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Abstract Potentially toxic metal(loid) assessment of tea and tea garden soil is a vital guarantee of tea safety and is very necessary. This study analyzed the distribution of seven potentially toxic metal(loid)s in different organs of the tea plants and soil at various depths in the Yangai tea farm of Guiyang City, Guizhou Province, China. Although soil potentially toxic metal(loid) in the study area is safe, there should be attention to the health risks of Cu, Ni, As, and Pb in the later stages of tea garden management. Soil As and Pb are primarily from anthropogenic sources, soil Zn is mainly affected by natural sources and human activities, and soil with other potentially toxic metal(loid) is predominantly from natural sources. Tea plants might be the enrichment of Zn and the exclusion or tolerance of As, Cu, Ni, and Pb. The tea plant has a strong ability for absorbing Cd and preferentially storing it in its roots, stems, and mature leaves. Although the Cd and other potentially toxic metal(loid)s content of tea in Guizhou Province is generally within the range of edible safety, with the increase of tea planting years, it is essential to take corresponding measures to prevent the potential health risks of Cd and other potentially toxic metal(loid)s in tea.

Long-term excessive fertilization and irrigation under greenhouse cultivation systems cause nitrogen leaching, while the residual content varies at different soil depths with cultivation durations. However, it remains unclear whether it changes the composition and assemblage of the soil bacterial community, especially at deeper layers (as deep as 4 m), after long-term intensified cultivation. This study selected soils from three sites in Shouguang (a typical representative intensive planting area), i.e., greenhouse monoculturing for 20 years (G20), greenhouse monoculturing for 10 years (G10), and an adjacent rotation field (F) for physicochemical property determination and high-throughput pyrosequencing. The results showed that, contrary to the vertical characterization of soil bacterial community composition, the 2-m soil was dominated by Methylomirabilota, a nitrate/nitrite-dependent anaerobic methane oxidizer, uncovered for the first time in the soil habitat. This was attributed to the high levels of dissolved organic carbon (DOC, 201.2–255.7 mg kg−1), proving that applying C-rich organic fertilizers, e.g. plant residues, is effective in preventing accumulated nitrate from moving downward and threatening groundwater in greenhouse soils. Besides, greenhouse cultivation increased the inter-layer composition differences of the bacterial community, and compared with the abundant, the rare subcommunity showed higher sensitivity to environmental changes. The total nitrogen most significantly affected the bacterial community composition and assemblage. Therefore, 20 years of consecutive monocropping significantly decreased the microbial co-occurrence network complexity and species dispersal rate, yielding a low-fitted neutral community model (NCM) and more specialized ecological niches, especially for the rare subcommunity. As far as is known, this is the first study that explores the likely changes in the bacterial community composition and quantifies the responses of the rare subcommunity to long-term greenhouse cultivation at this soil depth. Discovery of Methylomirabilota broadens our understanding of micro-biodiversity in deep-soil ecosystem, and hints its application potential in soil remediation.

Global warming can accelerate soil organic matter (SOM) decomposition resulting in faster carbon (C) loss and positive climate-C feedback. Previous studies on response of SOM decomposition to climate change mainly focus on plow soil layer. However, the effects of elevated CO2 and soil warming on soil organic carbon (SOC) and total nitrogen (TN) contents and mineralization are rarely studied in subsoil layer. In this study, soil samples were collected from the 0–50-cm paddy soil layer of the Tsukuba free-air CO2 enrichment experimental site with elevated CO2 (+200 ppm) and soil warming (+2 °C), Japan, after 5-year rice growth season. The amounts of SOC, TN, δ13C, and δ15N were analyzed. A 4-week anaerobic incubation experiment was conducted to measure C decomposition and N mineralization potentials. Due to the intrinsic variation in SOC and TN contents in soil layers and fields, the effects of elevated CO2 and soil warming on C decomposition and N mineralization potentials could not be determined here. However, the effect of elevated CO2 on δ13C was only found in 0‒10-cm soil layer. In the 0–50-cm soil profiles, significant correlations were observed among SOC and TN, δ13C and δ15N, decomposed C and mineralized N, and δ13C of decomposed C. The variables associated with soil C and N pools, and dynamics showed large spatial heterogeneity within paddy field, due to variation in the original land use history. Therefore, great caution should be exercised when evaluating the effects of elevated CO2 and temperature on SOM decomposition and sequestration in paddy soil profiles.

Improvement of cultivated cotton adaptability to extreme climate events under climate change promotes sustainable cotton production. Extreme rainfall leads to a significant decrease in cotton yield, which may be related to changes in soil water consumption (SWC) and the vertical distribution of yield, but relevant research is still scarce. Here, a two-year cotton sowing date experiment was conducted in which geostatistics, sensor technology, the spatial grid method, and principal component analysis were combined to analyze cotton utilization of soil water during extreme rainfall (2021) and normal (2022) years. The reasons for cotton yield reduction under extreme rainfall and strategies to improve cotton production adaptability to extreme rainfall were discussed. Under extreme rainfall, the morphogenesis and reproductive organ development of cotton were inhibited. The accumulation of SWC and its relationship with the biomass accumulation of cotton on different sowing dates under extreme rainfall exhibited nearly opposite characteristics to those in a normal year. Simultaneously, the two-year yield showed the opposite trend with the change in sowing date. There existed a trade-off strategy for the vertical distribution (i.e., on the upper, middle and lower fruiting branches) of cotton yield. Extreme rainfall reduced the yield at lower fruiting branches and increased the boll-forming rate of the upper fruiting branches, which was closely related to seed cotton yield, lint yield and water productivity (WP). Optimizing the cotton sowing date (early sowing should be appropriate in this study) may improve the adaptability of cotton production under extreme rainfall, but further long-term studies are needed. This study highlights the critical practice of climate-smart agriculture and has reference value for the sustainable development of cotton production.

ABSTRACTUnderstanding soil types in a specific region is crucial for developing effective approaches to control irrigation water usage and promote sustainable agriculture. This research aimed to characterize and classify the soils of Ajacho Lintala irrigation scheme located in Soro woreda of Southern Ethiopia. Through the analysis of 25 auger observations, 4 pedons, a comprehensive reconnaissance survey, and laboratory analysis, this study examined the morphological, and physicochemical characteristics of the soils in the irrigation. The study identified 16 soil samples from four pedons, consisting of both undisturbed and disturbed soil profiles, which were collected for laboratory analysis. The soils in the research irrigation scheme were classified using the FAO/WRB 2015 classification system. The findings revealed that the texture classes of the study irrigation scheme’s soils varied from loam to clay loam for Nitisols, silt loam to clay loam for Luvisols, and clay for Vertisols. Moreover, the available phosphorus, total nitrogen, and organic carbon in the soils were categorized as very low to low range, while cation exchange capacity and basic cations (Ca2+, Mg2+, K+, and Na+) were in the medium to high range. Based on morphological and physicochemical investigations, the soils were classified as Humic Nitisols, Rhodic Luvisols, Haplic Luvisols, and Pellic Vertisols. These classifications align with the equivalent USDA classification of Ultisols (Typic Haplustults), Alfisols (Typic Haplustalfs), and Vertisols (Typic Haplusterts), respectively. To maintain and enhance soil fertility a sustainable soil management system is recommended, which includes practices such as continuous crop cover, mulching, and organic manuring with suitable inorganic fertilizers. Additionally, implementing physical land management measures to control soil erosion in slope areas is crucial.

Nitrous oxide (N2O) emissions from organic waste and animal slurry contribute to climate change and endanger our ecosystems. For the development of efficient mitigation technologies, in-depth knowledge of emission processes is needed. This can be obtained by non-destructive, temporal measurements of in-situ soil profiles and the transformation of ammonium (NH4+) during events of emissions. Planar optode imaging is a non-destructive measuring method that can be used to visualize spatiotemporal changes of ammonia (NH3) and pH in soil systems. In this study, soil amended with dairy processing sludge (DPS) was incubated in static chambers for 23 days, and GHG emissions, NH3 concentrations and pH in the soil were measured simultaneously over time. The aim was to investigate the potential of applying different planar optodes to provide information that gives insight into processes of N2O emissions. The DPS was applied to the soil as a surface layer (SL), with untreated soil as a control (CK). We were able to measure N2O emissions while monitoring spatiotemporal changes of soil pH and NH3 concentrations. The visualized microscale heterogeneity of the soil contributed to a better understanding of N2O emission processes. While technical challenges (e.g., humidity sensitivity of the NH3 optode and airtightness of the chambers) still need to be overcome, the method is a promising non-destructive method to study soil processes after application of different types of soil amendments.

Introduction: Permafrost and seasonally frozen soil are widely distributed on the Qinghai–Tibetan Plateau, and the freezing–thawing cycle can lead to frequent phase changes in soil water, which can have important impacts on ecosystems.Methods: To understand the process of soil freezing-thawing and to lay the foundation for grassland ecosystems to cope with complex climate change, this study analyzed and investigated the hydrothermal data of Xainza Station on the Northern Tibet from November 2019 to October 2021.Results and Discussion: The results showed that the fluctuation of soil temperature showed a cyclical variation similar to a sine (cosine) curve; the deep soil temperature change was not as drastic as that of the shallow soil, and the shallow soil had the largest monthly mean temperature in September and the smallest monthly mean temperature in January. The soil water content curve was U-shaped; with increased soil depth, the maximum and minimum values of soil water content had a certain lag compared to that of the shallow soil. The daily freezing-thawing of the soil lasted 179 and 198 days and the freezing-thawing process can be roughly divided into the initial freezing period (November), the stable freezing period (December–early February), the early ablation period (mid-February to March), and the later ablation period (March–end of April), except for the latter period when the average temperature of the soil increased with the increase in depth. The trend of water content change with depth at all stages of freezing-thawing was consistent, and negative soil temperature was one of the key factors affecting soil moisture. This study is important for further understanding of hydrothermal coupling and the mechanism of the soil freezing-thawing process.

