. The elemental composition, infrared absorption spectra, concentrations of acid functional groups, and pK spectra of humic and fulvic acids were determined. Fulvic acids predominated in the upper soil horizons, and fraction of nonspecific dissolved organic substances predominated in the lower mineral horizons. The portion of humic acids in the humus horizons markedly decreased from the low-mountain soils to the high-mountain soils; the nitrogen content of humic and fulvic acids decreased in the same direction. Three classes of carboxyl and phenolic groups were determined in pK-spectra of humic and fulvic acids. The soils of high-mountain zones had stronger acidic properties of humic and fulvic acids in comparison with the soils of low-mountain zones. The determined characteristics of the composition of dissolved organic matter and the trends of their changes contribute to our knowledge of pedogenetic processes in the altitudinal sequence of forest landscapes of the Sikhote Alin Range.

Both stratigraphical and pedological exmaminations reveal all of surveyed reddish soils found in Northeast Japan being Relict Red Soils formed during past warmer periods, probably, interglacial stages or substages, in the Pleistocene. Reddish soils in West Japan, which have hitherto been regarded as “zonal soils” by several pedologists, also have been made under the similar condition to them.Though the precise datings of their formations are not fully established, at least three warmer periods may be assigned to their datings, that is, pre-Shimosueyoshi, Shimosueyoshi and post-Shimosueyoshi stages, among which more cases examined indicate their datings to the Shimosueyoshi stage, possibly Riss/Würm interglacial. The upper parts of the Relict Red Soil profiles are subjected to modification toward other genetic soil types to be developed under recent bio-climatic environments.Soil geographical extension of recent zonal soil patterns in the world, especially of those in the coastal region of the Chinese continent (compiled by Ma and Ven, 1958) toward the circumference of Japan suggests that typical zonal Red Soils find their home distribution in the Amami Islands, the southern end of Japanese territory, and the southern regions. Most parts of West Japan except along the Pacific coast seem to be characterized by zonal soils akin to the Yellow Brown Forest Soils in China, and East Japan, by ones similar to the Brown Forest Soils, unsaturated subtype proposed by Fridland (1953).The genetical environments of the Relict Red Soils in Japan are probably not so far from those suggested above, that is, being represented by middle part of the subtropical humid climatic zone with mean annual temperature of 20°C or more, annual precipitation of 1, 500-3, 000mm., and annual cumulative temperature of more than 5, 000°C, on the one hand, and by evergreen broadleaved forests of Machilus Thunbergii, Distylium racemosum, Shiia Sieboldii, Cyclobalanopsis stenophylla etc., on the other hand.Paleontological evidences so far obtained seem to offer no positive proof to this assumed environments of the Relict Red Soils, being too warmer than shown by the formers. It is reserved for further studies whether the apparent discrepancy is caused by ill preservation of appropriate fossil indicators or by over-evaluation of the mean annual temperature effect as a soil forming factor. The cumulative temperature and precipitation factors might be worthy of appreciation in the latter possibility, if at all.

Some prominent ecologists have stated that serpentine soils (soils with ultramafic parent materials) are azonal. Actually, only a small percentage of the serpentine soils are azonal. In order to rectify the inappropriate characterization of serpentine soils as azonal, it is helpful to review the origin and application of the zonal, intrazonal, and azonal terms in soil classification. A soil classification system based on the zonal, intrazonal, and azonal concepts was first developed by Sibirtzev in Russia (Glinka 1914). These concepts were subsequently utilized in the USA (Marbut 1927). Then they were abandoned in the precursor to the present Soil Taxonomy of the USDA (Soil Survey Staff 1960), because the zonal concepts are too ‘‘arbitrary’’ to apply objectively and consistently (Kellogg 1963). Zonal soils are those that reflect the influence of the regional climate. Very shallow soils and soils in recent alluvium, volcanic ash, eolian sand, or loess that lack significant pedological development are azonal soils. They are those rudimentary soils that in similar deposits are similar in all climatic regions (or zones), ignoring vegetative differences. Intrazonal soils are those that reflect the influence of local conditions such as poor soil drainage that make the soils different from the ‘‘normal’’ zonal soils. A major problem with these concepts is deciding what is normal. Is it a 10,000 yr old soil in glacial drift or is it a 100,000 yr old soil on basalt, granite, or serpentinized peridotite? The decision might depend on the common lithology in a region, but the soils in a region with predominantly one of these parent materials (for example, granite) might be quite different from the soils in a climatically similar region with different parent materials (for example, basalt). In fact, well drained and developed serpentine soils (those other than Entisols) might be considered zonal soils in a region where the lithology is predominantly ultramafic rocks. Most serpentine soils in the botanical California Region are Alfisols, Mollisols, and Inceptisols (Alexander et al. 2007). Only Entisols might definitely be called azonal soils, and Entisols occupy only about 0.8% of the serpentine area in the Region (Alexander 2004). Therefore most of the serpentine soils are either zonal or intrazonal, depending upon how one applies these concepts. Those who consider ultramafic rocks to be unusual components of the continental crust would assume that most serpentine soils are intrazonal. The zonal-intrazonal-azonal concepts are very useful, even though they are insufficiently definitive to use in a modern system of soil classification. The zonal and intrazonal concepts can be applied to plant associations as well as to soils. Zonal plant associations may be common on zonal soils and intrazonal plant associations may be common on intrazonal soils. The azonal concept, however, is not easily applied to plant communities. Perhaps the plant associations that conform most closely to the azonal concept are those in early stages of succession. Some plant species, such as Bryum argenteum Hedwig and Achillea millefolium L., have the azonal characteristics of being widespread across many climatic zones, but the azonal concept may not be applicable to plant associations. LITERATURE CITED

