Pedological trends and implications for forest productivity in a Holocene soil chronosequence, Calvert Island, British Columbia, Canada.

Chronosequence studies of soil formation and ecosystem development provide important insights into the pathways and rates of change occurring on centennial and millennial time scales. In cool or temperate humid environments, Podzols are the predominant soil type formed under coniferous forests in coarse-textured parent material and have been a major focus of chronosequence studies. This study examined the rate and mechanisms of Podzol development and related forest productivity in a sand dune chronosequence in a hypermaritime climate in coastal British Columbia (BC). The sequence spans 10,760 ± 864 years over eight sites and is the first documented chronosequence in coastal BC to span most of the Holocene Epoch. Soil samples from each genetic horizon were analyzed for bulk density, pH and concentrations of total carbon (C), pyrophosphate- and oxalate-extractable aluminum (Al) and iron (Fe), and total elements. Within ~3,500 years a mature Podzol had formed, with cemented horizons (ortstein and placic) present. Organo-metallic complexation appeared to be the dominant mechanism involved in podzolization . Despite a mild, moist climate conducive to chemical weathering, all soils had similarly low values for the Chemical Index of Alteration, suggesting that congruent dissolution of primary minerals may be occurring. Ecosystem retrogression is apparent in the latter stages of the chronosequence – a phenomenon not previously documented in coastal BC. Further research is needed to examine the interactions of nutrient limitation, soil physical barriers, and other possible drivers of ecosystem retrogression.

MORFOLOGI DAN KLASIFIKASI TANAH PADA TOPOSEKUEN LERENG BARAT GUNUNG KELUD, KEDIRI, JAWA TIMUR

The research that was conducted from April to December 2020 in the Supiturung Micro-Watershed, located on the western slope of Mount Kelud, Kediri was aimed to study the morphological characteristics and soil classification using a topo-sequence approach. Four pedons were observed across the physiographic positions (upper, middle and lower slopes) on dry-land farming land use. The method used in this research included 8 stages, namely the preparation stage, pre-survey, map making, field observations, laboratory analysis, soil classification, data processing, and reporting. On the field, cross-sectional profiles were carried out on four selected pedons by testing the soil profile measuring 1 x 1 meter with a depth of 150-200 cm, followed by soil horizon, soil thickness, texture, structure, consistency, effective depth, type and number of pores, as well as other characteristics. Soil samples were collected from the genetic horizon of the pedons for being analyzed using standard procedures, then taken to the laboratory for soil physical and chemical analysis. Soil morphology with physicochemical properties was then classified based on the Keys Taxonomy of Soil to the Sub Group level. The results showed that each pedon has a different Sub Group. This condition can be caused by many factors, such as differences in epipedon thickness, base saturation values, organic C levels, and other morphological conditions at the time of direct observation. Four pedons have lithologic discontinuities, recognition of these types of lithologic changes is important because pedogenesis and pedogenic interpretations are greatly influenced by changes in the parent material.

Influence of forest vegetation on color, reflectivity and humus content in soils of northern variant ravines of the steppe zone of Ukraine

Unique natural forests grow in the conditions of ravines of the steppe zone of Ukraine. Soil scientists have been researching the soils of ravines for more than 60 years. Despite long-term research, aspects of the genesis of specific ravine soils, which are reflected in their optical properties, are still virtually unexplored. Based on this, the aim of our work is to establish the characteristics of the influence of forest vegetation on color and reflectivity, as well as the closely related content of humus in the soils of the northern variant ravines of the steppe zone of Ukraine. Soil samples were taken from each genetic horizon of sections laid in the Glybokyy ravine (near the village of Andriivka, Novomoskovsk district, Dnipropetrovsk region). Soil color indices were determined by scanning soil samples followed by image analysis. The reflectivity of soils was investigated using a monochromator. The humus content in soils was determined by the standard method of wet oxidation of organic matter according to I. V. Tyurin. As a result of the performed researches it is established that the upper horizons of the soils of the Glybokyy ravine differ in the reduced values ​​of the indicators of the HSB, RGB and Lab systems, with depth their values ​​increase. The upper horizons of the ravine soils are characterized by reduced values ​​of brightness coefficients at wavelengths of 480, 650 and 750 nm, as well as the integrated brightness coefficient, with depth there is a gradual increase in their values. The color indicators of the RGB and Lab systems are the most successful for diagnosing and predicting the humus content in the soils of the ravine. Forest chernozems and forest-meadow soil of the ravine, which were formed under natural forest vegetation, are characterized by reduced values ​​of color indicators of HSB, RGB and Lab systems, reduced values ​​of brightness coefficients and increased humus content compared to chernozems, the genesis of which is related.