This study sheds light on the effect of diversity in the parent rock on some properties and development of soil profiles in the northern part of the coastal region of Syria. To achieve the goal of this study, several different profiles of the parent material were selected: profiles (P1, P2, P3, P4) on sedimentary rocks and profiles (P5, P6, P7. P8, P9) on ophiolites. Profiles were excavated, described morphologically, and samples were taken from each horizon to conduct the necessary analyzes, according to internationally accepted methods. The results showed that most soil properties are affected by changes in the parent material and its composition, such as carbonate content, amount of organic matter, soil texture and color, pH level, chemical composition, and other properties studied, thus affecting the classification of these soils. The Mollisols order dominated the areas where ophiolite rocks spread, while the orders varied between Mollisols, Entisols, and Vertisols in the areas of sedimentary rocks. The presence of forest vegetation, along with the mineral composition of the parent rock, in addition to secondary factors such as fires, played a role in the development of soils and their taxonomic level.

The dissolved organic matter (DOM) in forest ecosystems significantly impacts soil carbon cycling due to its active turnover characteristics. However, whether different plantation forest soil profiles exhibit distinct DOM characteristics remains unclear. Hence, utilizing fluorescence spectroscopy and the parallel factor analysis (PARAFAC) method, a 1-meter soil profile analysis was carried out on three distinct artificial forests (Pinus tabuliformis (PT), Quercus crispula (QC), and a mixed forest of PT and QC (MF)), concurrently assessing the impact of soil chemical properties and enzyme activity on dissolved organic matter (DOM). The findings indicated that the mean concentration of dissolved organic carbon (DOC) was greatest in the MF and lowest in PT, exhibiting considerable variation with soil depth, suggesting that mixed tree species may promote the discharge of organic matter. The fluorescence spectra revealed two distinct peaks: humic-like fluorescence peaks (Peaks A and C) and a protein-like fluorescence peak (Peak T), with the most intense fluorescence observed in MF soil. As the soil depth increased, the fluorescence intensity of Peaks A and C steadily declined, while the intensity of Peak T rose. Four DOM components were identified in three types of plantations forests: surface soil was dominated by humic acid-like fluorescent components (C1 and C2), while the deep soil was primarily characterized by protein-like fluorescence components (C3 and C4). Different soil profile fluorescence parameter indices indicated that the source of DOM in the surface soil (i.e., 0–20 cm) was mainly allochthonous inputs, whereas, in the deep soil (i.e., 60–100 cm), it was mainly autochthonous, such as microbial activity. The findings from the partial least squares path modeling (PLS-PM) revealed that TP, aP, NH4+-N, and the combined impact of soil enzymes were influential in shaping the diversity of DOM attributes. Put differently, alterations in DOM concentration were concomitantly influenced by forest classification, soil characteristics, and depth. It has been demonstrated that, in contrast to monoculture forests, the establishment of mixed forest models has been more advantageous in enhancing the soil dissolved organic matter (DOM). These discoveries offer innovative perspectives on the dynamic characteristics of DOM in soil profiles and its influencing factors under different plantations forest planting patterns.

More than half of the carbon pools in peatlands are stored in the soil layers below 30 cm, yet little is known about the carbon stabilizing factors at these depths. Although iron oxide minerals are considered to be important for stabilizing organic carbon (OC), their role in the preservation of OC in peatlands, especially in the deep layers, is poorly understood. Here, we collected 1 m soil profiles from six peatlands in Central and West China to quantitatively study the vertical distribution characteristics of iron-bound OC (Fe-bound OC), and the influencing physicochemical properties of the soil. The results showed that the content of reactive iron (FeR) was enriched in the top layer and decreased gradually with depth. While Fe-bound OC was positively correlated with FeR, its concentration did not decrease with depth in the peat profile. There were no obvious trends in the distributions of FeR and Fe-bound OC with water level fluctuations in the peat profile. In addition, the proportion of Fe-bound OC to soil organic carbon in the deep peat (31 to 100 cm) was equivalent to that in the surface peat (0 to 30 cm), indicating that iron oxide mineral provides comparable protection of OC in both layers. According to upper estimates of global peatland carbon storage (612 Pg), it could be predicted that 23.81 ± 11.75 Pg of OC is protected by association with FeR. These results indicated that iron oxide minerals are the effective ''rusty sink'' of OC sequestration in peatland, and a key factor for its long-term preservation. The results from this study make a valuable contribution to the carbon dynamics knowledgebase for peatlands, and provide a basis for improved predictive simulations.

Soil environmental quality related to the residents’ life, health, and safety, has been the hotspot issues in science of ecological environment protection. Evaluating the distribution characteristics, ecological risk, and source of heavy metals in farmland is important for protecting soil resources. The agricultural area of Lianhua town, Gongcheng County, Guilin is a typical karst landform. In response to the problem of heavy metal pollution and complex sources in the soil of this area, the characteristics and sources of heavy metal pollution in the soil profiles from farmland, abandoned land, and forest were studied using the single-factor index method, the geoaccumulation index (Igeo) principal component analysis (PCA) and positive matrix factorization (PMF) model. The results showed that: (1) that the contents of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in the soil profile of the study area were higher than that of the soil elements background values in Guangxi. The total and available forms contents of all heavy metal elements exhibited the characteristics of accumulation in the surface profile; (2) among the six heavy elements, the contents of Cd were in a moderately to heavily polluted state. The contents of Cd in some soil profiles exceeded the control standard for agricultural land soil pollution. The contents of Zn and Ni were from slightly to moderately polluted in areas with frequent agricultural activities; (3) according to the PCA and PMF model, there were three main sources of heavy metals in the study area. Among them, Cd, Cu, Ni, and Zn are related to agricultural activities; the elements As, Cd, Cr, and Hg are closely related to geological background; Pb and Zn are mainly affected by atmospheric sedimentation of transportation. Agricultural activities and natural geological background are the main contribution sources of heavy metals in soil. Human activities are the main factors that cause the accumulation of heavy metals in soil. This research has theoretical guidance and practical significance for the prevention and control of soil heavy metal pollution and the protection of farmland environmental quality in the region.

After the process of surface mining, stripping and covering, the vertical distribution of organic carbon (SOC) and total nitrogen (TN) in the reclaimed mine soil undergoes great changes, which directly determines the selection of vegetation species and the effectiveness of ecological restoration. Therefore, under the dual carbon target, monitoring and mapping SOC and TN in reclaimed soil profile (0−100 cm) are the important basis for evaluating ecological restoration and carbon sequestration in mining areas. Compared with traditional chemical methods, hyperspectral imaging is a rapid and non-destructive technique that can be used for the effective estimation of the important indicators of soil properties. Imaging spectroscopy technology has the advantage of spectral integration compared to point spectral measurement. Therefore, the reclaimed soil from arid and semi-arid grassland mining areas in northern China was selected as the research object, and soil profiles (0−100 cm) from different mining areas, modes and years were collected. The vertical distribution patterns and hyperspectral characteristics of SOC and TN in profiles were revealed under different cultivation years and patterns. And then, with the feature bands and spectral indices of SOC and TN, the interpretable machine learning models were constructed to achieve mapping SOC and TN contents in profiles. The results indicated that: ① The spectral reflectance of the soil samples decreased with the increase of SOC and TN contents. By combining stacked feature selection methods (Pearson correlation coefficient–successive projections algorithm, PCC-SPA), hyperspectral data were reduced in dimension. 30 bands of SOC and 18 bands of TN were clearly identified, and three-dimensional (3D) spectral indices were established; ② By comparing different machine learning algorithms (partial least squares regression; PLSR, random forest; RF, and radial basis function model; RBF), the prediction accuracy could be improved by filtering and transforming the selective bands of hyperspectral data. The RF with selective bands and optimal 3D spectral indices demonstrated the best results with R2=0.97, RMSE=7.5 g/kg, LCCC=0.84, bias=3.70 for SOC and R2=0.78, RMSE=0.33 g/kg, LCCC=0.74, bias=0.19 for TN; ③ Using SHAP value to explain the importance ranking of input features in machine learning models, it was found that the contribution of 3D spectral index to model prediction is greater than that of most feature bands; ④ With the optimization model, the SOC and TN content of each pixel in the hyperspectral image could be quickly predicted, and the mapping and visualization of the SOC and TN contents in the mine soil profile could be realized. Mapping profiles of reclaimed soil in open-pit coal mining areas based on imaging hyperspectral technology can help understand and reveal the formation and evolution process of reclaimed soil, clarify the driving forces of reclamation years and vegetation types in the succession process of the profile. It can also provide important data sources and technical support for dynamic monitoring of carbon sequestration potential of reclaimed soil in open-pit coal mining areas and evaluation of the benefits of soil carbon sequestration technology.