Abstract. Here we explore the potential of magnesium (δ26Mg) isotope time-series data as continental climate proxies in speleothem calcite archives. For this purpose, a total of six Pleistocene and Holocene stalagmites from caves in Germany, Morocco and Peru and two flowstones from a cave in Austria were investigated. These caves represent the semi-arid to arid (Morocco), the warm-temperate (Germany), the equatorial-humid (Peru) and the cold-humid (Austria) climate zones. Changes in the calcite magnesium isotope signature with time are compared against carbon and oxygen isotope records from these speleothems. Similar to other proxies, the non-trivial interaction of a number of environmental, equilibrium and disequilibrium processes governs the δ26Mg fractionation in continental settings. These include the different sources of magnesium isotopes such as rainwater or snow as well as soil and host rock, soil zone biogenic activity, shifts in silicate versus carbonate weathering ratios and residence time of water in the soil and karst zone. Pleistocene stalagmites from Morocco show the lowest mean δ26Mg values (GDA: −4.26 ± 0.07‰ and HK3: −4.17 ± 0.15‰), and the data are well explained in terms of changes in aridity over time. The Pleistocene to Holocene stalagmites from Peru show the highest mean value of all stalagmites (NC-A and NC-B δ26Mg: −3.96 ± 0.04‰) but only minor variations in Mg-isotope composition, which is consistent with the rather stable equatorial climate at this site. Holocene stalagmites from Germany (AH-1 mean δ26Mg: −4.01 ± 0.07‰; BU 4 mean δ26Mg: −4.20 ± 0.10‰) suggest changes in outside air temperature was the principal driver rather than rainfall amount. The alpine Pleistocene flowstones from Austria (SPA 52: −3.00 ± 0.73‰; SPA 59: −3.70 ± 0.43‰) are affected by glacial versus interglacial climate change with outside air temperature affecting soil zone activity and weathering balance. Several δ26Mg values of the Austrian and two δ26Mg values of the German speleothems are shifted to higher values due to sampling in detrital layers (Mg-bearing clay minerals) of the speleothems. The data and their interpretation shown here highlight the potential but also the limitations of the magnesium isotope proxy applied in continental climate research. An obvious potential lies in its sensitivity for even subtle changes in soil-zone parameters, a hitherto rather poorly understood but extremely important component in cave archive research. Limitations are most obvious in the low resolution and high sample amount needed for analysis. Future research should focus on experimental and conceptual aspects including quantitative and well-calibrated leaching and precipitation experiments.

Soil pH and C/N ratio determines spatial variations in soil microbial communities and enzymatic activities of the agricultural ecosystems in Northeast China: Jilin Province case

