Original Soil Research Articles

Effects of different water and fertilizer treatments on the matrix properties and plant growth of tailings waste

Vegetation ecological restoration technology is widely regarded as an environmentally sustainable and green technology for the remediation of mineral waste. The appropriate ratio of amendments can improve the substrate environment for plant growth and increase the efficiency of ecological restoration. Herbs and shrubs are preferred for vegetation restoration in abandoned mines because of their rapid establishment and easy management. This study probed into their improvement effects on abandoned mine tailings from aspects such as plant growth and nutrient content. Based on this, the trail explored the impacts of different ratios of quarry waste matrix on different plant growth and the physical and chemical properties of the quarry matrix. The original soil, without fertilizer and with 45% water treatment, was taken as the control (CK), while the experimental group comprised of composite soil with different ratios of original soil and slag, combined with various water and nitrogen fertilizer treatments. Pennisetum alopecuroides (L.) Spreng, Campsis grandiflora (Thunb.) Schum, Setaria glauca (L.) Beauv, Periploca sepium Bunge, and mugwort (Artemisia argyi Levl. Et Vant.) were planted, respectively, in the control and experimental groups. After a 30-day period of nitrogen fertilizer and water treatment, an analysis was conducted to evaluate the physicochemical properties and growth status of the tailing matrix for different treatments. The results demonstrated that the M7 treatment significantly promoted the growth of mugwort, whereas the M2 treatment stimulated the growth of Campsis grandiflora (Thunb.) Schum. Additionally, the M3 treatment proved to be advantageous for enhancing the growth of Setaria glauca (L.) Beauv, Pennisetum alopecuroides (L.) Spreng, and Periploca sepium Bunge. The soil matrix pH of Pennisetum alopecuroides (L.) Spreng, Campsis grandiflora (Thunb.) Schum, Setaria glauca (L.) Beauv, Periploca sepium Bunge, and mugwort is all above 7.5, while macronutrient elements including TK, AK, TN, AN, TP, and AP exhibit varying degrees of enhancement. PCA analysis disclosed that there were significant disparities in substrate properties and plant growth properties among treatments for Pennisetum alopecuroides (L.) Spreng, Campsis grandiflora (Thunb.) Schum, Setaria glauca (L.) Beauv, Periploca sepium Bunge, and mugwort (P < 0.05). The correlation network and structural equation analysis revealed a significant positive correlation between the water and fertilizer matrix and soil AN and TN (P < 0.05). Additionally, TK exhibited a positive correlation with the growth status of all five plant species. Moreover, the water and fertilizer substrate displayed a positive association with the growth status of Pennisetum alopecuroides (L.) Spreng, Setaria glauca (L.) Beauv, Periploca sepium Bunge, as well as mugwort; however, it showed a negative correlation with the growth status of Campsis grandiflora (Thunb.) Schum.

How Rilling and Biochar Addition Affect Hydraulic Properties of a Clay‐Loam Soil

ABSTRACTRill erosion is a significant problem worldwide as it determines relevant amounts of soil loss on hillslopes. Although, in the last few years, many studies have focused on rill erosion and biochar as soil amendment, their influence on soil hydrological properties and relevance on soil conservation strategies is still uncertain. In this paper, the effects of rill formation and biochar addition on the physical and hydraulic properties of a clay‐loam soil were assessed by laboratory measurements (water retention, hydraulic conductivity, minidisk infiltrometer data and 1H Nuclear Magnetic Resonance (NMR) relaxometry with the fast field cycling (FFC) setup) and field tests (rill formation tests at the plot scale). The rilled and non‐rilled soils did not show any difference in the volume of pores with a diameter (d) &gt; 300 μm, but the former showed a smaller volume for the pores in the size range between 300 and 0.2 μm. As compared with an untreated rilled soil, the addition of 5% (w w−1) biochar in the soil in which the rill is incised did not change the volume of pores with d &gt; 300 μm, while there were more pores of both 30 ≤ d ≤ 300 μm and 0.2 ≤ d ≤ 30 μm. Moreover, there were less pores with d &lt; 0.2 μm. Shaping the rill did not influence the hydraulic conductivity of the nearly saturated soil (pressure head, h = −1 cm), while it determined a significant decrease of the soil ability to transmit water in more unsaturated conditions (h ≤ −3 cm). The addition of biochar to the soil improved, in general, the soil aptitude to transmit water, regardless of the pore size. However, this improvement was statistically irrelevant in the case of a transport process governed by larger pores. The hydrological measurements also demonstrated that the addition of a large amount of biochar (5%) impedes soil characteristics alteration as the changes due to rilling are balanced by adding biochar in the soil. NMR was also used to measure the structural and functional connectivity of the original soil, the biochar and a mixture with three biochar concentrations (i.e., BC = 1%, 3% and 5% w w−1) traditionally applied in agronomical activity. These measurements revealed that the mixture of soil and biochar was characterised by longitudinal relaxation time (T1) values, which are related to pore sizes, longer than those measured for the soil. In addition, the soil empirical cumulative frequency distribution of T1 was always skewed towards shorter T1 values, thereby suggesting that the macro‐pore component (i.e., the largest T1 values) was never dominant while biochar addition increased the size of mesopores and micropores. Biochar concentrations larger than 3% (w w−1) did not produce appreciable changes in the pore distribution inside the mixture. The biochar component improved the structural connectivity up to BC = 5%, while decreased the functional connectivity up to BC = 3%. A relationship between the water volume contained in soil pores and the NMR data were established for the micropores (d ≤ 0.2 μm). The biochar‐amended soil was characterised by fewer small pores, but these micropores were greater than those in non‐treated soil.