Recently, the problem of preserving biodiversity on the planet has become increasingly relevant. Therefore, research on the ecological characteristics of organisms that play an important role in the functioning of biogeocoenoses is especially relevant. Chilipoda millipedes are one of these groups. Currently, many questions on the ecology of Chilopods, especially in the territory of Albania, remain unresolved. This motivates researchers to seek answers to these issues. The primary research aim is to analyse the specific features of the ecology of the Chilipoda millipedes inhabiting Vlora. The material used for the study was the author's collections of centipedes. Manual collection and soil sampling methods were used in the research. Determination of the taxonomic affiliation of centipedes was performed by examining the morphological features of centipedes under a stereoscopic microscope and further determining specimens with the help of determination keys. In the field under investigation, the Chilipoda fauna is represented by 6 species from 4 orders, 6 genera, and 5 families. Temperature and humidity have been shown to have a significant influence on the geographical distribution of chilopods: thus, the occurrence of centipedes in litter and the upper soil layer decreases significantly with the onset of drought. The character of flora plays a secondary role in the distribution of centipedes. It was established that soils with high content of humus and nitrogen are a favourable habitat for centipedes. The paper presents, for the first time for the Vlora region, data on the vertical distribution of S. coleoptrata along the soil profile. Scootigers preferred litter and did not migrate into the soil. Other representatives of Chilipoda were mainly found in the uppermost soil layer (0-10 cm), moreover Chilipoda were concentrated in the litter, and only a small part of them descended to a depth of 20 cm. The obtained results contribute to the knowledge of the ecological features of chilopods

To grow fruit plants, farmers in the Vietnamese Mekong Delta (VMD) must use raised bed constructions to avoid waterlogging during the rainy season. This study aimed to evaluate the effects of the age of the raised beds on the soil physicochemical properties of longan orchards located in the VMD. Two raised bed systems were evaluated: a young bed constructed 10 years ago and an old bed constructed 42 years ago. Soil samples were collected from five different soil layers (0–20, 20–40, 40–60, 60–80, and 80–100 cm) with four replicates per layer. Soil samples were tested for pH, electrical conductivity (EC), available phosphorus (AP), total nitrogen (TN), soil organic matter (SOM), exchangeable cations (Ca2+, K+, Mg2+, and Na+), cation exchange capacity (CEC), bulk density (BD), soil porosity, available water-holding capacity (AWC), particle composition (sand, silt, and clay), and size. The soil pH was approximately 1.0 units lower in the old bed compared to the young bed at depths of 0–20 and 20–40 cm. The BD was higher in the old bed (0.15 g cm−3) than in the young bed at a soil depth of 0.4 m. SOM, AP, exchangeable cations (Ca2+, Na+, and Mg2+), AWC, and soil porosity were significantly lower in both the topsoil (0–20 cm) and subsoil (20–40 cm) layers in the old bed than in the young bed. In particular, the SOM, AP, AWC, and soil porosity contents in the old bed decreased by 18%, 20%, 15%, and 17%, respectively, compared with those in the young bed at soil depths of 0–40 cm. Therefore, cultivating raised bed soil for a longer period significantly reduced the soil exchangeable cations, porosity, and fertility of the surface and subsurface soils. Based on these results, farmers should use soil conservation practices, such as cover crops, rice straw mulching, and soil amendments in their orchards to mitigate topsoil degradation.

This article aimed to investigate the feasibility of using imaging spectroscopy (IS) to predict soil organic carbon density (SOCD) either directly or indirectly through soil organic carbon (SOC). Three methods, partial least square regression, support vector machine (SVM), and random forest, were utilized to calibrate the models and map the SOCD. The results showed that direct prediction was better than indirect prediction and the best model SVM had high R2 of 0.94 and 0.93 for calibration and validation, respectively. The measured SOCD was mainly concentrated in the surface soil layer from 0 to 40 cm, and the deeper layer tended to be gentle. The continuous depth variation trend of SOCD in the topsoil (0–40 cm) was relatively close to the measured values, while in the deeper layers (below 40 cm), it was much higher than the measured values. This article also found that the best fitting function of measured SOC stocks over time varied from linear to power and then to logarithmic with increasing depth, indicating less efficient accumulation of SOC in deep soil compared to topsoil, resulting in an overall decrease in SOC accumulation rate across soil depth. The best temporal functions for the predicted values differed from the measured values at each depth, but the changing trends of the three functions were basically consistent. It suggests that IS technology has the potential to quantitatively reveal the process of coastal soil evolution and offers a new insight for the rapid monitoring of soil property changes.

A toposequence soils study was undertaken along Donga River in Manya, Takum LGA Northeast Nigeria. Three (3) profile pits were sunk using physiographic positions (upper slope, mid-slope and valley bottom) and the soil samples were collected based on genetic horizon differentiation, the samples were subjected to routine laboratory analysis. Data generated was analyzed statistically using coefficient of variance and weighted mean. All profile pits were geo-referenced using hand held GPS receiver. Soil colour ranged from dark brown (7.5YR 3/2) in the Ap horizons to strong brown (7.5YR 5/8) in the Bt horizons. Sand and silt dominated the fractions (sand mean content 43.00 g/kg1 , 71.47 g/kg1 and 39.64 for Pedons 1, 2 and 3 respectively and silt mean at Bt2 had 558 g/kg1 , 366 g/kg1 and 680 g/kg1 for Pedons 1, 2 and 3 respectively). The bulk density was higher in the top soils than in the sub soils, the highest mean was recorded in pedon 3 (1.57 g/cm3 ). The silt clay ratio (SCR) was indicative of soils with weatherable minerals. The soil pH ranged from moderately acid to slightly acid (6.48, 5.80, 5.95) in pedons 1, 2 and 3 respectively. The negative ∆pH values obtained are indicative that the colloidal fraction had exchangeable capacity. The total nitrogen was rated low while available phosphorus was rated very high to high. The percentage base saturation had mean from 96.72%, 97.12% and 95.79% in pedons 1,2 and 3 respectively, suggestive of Alfisols -Entisols mix. There were varied results for coefficient of variation (CV) in soil properties among the different positions on the toposequence. Therefore, the soils were classified as Typic Isohyperthermic Haplustalfs in pedons 2 and 3 with fluvic characters in pedon 1 (USDA) which corresponded to Arenic Luvisols (WRB).

To investigate the responses of crop production and soil profile nutrient status to biochar (BC) application, we conducted a soil column experiment considering two BC addition rates (0.5 and 1.5 wt% of the weight of 0–20 cm topsoil) combined with two nitrogen (N) input levels (low N: 144 kg ha−1, LN; high N: 240 kg ha−1, HN). The results showed that BC application increased the soil pH. The soil pH of the 0–10 cm profile under LN and the 20–40 cm profile under HN were both significantly increased by 0.1–0.2 units after BC addition. Under LN, BC addition significantly increased NH4+-N (17.8–46.9%), total N (15.4–38.4%), and soil organic carbon (19.9–24.0%) in the 0–10 cm profile, but decreased NH4+-N in the 20–30 cm soil profile and NO3−-N in the 10–30 cm profile by 13.8–28.5% and 13.0–34.9%, respectively. BC had an increasing effect on the available phosphorus, the contents of which in the 10–20 and 30–40 cm soil profiles under LN and 20–30 cm profile under HN were significantly elevated by 14.1%, 24.0%, and 23.27%, respectively. However, BC exerted no effect on the available potassium in the soil profile. BC had a strong improving effect (15.3%) on the wheat yield, especially the N144 + BC0.5% treatment, which could be compared to the HN treatment, but there was no yield-increasing effect when high N fertilizer was supplied. In summary, BC improved the fertility of agriculture soil (0–20 cm) with wheat. In particular, low N inputs together with an appropriate rate of BC (0.5 wt%) could not only achieve the low inputs but also the high outputs in wheat production. In future study, we will compare the effects of multiple doses of N and BC on soil fertility and crop production.

Determination of the microbial and enzymatic properties in soil is primarily concentrated on the surface layers of the soil profiles; however, it is well known that the transformation of soil organic matter also occurs in the deeper horizons of the soil profile. The aim of this study was to assess any changes in specific sets of enzyme activities and their associated physicochemical properties as affected by two different agricultural land-use systems and soil depth. Changes in the studied properties were determined across four Luvisol profiles in two agricultural land uses (arable land and vineyards). The enzyme activities associated with the transformation of C, N and P were analyzed. Additionally, the activity of some oxidoreductases and the fluorescein diacetate hydrolysis (FDAH) rate were also determined. Moreover, the content of the various forms of soil carbon, nitrogen, phosphorus (including microbial biomass C, N and P) and some other properties (pH, clay and silt content) were assessed. Agricultural land use significantly affected the microbial biomass content and as well as the studied enzyme activities. Most of the studied enzymes exhibited a higher activity in the grapevine (GV) profiles, which was followed by the winter wheat (WW) profiles; however, the largest variability occurred for the urease activity. There was no clear differentiation between the two studied land uses for the activity of nitrate reductase, dehydrogenases, acid phosphatase, or endo- and exo-cellulase. Irrespective of the plant being cultivated, the soil variables decreased significantly with increasing soil depth, wherein the greatest changes were observed between the surface and sub-surface soil horizons (I–II). The activity of some enzymes (e.g., the urease activity in WW profiles) decreased gradually across the soil profiles, while others were located almost solely within the surface layers (e.g., the nitrate reductase activity in the GV profiles as well as invertase in the WW profiles). The α-glucosidase activity did not exhibit any statistically significant changes along the analyzed profiles. The activity of phenol oxidase and peroxidase also revealed different trends along the studied profiles compared to the other enzymes and did not decrease gradually with depth. The microbial biomass of the C, N and P content was generally the highest in the upper horizons and gradually decreased with depth, wherein the largest decrease was observed between the surface and sub-surface horizon. The studied enzyme activities were more dependent on the soil carbon content compared to the other soil properties. And thus, in the C-rich horizons (C > 4 g kg) for the surface and subsurface layers the enzyme activities were highly correlated with TOC, DOC and MBC content as compared to the deeper, C-low horizons (C < 4 g kg). By examining how the microbial and enzymatic properties change across the soil profiles, it is possible to gain valuable insight into the long-term biogeochemical processes that are involved in soil fertility and in the health of agricultural ecosystems.