Soil Organic Carbon Distribution in a Humid Tropical Plain of Cameroon: Interrelationships with Soil Properties

Soil organic carbon (SOC) determination is very important in the assessment of agronomic potential of a soil. The objective of this study was to determine SOC contents and stock distribution with depth in relation to selected soil properties. Five types of soils, namely, Mollic Endoaquents, Oxyaquic Paleudalfs, Oxyaquic Udifluvents, and Mollic Udifluvents from a humid tropical plain and Typic Eutrudepts from an adjacent foot slope, were studied. The soils have all developed from fluvial sediments. Morphological and physicochemical characteristics of the soils were obtained using standard methods. Soil texture varied across the different sites and within soil profiles with textural classes of genetic horizons ranging from sandy loam to heavy clay. The soils are generally young soils under development as indicated by their high silt/clay ratios which ranged between 0.23 and 2.45. All the soils were generally acidic with pH-H2O values ranging from 4.5 to 6.2. Exchangeable H+ and Al3+ ranged from 0.5 to 2.3 and 0.2 to 3.3 cmolckg−1, respectively. SOC contents are generally higher in surface horizons and decrease with depth. In general, SOC correlated significantly with bulk density (BD) (r = −0.648, p < 0.01 ), water holding capacity (r = 0.589, p < 0.01 ), exchangeable Al3+ (r = 0.707, p < 0.01 ), and exchangeable H+ (r = 0.456, p < 0.05 ). The correlation between SOC and exchangeable Al3+ was strongest in the Mollic Endoaquents (r = 0.931, p < 0.01 ). SOC contents correlated significantly with Munsell soil color attributes, explaining between 40 and 57% of SOC variation. Total SOC stocks at a depth of 100 cm varied between 260.1 and 363.5 t·ha−1, and the variation in SOC stocks across a profile appears to be controlled by genetic horizon depth, while land use type influences SOC stock variations across genetic surface horizons.

Undisturbed Soil Pedon under Birch Forest: Characterization of Microbiome in Genetic Horizons

Vast areas of land in the forest-steppe of West Siberia are occupied by birch forests, the most common ecosystems there. However, currently, little is known about the microbiome composition in the underlying soil, especially along a sequence of soil genetic horizons. The study aimed at inventorying microbiome in genetic horizons of a typical Phaeozem under undisturbed birch forest in West Siberia. Bacteria and fungi were studied using 16S rRNA genes’ and ITS2 amplicon sequencing with Illumina MiSeq. Proteobacteria and Acidobacteria together accounted for two-thirds of the operational taxonomic units (OTUs) numbers and half of the sequences in each genetic horizon. Acidobacteria predominated in eluvial environments, whereas Proteobacteria, preferred topsoil. The fungal sequences were dominated by Ascomycota and Basidiomycota phyla. Basidiomycota was the most abundant in the topsoil, whereas Ascomycota increased down the soil profile. Thelephoraceae family was the most abundant in the A horizon, whereas the Pyronemataceae family dominants in the AEl horizon, ultimately prevailing in the subsoil. We conclude that soil genetic horizons shape distinct microbiomes, therefore soil horizontation should be accounted for while studying undisturbed soils. This study, representing the first description of bacterio- and mycobiomes in genetic horizons of the Phaeozem profile, provides a reference for future research.

Characterization and Classification of Soils of Zamra Irrigation Scheme, Northeastern Ethiopia

Understanding soil types of a given area is an important prerequisite to design optimum management strategies such as irrigation water management. The study was thus conducted on characterization and classification of Zamra irrigation scheme in Abergelle district of Amhara Region, which has an area of 196.16 ha. For this study, 53 auger observations, four profile pits, extensive visual observations, reconnaissance survey, and descriptions of soil profiles and laboratory analysis were used to study the morphological and physicochemical properties of the soils of the scheme. Twelve disturbed and undisturbed soil samples were collected from all profiles of each genetic horizon for laboratory analysis. The soils of the study area were identified based on Food and Agricultural Organization of the United Nations/World Reference Base for Soil Resources (FAO/WRB) 2015. The results revealed that the textural classes of all profiles of the study site ranged from sandy clay loam to sandy loam. The chemical properties of the soil in terms of total nitrogen, organic matter, and available phosphorus were in the very low and low categories as per the criteria developed by Tekalign and Olsen, respectively, whereas exchangeable bases (Ca, Mg, K, and Na), cation exchange capacity, and extractable micronutrients (Fe, Mn, Zn, and Cu) were medium to high. Based on morphological, physical, and chemical analyses, the soils were classified as Leptic Regosols (Eutric, Loamic; 21.99% of the area), Vertic Cambisols (Hypereutric; 17.87%), Haplic Regosols (Eutric; 36.69%), and Rhodic Nitisols (Eutric; 23.44%). Therefore, management techniques that enhance soil fertility (including crop rotations, manuring, fallow periods, proper management of crop residues, and leguminous cover crops) and water-saving technologies suitable to the terrain of the area are the best options to enhance land productivity in the area.