Soil compaction caused by mechanized wood harvesting can have long-lasting negative impacts on forest soils and impair forest ecosystem functioning and productivity for decades. However, soil compaction in forest ecosystems cannot be resolved by tillage. Thus, it is of paramount importance to prevent or minimize soil compaction in forest ecosystems. A primary step to achieve this goal is to determine the vulnerability of forest soils to compaction in different climatic zones. In this study, we performed a meta-analysis with 996 observations or 498 pairs of observations (effect sizes; compacted versus not compacted) of soil bulk density (BD) extracted from 57 peer-reviewed publications to assess the effects of climate and initial soil conditions on soil vulnerability to compaction. Forest soils of tropical and temperate zones were most vulnerable to compaction (14.9% and 12.7% increase in BD, respectively), while forest soils of cold and arid zones were less vulnerable (5.2% and 6.4% increase in BD, respectively). Climatic zones with high (> 1000 mm) and moderate (400 ─ 1000 mm) effective precipitation had the most vulnerable soil conditions to compaction (approximately 12% increase in BD) and the soils of climatic zones with low (< 400 mm) effective precipitation were less vulnerable (3.5% increase in BD). Our analyses indicated that the soils of climatic zones with high effective precipitation (tropical and temperate) are characterized by high soil organic carbon and are often wet, leading to low soil bulk densities and high vulnerability to compaction. Finally, we developed maps to illustrate the global pattern of soil vulnerability to compaction in forest ecosystems.

Total elemental composition of soils in Sub-Saharan Africa and relationship with soil forming factors

Nine soils, representing the dominant groups in the major soil zones of Alberta, were characterized with respect to the distribution and selected properties of organic fractions. Detailed results are presented only for A horizon samples. Well humified materials in surface horizons exhibited remarkable similarities despite the range of conditions under which they accumulated.In general, differences between organic components of soils within a soil zone were much less distinct than differences between soil zones. In the sequence Gray Wooded to Black to Brown soil zones, Ah horizons showed decreasing organic matter content, decreasing hexose and pentose content, but little change in organic P content or hexose as percent of total organic matter.De-ashed humic acid fractions showed little variation between soils with respect to elemental composition, functional groups, amino acid and carbohydrate components, electrophoretic behavior or infrared, spectra. Optical properties and behavior toward electrolytes of humic acid solutions showed some differences between soil zones.

The work is devoted to the study of pollution by technogenic magnetic particles and heavy metals of soils in the city of Gubakha, Middle Ural (Russia). The aim of the work is the ecological and geochemical assessment of the elemental chemical composition of the soils of the city of Gubakha, and the establishment of the geochemical role of technogenic magnetic particles (TMPs). For the first time, the regularities of the spatial distribution of magnetic susceptibility in the soils of the city of Gubakha were revealed, and the morphology, elemental and mineralogical compositions of magnetic particles in the soils of an industrial city in the Middle Urals were characterized using the methods of the chemical extraction of iron compounds, magnetic separation, ESEM/EDS, and Mössbauer spectroscopy. The magnetic phase of soils contains magnetite/maghemite, hematite, pyrrhotite, intermetallic alloys and chromite. Spherical magnetic particles are hollow, and have a magnetite shell and a varied surface texture. The crystal lattice of magnetite is characterized by low stoichiometry. The heavy metals Zn, Cu, Ni and Cr are concentrated in magnetic particles and have a high correlation coefficient with magnetic susceptibility. The level of contamination of Cu, Ni, Zn, Cr and Mn in the soils of a residential zone of Gubakha, estimated by the value of the pollution load index (PLI), was high. The Igeo index for Fe ranges from 6.2 to 12.2, for Cu–1.1 and Ni–1.1. The combination of methods for measuring magnetic susceptibility, determining the mineralogical composition of iron compounds, and determining the elemental chemical composition by X-ray fluorescence, has shown the effectiveness of an integrated approach for carrying out an ecological–geochemical assessment of the soil cover of Gubakha.

The aim of the study was to investigate the dynamics of elemental composition and the content of low-molecular organic compounds during experimental destruction of different peat types in three communities of the Bakchar Bog (West Siberia, Russia). Location and time of the study. The field experiment was carried out in three communities of the Bakchar Bog (56°51” N, 82°50” E): the pine-dwarf shrub-Sphagnum community (ryam), dwarf shrub-cotton grass-Sphagnum community at the edge of a poor fen and the sedge-Sphagnum community in the center of the poor fen. After preparation peat samples were placed at the depths of 5-10 and 25-30 cm, and after 4 and 16 months the samples were collected for analyses. Methods. Total soil carbon, hydrogen and nitrogen content was determined on a Perkin Elmer 2400 Series II CNHS/O analyzer (USA). Phosphorus was determined colourimetrically, whereas soil exchangeable potassium, sodium, calcium, magnesium and iron were determined by atomic absorption. Extractive low-molecular organic compounds were analyzed by gas chromatography-mass spectrometry (Clarus 500 MS gas chromatograph, Perkin Elmer, USA) with a quadrupole detector. Results. During the experiment, the carbon content decreased in all samples, while the nitrogen content and the H/C and C/N ratios changed differently among communities and depths. The C/N ratio was not the important driver of the peat decomposition intensity at the studied sites. The phosphorus, potassium and sodium content decreased in most cases. The concentration of magnesium and iron increased in the fen communities, whereas calcium decreased in the dwarf shrub-cotton grass-Sphagnum community of the fen edge. The aerobic layer of the ryam differed from other locations by the increased concentration of all the elements. After destruction the content of low-molecular organic compounds increased in the aerobic zone of the ryam and decreased in the fen. The content of individual groups of organic compounds changed differently, i.e. from a small change to a fourfold one. Conclusions. Specific patterns of peat decomposition in the Bakchar Bog were found for each of the studied communities, based on the dynamics of the elemental composition and low-molecular organic compounds. In the aerobic zone of the ryam, the concentration of all elements and organic compounds increased, accompanied by the greatest mass loss. In the dwarf shrub-cotton grass-Sphagnum community, the concentration of elements both decreased and increased, and the content of organic compounds decreased. In the sedge-Sphagnum community, the leaching of the elements occurred. Most likely, such dynamics was due to the development of different communities of destructors: micromycetes in the aerobic zone of the ryam soils and bacteria at the edge of the poor fen. In the deep peat layer of the ryams and in the center of the poor fen, decomposition was negligible due to anaerobic conditions.