Relevance. Currently, there is an acute problem of meeting the growing demand for berry and fruit products. One of the ways to intensify agricultural production in the field of horticulture and crop production is to increase the efficiency of environmental management through the use of resource-saving technologies. One of these technologies is drip irrigation, which improves the quality of crop production.Materials and methods. Field studies were carried out on the territory of the educational and experimental farm of the laboratory "Michurinsky Garden" of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. The experiment was established in the fall of 2018 and is a two-factor study of various levels of moisture on the growth and development of raspberry seedlings. The first factor included options for maintaining soil moisture in the range: 1) control (without irrigation); 2) not less than 60% of the lowest moisture capacity; 3) not less than 70% of the lowest moisture capacity; 4) not less than 80% of the lowest moisture capacity. The second factor was the raspberry varieties Solnyshko and Nagrada.Results. Constructed moisture contours according to the study options showed that drip irrigation contributes to the optimum moisture concentration in the soil for seedlings. The most developed root system in comparison with the control was obtained on irrigated variants with maintaining a moisture content of at least 70 and 80% of the lowest moisture capacity. Here, the maximum values of the volume of the root system, the number of roots, and the average length of the root were obtained. It was revealed that in variants with irrigation, the root system of seedlings spreads in the upper layer (mainly 5-15 cm).

Soil organic carbon (SOC) and nitrogen (N) are two of the most important indicators for agricultural productivity. The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile (up to 100 cm) and their relationships with crop productivity under the influence of long-term (since 1990) fertilization in the wheat-maize cropping system. Treatments included CK (control), NP (inorganic N and phosphorus (P) fertilizers), NPK (inorganic N, P and potassium fertilizers), NPKM (NPK plus manure), and M (manure). Crop yield and the properties of topsoil were measured yearly from 2001 to 2009. C and N contents were measured at five different depths in 2001 and 2009. The results showed that wheat and maize yields decreased between 2001 and 2009 under the inorganic fertilizer (NP and NPK) treatments. The average yield between 2001 and 2009 under the NP, NPK, NPKM, and M treatments (compared with the CK treatment) increased by 38, 115, 383, and 381%, respectively, for wheat and 348, 891, 2 738, and 1 845%, respectively, for maize. Different long-term fertilization treatments significantly changed coarse free particulate (cfPOC), fine free particulate (ffPOC), intramicroaggregate particulate (iPOC), and mineral-associated (mSOC) organic carbon fractions. In the experimental years of 2001 and 2009, soil fractions occurred in the following order for all treatments: mSOC>cfPOC>iPOC>ffPOC. All fractions were higher under the manure application treatments than under the inorganic fertilization treatments. Compared to the inorganic fertilization treatments, manure input enhanced the stocks of SOC and total N in the surface layer (0–20 cm) but decreased SOC and N in the deep soil layer (80–100 cm). This reveals the efficiency of manure in increasing yield productivity and decreasing risk of vertical loss of nutrients, especially N, compared to inorganic fertilization treatments. The findings provide opportunities for understanding deep soil C and N dynamics, which could help mitigate climate change impact on agricultural production and maintain soil health.

Partial substitution of synthetic nitrogen fertilizer with manure (organic substitution) is highly recommended to minimize environmental risks without compromising crop productivity in intensive agricultural systems. However, our understanding of the effect of organic substitution on soil organic carbon (OC) and total nitrogen (TN) in deep soil and its impact on crop productivity remains limited. Here we investigated OC and TN changes in soil profile down to 100 cm, crop yield, and sustainable yield index under synthetic nitrogen, phosphate, and potassium fertilizers (NPK), NPK plus straw (NPKS), and organic substitution (NPKM) treatments over two decades in four upland fields across different climate zones. Compared with the initial values, two decades of NPKM treatment significantly (p < 0.05) increased OC and TN stocks in either topsoil (by 25.6–103.8 and 15.8–89.8%) or deep soil (by 2.9–71.3 and 5.7–36.9%), respectively, across all sites. The increases in OC and TN stocks in 0–100 cm soil receiving NPKM were significantly higher than those receiving NPK at all sites and NPKS at three high-evaporation sites. Compared with NPKS and NPK treatments, crop yield and N uptake were significantly increased under NPKM treatment only at the Qiyang site. Furthermore, OC sequestration in the entire soil profile down to 100 cm and TN accumulation in topsoil exhibited significant positive correlations with crop N uptake, relative crop yield, and sustainable yield index. In conclusion, long-term partial substitution of synthetic N fertilizer with manure facilitates soil OC and TN sequestration in the entire 100 cm profile and thus maintains high crop productivity in upland areas.

Maintaining nitrogen (N) balance and inhibiting N leaching loss in the soil-crop system is crucial to maintaining yield and reducing the environmental pollution. This study investigated the effects of soil NO3--N content and accumulation, eggplant yield, N leaching and balance response to biochar addition, including regular fertilisation and irrigation (W + F), biochar addition with regular fertilisation and irrigation (W + F + B), and biochar addition with 20% fertilisation and irrigation reduction (0.8W + 0.8F + B) treatments. Compared with W + F, W + F + B and 0.8W + 0.8F + B increased soil NO3--N content in 0-40 cm and soil NO3--N accumulation in 0-20 cm, and raised harvest index, N surplus and balance. Simultaneously, 0.8W + 0.8F + B compared to W + F enhanced N use efficiency and N partial factor productivity, conversely, it decreased N dry matter production efficiency, N surplus and balance. Stepwise regression analysis demonstrated that the effect of NO3--N leaching lasted in 60 cm under biochar addition in the first year, and lasted in 20 cm without biochar application in the next year. Altogether, biochar addition with 20% fertilisation and irrigation reduction is the most suitable management strategy to decrease N surplus and leaching, and maintain eggplant N uptake in a two-year cycle system on greenhouse vegetables in Mollisols.

Investigating the dynamics and distribution of soil phosphorus (P) fractions can provide a basis for enhancing P utilization by crops. Four treatments from a 29-year long-term experiment in black soil with maize cropping were involved in this study: no fertilizer (CK), inorganic nitrogen and potassium (NK), inorganic nitrogen, phosphorus, and potassium (NPK), and NPK plus manure (NPKM). We analyzed soil P fractions in different soil layers using a modified Hedley sequential method. The long-term NPKM treatment significantly increased total P by 0.6–1.6 times in the different soil layers. The Olsen-P concentration far exceeded the environmental threshold for soil Olsen-P (50.6 mg kg−1) in the NPKM treatment in the 0–60 cm soil profile. Moreover, the concentrations and proportion of labile and partially labile inorganic P (Pi) fractions (i.e., NaHCO3-extracted Pi, NaOH-extracted Pi, and dilute HCl-extracted Pi) to the sum of all P fractions (Pt) in the 0–60 cm soil profile were higher in the NPKM treatment than in the NPK treatment, indicating that manure could promote the transformation of non-labile into more labile forms of P in soil, possibly by manure reducing P fixation by soil particles. Soil organic matter, Mehlich-3 extractable iron (Fe), and organic-bound aluminum were increased by fertilization, and were the main factors influencing the differences in the P fractions in the 0–20 cm soil layer. Soil mineral components, i.e., free Fe oxide and CaCO3, were the main factors influencing the P fractions in the subsoil. The soil P transformation process varied with soil layer and fertilization. Application of manure fertilizer can increase the labile (Olsen) P concentrations of the various soil layers, and thus should reduce the mineral P fertilizer requirement for crop growth and reduce potential environmental damage.

Dallisgrass (Paspalum dilatatum Poir.) control with postemergence herbicides is inefficient and inconsistent from year to year. Control with acetolactate synthase (ALS)-inhibiting herbicides may be enhanced through root absorption, but herbicide movement through dense turfgrass canopies may be difficult. The objectives of this research were to evaluate the influence of verticutting on the postemergence control of dallisgrass and the presence of ALS-inhibiting herbicides within the soil profile. Long-term dallisgrass control [17 weeks after initial treatment (WAIT)] was enhanced in response to verticutting at one of two locations. This may be attributed to differences in turfgrass management (mowing height) before trial initiation that impacted dallisgrass carbohydrate content and herbicide absorption. However, dallisgrass control with certain herbicides was enhanced at the second location in response to verticutting at earlier rating dates. Thiencarbazone + foramsulfuron + halosulfuron (TFH) and trifloxysulfuron at 112 g·ha−1 a.i. and carrier volume of 1628 L·ha−1 (TRI High CV) following mowing + verticutting resulted in the greatest long-term control 17 WAIT at one of two trial locations, 86% and 85%, respectively. Greenhouse experiments confirmed that mowing + verticutting dallisgrass before treatment followed by irrigation led to an increase in herbicide presence within the soil profile, regardless of herbicide. Presence of TFH went from 6.4 to 8.2 mm, trifloxysulfuron at 28 g·ha−1 a.i. and carrier volume of 407 L·ha−1 went from 6.7 to 8.5 mm, and TRI High CV went from 8.6 to 11.8 mm.