Soil-Forming and Evolution Related to the Geological Formations, A Case Study of the Southern Part of Urmia Plain

The objective of this article was to study the effect of geographical features and geological formations on some physicochemical properties of soils in order to better identify the soil and optimize land management for sustainable agriculture in the southern part of the plain. Urmia, with an area of 35000 (ha) in the province of Western Azarbaijan, Iran. In this investigation, satellite images, aerial photographs, topographic and geological maps were used to identify and distinguish different land forms, soil series classified based on geomorphological and geophysical methods. 30 soil profiles were drilled and the FAO standard dimensions were described. Samples were taken from five soil profiles in each genetic horizon and transferred to the laboratory. The soil moisture and temperature regime was determined as Xeric and Mesic. The soils of the studied area were classified as Fluventic Inceptisols and grid subgroups. The most dominant formations in the Barandoz and Ghasemlou river basins were limestone and lime, which is one of the determining factors in rock formation in different soils in the study area. On the other hand, physiography and topography have also played an important role, so that the upper terraces have more developed soils and some sloping regions have younger and less developed soils. With the decrease in height and proximity to Lake Urmia, the effect of the groundwater level and its salinity on the profiles is evident. Meanwhile, the river bank has young and uncovered soils due to the sediments of the current era.

Compressing soil structural information

&lt;p&gt;The ability of correlation functions to describe structure (Karsanina et al., 2015; Karsanina et al., 2018) and provide means to reconstruct the structure based on correlation functions (Gerke and Karsanina, 2015; Karsanina and Gerke, 2018) alone was proposed as means to effectively compress and store structural information (Gerke et al., 2015). This is especially appealing considering the fact that truly multi-scale digital 3D soil structure model for a single genetic horizon even with the resolution not finer than 1 &amp;#181;m will contain enormous amount (approx., up to 10^15 voxels or even more) of data. Effective management and pore-scale simulations based on such datasets does not seem feasible at the moment. Another approach would be to retrieve only a relevant part of the dataset and operate on it indirectly, in particular based on correlation functions or stochastic reconstructions. The main aim of this work was to investigate the possibility to compress soil structural data, as resulted from X-ray microtomography data and directional correlation functions computation (Gerke et al., 2014), into a very limited number of parameters, potentially with minimal information content loss. We show that with the help of the proposed technique it is possible to compress a 3D image of 900^3-1300^3 voxels into a set of correlation functions, that with the help of fitting of an analytical function in the form of the superposition of three different basis functions may help to map all these correlation functions in a vector of six parameters. We apply the proposed methodology to 16 different soil 3D images and discuss numerous important implications that can help to achieve the ultimate goal of building 3D multi-scale soil structure model from meter to nm. Such model would help in establishing a fully multi-scale hydrological model operating from first principles as opposed to coarse continuum scale models.&lt;/p&gt;&lt;p&gt;This work was supported by Russian Science Foundation grant 19-72-10082 (correlation functions) and Russian Foundation for Basic Research grant 18-34-20131 &amp;#1084;&amp;#1086;&amp;#1083;_&amp;#1072;_&amp;#1074;&amp;#1077;&amp;#1076; (soil data).&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;Karsanina, M. V., Gerke, K. M., Skvortsova, E. B., Ivanov, A. L., &amp; Mallants, D. (2018). Enhancing image resolution of soils by stochastic multiscale image fusion. Geoderma, 314, 138-145.&lt;/p&gt;&lt;p&gt;Gerke, K. M., Karsanina, M. V., &amp; Mallants, D. (2015). Universal stochastic multiscale image fusion: an example application for shale rock. Scientific reports, 5, 15880.&lt;/p&gt;&lt;p&gt;Karsanina, M. V., &amp; Gerke, K. M. (2018). Hierarchical Optimization: Fast and Robust Multiscale Stochastic Reconstructions with Rescaled Correlation Functions. Physical Review Letters, 121(26), 265501.&lt;/p&gt;&lt;p&gt;Gerke, K. M., &amp; Karsanina, M. V. (2015). Improving stochastic reconstructions by weighting correlation functions in an objective function. EPL (Europhysics Letters), 111(5), 56002.&lt;/p&gt;&lt;p&gt;Gerke, K. M., Karsanina, M. V., Vasilyev, R. V., &amp; Mallants, D. (2014). Improving pattern reconstruction using directional correlation functions. EPL (Europhysics Letters), 106(6), 66002.&lt;/p&gt;&lt;p&gt;Karsanina, M. V., Gerke, K. M., Skvortsova, E. B., &amp; Mallants, D. (2015). Universal spatial correlation functions for describing and reconstructing soil microstructure. PLoS ONE, 10(5), e0126515.&lt;/p&gt;

