Regional Soil Research Articles

Maize-Soybean Rotation and Intercropping Increase Maize Yield by Influencing the Structure and Function of Rhizosphere Soil Fungal Communities.

Soil-borne diseases are exacerbated by continuous cropping and negatively impact maize health and yields. We conducted a long-term (11-year) field experiment in the black soil region of Northeast China to analyze the effects of different cropping systems on maize yield and rhizosphere soil fungal community structure and function. The experiment included three cropping systems: continuous maize cropping (CMC), maize-soybean rotation (MSR), and maize-soybean intercropping (MSI). MSI and MSR resulted in a 3.30-16.26% lower ear height coefficient and a 7.43-12.37% higher maize yield compared to CMC. The richness and diversity of rhizosphere soil fungi were 7.75-20.26% lower in MSI and MSR than in CMC. The relative abundances of Tausonia and Mortierella were associated with increased maize yield, whereas the relative abundance of Solicoccozyma was associated with decreased maize yield. MSI and MSR had higher proportions of wood saprotrophs and lower proportions of plant pathogens than CMC. Furthermore, our findings indicate that crop rotation is more effective than intercropping for enhancing maize yield and mitigating soil-borne diseases in the black soil zone of Northeast China. This study offers valuable insights for the development of sustainable agroecosystems.

Effects of Conservation Tillage on Agricultural Green Total Factor Productivity in Black Soil Region: Evidence from Heilongjiang Province, China

The implementation of conservation tillage is crucial for the preservation and utilization of black soil. This study examined 297 new agricultural management entities in five pilot counties in the black soil region of northeast China. Using the SBM-Undesirable model, this study measured and evaluated the agricultural green total factor productivity (AGTFP) of these entities. We further employed the Tobit model to explore the impact of conservation tillage on the AGTFP. The findings revealed that the average AGTFP value of the sample entities was 0.4364, indicating a generally low degree of AGTFP that exhibited significant variation. Improvement in input indicators (such as machinery) and undesirable output indicators (such as net carbon emissions) was particularly needed. Additionally, conservation tillage had a significant positive impact on AGTFP, with a higher number of applied technologies correlating with increased productivity. Material subsidies for conservation tillage offered greater direct cost relief and had a stronger positive effect on AGTFP in comparison with cash subsidies. Furthermore, apart from policy factors, key production and operation characteristics—such as access to agricultural materials—also significantly influenced AGTFP. The results of this study offer a valuable decision-making framework and scientific reference for countries in black soil regions worldwide, enabling them to enhance the conservation and sustainable utilization of this vital resource.

Fertility and ecotoxicological condition of light gray forest soils of the Ivanovo region

The results oflong-term monitoring of light gray forest soil for agricultural purposesin theIvanovo region are presented, which was carried outto establish the level of fertility according to the mainagrochemical indicators, the content of mobile forms of trace elementsand sulfur, the ecotoxicological state according to the content ofgross and mobile forms of heavy metals, arsenic, caesium-137 andstrontium-90.The average values of the indicators, their levels ofchange and trends in changes in the metabolic and hydrolyticacidity of the soil, availability of organic matter, mobile formsof nitrogen, phosphorus, potassium, exchangeable calcium, magnesium and other bases,mobile forms of boron, copper, zinc, molybdenum, cobalt, manganese andsulfur have been established.According to the content of traceelements in the soil, the needs for the use ofmicronutrients are determined.Changes, concentrations and trends in the mobileforms of cadmium, lead, copper, zinc, nickel, chromium, mercury andarsenic in the soil have been determined.The study establishedbackground values, changes and trends in the specific activities ofcaesium-137 and strontium-90, the density of their contamination of thesoil of the site and the power of the exposuredose of gamma radiation.According to thePearson–Spearman correlation coefficients,the peculiarities of the influence of the content of organicmatter, the level of acidity and the capacity of cationexchange on the content of mobile forms of trace elements,sulfur, gross and mobile forms of metals and radionuclides wereestablished.