Promoting cropland carbon (C) sequestration through straw return has always been the focus of numerous studies. However, there is still a lack of comprehensive understanding of the straw return effects on soil organic carbon (SOC) and soil inorganic carbon (SIC) sequestration. Therefore, the present study aims to investigate the effects of long-term straw return on SOC and SIC sequestration across the 0–100 cm soil profile in the maize planting cropland in Northeastern China. The results showed an increasing trend in SOC contents in the 0–100 cm soil profile following long-term straw return, while significant decreases in SIC contents were observed in the surface (0–20 cm) and subsoil (20–60 cm) layers, respectively. In addition, the SOC stock increased significantly in the subsoil layer following long-term straw return, by an average value of 44%, which is higher than those observed in other soil layers. On the other hand, the SIC stock in the subsoil layer increased by an average value of 24% and decreased in the surface and under-subsoil layers by average values of 53% and 33%, respectively. Moreover, the exchangeable calcium contents were positively correlated with SOC and SIC stock, demonstrating the soil calcium contributes to SOC and SIC sequestration. The present study highlighted the importance of the subsoil layer for effective straw return strategies in cropland to promote SOC and SIC sequestration in croplands.

Microbial communities and functions play an important role in soil carbon and nitrogen transformations, and, in recent decades, the abandonment of terraces is prevalant in the hilly areas of China. However, it is unclear how soil carbon and nitrogen contents and prokaryotic communities changed as a result of the abandonment of ancient rice terraces. Soil profiles ranging from 0 to 120 cm were excavated on drylands, forestlands (both converted due to the abandonment of ancient rice terraces), and ancient rice terraces. The FAPROTAX database was used to predict soil prokaryotic functional groups. The results showed that soil organic carbon (SOC) and total nitrogen (TN) contents of abandoned ancient rice terraces in drylands (51.09 and 33.20%) and forestlands (31.76 and 16.59%) were significantly reduced. Soil prokaryotic diversity and community composition changed dramatically after the abandonment of terraces and were mainly affected by soil pH and ammoniacal nitrogen (NH4+-N). Community composition was more similar in drylands and forestlands. Moreover, the abundance of transformation functional genes of carbon (57.01 and 50.80%) and nitrogen (15.25 and 22.36%) in bacterial communities was significantly reduced, and of carbon in the archaeal communities decreased sharply (28.10 and 46.50%), in drylands and forestlands. These findings indicate that short-term abandonment of ancient rice terraces reduces soil carbon and nitrogen contents, which may be closely related to the decline of prokaryotic functional groups. The prevalence of short-term abandonment of rice terraces in the hilly areas of China may pose adverse ecological risks.

Increased population density has led to a lot of pressure on the limited natural/land resources of south-eastern Nigeria. This includes the need for laterite, sand, kaolin, gravel and clay for buildings, backfills and road construction. This has led to extensive unmoderated excavation of these resources, particularly in Anambra state. The excavation has in turns, culminated in increased intensity of land degradation in the state, underscoring the need to characterize and evaluate the land use potentials of such sites to better understand the nature of the soils and the impacts of the attendant land use. Samples were collected from the different horizons of the profile to evaluate the physical, chemical and morphological properties of the soils. Coefficient of variation was used to measure the soil variability within the profile. Land capability class was determined, which informed the land use and management recommendations. The results show that the soil is very deep (>21.5m). The soil texture ranged from sandy clay loam to sandy. Infiltration rate and saturated hydraulic conductivity decreased by up to 300 to 560 % with excavation. The soils were strongly acidic; organic carbon and total nitrogen was low but highly variable; Al, H, Ca, Mg, K, Na, and phosphorus were moderately variable while pH, CEC and base saturation (BS) were the least variable. The land capability class was IIIes. Given the evidence of erosion and preponderance of erodible Nanka sands in the subsoil, the site should be reclaimed as soon as the mining activities are discontinued.

The concentrations of inorganic elements in soils of Saje, Ita-Oshin, Premier, and Oke-Diya dumpsites were determined using an X-Ray Fluorescence spectrometer to assess the soil quality through chronological changes with depths. A soil core sampler collects 56 samples at 20, 40, 60, and 80 cm depths. Saje showed high mean concentrations of Ca, K, Fe, Rb, and Ti at all depths, while Oke-Diya revealed high mean concentrations of Ca, K, Fe, Rb, Ti, Mn, Zn, V, Cr, and Ni at all depths. These concentrations were in a closed range suggesting a build-up of elements in the soil profiles. Oke-Diya had the highest pollution index, followed by Saje, and the contaminations were from anthropogenic and geologic sources. The mean concentrations of Fe, Zn, Ni, Mn, Ti, K, and Ca were high at all depths in Ita-Oshin, and in Premier, the mean concentrations of K and Fe were high at all depths. Premier had the lowest pollution index. Ita-Oshin and Premier enrichment factors showed geologic sources. Saje and Oke-Diya revealed unacceptable non-carcinogenic risks for adults and children, and Ita-Oshin and Premier recorded acceptable limits. Saje and Oke-Diya samples had high carcinogenic risks for adults due to Cr, Pb, and As. Elements Cr and As in Ita-Oshin, and Pb in Premier evinced unacceptable carcinogenic risks for adults. Saje, Oke-Diya, and Premier indicated unacceptable carcinogenic risks for children due to Cr. The study showed toxins build-up in the soil system, and the study areas are not suitable for growing crops and sinking water wells for agricultural and domestic uses.

The concentrations of inorganic elements in soils of Saje, Ita-Oshin, Premier, and Oke-Diya dumpsites were determined using an X-Ray Fluorescence spectrometer to assess the soil quality through chronological changes with depths. A soil core sampler collects 56 samples at 20, 40, 60, and 80 cm depths. Saje showed high mean concentrations of Ca, K, Fe, Rb, and Ti at all depths, while Oke-Diya revealed high mean concentrations of Ca, K, Fe, Rb, Ti, Mn, Zn, V, Cr, and Ni at all depths. These concentrations were in a closed range suggesting a build-up of elements in the soil profiles. Oke-Diya had the highest pollution index, followed by Saje, and the contaminations were from anthropogenic and geologic sources. The mean concentrations of Fe, Zn, Ni, Mn, Ti, K, and Ca were high at all depths in Ita-Oshin, and in Premier, the mean concentrations of K and Fe were high at all depths. Premier had the lowest pollution index. Ita-Oshin and Premier enrichment factors showed geologic sources. Saje and Oke-Diya revealed unacceptable non-carcinogenic risks for adults and children, and Ita-Oshin and Premier recorded acceptable limits. Saje and Oke-Diya samples had high carcinogenic risks for adults due to Cr, Pb, and As. Elements Cr and As in Ita-Oshin, and Pb in Premier evinced unacceptable carcinogenic risks for adults. Saje, Oke-Diya, and Premier indicated unacceptable carcinogenic risks for children due to Cr. The study showed toxins build-up in the soil system, and the study areas are not suitable for growing crops and sinking water wells for agricultural and domestic uses.

Soil organic carbon is an important factor for the cultivation and production of traditional Chinese medicine. This study aimed to reveal the spatial distribution of the soil organic carbon density (SOCD) and the effects of the climatic and topographic factors in Longxi County (Gansu Province, China). The soil organic carbon (SOC) from 200 sampling points were collected and analyzed in 2018. Results showed that the total SOCD was 26.7 ± 10.2 Mg ha-1, while the SOCDs at a soil depth of 0–10, 10–30, and 30–50 cm were 6.3 ± 1.7, 11.0 ± 3.8, and 9.3 ± 4.8 Mg ha-1, respectively. The temperature, precipitation, elevation, and stream power index showed significant correlations with the SOCD at each soil layer. With an increasing soil depth, the correlation between the slope, relief amplitude, surface roughness, and SOCD gradually decreased. From the central plains to the mountainous areas, the SOCD increased with rising elevation, while the valley plain that formed by the river basin showed low levels of SOCD. Therefore, the scientific management of soil fertility and the development of precision agriculture, combined in a soil testing fertilization formula, will guarantee the healthy development of the Chinese herbal medicine planting.