ПОЧВЫ ПРОМЫШЛЕННЫХ ПЛОЩАДОК И ИХ ЭКОЛОГИЧЕСКАЯ ДЕМУТАЦИЯ (НА ПРИМЕРЕ САХАРНЫХ ЗАВОДОВ)

Industrial technogenesis is considered as an independent soil-forming process resulting in a special type of soils, i.e. industrial soils. Their diagnostic horizon is the genetic horizon FR formed by substances and objects involved in the production cycle and industrial construction. The soil cover of the territories of factories, industrial complexes, mines, power plants, and industrial zones in general is represented by the dominant industrial soils, as well as by other types of altered/man-made soils. In general, industrial soils cannot be regarded as a sort of urban and chemically contaminated soils as it follows from the presented examples of technogenic soil-forming substrates and industrial sites of sugar mills in Ukraine. It is shown that, when the effect of technogenesis is removed or attenuated, the processes of juvenile soil formation and ecological demutation develop on technogenic substrates and industrial sites of sugar mills. The leading natural components of such industrial demutation are sod and humus formation and gley and dealluvial processes. Specific technogenic demutation processes include squeeze-humus formation, elemental sulfur oxidation, lime quenching, etc. During about 100 years of dealluvial inwashing processes in demutating industrial grounds of abandoned sugar mills there may be formed humus horizons of an up to 50 cm capacity, which leads to the formation of young chernozem soils on industrial grounds. Soil-forming substrates and soils of abandoned sugar mills are avidly occupied by vegetation, which forms communities referred to Artemisietea vulgaris, Robinietea and Sisymbrietea classes.

Technique for preparation thin sections of structural soil aggregates of certain size fractions

Morphological properties of poil aggregate aer developed in the process of pedogenesis and reflect the complex of structure formation processes. The peds' size, shape, and internal structure are peculiar to each corresponding soil type and genetic horizon. The technique proposed allows preparing thin sections on every sizes of structural units and, in contrast to known methods, it provides not only a ped immobilization in the mass of fixing material, but also pore space saturation with natural resin. It is also possible to prepare the sections with marking of large aggregates orientation in space; it requires application of gypsum marks on the aggregate surface in the process of their sampling from the soil profile. The technique modified consists of following stages: selection of aggregates with required fractions; preparation of sections with separate aggregates larger than 5 mm; preparation of sections with aggregations smaller than 5 mm. In preparation of aggregates larger than 5 mm, a technique similar to that of preparing large soil block samples is used because it makes possible to process each soil aggregate separately. Another approach is required for processing of structural units up to 5 mm in size because it is impossible to prepare a section of individual issue with this size. The problem is solved when the units are saturated and processed not separately, but as a whole block sample which include a mass with peds of separate fraction. For this purpose, it is required to prepare cups comprised of walls from thick paper and a gypsum bottom. For preparation the caps use a gypsum in the form of fine white powder rapidly solidified in addition of water in a certain proportion and forms a firm bottom of the paper сup. Cut out a square of 4×4 cm in size and a strip from thick paper and glue them together to gain a tube of 5 cm in height and 1.5–2 cm in diameter (i.e. 10×5 cm). Apply on the paper squares a prepared gypsum mass sufficient to retention of the paper tube until gypsum hardening. Fill a fraction of aggregates into the prepared cup in one-third of its height and cover it with prepared fixing substance with solvent. Saturation is carried out in accordance with the standard technique of section preparing using natural resins (Gagarina, 2004). After complete saturation, paper cups with a mass of aggregates in them turn into monoliths that should be processed in the same way as large soil samples. As a result of all operations, significant number of structural soil aggregates with same sizes may be found within the section plane.