Legacy Effects of Cropping System and Precipitation Influence the Core Camelina sativa Microbiome

Camelina (Camelina sativa L.) is a potential biofuel crop and beneficial rotation crop in dryland cropping systems. Little is known about camelina microbiota or the legacy effect of soil origin/cropping system zones on camelina-associated microbiome assembly. To explore camelina-microbe associations, we grew camelina in the greenhouse using soil transplanted from 33 locations in the dryland wheat production area of eastern Washington. Bacterial, archaeal and fungal communities from bulk soil, rhizosphere and endosphere were characterized with 16S rRNA and ITS amplicon sequencing and were analyzed alongside site-specific climatic and edaphic data. We found soil from the highest precipitation zone had higher alpha diversity than soil from the driest zone, but this effect was not seen in the greenhouse rhizosphere or endosphere. Plant compartment, cropping system zone, and soil origin all significantly influenced microbial composition with soil pH and organic matter as well as precipitation at origin as major predictors. Analysis of abundance-occupancy distributions suggests that camelina selects for several different Actinobacteria (though distinct genera in the rhizosphere and endosphere). Rhizobium, and Clostridium. Sphingomonas ASVs were also consistently enriched in the rhizosphere, suggesting that they are present in soils collected throughout eastern Washington and may represent good candidate biostimulants. Several lignin decomposing fungi had site-specific rhizospheric distributions suggesting that they may be dispersal-limited or result from the legacy effect of long-term wheat cropping. Overall, this study contributes to our understanding of microbiome assembly in and on camelina roots while also highlighting the potential impact of cropping history on soil and plant-associated microbiomes.

Soil maps of cities for the unified digital model of the soil cover of Russia

The soil cover of cities and towns within their administrative boundaries is composed of soils, more or less modified by the urban environment along with native, agricultural soils and non-soils. For preserving this diversity when introducing these new objects to the unified digital model of the soil cover of Russia, soil maps of 10 “test” cities have been compiled. The cities are located in several natural zones, and are intermediate in terms of their population. Mapping was performed by means of detailed purposeful deciphering, data on mapping units on the original soil map, and recent systematics of urban soils and their dependence on the urban environment. The approaches applied were supported by the experience in soil mapping of St-Petersburg, Moscow, Volgograd and few other cities. Soils were qualified in the system of Russian soil classification, and their areas, along with those of non-soils, were regarded as units in the theory of soil cover patterns. In all cities investigated, soil associations comprised urban soils per se, transitional soils including agro-soils and conventionally native ones; their ratios in the soil cover depend on both historical-socio-economical reasons and the natural enviroment.