Effect of Low Molecular Weight Organic Acids and Liming on Phosphorus Adsorption in Acidic Tea Soils in the Black Sea Region, Türkiye

ABSTRACT Agricultural productivity is significantly hindered by the limited availability of phosphorus in acidic soils due to the presence of aluminum and iron phosphates. Soil liming is commonly employed to enhance soil fertility. However, modifying the pH might also impact the interactions involving existing soil organic matter, leading to changes in the effective concentrations of competing low-molecular-weight acids (LMWOACs) participating in phosphorus adsorption. This study explored the impacts of citric, oxalic, and malic acids in acidic soils from tea cultivation regions within the Eastern Black Sea. These soils had undergone various levels of liming and were incubated for 15 months to assess their effects on phosphorus (P) adsorption in 7 acidic soils. The experimental sorption data were utilized to calculate the soil Langmuir and Freundlich adsorption parameters. In addition, the influences of organic acids and liming levels on the Freundlich and Langmuir model parameters were subjected to ANOVA analysis. The findings indicated that citric acid demonstrated the highest efficiency in diminishing phosphorus adsorption among the tested organic acids, followed by oxalic and malic acids. Three carboxyl groups (−COOH) in citric acid facilitated the formation of more complexes with adsorbed phosphorus on the soil surface. Furthermore, the 100% LR ratio of liming notably decreased phosphorus adsorption, especially in the lower end of the isotherms. Therefore, it can be concluded that the combination of LMWOACs and liming treatments could be used to overcome P deficiency in acid soils with very high P sorption ability.

The effect of land use and land cover on soil carbon storage in the Yellow River Delta, China: Implications for wetland restoration and adaptive management

Gaining a comprehensive understanding of the effect of land use/land cover (LULC) and soil depth on soil carbon storage, through the manipulation of external carbon input and turnover processes, is crucial for accurate predictions of regional soil carbon storage. Numerous research investigations have been conducted to examine the impact of LULC on the storage and cycling of carbon in the surface soils of coastal wetlands. Nevertheless, there remains a dearth of understanding concerning the implications of this phenomenon on subterranean soils, a crucial factor in discerning the capacity for carbon sequestration in coastal wetlands and implementing measures for their preservation. The study focused on the Yellow River Delta (YRD) in China, which serves as a representative model system. It aimed to assess the impact of LULC as well as soil depth on carbon storage. This was achieved by a combination of remote sensing interpretation and field samplings. The findings of the study indicate that there was an increase in soil organic carbon storage with both the area covered and the depth of the soil across the four different land use types, namely forest, grass, tidal flat, and cultivated land. Cultivated land was identified as the predominant LULC type, encompassing 41.73% of the entire YRD. Furthermore, it accounted for a substantial carbon storage of 76.08%. In comparison to soil layers at depths of 0–20 cm and 20–40 cm, 40–60 cm was discovered to have the maximum carbon storage, accounting for 42.29% of total carbon storage. Furthermore, one of the main factors influencing carbon storage is salinity, which shows a negative association with carbon storage. Moreover, the aforementioned findings underscore the significance of the conjoined physical and chemical properties induced by LULC in influencing the dynamics of soil carbon. This suggests that the inclusion of deep soil carbon in the estimation and restoration of soil carbon storage is necessary. This inclusion will support the realization of the United Nations' “Toward Zero Carbon” effort and facilitate the implementation of China's national carbon neutrality objectives.

Organic carbon estimation in a regional soil Vis-NIR database supported by unsupervised learning and chemometrics techniques