The humus content, elemental composition and optical density of humic acids in virgin and irrigated soils of the Tashsakinsky massif of the Khorezm region of Uzbekistan were estimated. The studied desert virgin and irrigated soils have characterized by light and medium loamy granulometric composition, dusty-granular structure and slightly alkaline reaction. Carbonates present in small quantities - 3.10-10.60%. The total humus content in the upper horizons varies from 0.19% to 0.76%. In virgin grey-brown soils the humus type is humate-fulvate, agriculture soils are humate. The degree of humification of organic matter in newly irrigated gray-brown-meadow and meadow-marsh soils is higher than in virgin gray-brown soils and decreases down the profile. It was revealed that the optical density of humic acids of virgin gray-brown, irrigated meadow and meadow-marsh soils is characterized by high values. The percentage of the sum of humic acid elements differs little from virgin soils to old-irrigated meadow soils. In the lower horizons, oxidation increases by 1.02 times compared to other studied soils. For the first time, the elemental composition of humic acids in virgin and irrigated soils of the desert zone of the Tashsakinsky massif of the Khorezm region was determined. The elemental composition of humic acids showed the oxidizability of humic acids, which decreases from top to bottom along the profile, which is associated with the features of the genesis of the studied soils, the age of irrigation and the degree of cultivation of these soils.

Post-agrogenic transformation of fallow soils leads to changes in soil carbon content, the molecular composition of humic substances, and rates of organic matter stabilization, which can affect climate change on the planet. In this regard, we analyzed the molecular composition of humic acids isolated from natural and fallow soils in the southern Taiga zone of northwest Russia. Different-aged soils on fallow lands represent a model of soil transformation in time, and data on the transformation of soil humic acid molecular composition make a significant contribution to the understanding of soil organic matter stabilization aspect issues. In this case, the molecular structure of humic acids isolated from natural and fallow soils in northwest Russia was analyzed. To study the molecular composition of HAs, the elemental composition was analyzed, and 13C (CP/MAS) NMR spectroscopy of HAs isolated from different aged abandoned soils and soils of different types of use was carried out. The obtained data showed that with the increasing age of soils in the fallow state, there is an increase in the carbon content of humic acids as well as a decrease in nitrogen content. As a result of the increasing age of soils in the fallow state, there are dynamics in the content of aromatic structural fragments in humic acids: 34% for 40 years old, 28% for 80 years old, and 31% for 120 years old. This is due to changes in the precursors of humification and the further transformation of plant residues in the soil. Re-involved fallow land soils lead to an increase in the content of aromatic structural fragments in the composition of HA in relation to HA extracted from mature soils. The lowest content of aromatic structural fragments was observed in the humic acids of 130-year-old agricultural soil, which is associated with the long-term application of organic fertilizers.