Due to the introduction of zero-till wheat in the Indo-Gangetic plains (IGP) in India, irrigation and fertilizer nitrogen (N) management needs to be modified from that followed under conventionally tilled fields. A field experiment was conducted to study the effect of irrigation and N levels on yield and N uptake by zero-till wheat, fertilizer N-use efficiency, and distribution of nitrate-N (NO3-N) in a soil profile under zero-till conditions in an acidic alluvial soil of the eastern IGP. The experiment was laid out in a split-plot design with four levels of irrigation as main plots (I0-no irrigation, rain-fed, I1-122 mm in one irrigation at 21 days after sowing (DAS), I2-263 mm in two irrigations at 21 and 42 DAS, and I3-386 mm in three irrigations at 21, 42, and 84 DAS) and 4 N levels [0 (N0), 60 (N1), 120 (N2), and 150 (N3) kg N ha−1] as subplots. Grain and straw yields were significantly higher at the irrigation level-I2 and 120 kg N ha−1-N2 over the control (I0 and N0) and were at par with the highest applied levels of irrigation and N (I3 and N3). The nitrogen uptake by wheat followed a trend similar to yield for irrigation levels; however, it increased significantly up to 150 kg N ha−1. After the harvest of wheat crop, more NO3-N was observed in the 60–90 cm subsurface soil layer than in the surface 0–15 cm and/or 15–30 cm and 30–60 cm subsurface soil layers. The highest NO3-N concentration was recorded in the treatment I2N2. Accumulation of NO3-N in the soil increased up to irrigation levels I2 and with increasing doses of fertilizer N application. Combined applications of irrigation and N had a positive and significant influence on agronomic efficiency (AE) and apparent N recovery (ANR) but had no significant effect on physiological efficiency (PE). This study suggests that an appropriate combination of irrigation and N levels in zero-till wheat can lead to not only high-yield levels and N-use efficiency but also adequately control NO3-N leaching under acidic alluvial soils in the eastern IGP.

Alterations in land use and vegetation cover cause CO2 transfer not only to the soil surface but also across soil profiles. To explore the vertical diffusion characteristics of CO2 in deep soil profiles and their driving factors, we calculated CO2 flux and measured environmental factors in sections situated from 0 to 200 cm in Robinia pseudoacacia forests (Loess Hilly Region, China). The results found that (1) Deep soils (>80 cm) exhibited a stable contribution to the soil-atomosphere CO2 flux, ranging from 21.81% to 24.42%. (2) The total CO2 storage within deep layers accounted for 55.03–79.98% of the total storage in the layer at 0–200 cm. The stable storage of CO2 at deep layers helped suppress the mineralization of organic carbon in deep soil; (3) Soil temperature, moisture, CO2 concentration, aerated porosity, SOC content, bulk density, total porosity, root density, microbial biomass carbon (MBC), pH, and profile depth explained 86.0% and 89.1% of the variance in CO2 flux at shallow and deep layers, respectively. Soil moisture was the key limiting factor for vertical differentiation of CO2 fluxes in deep and shallow layers. The sensitivity of temperature and aerated porosity on CO2 flux increased with soil depth increasing. While the soil microbial biomass carbon had a weaker effect on CO2 flux both in the deep and shallow layers. Root stimulation was more likely to induce CO2 emission in deep layers. However, increase of pH was more conducive to CO2 fixation and flux reduction in deep layers. Our results help to further clarify the mechanisms of carbon emission in deep soil carbon pools, and provide a theoretical basis for scientific evaluation of soil carbon emissions.

Plant growth-promoting (PGPR) bacteria are beneficial soil bacteria that enhance plant growth against biotic and abiotic stress. Numerous studies have been carried out over the past three decades on the isolation and characterization of rhizospheric bacteria. However, no studies have been conducted on the bacteria present in the rhizosphere of the wild legume plant Chamacytisus ruthenicus when growing in chalky soil. The purpose of this study was to evaluate the abundance of culturable bacteria, assess the morphology of the bacterial cells, profile the chalky soil bacterial community, and characterize its ability to stimulate plant growth. Three soil samples were collected in January at a temperature of 2–4 °C. The first sample was taken from the topsoil, the second sample from the soil 15 cm beneath the surface, and the third sample from the rhizosphere. The results of the study revealed that the abundances of bacteria in the first, second, and third soil samples were 4.25 × 108 cfu/g, 3.58 × 108 cfu/g, and 10.1 × 107 cfu/g, respectively. Furthermore, a total of 23 rhizospheric bacteria were isolated based on differences in their morphological characteristics. The 16S rRNA soil profiling result showed that bacteria belonging to Proteobacteria, Actinobacteria, Gemmatimonadetes, Acidobacteria, and Bacteroidetes were the most dominant groups in the community. Six bacterial isolates (Z10, Z11, Z12, Z15, Z26, and Z44) were chosen to examine the inhibition effects on phytopathogenic microbes and their ability to promote plant growth. The bacterial isolates Z11 and Z15 showed good inhibition against all tested phytopathogenic fungi, while bacterial isolates Z10, Z12, Z15, Z26, and Z44 showed stimulatory effects on the length and fresh weight of the shoots and roots of wheat, maize, and oat seeds. In conclusion, the present study is the first report of chalky soil-associated bacteria found in the rhizosphere of the wild legume plant in the Belgorod region of Russia.

Soil profile moisture is a crucial parameter of agricultural irrigation. To meet the demand of soil profile moisture, simple fast-sensing, and low-cost in situ detection, a portable pull-out soil profile moisture sensor was designed based on the principle of high-frequency capacitance. The sensor consists of a moisture-sensing probe and a data processing unit. The probe converts soil moisture into a frequency signal using an electromagnetic field. The data processing unit was designed for signal detection and transmitting moisture content data to a smartphone app. The data processing unit and the probe are connected by a tie rod with adjustable length, which can be moved up and down to measure the moisture content of different soil layers. According to indoor tests, the maximum detection height for the sensor was 130 mm, the maximum detection radius was 96 mm, and the degree of fitting (R2) of the constructed moisture measurement model was 0.972. In the verification tests, the root mean square error (RMSE) of the measured value of the sensor was 0.02 m3/m3, the mean bias error (MBE) was ±0.009 m3/m3, and the maximum error was ±0.039 m3/m3. According to the results, the sensor, which features a wide detection range and good accuracy, is well suited for the portable measurement of soil profile moisture.

Abstract Background Straw retention is a substitute for chemical fertilizers, which effectively maintain organic matter and improve microbial communities on agricultural land. The purpose of this study was to provide sufficient information on soil fungal community networks and their functions in response to straw retention. Hence, we used quantitative real-time PCR (qRT-PCR), Illumina MiSeq (ITS rRNA) and FUNGuild to examine ITS rRNA gene populations, soil fungal succession and their functions under control (CK) and sugarcane straw retention (SR) treatments at different soil layers (0–10, 10–20, 20–30, and 30–40 cm) in fallow fields. Result The result showed that SR significantly enhanced ITS rRNA gene copy number and Shannon index at 0–10 cm soil depth. Fungi abundance, OTUs number and ACE index decreased with the increasing soil depth. The ANOSIM analysis revealed that the fungal community of SR significantly differed from that of CK. Similarly, significant difference was also observed between topsoil (0–20 cm) and subsoil (20–40 cm). Compared with CK, SR decreased the relative abundance of the pathogen, while increased the proportion of saprotroph. Regarding soil depth, pathogen relative abundance in topsoil was lower than that in subsoil. Besides, both sugarcane straw retention and soil depths (topsoil and subsoil) significantly altered the co-occurrence patterns and fungal keystone taxa closely related to straw decomposition. Furthermore, both SR and topsoil had higher average clustering coefficients (aveCC), negative edges and varied modularity. Conclusions Overall, straw retention improved α-diversity, network structure and fungal community, while reduced soil pathogenic microbes across the entire soil profile. Thus, retaining straw to improve fungal composition, community stability and their functions, in addition to reducing soil-borne pathogens, can be an essential agronomic practice in developing a sustainable agricultural system.

Abstract Assessment of nitrogen (N) saturation of forests is critical to the evaluation of the manner in which ecosystems will respond to current and future global changes such as N deposition. However, quantifying N saturation remains a challenge. We developed a conceptual model of N saturation stages in forest ecosystems based on (1) a hypothetical relative rate of ammonification, nitrification, and denitrification, (2) concentrations of ammonium and nitrate in the soil, and (3) 15N enrichment pattern of bulk soil N, ammonium, and nitrate in the soil profile. We tested the hypotheses using data from forests located at five sites across eastern Asia. The fraction of nitrate in total inorganic N indicated that the sites represent an N saturation gradient with one boreal forest at stage 1 (least saturated), three temperate forests at stage 2, and one tropical forest at stage 3 (most saturated). The δ15N of bulk soil N increased from topsoil to subsoil more sharply at N‐limited sites than at the N‐rich sites along the N deposition gradient. We also found distinct 15N enrichment patterns of bulk soil N, ammonium, and nitrate in the soil profile across the study sites. At stage 1, nitrate was more 15N‐depleted than ammonium only in the organic soil horizon, indicating limited nitrification, while the 15N depletion of nitrate to ammonium was observed in the deeper mineral soil at stages 2 and 3. Furthermore, ammonium was more 15N‐depleted than bulk soil N at stages 1 and 2 but more 15N‐enriched than bulk soil N at stage 3. Our study suggests that soil profile patterns of δ15N of bulk soil N, ammonium, and nitrate provide information about the relative rates of mineralization, nitrification, and denitrification and thus can be an additional measure of N saturation of forest ecosystems across broad environmental gradients.

The paper considers the problem associated with the creation of databases. The review of available global, traditional soil databases is given. It is noted that they are of great scientific and practical importance. The description of the developed relational database «Heat Soil Portraits» in Microsoft Access is presented, based on the positive concept of representative soil profiles. The database contains information about the structural organization and thermal properties of natural and technogenic soils in Central Siberia. To create the database, we used materials from a morphological description, photographing, and ground radiometric survey in the thermal range of soil profiles obtained by the authors during the expeditionary work. Radiometric survey of soils was carried out according to the author’s method using a portable thermal camera. The structure of the designed database, its content and attributes are developed. Currently, the database includes information on 20 soil profiles of the main soil types and technogenic surface formations that are common in Central Siberia. The procedure for replenishing the created database with new information is simple to perform. A feature of the proposed database is the presence of photographs and thermal portraits attached to the description of a particular soil profile, which display the temperature distribution and structural organization of the soil profile. For each soil profile, temperature gradients are calculated that characterize the specific thermophysical properties of organogenic and mineral horizons. The prospect of DB development is replenishment with the results of radiometric surveys carried out in different seasons of the year and in different conditions of soil formation. Thus, the materials contained in the database can be used to assess the temporal and spatial variability of soils as a result of exposure to natural and anthropogenic factors.