The main assumptions of this study were: (i) that spectrally similar soils are similar according to SOC content; and (ii) that using spectral-based clustering might enhance the quality of the prediction model. A total of 939 sample's soil spectral data and SOC content were selected from the regional soil Vis-NIR database of Dalmatia, Croatia. The spectral dataset was partitioned into distinct clusters using unsupervised learning (UL) techniques: Principal Component Analysis (PCA) and Fuzzy C-means (FCM) method. The ellipsoidal shape of the soil spectral data set was best separated into three clusters, indicating a reasonable quality of clustering as seen by the Silhouette score of 0.57. The most important wavelengths for clustering were at the following ranges: 1980–2025 nm, 1900, 735–775, 490–530, 1200, 2100, 2200, 2130, 2400 485, and 440 nm. The identified clusters had mean SOC content values of 22.25, 13.36, and 17.29 g C kg−1. At a significance level of 0.05, these values exhibit a statistically significant difference. The FCM clustering enhanced PLSR model's precision as measured by the Prediction Interval (PI). However, it had little impact on accuracy for SOC predictions as assessed using the Residual prediction deviation (RPD). Our models are suitable for performing approximate or preliminary screenings for the prediction of SOC content. Therefore, we recommend using UL techniques and chemometrics combined with Vis-NIR spectroscopy to supplement conventional SOC content laboratory analyses.

Provenance of soil parent materials in relation to regional environmental changes in the Songnen Plain, Northeast China

Parent materials have a strong control on soil formation process and soil properties, understanding their provenance can provide important information for soil genesis, classification, and regionalization. The Songnen Plain in northeast China has large areas of Phaeozems and Chernozems, popularly known as “black soils”, but their parent material provenance and sedimentary processes are still unclear. Therefore, this paper analyzes the types and formation process of soil parent materials in the context of regional environmental changes. This analysis is based on the characteristics of grain size distribution and quartz particle morphology at the regional and profile scales. The results indicate that aeolian loess is the predominant parent material. For instance, the surface of quartz particles exhibits characteristics indicative of mechanical impact, which is produced during the process of wind transportation. The particle size distribution curve displays a bimodal pattern, and the soil particle size tends to become finer from west to east. However, in some areas, the soil is influenced by river or lake sediments. The main source areas of aeolian deposits are likely the Gobi and sandy land in the upwind direction of the study area, while the Songhua River alluvial deposits only provide source material in local areas. High-resolution grain size analysis and K-feldspar single-particle OSL chronology show that from the Last Glacial Maximum to the Early Holocene, far-source materials dominated the deposition process. In the Middle Holocene, climate warming increased the frequency of dust activities and accelerated the deposition process. In the late Holocene, climate fluctuations and intensified human activities led to more intense dust storms in the provenance area, which in turn promoted the continuous accumulation of parent materials for soils that developed into Phaeozems and Chernozems.

Bridging ecological processes to diversity formation and functional profiles in belowground bacterial communities

Revealing the generation and maintenance of biodiversity is a central goal in ecology, but how dispersal, selection, and regional taxon pool size shape soil microbial communities is not well understood. Here, we examined how dispersal and environmental selection affected soil bacterial diversity and their related metabolic functions by leveraging large-scale cross-biome soil surveys of ∼ 1,400 samples from diverse ecosystems across China, including agricultural, forest, grassland, and wetland soils. Our results showed that high dispersal increased α-diversity and decreased β-diversity, whereas strong selection generated the opposite pattern in various ecosystems. This is likely due to dispersal enabling species access to otherwise unreachable habitats, and environmental selection excluding non-adapted species from communities. The α-diversity increased with γ-diversity, whereas β-diversity did not covary. We also showed that bacterial phylotypes positively associated with dispersal and selection exhibited distinct metabolic diversity. Dispersal-induced phylotypes, which were abundant in agricultural soils, exhibited more metabolic diversity in fructose and mannose, starch and sucrose, and nitrogen metabolism. Conversely, selection-induced phylotypes, dominated in wetland soils, were primarily associated with sulfur and methane metabolism. In addition, the complexity of taxon associations increased when communities had higher selection increasing β-diversity. Our study establishes the predictive links of ecological processes to microbial diversity, metabolic functions, and taxon coexistence, thus facilitating a better understanding of the mechanisms underlying biodiversity generation and conservation.