PENGARUH PUPUK IKAN RUCAH DAN KANDANG PADA TANAH GARAMAN LAHAN BASAH TERHADAP BEBERAPA SIFAT TANAH SERTA HASIL TANAMAN SISTEM POT

The nature of the soil studied in the wetland area (coastal) is massive (solid) and saline, less fertile for horticultural crops such as shallots and mustard greens. Experiments using the original soil mixed with quartz sand (35% w/w), leached with ion-free water (3 liters/kg/pot), the irrigation method is soaked-drown it (1/3 of the height of the bottom of the pot) and treated with 5% organic fertilizer (w/w) in the form of fish manure (bycatch) mixed with water hyacinth-Eichornia crassipes (RE) or rice husk (RM) and manure from broiler chicken manure. Treatment per pot: K (control) = original soil (1 kg); RE = (35 g trash + 15 g water hyacinth); RM = (35 g trash + 15 g rice husk); Chicken Manure A1=50 g/pot and, A2 =100 g/pot. The results are as follows: (1) Soil properties: The highest soil water absorption content is in A1 and A2; The lowest bulk density is in A2, RE, RM; The highest pH is in RM; and the highest EC (or DHL) and does not differ in A2, RE, or R; The highest exchangeable K, Na, Ca are in A2 and exchangeable Mg are not affected; The highest organic C is in A2, the highest total N is in A2 or RM, and the lowest C/N is in RM; (2) Mustard plant properties for the age of 4-6 weeks after planting (MST): the highest plant height, the largest number of leaves, and the largest number of leaf areas are in A1 or A2, and (3) Shallot plant properties for plant height and number of shallot leaves at the age of 4, 5, and 6 MST: the highest in K, A1, or A2. Overall, the A1 or A2 treatment, namely the application of chicken manure 50-100 g/pot/kg of soil is the highet (best) result.

Effect of Acid Production from Forest Litter on the Availability of Heavy Metals in Soil

Forest leaf litter is an important source of soil nutrients, but how its decomposition products affect the availability of soil heavy metals is not totally clear. In order to understand the effects of leaf litter decomposition on soil heavy metal availability in a forest ecosystem, leaf litter samples were collected from Daluoshan in Wenzhou and the Wuyanling National Nature Reserve of Zhejiang and subjected to analysis. The leaf litter was produced by the forests’ dominant tree species, such as Myrica ruba, Bambusa cerosissima, Pinus sylvestris, Machilus thunbergia, Cunninghamia lanceolata, and Quercus acutissima. Decomposition of the leaf litter samples at room temperature and leaching decomposition of the samples were carried out to analyze the acid production characteristics of the litter samples and their impact on soil heavy metal availabilities. Oxalic acid, lactic acid, fumaric acid, succinic acid, malic acid, and citric acid were the dominant organic acids in the leaf litter decomposer, and the sum of these six organic acids accounted for more than 50% of the total organic acid. During a 30-day litter decomposition, the levels of organic acids basically increased, with significant increases appearing in the early stage. After leaching, the available contents of Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb increased by a maximum of 11.95, 2.33, 12.00, 0.80, 0.83, 0.54, 51.50, and 0.28-fold, respectively, compared with those of the original soil sample. During leaching, the higher the content of low molecular weight organic acids in the leaf litter, the longer the leaching time required and the more obvious the influence on the level of available heavy metals. A stronger leaching effect was found for the soil samples taken from a depth of 0–20 and 20–40 cm accompanied by a more obvious increase in the available heavy metals in the soil. PLSPM results showed that there were significant differences between the soil acidity index and the available heavy metals in Daluoshan (p &lt; 0.05) and that there were significant differences between the soil acidity index and the available heavy metals in Wuyanling (p &lt; 0.01). The decomposition of litter produced low molecular weight organic acids, which caused a decrease in soil pH and an increase in exchangeable H+ and Al3+. Both changes had an impact on soil organic matter and further led to an increase in the activity of heavy metals in the soil. This will further lead to the increase of ecological and environmental risks to forest soil.

Morphological variability and vitality of Rindera tetraspis (Boraginaceae) in the South Urals and Western Kazakhstan

Population studies of Rindera tetraspis Pall., a rare endemic species of the steppe zone of the European part of Russia and Kazakhstan, were carried out. The study of the habitats of 11 populations in the Orenburg Region and the Republic of Kazakhstan has shown that the species is confined to various variants of calciphyte steppes on chalk substrates or sandstones. In terms of most morphometric indicators, the northern coenopopulation “Rodnichny” is the leader; the minimum values are noted in the coenopopulation “Verkhnechebendinskie Chalk Mountains, northern extremity”. The discriminant analysis has revealed morphostructural differences between individuals from the majority of coenopopulations. In terms of vitality, four coenopopulations are prosperous, seven ones are depressed. The optimal conditions for the species growth are in the northern part of its range, in more favorable climatic conditions in terms of temperature and humidity, mainly on soils of sand origin. When moving southward, a decrease in size parameters of individuals is observed, associated with insufficient moisture, while their morphological diversity increases. The state of R. tetraspis coenopopulations is stable, but the species is not provided with proper protection measures, so further monitoring of its habitats and improvement of conservation measures are necessary.