In the present study, six soil profiles belonging to five soil types were dug, described and sampled. Soil samples were analyzed for the determination of different physicochemical properties and total and DTPA-extractable iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), lead (Pb), and cadmium (Cd). Considering the variability of pH and calcium carbonate equivalent, the examined soils were alkaline and calcareous. A considerable change in the values of the DTPA fraction of Fe (1.4-25.8 mg/kg), Zn (0.01-3.3 mg/kg), Cu (0.32- 6.2 mg/kg), Mn (1-11.8 mg/kg), Cd (0.05- 0.12 mg/kg) and Pb (0.22- 2.56 mg/kg) as well as in the total fraction of Fe (10.6-20.6 g/kg), Zn (35- 67.5 mg/kg), Cu (9 to 26.40 mg/kg), Mn (262- 588.8 mg/kg), Cd (0.5- 1.75 mg/kg) and Pb (17- 31.3 mg/kg) was observed in different soils. The content and pattern of both DTPA and total fraction of the metal were varied among the soil types, which could be related to several processes such as the diversity of weathering rate, geomorphologic condition, soil formation process, different physicochemical properties of soils, and the inputs of different agrochemical compounds. The concentration of both DTPA and total fraction of the metal were in the acceptable maximum level in the majority of the soil samples.

Soil organic matter (SOM) is a key factor in maintaining soil quality. The main aim of this research was to investigate the distribution of soil organic matter in the coastal region of Syria. For this purpose, thirty-one representative soil profiles were prepared in Latakia governorate from three different land types according to usage (i.e. forest land, rangeland, and agricultural land). Soil samples were collected from the top layer, then analyzed. Results showed that the total organic matter (TOM%), as well as soil properties, varied between the studied agroecosystems. Notably, the average recorded TOM percentages were 5.34%, 4.38%, and 4.07% in forest land, rangeland, and agricultural land respectively. Additionally, matrix correlation between different soil aspects indicated a positive significant (p

Statistical and graphical interpretation of 90Sr vertical distributions in soil profiles up to a depth of 1.0 m was presented based on the study of the typical Scots pine stands forest at 14 experimental sites within the Chernobyl exclusion zone. Significant differences were found between 90Sr activity distribution in soil profiles collected at different sites. The part of 90Sr activity below of a depth of 30 cm varied from 15 to 71 %. 90Sr transfer factors from soil to anatomical structures of the stem wood were estimated based on values of soil contamination density, which were calculated for the depth of 0.3 and 1.0 m. The statistically significant correlation between the transfer factors of 90Sr to stem wood (heartwood, sapwood) and its vertical distributions in soil profiles have not been observed. Among the forest inventory parameters for pine stands only the average diameter of trees significantly correlated with 90Sr transfer factors to stem wood.

Aim. Laboratory evaluation of the characteristics of spatial distribution and migration of heavy metals (HM) in model soil profiles of varied genesis through measurement of the electrokinetic potential of soil solutions. Material and Methods. Undisturbed soils of forest parks landscapes and continental floodplain meadows of the Kursk agglomeration were studied. Experiments were carried out in laboratory conditions. The short‐term temporal dynamics were studied of vertical distribution and migration of the introduced HMs in model soil columns which imitated soil profiles. Results. Analysis of the kinetics of soil solutions and of lysimeter waters of control and polluted samples showed that the model profile of typical dark‐gray soil has the least capacity to capture lead ions from polluted soil solutions. Minimum sorption capacity with respect to zinc was found to be characteristic of sod‐podzol illuvialferruginous soil profiles. Maximum ability to deposit the HMs under analysis (Zn and Pb) was shown in leached chernozem medium loamy soils. Conclusion. The dynamics and kinetics of lead and zinc in soils of the Kursk agglomeration differ significantly and depend on a number of soil factors. In the soils studied, the spatial distribution and the intensity of migration of lead and zinc were determined by the capacity and contrast indices of the internal soil geochemical barriers. Inhibition of the processes of vertical migration of Pb and Zn in the model soil profiles was observed in those rich in humusified humus‐accumulative genetic horizons as well as in mineral horizons with highly contrasting acid‐base and redox conditions. Adsorption zones of lead and zinc are formed with a significant increase in granulometric texture and a decrease in pHKCl.

The vertical mobility of heavy metals in the soil profile may affect their bioavailability. In the present study, a field experiment was conducted for 11 years to investigate the vertical mobility of copper (Cu) and nickel (Ni) and the effects on their bioavailability in soil. It was found that the type and concentration of heavy metals are factors that affect mobility. After 11 years, the mobility and movement of Ni were greater than that of Cu from topsoil (0–20 cm) to subsoil (20–60 cm). The vertical mobility of Cu decreased with the increased addition of Cu, while Ni had the highest vertical mobility when its concentration was the highest in soil. The aging processes and vertical movement could lead to decreases in Cu availability (68–78%) and Ni availability (83–89%). For the decrease of Cu availability in soil, the main driving factor was the vertical movement at low added concentrations, but gradually became aging processes with the increase of added Cu concentrations, while Ni had the opposite tendency. Compared with Cu, aging and vertical mobility played a more prominent role in decreasing the bioavailability of Ni, the bioavailability of Cu changed less than that of Ni after 11 years. The decreased rate of Cu in wheat grains was about 0.26–1.05% while that of Ni was about 2.48–9.46% per year from 2009 to 2018. Therefore, the influence of the vertical downward movement of heavy metals should not be ignored in the assessment of the risk and bioavailability of heavy metals in soil.

Tea plants are widely planted in tropical and subtropical regions globally, especially in southern China. The high leaching and strong soil acidity in these areas, in addition to human factors (e.g., tea picking and inappropriate fertilization methods) aggravate the lack of nutrients in tea garden soil. Therefore, improving degraded tea-growing soil is urgently required. Although the influence of biological factors (e.g., tea plant variety) on soil nutrients has been explored in the existing literature, there are few studies on the inhibition of soil nutrient degradation using different tea plant varieties. In this study, two tea plant varieties with different nutrient efficiencies (high-nutrient-efficiency variety: Longjing43 (LJ43); low-nutrient-efficiency variety: Liyou002 (LY002)) were studied. Under a one-side fertilization mode of two rows and two plants, the tea plant growth status, soil pH, and available nutrients in the soil profiles were analyzed, aiming to reveal the improvement of degraded soil using different tea varieties. The results showed that (1) differences in the phenotypic features of growth (such as dry tea yield, chlorophyll, leaf nitrogen (N), phosphorus (P), and potassium (K) content) between the fertilization belts in LJ43 (LJ43-near and LJ43-far) were lower than those in LY002. (2) RDA results showed that the crucial soil nutrient factors which determine the features of tea plants included available P, slowly available K, and available K. Moreover, acidification was more serious near the fertilization belt. The pH of the soil near LJ43 was higher than that near LY002, indicating an improvement in soil acidification. (3) Soil nutrient heterogeneity between fertilization belts in LJ43 (LJ43-near and LJ43-far) was lower than in LY002. In conclusion, the long-term one-side fertilization mode of two rows and two plants usually causes spatial heterogeneities in soil nutrients and aggravates soil acidification. However, LJ43 can reduce the nutrient heterogeneities and soil acidification, which is probably due to the preferential development of secondary roots. These results are helpful in understanding the influence of tea plant variety on improving soil nutrients and provide a relevant scientific reference for breeding high-quality tea varieties, improving the state of degraded soil and maintaining soil health.

Landscape-geochemical assessment of the industrial areas is of particular interest. This paper describes the microelement composition of soils, investigates hydrochemical composition of surface waters and vegetation of the territory. A landscape-geochemical analysis of the Khromtau industrial zone was carried out. The article includes results of studying of the patterns of the profile distribution of the morphological, physico-chemical properties of soils and their transformation under the influence of the mining industry and urban loads. The study reveals main types of rearrangements of the ecological and geochemical structure of soil profiles, which sharply differ from the background soils of the region. During field research, key areas were laid. In the key areas, soil pits were laid for sampling soil from various horizons, for subsequent chemical analysis of the constituent components, and vegetation was selected for chemical analysis. Geoenvironmental analysis allows scientific justifying creation of technogenic reservations as a basis for protection of recreational areas. The work contains conceptual and methodological approaches to ensuring geo-ecological assessment of geosystems. The analysis of the interaction of the natural, economic, social subsystems and control systems with modern geosystems, based on the ecosystem services, provided by natural subsystem demanded by society and economy. A model of technogenic geosystem and a series of the indicators reflecting properties, quantitative and qualitative features of each block of subsystems has been developed. Structural variations which arise in geosystem as a result of anthropogenous transformation lets to establish quality of technogenic geosystem and to rank them from steadily functioning to the actively degrading.