Effect of reinforcement layer on dynamic wetting behavior and accumulative deformation of granite residual soil subgrade

This paper contributes to investigate the impact of reinforcement layer on the dynamic wetting behavior and accumulative deformation of granite residual soil subgrade of expressways in southern China. The wetting test combined with vehicle test and vibration test were conducted in two selected test sections with a reinforcement layer (WRL) and without a reinforcement layer (NRL), respectively. The influence of vehicle speed, moving load, repeated loading, and loading number on the dynamic stress, dynamic acceleration, and dynamic displacement of both the NRL and WRL subgrades was explored under different wetting conditions. The impact of the wetting number and traffic loading on the time-domain characteristics of the dynamic response and the accumulative deformation were revealed. The results indicate that the WRL subgrade can effectively reduce the dynamic response compared to the NRL subgrade. The influence depth of the WRL subgrades is 1.3 m, while the influence depth of the NRL subgrades is 3.3 m. Dynamic stress, dynamic acceleration, and dynamic displacement increase with increasing the wetting number, moving load, and repeated loading. The peak values of the dynamic stress and dynamic acceleration time-domain curves for the NRL subgrade are 27 % and 24 % higher than those of the WRL subgrade, respectively. At 3 million loading numbers, the accumulative deformation of the NRL subgrades is 53.7 % higher than that of the WRL subgrade. The dynamic stress, dynamic acceleration, and dynamic displacement of the NRL subgrade are generally higher than those of the WRL subgrade. The predictive models are established to correlate the wetting, dynamic load, and the dynamic response for both NRL and WRL subgrades. The dynamic stress, dynamic acceleration, and dynamic displacement measured in the vibration test are generally higher than those measured in the vehicle test. The research results provide a reference for the design of durability subgrade in granite residual soil regions.

Effect of Land Use Type on Soil Moisture Dynamics in the Sloping Lands of the Black Soil (Mollisols) Region of Northeast China

This study investigates the spatial and temporal heterogeneity of soil moisture on slopes of China’s northeastern black soil region, focusing on the effects of terrain adjustment and vegetation. Soil moisture dynamics in the 0–60 cm soil layer were measured at 10 cm intervals using the TRIME-PICO64 TDR® device on slopes with similar gradients representing three land use types: transverse ridge tillage (TRT) farmland, terraced fields (TFs) farmland, and pure forest woodland (WL). The results indicate significant variations in soil moisture content and water storage across different land use types in the order of TF > TRT > WL. The study further identified that soil bulk density, porosity, and water-holding indicators were in the order of WL > TF > TRT, inconsistent with the soil moisture results, indicating that soil quality cannot be the sole reason for the differences in moisture. The moisture differences between farmland types (TRT and TF) and WL are substantial, especially during the rainy season. In the rainy season (0–60 cm) and the dry season (30–60 cm), significant differences in moisture content are observed (p < 0.05). Significant differences in moisture content between farmland types are found at 0–40 cm during the rainy season and at 0–10 cm during the dry season. In the rainy season, soil moisture for TRT and TFs first decreases from 26.76% and 30.85% to 22.44% and 25.38%, then slightly increases to 27.01% and 27.07% along the slope. Meanwhile, WL displays the opposite pattern on upper, relatively steep slopes, with soil moisture increasing from 16.66% to 17.81%, and exhibits a pattern of change similar to TRT and TFs on lower, gentler slopes. TFs consistently show higher soil moisture and water storage at all slope positions than TRT and WL. TFs improve soil quality, reduce erosion and sedimentation, and shift the lowest soil moisture content to a lower slope position. During the dry season, soil moisture differences between slope positions for TRT and WL were small. In general, terracing can effectively modulate moisture distribution along slopes, increasing moisture by an average of 0.26~12.43%, while afforestation, despite improving soil quality, leads to an 18.14~31.13% reduction in soil moisture content, with the impact being particularly significant during the rainy season. These findings provide important insights for optimizing land use and ecological construction, including keeping the balance between soil and water conservation, especially for sub-humid slope terrain areas.