Trade-offs and adaptation to metalliferous soils: The role of soil microbiome in metal tolerance and uptake in Arabidopsis halleri ecotypes from a reciprocal transplant experiment

Soil contamination with trace metal elements is a worldwide issue, prompting research on plant species capable of hyperaccumulating metals to reduce soil toxicity. Previous research suggests that both plant species and their populations can affect soil microbial communities, yet little is known about how different populations of hyperaccumulator species influence these microbial communities to enhance metal-uptake and tolerance. This study evaluated the effect of soil origin, soil microbiome, and plant population on phytoextraction efficiencies of Cd and Zn among four A. halleri populations: two each from metalliferous and non-metalliferous sites. In a controlled transplant experiment, clonal replicates of A. halleri were grown in native and three non-native soils for six months. Biogeochemical analyses of plants and soils were conducted, alongside sequencing of root-associated soil bacterial/archaeal and fungal DNA. Soil treatments primarily differed in pH, total Cd, Pb, and Zn, as well as acid and alkaline phosphatase enzyme activities. A combined effect of soil origin and population was noted for arylsulfatase and β-glucosidase activities, as well as ammonium and nitrate concentrations. Both non-metallicolous and metallicolous populations accumulated high levels of Cd and Zn in metalliferous soils with the non-metallicolous population NM_PL14 outperforming the metallicolous populations in Zn hyperaccumulation. Interestingly, non-metallicolous populations grown in metalliferous soils exhibited no trade-offs in plant performance despite higher Cd and Zn accumulation. Soil origin had a stronger effect on the bacterial/archaeal and fungal community composition than plant ecotype. Partial least square regression models explained 66 % and 79 % of the variability in A. halleri Cd and Zn hyperaccumulation. There was a positive association between Zn-uptake and specific microbial taxa (e.g., Cornebacteriales, Microbacteriaceae, Propionibacteriales, Rhizobiaceae, Basidiomycota, Oidiodendron, Phallaceae) and functional activity (e.g., arylsulfatase, S oxidation) in metalliferous soils. Taken together, our findings suggest that non-metallicolous A. halleri populations may be better suited for Zn phytoextraction applications.

The Origin and Geography of Brown Forest Soils

Brown soils, Brown forest soils, Burozems or Cambisols have been studied for more than 100 years, and to this day, their nature, origin and process organization remain controversial. In addition, issues of their geography are quite controversial, especially in such a large country as Russia. A brief review of the literature on the morphological diversity features of the genesis and origin of brown soils in the various geographical locations of Eurasia is given. It was shown that the genesis of brown soils is not as closely related to the type of forest vegetation as previously thought, although, at the same time, the vast majority of brown soils are forest soils. Depending on the geographic situation and local climatic and geogenic conditions, Brown forest soils have related subtypes among adjacent soil types in different natural zones. Thus, in the polar zone, they are close to Entic Podzols, in the subtropics to Cinamonic soil, and in the forest-steppe, they replace zonal Retisols in positions with a relatively less contrasting and even climate. Being to a certain extent intrazonal soils, brown soils are combined with other more intrazonal soils—Rendzinas—and form the so-called Burozem-Rendzinas on uplands, composed of carbonate rocks in various natural zones. The article is illustrated with original photographs of Brown forest soils from various natural zones, taken by the author during numerous expeditions. It has been established that Burozems combine the characteristics of intrazonal soil, which is inherent in all natural zones, and have elements of zonal soils, as well as adjacent intrazonal soils in invariant combinations of soil-forming factors. From this, two conclusions can follow about their further classification fate: a more thorough justification for an independent soil type or a classification of structural metamorphism and in situ transformation of minerals among various existing zonal soil types.

Creation of Cellulolytic Communities of Soil Microorganisms-A Search for Optimal Approaches.