The tight relationship between root architecture and uptake capacity of soil water and minerals, is well established. Support roots, generally long-lived, perform support functions such as transportation and food storage. Absorbing roots, thin and short-lived, absorb nutrients and regulate plant metabolism. Roots distribution in the soil profile is crucial for plant development. It optimizes resource usage and ensures a prompt response to seasonal changes. This work aimed to study the vertical distribution of the root system of nine-year-old oil palms in a haplic Luvisol, low fertility, moderately acidic, with Nitrogen (N) and Potassium (K) deficiency, average content of Phosphorous (P), and medium to low Cation Exchange Capacity (CEC). Using the cylinder method, soil samples were collected every 10 cm and down to 150 cm of soil depth, from each cardinal side of three soil profiles. The results showed that oil palms had good root development. Most roots (73%) were found in the first 30 cm of soil, with a predominance of fine roots (78%). At 50 cm in depth, fine roots represented 88%, thin roots, 67% and medium roots, 94%. Further study should assess root length density at 15, 20, 25, and 30 years. Highlights - Haplic luvisols are optimal soils for oil palm cultivation due to their depth (> 150cm), over 50% base saturation, and pH of 5.5-6.6. - Root length density (RLD) decreased as soil depth increased. Although most oil palm roots are found in surface horizons, roots can still be found at depths of up to 1.5-5 m. - The highest number of oil palm roots (73%) was found in the first 30 cm, with 78% of fine roots. - Fine roots were distributed throughout the entire soil profile, evidencing high nutrient-absorption and metabolic activities.

Although the phosphatase enzymes regulate phosphorus (P) turnover throughout the soil profile, at present, they are rarely studied and are less well understood in the deeper soil layers than in the surface horizons. Hence the changes in P-associated soil properties were assessed throughout five Phaeozem profiles for different agricultural land uses including alfalfa, winter wheat, grapevine, apple trees and hops. The acid phosphatase (AcP), alkaline phosphatase (AlP) and phosphodiesterase (PDE) activity was assayed, as were the microbial biomass carbon (MBC) and phosphorus (MBP) contents and also other properties (e.g., available phosphorus, total organic carbon, total nitrogen). We have also determined the mass, length and surface area of the plant roots. In general, the activities of the studied enzymes were highest in the topsoil in four out of the five profiles studied, which corresponded to the highest level of root mass. The older the plant, the greater the root mass and increased enzymatic activity in the deeper horizons of apple trees and hop profiles in comparison to the surface layers. The greatest enzymatic activity, MBC and MBP contents were found in the horizons with a TOC content >0.5% and decreased down the soil profiles similarly to the changes in TOC and TN contents. While the studied properties were determined to varying degrees by means of the organic C content and availability in all of the genetic horizons, the influence of the prevailing conditions and the factors related to soil depth and pedogenic processes were less pronounced. The clay content was related to a significant extent to all of the studied enzyme activities, but only in horizons with a TOC content

As one of the important factors affecting forest soil organic carbon stocks, the effect of understory vegetation types on soil organic carbon and its components was explored to provide a theoretical basis for understory vegetation management and sustainable management in plantation forests. In order to determine the characteristics of soil organic carbon and its components under different understory vegetation types in Subtropical Cunninghamia lanceolata plantation, Indocalamus tessellatus, Diplazium donianum and Oreocnide frutescenssp were taken as research objects. The mass fractions of total organic carbon, recalcitrant organic carbon, readily oxidizable organic carbon, microbial biomass carbon and dissolved organic carbon in each soil layer at 0–10, 10–20, 20–40 and 40–60 cm were measured, and the change characteristics of soil organic carbon components were also studied and compared. The results showed that: (1) The mass fractions of total organic carbon, recalcitrant organic carbon, readily oxidizable organic carbon and microbial biomass carbon in the soils of the three understory vegetation types showed significant decreasing trends along the profile, while the mass fraction of dissolved organic carbon in 0–40 cm soil layer was significantly higher than those in 40–60 cm soil layer. (2) The mass fraction of total organic carbon (5.98–20.66 g·kg−1) had no significant difference among understory vegetation types. The mass fraction and proportion of microbial biomass carbon were higher in the 0–60 cm soil layer under cover of Indocalamus tessellatus, and the mass fractions of recalcitrant organic carbon in the 20–40 cm soil layer under Indocalamus tessellatus cover (8.57 g·kg−1) was significantly higher than that of Oreocnide frutescenssp (5.73 g·kg−1). The soil layer of 0–20 cm under the Diplazium donianum community has a higher mass fraction and proportion of readily oxidizable organic carbon. (3) Correlation analysis showed that soil organic carbon and its components were positively correlated with total nitrogen, dissolved total nitrogen, dissolved organic nitrogen and microbial biomass nitrogen. There is a significant positive correlation among the components of soil organic carbon. (4) Redundancy analysis showed that soil bulk density (41.6%), microbial biomass nitrogen (41.2%), dissolved total nitrogen (43.7%), total nitrogen (9.9%), dissolved organic nitrogen (43.6%) and pH (6.6%) were the most significant environmental factors affecting organic carbon components in four soil layers. Understory vegetation type can influence the distribution characteristics of soil organic carbon components in Cunninghamia lanceolata plantation, and soil active organic carbon components are more susceptible to the influence of understory vegetation type than total organic carbon and recalcitrant organic carbon.

Mung bean residues stimulate the hatching of soybean cyst nematode (SCN). In our previous study, combined incorporation of mung bean residues and biochar into soil can be effective in suppression of the soybean cyst nematode (SCN), Heterodera glycines, in the upper layer soil. However, there are no data available as to whether such effects are transmissible, and could for example be manifest in subsoil zones where such incorporation is confined to topsoils, via water-based pathways. We evaluated the effects of leachate passage from a biochar-amended soil in an upper soil zone to a lower zone in a microcosm-based system, upon a range of physicochemical properties and density of SCN. Disturbed soil was filled in a total of 9 cylindrical cores with two layers. The upper layer (0–15 cm) was amended with biochar at rates equivalent to 0, 0.3% or 1.8%, with bulk density set at of 1.1 g cm−3. The lower layer (15–25 cm) without biochar amendment was compacted to 1.2 g cm−3. Mung beans were grown for two weeks and incorporated into the upper layer. Water was surface-applied to the cores 4, 6, and 8 weeks after mung bean incorporation. After 16 weeks, the upper and lower layer soils were separately collected and assayed. The presence of biochar in the upper layer reduced the abundance of free-living nematodes, mainly bacterivorous, but increased that of a predator genus Ecumenicus in this zone. In the lower layer of soil under a biochar-amended upper layer, available P and soluble cations were increased as were abundances of total nematodes including Ecumenicus, resulting in greater maturity index, basal and structure indices. Notably, SCN density was decreased in lower zones by more than 90% compared to zero-biochar controls. This demonstrates that the effects of biochar upon soil properties, including impacts on biota and plant pathogens, are transmissible.

The evaluation of localized soil-liquefaction potential is based primarily on the individual evaluation of the liquefaction potential in each borehole, followed by calculating the liquefaction-potential index between boreholes through Kriging interpolation, and then plotting the liquefaction-potential map. However, misjudgments in design, construction, and operation may occur due to the complexity and uncertainty of actual geologic structures. In this study, the coupled Markov chain (CMC) method was used to create and analyze stratigraphic profiles and to grid the stratum between each borehole so that the stratum consisted of several virtual boreholes. The soil-layer parameters were established using homogenous and random field models, and the subsequent liquefaction-potential-evaluation results were compared with those derived using the Kriging method. The findings revealed that within the drilling data range in this study, the accuracy of the CMC model in generating stratigraphic profiles was greater than that of the Kriging method. Additionally, if the CMC method incorporated with random field parameters were to be used in engineering practice, we recommend that after calculating the curve of the mean, the COV should be set to 0.25 as a conservative estimation of the liquefaction-potential interval that considers the evaluation results of the Kriging method.

Background. Fine roots play a crucial in ecosystem functioning as they supply nutrients and water to plants and represent one of the main pathways for carbon transfer to the soil. Objective. This study assessed the vertical distribution of fine root density and analyzed its relationship with soil properties from a land use change perspective in three vegetation cover types (tropical mountain cloud forest, grassland, coffee crop). Methodology. Soil samples of known volume per horizon were extracted from the soil profile. In laboratory, fine roots (≤ 2 mm in diameter) were tweezers picked, rinsed with water and subsequently oven-dried (70 °C), and weighed. While, the soil was air-dried for chemical analysis. Results. In all soil profiles, average fine root density was greater in grassland (16.06 kg m-3 ± 3.5, average ± SE) than in tropical mountain cloud forest (8.45 kg m-3 ± 1.3), and coffee crop (2.73 kg m-3 ± 0.44). On average, grassland, tropical mountain cloud forest, and coffee crop showed 78.4%, 73.2%, and 65%, respectively, of fine root density on the first soil horizon. Implications. Soil properties were strong predictors of fine root density variation. For example, there was a significant positive correlation between fine root density and soil organic carbon, total soil nitrogen, and effective cation exchange capacity (nutrient availability) in all vegetation covers. A significant negative correlation was observed between fine root density and pH in tropical mountain cloud forest but was not correlated in grassland and coffee crop. In all vegetation covers, there was a significant negative correlation between fine root density and soil bulk density and a strong positive correlation between it and soil water content at field capacity. Conclusion. This research contributes data that will improve our understanding of fine root density-soil interactions in a changing regional environment.