Developing ecological protection redline policy for land use pattern optimization in the typical black soil region of Northeastern China

Typical black soil regions in Northeastern China (TBSN) are facing problems of degradation of ecosystem services (ESs) and spatial conflicts between cropland and ecological land. Ecological Protection Redline (EPR) policy is one of the first national policies to utilizing multiple ESs. However, there is no standardized framework of delineation and validation for TBSN. In this study, the framework of Ecological Protection Redline delineation was further improved in three aspects of the ecosystem, namely, service function, ecological sensitivity, and biodiversity. Specifically, the framework considered the conflict between high-quality cropland and ecological land in the TBSN. We examined EPR effectiveness by comparing ESs and trade-off/synergistic relationships of different land use scenarios for 2035. The results show that 1) the EPR delineation threshold for each key indicator was determined to be 15%, considering the quality level of cropland. The ecological redline area of 89,593.63 km2 was identified, which was concentrated in the southwestern part of the Mengdong typical black soil subzone and Songnen typical black soil subzone. 2) Compared to the current ecological protection scenario and current ecological protection redline scenario, the optimized EPR scenario was the best solution to guarantee the sustainable development of the TBSN, maximizing ESs, weakening trade-offs, and strengthening synergistic relationships between them. The results of the study provided a theoretical basis for land use planning and the scientific management of ecosystems in the TBSN.

Assessment of potential human health, radiological and ecological risks around mining areas in northeastern Brazil.

Mining is responsible for the release of metallic pollutants and radioactive materials into the environment, which have the potential to disrupt ecosystems and pose significant risks to human health. Significant mining activity is concentrated in the municipality of Caetité (northeastern Brazil), where Latin America's only active uranium mine and significant iron ore deposits are located. Although previous studies have shown that the regional soil and water resources are highly contaminated by various toxic elements and that exposure to these elements is known to have adverse effects on human health, the health risks in this mining region have never been assessed. The aim of this unprecedented comprehensive investigation was to assess the health, radiological and ecological risks in this mining region, which is home to nearly 100,000 people. To achieve our goal, soil and water samples were collected in the vicinity of the mines and in the main settlements in the region. Fifteen metallic toxic elements were determined using Instrumental Neutron Activation Analysis and Inductively Coupled Plasma Optical Emission Spectrometry. The HERisk code, which follows the main methodological guidelines for risk assessment, was used to quantify human health, radiological and ecological indices. The average values of the total risk and cancer risk indices indicated that region falls into the moderate risk category (1.0 ≤ HItot < 4.0). However, 63% of the sites had high risk values, with Fe, Co and As being the metals contributing most to total and cancer risk, respectively. Near the mining areas, the potential ecological risk can be considered extreme (PERI ≥ 600). The values of the calculated radiological indices correspond to typical values ​​in natural uranium areas. However, in the communities near the mine, the dose values are slightly above the permissible limit (1 mSv y-1), so they must be continuously monitored, and risk mitigation measures must be taken.

The inversion of arid-coastal cultivated soil salinity using explainable machine learning and Sentinel-2

The escalating salinization of cultivated soil poses a significant threat to the ecological environment. It is imperative to establish a monitoring system and mitigate the spread of salinization in arid and coastal areas through remote sensing, incorporating high-precision cross-regional models for soil salt content inversion. This study focuses on typical saline-alkali soils in arid and coastal regions of China. Using Sentinel 2 data (including 6 bands and 27 spectral indices), along with soil texture, moisture content, temperature, precipitation, and digital elevation model (DEM) data to establish an arid-coastal salinity inversion model. Variable selection methods such as pearson correlation coefficient (PCC), variable importance in projection (VIP), gray relational analysis (GRA), and gradient boosting machine (GBM) were used, while using 9 models including adaptive boosting (Adaboost), extremely randomized trees (ERT), and light gradient boosting machine (LightGBM). The best model was further elucidated using the Shapley additive explanations method. Results indicate that the common sensitive characteristic variables of arid-coastal areas were spectral indices and soil properties in PCC, the spectral variable bands and indices in VIP, and all variables in GRA and GBM. The best inversion model GBM-ERT (R2 = 0.91, RMSE = 1.06) in arid areas exhibited higher accuracy than the best inversion model GBM-Adaboost (R2 = 0.77, RMSE = 1.74) in coastal areas. The arid-coastal inversion model PCC-LightGBM demonstrated the best inversion performance (R2 = 0.64, RMSE = 2.29) and simulation performance in arid (R2 = 0.67) and coastal areas (R2 = 0.63). Dead fuel index (DFI) had the most significant impact on model prediction (0.89) and the second ratio index (RI2) contributed the highest relative importance (18 %) to the model. Our analysis indicates that the arid-coastal model of PCC-LightGBM established using common characteristic variables, can effectively monitor large-scale soil salinity.