For the targeted selection of microbial communities that provide cellulose degradation, soil samples containing cellulolytic microorganisms and specific plant residues as a substrate can be used. The details of this process have not been studied: in particular, whether the use of different soils determines the varying efficiency of communities; whether these established cellulolytic communities will have substrate specificity, and other factors. To answer these questions, four soil microbial communities with different cellulolytic activity (Podzol and the soil of Chernevaya taiga) and substrates (oat straw and hemp shives) with different levels of cellulose availability were used, followed by trained communities that were tested on botrooth substrates (in all possible combinations). Based on the analysis of the taxonomic structure of all communities and their efficiency across all substrates (decomposition level, carbon, and nitrogen content), it was shown that the most important taxa of all trained microbial cellulolytic communities are recruited from secondary soil taxa. The original soil does not affect the efficiency of cellulose decomposition: both soils produce equally active communities. Unexpectedly, the resulting communities trained on oats were more effective on hemp than the communities trained on hemp. In general, the usage of pre-trained microbial communities increases the efficiency of decomposition.

Assessment and Application of Multi-Source Precipitation Products in Cold Regions Based on the Improved SWAT Model

In hydrological modeling, the accuracy of precipitation data and the reflection of the model’s physical mechanisms are crucial for accurately describing hydrological processes. Identifying reliable data sources and exploring reasonable hydrological evolution mechanisms for hydrology and water resources research in high-altitude mountainous regions with sparse stations and limited data constitute a significant challenge and focus in the field of hydrology. This study focuses on the Yarkant River Basin in Xinjiang, which originates from glaciers and contains a substantial amount of meltwater runoff. A dynamic glacier melt module considering the synergistic effects of multiple meteorological factors was developed and integrated into the original Soil and Water Assessment Tool (SWAT) model. Four precipitation datasets (ERA5-land, MSWEP, CMA V2.0, and CHM-PRE) were selected to train the model, including remote sensing precipitation products and station-interpolated precipitation data. The applicability of the improved SWAT model and precipitation datasets in the source region of the Yarkant River was evaluated and analyzed using statistical indicators, hydrological characteristic values, and watershed runoff simulation effectiveness. The optimal dataset was further used to analyze glacier evolution characteristics in the basin. The results revealed the following: (1) The improved model fills the gap in glacier runoff simulation with respect to the original SWAT model, with the simulation results more closely aligning with the actual runoff variation patterns in the study area, better describing the meltwater runoff process. (2) CMA V2.0 precipitation data has the best applicability in the study area. This is specifically reflected in the rationality of the spatial and temporal distribution patterns of the inverted precipitation, the accuracy observed in capturing precipitation events and actual precipitation characteristics, the goodness of fit in driving hydrological models, and the observed precision in reflecting the composition of watershed runoff, all of which are superior to those pertaining to other precipitation products. (3) The glacier melt calculated using the improved SWAT model informed by CMA V2.0 shows that during the study period, the basin formed a pattern with a positive–negative glacier balance demarcation at 36.5° N, featuring melting at higher latitudes and accumulation at lower latitudes. The results of this study are of significant importance for hydrometeorological applications and hydrological and water resources research in this region.

Origin, transformation and classification of organic soils in Poland

Origin, transformation and classification of organic soils in Poland

Enhancing wine authentication: leveraging 12,000+ international mineral wine profiles and artificial intelligence for accurate origin and variety prediction

For the wine industry, ensuring quality and authenticity hinges on the precise determination of wine origin. In our study, we developed a fast semi-quantitative method to analyse 41 chemical elements in wine, employing inductively coupled plasma mass spectrometry (ICP-MS). This methodology characterises what we term the mineral wine profile (MWP). In contrast to an organic molecular profile, the mineral composition of a wine remains constant from the moment it is bottled. Mineral elements play a crucial role in the terroir of wine: they pass primarily from soil to grape and are then influenced by various vinification techniques. Indeed, it is widely recognised that the original soil characteristics are altered by a multitude of winemaking procedures, presenting a considerable challenge when endeavouring to extract origin-related information in a typical scenario. Our study demonstrates that statistical analyses and artificial intelligence (AI) could be a tool for accurately deciphering origin information within the MWP, provided sufficient mineral elements are measured and a comprehensive database of wine samples is employed to establish effective learning. In this study, a dataset comprising 12,966 MWPs was created in just over a year. The first analysis revealed correlations between the elements in wine, especially between rare earth elements, between macronutrients and between micronutrients. A machine learning method was then developed to assess wine origin and principal grape variety. Six models were tested by comparing the area under the receiver operating characteristic curve (AUC), with eXtreme Gradient Boosting as the chosen model. Mean accuracies of 92 % for country classification, 91 % for the French wine region, and 85 % for the main grape variety were obtained, and mean AUC scores of 0.964 for country classification, 0.961 for the French wine region and 0.914 for the main grape variety. This study represents the first comprehensive investigation at this scale on wine samples, and underscores the importance of using a comprehensive MWP dataset for AI applications when verifying wine origin. The authentication of a wine with over 99 % specificity could be routinely achievable through this approach.