Geochemical and mineralogical characterization of speleothems from the karst of Croatia as potential sources of data for environmental researches

Purpose. To carry out a comprehensive study and evaluation of new medium-maturing potato (S. tuberosum) varieties for yield, starch content and stability under the conditions of the Ukrainian Forest Steppe and Polissia. Methods. The qualification examination of potato varieties for their suitability for distribution in Ukraine (VSD) was conducted in 2021 and 2023 at eight research sites of the Ukrainian Institute for Plant Variety Examination located within the soil and climatic zones of the Forest-Steppe and Polissia. The area of the accounting plot was 25 m2, the location of the plots was randomised, replicated four times. Results. The economic and valuable characteristics of Ukrainian medium-maturing potato varieties – ‘Fanatka’, ‘Svitana’, ‘Marfusha’ and ‘Melaniia’, as well as foreign varieties – ‘TRIPLE7’, ‘Tiger’, ‘CAMELIA’ and ‘CARDYMA’ were analysed. The average yield of ‘Fanatka’, ‘Svitana’, ‘TRIPLE7’, ‘Tiger’, ‘CAMELIA’ and ‘CARDYMA’ in the Forest-Steppe was 3–12% higher than in Polissia. The maximum values of this indicator in both soil and climatic zones were shown by the varieties ‘Svitana’ (Forest-Steppe – 28.2 t/ha; Polissia – 26.0 t/ha) and ‘CAMELIA’ (Forest-Steppe – 29.3 t/ha; Polissia – 27.7 t/ha). In 2021, the highest average potato yield was obtained in the Forest-Steppe zone (23.3 t/ha); in 2023, in Polissia (21.1 t/ha). ‘Fanatka’ and ‘TRIPLE7’ varieties were more stable than ‘Svitana’, ‘Melaniia’, ‘CAMELIA’, ‘CARDYMA’, ‘Marfusha’ and ‘Tiger’, whose yields were highly dependent on the growing conditions. In terms of quality indicators, the best foreign varieties were ‘TRIPLE7’, ‘Tiger’ and ‘CARDYMA’. Their starch content was 15.6–17.8% in the Forest-Steppe and 17.1–18.1% in Polissia; dry matter – 23.9–25.8% in the Forest-Steppe and 25.4–25.8% in Polissia. Conclusions. According to the results of the VSD qualification test, the varieties ‘Fanatka’, ‘Svitana’, ‘Melaniia’, ‘TRIPLE7’, ‘CAMELIA’ and ‘CARDYMA’ are recommended for cultivation in the Forest-Steppe and Polissia zones; ‘Marfusha’ and ‘Tiger’ are recommended for Polissia only. According to qualitative indicators, the variety ‘TRIPLE7’ stood out with starch content of 17.8% in Forest-Steppe and 18.1% in Polissia; dry matter – 25.8% in both soil and climatic zones.

Conventional tillage methods and indiscriminate use of chemical fertilizers are causes of edaphic problems like soil degradation and loss of soil fertility which reduces crop yield. Puddling now-a-days, has become a major challenge for farmers due to breaking the soil structure, deficit water regimes, and depletion of soil health. Keeping in view, the absolute need to fulfill food security as well as sustainability, an experiment was conducted for 2 years on a rice-lentil cropping system during 2018–2019 and 2019–2020 in sandy clay loam soil of a new alluvial zone of eastern India to evaluate effects of minimum tillage and integrated nutrient management on yield and soil health. Conventional tillage (CT) direct seeded rice-lentil, Minimum tillage(MT) direct seeded rice-lentil, MT transplanted rice-lentil and MT direct seeded rice-lentil were kept as main plot treatments and control (without any fertilizer), 100% RDF, 75% nitrogen + FYM, 75% nitrogen + FYM + Azospirillum and 75% Nitrogen + FYM + Azospirillum sp. + Zinc Sulphate were kept as subplot treatments during the study. Though conventional tillage treatments recorded higher LAI, CGR and yield in the first year of study in the case of rice; during the second year, minimum tillage treatments showed significantly (p ≤ 0.05) better results in the aforesaid aspects with MTDSR-L having a maximum yield of 5.17 t ha−1. In the case of lentil minimum tillage treatments had better results for both years, with MTDSR-L treatment having the highest yield of 8.084 t ha−1. Among the nutrient schedules, the crops had better LAI, CGR and yield during the first year in the case of 100% RDF treatment, but in the second year, 75% Nitrogen + FYM + Azospirillum sp. + Zinc Sulphate had the highest respective values. Soil organic carbon was marginally improved by both tillage and nutrient treatments, while soil microbial biomass carbon, dehydrogenase activity and microbial count were significantly influenced. The combination of MTDSR-L and 75% Nitrogen + FYM + Azospirillum sp. + Zinc Sulphate (N5) treatment showed the maximum values for all soil biological parameters leading to improve soil health. The results of the experiment concluded that the practice of minimum tillage and integrated nutrient management may be recommended to enhance the yield and stability of rice-lentil cropping systems in sandy clay loam soil of a new alluvial zone of eastern India by acting as an alternative for the decline of soil health.