A method for estimating the bulk density and particle density of granite residual soil based on the construction of pedotransfer functions

AbstractParticle density (ρs) and bulk density (ρb) are key factors in the calculation of total soil porosity. However, direct measurements of ρs and ρb are labour‐intensive, time‐consuming, and sometimes impractical. Pedotransfer functions (PTFs) provide alternative methods for indirect estimation of ρs and ρb. In this paper, the accuracy of typical 12 ρs and 9 ρb PTFs was evaluated using easily measurable soil properties (sand, silt, clay, and soil organic matter (SOM) content) from granitic residual soils collected from six study areas in subtropical China, and the accuracy of PTFs constructed based on multiple linear stepwise regression (MSR) and machine‐learned algorithms (backpropagation neural network, k‐nearest neighbour algorithms, random forests, support vector machines, and gradient boosted decision trees) was compared to determine the accuracy of PTFs. The results show that typical PTFs have poor accuracy (R2adjusted &lt; 0.020) and are not applicable to the indirect estimation of ρs and ρb in granitic residual soils. The PTFs constructed by machine learning algorithms all performed better than MSR, with the highest estimation accuracy of the PTFs constructed by the random forest algorithm, with R2adjusted values of 0.923 and 0.933 for the ρs and ρb PTFs, respectively, and root‐mean‐square error of 0.020 g·cm−3 and 0.023 g·cm−3, respectively. Compared with MSR, the random forest algorithm has greater accuracy and eliminates the restriction of PTFs on predictors, which provides support for understanding the changing rules of ρs and ρb in granite residual soils in subtropical regions, evaluating soil quality and improving soil structure.

Analysis on the cooperative variation law of pile-soil temperature field in Island permafrost region

To determine the cooperative variation laws of temperature fields in bridge concrete piles and the surrounding frozen soil during the freezing process in high-latitude, low-altitude insular permafrost regions, we utilized a practical bridge construction project within the frozen soil area of the Daxing'an Mountains, China. This served as the foundation for developing a method to remotely and dynamically monitor the temperatures of piles and soil in permafrost regions, enabling continuous, automatic monitoring of pile-soil temperature data. Employing this automatic temperature monitoring system, we collected temperature data from two 15-m-long concrete bored piles before and after freezing, and monitored the freezing process of the pile foundations in real-time. The cooperative variation laws of the pile-soil temperature field over time were summarized, and a calculation equation for the pile foundation's freezing time was established based on finite element analysis results. Monitoring and analysis reveal that under the influence of the frozen soil temperature field, the pile foundation initially freezes from the bottom up in a unidirectional manner. When the atmospheric temperature falls below 0 °C, the pile foundation freezes simultaneously from both the upper and lower directions. Post-freezing, the internal temperature of the pile body aligns with the surrounding soil temperature, with a temperature difference of less than 0.1 °C at the same depth. For similar in-place temperatures, the freezing time for a test pile with a 1.2m diameter is 1.14 times that of a 1.0m diameter test pile. The range of the hydration heat effect of cement concrete extends 1–2 times the pile diameter.

Effects of Frozen Layer on Composite Erosion of Snowmelt and Rainfall in the Typical Black Soil of Northeast China