Providing quality-assessed and standardised soil data to support global mapping and modelling (WoSIS snapshot 2023)

Abstract. Snapshots derived from the World Soil Information Service (WoSIS) are served freely to the international community. These static datasets provide quality-assessed and standardised soil profile data that can be used to support digital soil mapping and environmental applications at broad scale levels. Since the release of the preceding snapshot in 2019, refactored ETL (extract, transform and load) procedures for screening, ingesting and standardising disparate source data have been developed. In conjunction with this, the WoSIS data model was overhauled, making it compatible with the ISO 28258 and Observations and Measurements (O&amp;amp;M) domain models. Additional procedures for querying, serving and downloading the publicly available standardised data have been implemented using open software (e.g. GraphQL API). Following up on a short discussion of these methodological developments we discuss the structure and content of the “WoSIS 2023 snapshot”. A range of new soil datasets was shared with us, registered in the ISRIC World Data Centre for Soils (WDC-Soils) data repository and subsequently processed in accordance with the licences specified by the data providers. An important effort has been the processing of forest soil data collated in the framework of the EU-HoliSoils project. We paid special attention to the standardisation of soil property definitions, description of the soil analytical procedures and standardisation of the units of measurement. The 2023 snapshot considers soil chemical properties (total carbon, organic carbon, inorganic carbon (total carbonate equivalent), total nitrogen, phosphorus (extractable P, total P and P retention), soil pH, cation exchange capacity and electrical conductivity) and physical properties (soil texture (sand, silt and clay), bulk density, coarse fragments and water retention), grouped according to analytical procedures that are operationally comparable. Method options are defined for each analytical procedure (e.g. pH measured in water, KCl or CaCl2 solution, molarity of the solution, and soil / solution ratio). For each profile we also provide the original soil classification (i.e. FAO, WRB and USDA system with their version) and pedological horizon designations as far as these have been specified in the source databases. Three measures for “fitness for intended use” are provided to facilitate informed data use: (a) positional uncertainty of the profile's site location, (b) possible uncertainty associated with the operationally defined analytical procedures and (c) date of sampling. The most recent (i.e. dynamic) dataset, called wosis_latest, is freely accessible via various web services. To permit consistent referencing and citation, we also provide a static snapshot (in this case, December 2023). This snapshot comprises quality-assessed and standardised data for 228 000 geo-referenced profiles. The data come from 174 countries and represent more than 900 000 soil layers (or horizons) and over 6 million records. The number of measurements for each soil property varies (greatly) between profiles and with depth, this generally depending on the objectives of the initial soil sampling programmes. In the coming years, we aim to gradually fill gaps in the geographic distribution of the profiles, as well as in the soil observations themselves, this subject to the sharing of a wider selection of “public” soil data by prospective data contributors; possible solutions for this are discussed. The WoSIS 2023 snapshot is archived and freely available at https://doi.org/10.17027/isric-wdcsoils-20231130 (Calisto et al., 2023).

Влияние лесозаготовительной техники на динамику естественного возобновления леса после рубки хвойно-лиственного насаждения средней тайги

The work presents the results of experimental studies on assessment of preliminary and subsequent reforestation depending on the disturbance of the soil cover by logging equipment. The initial survey of the reforestation in the clearing showed the uneven settlement of the territory by woody plants in most parts and individual technological elements. According to morphological characteristics and a set of soil genetic horizons, the soil can be classified as typical Albic Retisols, which develop on loamy soil-forming rocks in well-drained landscapes. We found that the soil of the skidding trail is morphologically close to the original soil. The drag soils have undergone both morphological and chemical changes. The key difference is the change in the composition of the organic horizon following the arrival of a large amount of felling residues and changes in the composition of the ground cover plants. The morphometric parameters of the trees in the mixed stand and undergrowth are of high lability. The stand was dominated by small trees and small undergrowth. The stand and undergrowth are characterized as “healthy”. Relatively good uniformity of its settlement by woody plants was revealed only on portages in ruts with a predominant regeneration of small-leaved species. When the trails are heavily littered, there is no appearance of woody plants. There is no regeneration in the reclaimed felling areas in the first and second years. There is no resumption in sections with aligned tracks in the first and second year.