Composite erosion caused by snowmelt and rainfall causes considerable soil loss during spring thawing. However, research on the impact of frozen soil layers (FSL) on composite erosion is lacking. Therefore, indoor simulation experiments were conducted on soil conditions of 0 cm (unfrozen soil, FSLUN) and 3 cm thawing depths to explore the influence of FSL on composite erosion in the black soil region of Northeast China. Three snowmelt runoff (SR) discharges (0.34 L min−1, 0.5 L min−1, and 0.67 L min−1), three rainfall (RF) intensities (80 mm h−1, 120 mm h−1, and 160 mm h−1), and three snowmelt–rainfall interactions (SRI; 0.34 L min−1–80 mm h−1, 0.5 L min−1–120 mm h−1, and 0.67 L min−1–160 mm h−1) were used in this study. The results indicate that FSL advanced the initial erosion times of SR, RF, and SRI by 42.06%, 43.33%, and 45.83%, respectively. FSL increased the soil erosion rate (SER) of SRI by 1.2 (1.0–1.6) times that of unfrozen soil, which was smaller than that of SR (16.3, 5.6–25.0) and RF (1.7, 1.6–1.9), indicating that the interaction had an inhibitory effect on the increase in water erosion in the frozen layer. Under FSL and FSLUN conditions, RF erosion was 1.5–4.1 times and 14.5–24.3 times greater than SR erosion. The SRI erosion was not a simple linear superposition of multiple types of single-phase erosion; it had a significant nonlinear superposition amplification effect (SAE), with SAE of ~100% and ~300% under frozen and unfrozen soil conditions. Flow velocity (0.11 &lt; R2 &lt; 0.68), stream power (0.28 &lt; R2 &lt; 0.88), and energy consumption (0.21 &lt; R2 &lt; 0.87) exhibited significant (p &lt; 0.05) linear relationships with SER in both FSL and FSLUN. The research results deepen our understanding of the composite erosion process during the spring thawing period in the black soil region of Northeast China and provide a basis for the prevention and control of soil erosion in the region.

Multiresidues of pesticides in the particulate matter (PM10) emitted by rural soils of the semiarid pampas, Argentina. A potential source of air pollution

The aim of this work was to evaluate the presence of 40 pesticides in the PM10 emitted by rural soils of the semiarid region of Argentina. Six agricultural soils for grain production under no till and with high use of pesticides (AG), 5 agricultural soils for forage and grain production under conventional tillage (AFG) and 5 unpaved rural roads (RR) were sampled. The PM10 was generated using the Easy Dust Generator and it was collected with an electrostatic precipitator. The presence of 20 herbicides, 14 insecticides and 6 fungicides was analyzed in the soil and in the PM10. More than 70% of the pesticides analyzed were detected in the soil and in the PM10. All agricultural soils and 87% of RR soils showed at least one residue of pesticides. Multiresidues of pesticides were found in the 100% of PM10 emitted by rural soils. The mean number of pesticides was higher in the PM10 (7) than in the soil (5). Some pesticides were not detected in the soils but they were detected in the PM10 (triticonazole, carbofuran, metsulfuron methyl) and vice versa. In general, the concentrations of herbicides were higher in the PM10 than in the soil, while the concentrations of insecticides and fungicides were lower in the PM10 than in the soil. These results suggest that the concentrations of pesticide in the PM10 (inhalable fraction) should be used instead the concentrations of pesticide in the soil to calculate the exposure factor to pesticides by dust inhalation. This study provides the initial evidence of the presence of multiple pesticide residues in PM10 emitted by rural soils under different land management. Also confirms that the PM10 is a potential source of air contamination with pesticides. Future studies should be driven to measure the concentrations of pesticides and their dynamics in the PM10.

Resistome Signature and Antibiotic Resistance Mechanisms in Rhizospheric Soil Bacteriomes of Mecca Region, Saudi Arabia: Insights into Impact on Human Health.