Environmental Factors Drive the Biogeographic Pattern of Hippophae rhamnoides Root Endophytic Fungal Diversity in the Arid Regions of Northwest China.

Hippophae rhamnoides subsp. sinensis Rousi (Abbrev. H. rhamnoides) stands as a vital botanical asset in ameliorating the ecological landscape of the arid regions in Northwest China, where its rhizospheric microorganisms serve as linchpins in its growth and developmental dynamics. This study aimed to explore the community structure characteristics and origin differences of root endophytic fungi in H. rhamnoides. Samples were collected from 25 areas where H. rhamnoides is naturally distributed along an altitude gradient in the northwest region. Then, endophytic fungi from different regions were analyzed by using high-throughput sequencing technology to compare the structural characteristics of endophytic fungi and examine their association with environmental factors. FUNGuild was employed to analyze the community structure and functions of endophytic fungi, and the results showed that each region had its own dominant endophytic fungal flora, demonstrating the differences in origin of endophytic fungi, and the specific endophytic flora acquired from the original soil in the growing season of H. rhamnoides will help us construct the microecological community structure. Furthermore, the study identified and assessed the diversity of fungi, elucidating the species structure and highlighting dominant species. The RDA analysis revealed that available phosphorus (AP), available potassium (AK), and total nitrogen (TN) exhibit significant correlations with the composition and diversity of root-associated fungi. In conclusion, the fungal community structure is similar within the same region, while significant differences exist in the taxonomic structure and biodiversity among different regions. These findings shed light on the intricate interplay and mechanisms governing the ecological restoration of H. rhamnoides, offering a valuable framework for advancing green ecology initiatives and harnessing the potential of root-associated microorganisms in this species.

Effects of Microplastics and Organic Fertilizer Regulation on Soil Dissolved Organic Matter Evolution.

Microplastics are pollutants of global concern nowadays. However, the effects of microplastics addition to soil as a carbon source and the combined effects of microplastics and organic fertilizer on soil-dissolved organic matter (DOM) evolution are still unclear. This study focused on the evolution of DOM in soil with the addition of microplastics and investigated the variations in the content and composition of DOM in unfertilized and fertilized soil with different particle sizes of microplastics. It was observed that the TOC concentration of the soil DOM in the treatment with organic fertilizer and microplastics increased more (129.97-161.43 mg kg-1) than that in the treatment with microplastics alone (117.17-131.87 mg kg-1) and was higher than that in the original soil (95.65 mg kg-1). According to the humic acid relative abundance in DOM after 40 days of incubation, the humic acid relative abundance in DOM of the soil samples with microplastics and organic fertilizers addition was found to be higher than that in those with microplastic addition alone, reaching more than 80% in a short time. In conclusion, the TOC concentration of the soil DOM increased with the addition of microplastics, and the increase was more pronounced when organic fertilizers and microplastics were added together. Moreover, the soil humification increased to a higher level in the short term with the combined addition of microplastics and organic fertilizers, which was maintained during the long-term incubation process.

Enhanced Water Resistance of TiO2-GO-SMS-Modified Soil Composite for Use as a Repair Material in Earthen Sites.

Most earthen sites are located in open environments eroded by wind and rain, resulting in spalling and cracking caused by shrinkage due to constant water absorption and loss. Together, these issues seriously affect the stability of such sites. Gypsum-lime-modified soil offers relatively strong mechanical properties but poor water resistance. If such soil becomes damp or immersed in water, its strength is significantly reduced, making it unviable for use as a material in the preparation of earthen sites. In this study, we achieved the composite addition of a certain amount of sodium methyl silicate (SMS), titanium dioxide (TiO2), and graphene oxide (GO) into gypsum-lime-modified soil and analyzed the microstructural evolution of the composite-modified soil using characterization methods such as XRD, SEM, and EDS. A comparative study was conducted on changes in the mechanical properties of the composite-modified soil and original soil before and after immersion using water erosion, unconfined compression (UCS), and unconsolidated undrained (UU) triaxial compression tests. These analyses revealed the micro-mechanisms for improving the waterproof performance of the composite-modified soil. The results showed that the addition of SMS, TiO2, and GO did not change the crystal structure or composition of the original soil. In addition, TiO2 and GO were evenly distributed between the modified soil particles, playing a positive role in filling and stabilizing the structure of the modified soil. After being immersed in water for one hour, the original soil experienced structural instability leading to collapse. While the water absorption rate of the composite-modified soil was only 0.84%, its unconfined compressive strength was 4.88 MPa (the strength retention rate before and after immersion was as high as 93.1%), and the shear strength was 614 kPa (the strength retention rate before and after immersion was as high as 96.7%).

Carbon Sequestration Capacity after Ecological Restoration of Open-Pit Mines: A Case Study in Yangtze River Basin, Jurong City, Jiangsu Province

Open-pit mining seriously damages the original vegetation community and soil layer and disturbs the carbon cycle of vegetation and soil, causing instability in the mining ecosystem and decrease in the carbon sequestration capacity of the mining area. With the deepening of environmental awareness and the influence of related policies, the ecological restoration of open-pit mines has been promoted. The mining ecosystem is distinct owing to the disperse distribution of mines and small scale of single mines. However, the carbon sequestration capability of mines after ecological restoration has not been clearly evaluated. Therefore, this study evaluated the carbon sequestration capacity of restoration mines, taking the mines of the Yangtze River Basin in Jurong City, Jiangsu Province as the research objects. Firstly, the visual effects of the vegetation and soil in their current status were determined through field investigation, the methods for sampling and data collection for the vegetation and soil were selected, and the specific laboratory tests such as the vegetation carbon content and soil organic carbon were clarified. Meanwhile, the evaluation system consisting of three aspects and nine evaluation indexes was established by using the analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE). The process of evaluation included the following: the establishment of the judgment matrix, calculation of the index weight, determination of the membership function, and establishment of the fuzzy membership matrix. Finally, the evaluation results of the restoration mines were determined with the ‘excellent, good, normal and poor’ grade classification according to the evaluation standards for each index proposed considering the data of the field investigation and laboratory tests. The results indicated that (1) the evaluation results of the mines’ carbon sequestration capacity were of excellent and good grade at a proportion of 62.5% and 37.5%, which was in line with the field investigation results and demonstrated the carbon sequestration capacity of all the restored mines was effectively improved; and (2) the weights of the criterion layer were ranked as system stability &gt; vegetation &gt; soil with the largest value of 0.547, indicating the stability of the system is the main factor in the carbon sequestration capacity of the mines and the sustainability of the vegetation community and the stability of soil fixation on the slope. The proposed evaluation system effectively evaluates the short-term carbon sequestration capability of the restoration mining system according to the visual effects and the laboratory testing results, objectively reflecting the carbon sequestration capacity via qualitative assessment and quantitative analysis. The evaluation method is relatively applicable and reliable for restoration mines and can provide a reference for similar ecological restoration engineering.

Soil cross breeding: Mechanical strength analysis of intermixed soils used as unfired earth brick

Mechanical strength of brick is significantly influenced by soil properties, deeming some soils unusable. This paper investigates the effect of mixing soils from different sources, Hyogo (a chlorite soil) and Tokyo (an albite soil) from Japan, on the flexural and compressive strength of unfired earth brick. Before conducting strength tests on moulded bricks made from original soil mixes and intermixed soils, both soil samples were individually separated into two portions, sand and fines. To better understand the strength behaviour of the resulting brick specimen, the physical and chemical properties of used raw materials were characterised using various techniques including X-ray computed tomography (X-ray CT) X-ray diffraction (XRD), water and nitrogen sorption, X-ray fluorescence (XRF) and ionic conductivity. The results revealed that the replacement of the fines portions in unadulterated soil mixes induced an increase in flexural and compressive strength for brick specimen made with albite soil, while significant reduction in strength was recorded with brick specimen made with fines portion replaced in chlorite soil. Furthermore, the former intermixed soil exhibited higher strengths than specimen made from unadulterated soils. Chlorite clay minerals comprised of desired properties to enhance performance of albite soil sand particles in a brick composite. This justified the dependence of selected soil parameters that play critical roles in the performance behaviour of the produced bricks. The obtained findings could serve as guidelines to production and performance enhancement of unburnt brick by amalgamating various soils.