The objective of this investigation is to ascertain the distinctive profile of the rhizospheric soil resistome within the Mecca region, while also evaluating the potential risks associated with the horizontal transfer of resistome determinants to the open environment and human clinical isolates. We have made metagenomic whole-genome shotgun sequencing for rhizospheric microbiomes of two endemic plants, namely Moringa oleifera and Abutilon fruticosum. The rhizospheric resistomes of the two plants and the abundance of antibiotic resistance genes (ARGs) were identified by cross-referencing encoded proteins with the comprehensive antibiotic resistance database (CARD). The identified ARGs were then analyzed for their antimicrobial resistance (AMR) mechanisms. Predominantly within this soil are the two bacterial species Pseudomonas aeruginosa and Mycobacterium tuberculosis. These opportunistic human pathogens are implicated in respiratory infections and are correlated with heightened mortality rates. The most prevalent array of ARGs existing in this soil comprises mexA, mexC, mexE, and cpxR, associated with mechanisms of antibiotic active efflux, along with ACC(2), ACC(3), AAC(6), and APH(6), in addition to arr1, arr3, arr4, iri, rphA, and rphB, implicated in antibiotic inactivation. Furthermore, vanS, vanR, and vanJ are identified for antibiotic target alteration, while rpoB2 and RbpA are noted for antibiotic target replacement and protection, respectively. These mechanisms confer resistance against a diverse spectrum of drug classes encompassing fluoroquinolones, aminoglycosides, glycopeptides, and rifampicins. This study underscores the potential hazards posed to human health by the presence of these pathogenic bacteria within the rhizospheric soil of the Mecca region, particularly in scenarios where novel ARGs prevalent in human populations are harbored and subsequently transmitted through the food chain to human clinical isolates. Consequently, stringent adherence to good agricultural and food transportation practices is imperative, particularly with regard to edible plant parts and those utilized in folkloric medicine.

Assessment of the Levels of Pesticide Residues and Trace Metal Elements (TME) in Soils in the Cotton-Growing Region of North-West Benin

ABSTRACT The objective of the study was to evaluate the levels of pesticide residues and trace metal elements (ETM) in the soils of the cotton-growing zone in north-west Benin. The soils under cotton, maize and soybean were retained in a Complete Random Block design with 12 repetitions. 36 sites were sampled, with 12 of them being allocated to each crop. The analysis involved determining permethrin, cypermethrin, and glyphosate from soil samples taken by HPLC. The determination of Cd and Pb was carried out by mass spectrometry with inductively coupled plasma after organic matter destruction. A analysis of variance was used to compare soil types with the data obtained. Linear regression equation models were created to estimate trace metal elements values based on pesticide residue values. The results showed that the average amounts of permethrin (0.61 ± 0.03 µg/mg), cypermethrin (0.69 ± 0.07 µg/mg), glyphosate (0.82 ± 0.01 µg/kg), cadmium (Cd) (1.78 ± 0.21 µg/kg), lead (Pb) (1.04 ± 0.14 µg/kg) were higher (p < 0.05) in soils under cotton crops. As for lead, it can only be estimated using permethrin (Pb = 0.18 + 0.37 Per) or cypermethrin (Pb = 0.24 + 0.34Cy) or both with high determination coefficient R2 (R2= 82.01%).

Effect of Fertilizers, Seeding Rates of the Legume Component and Weather Conditions on Yield and Accumulation of Plant Residues of LupineCereal Mixtures on Grain in the Center of the NonChernozem Region

On mediumcultivated mediumloamy sod-podzolic soils of the Central NonChernozem region, well provided with mobile phosphorus and potassium (IV–V class), the cultivation of lupine–cereal mixtures for grain with the participation of narrowleaved lupine varieties Ladny, spring wheat, barley and oats varieties of Nemchin breeding after grain precursors in a changing climate ensured grain production in an average of 5 up to 3.0–3.7 t/ha with a share of the legume component of 29–57% and the remaining dry mass of plant residues in the soil up to 6–8 t/ha with the accumulation of total nitrogen in it up to 40–60 kg/ha and biological – 12–17 kg/ha. In arid conditions (GTK = 0.80–0.92), a mixture of lupine and barley was distinguished for the better in terms of yield and weight of plant residues, and in case of waterlogging (GTK = 2.47) – mixtures with oats and spring wheat. The inclusion of liquid micronutrients of organic nature in the technological process with a stimulating effect for non-root top dressing eliminated the need for pre-sowing application of nitrogen fertilizer and, in conditions of moderate aridity, increased grain yield, depending on the composition of the mixture, to 3.9–4.9 t/ha (by 53–59%), the yield of plant residues – up to 7–11 t/ha (by 54–139%) and in them there is an accumulation of symbiotically bound nitrogen – up to 15–25 kg/ha or 5–8 times more than without their use.