Soil Type Research Articles

The Multifaceted Soils of Himachal Pradesh, India: Types and Characteristics

The soils of Himachal Pradesh face a multitude of pressing issues that threaten their health and agricultural productivity. The diverse geographical features, temperature regimes and biological zones of Himachal Pradesh have resulted into a vast range of soil types in the state. Alpine, forest, alluvial and sub-mountain soils are the four major soil categories into which the state's soils can be generally divided. Only a particular species and adapted plants can thrive in the extreme weather circumstances of alpine soils, which are located at higher elevations and possess soils having thin, stony and acidic in reaction. The mid-hill areas are dominated by forest soils which are distinguished by their high levels of organic matter and nutrients. These soils support luxuriant vegetation and make effective agricultural methods possible. Alluvial soils, which are mostly found in river valleys and are deposited by ravine systems are extremely rich and perfect in fertility and suitable for growing a range of crops including vegetables, rice and maize. Located in the foothills, sub-mountain soil exhibits a blend of traits from alluvial and forest soils, thus providing a range of uses for horticulture and agriculture. In addition to supporting a diverse array of plant and animal life, Himachal Pradesh's varied soil types are vital to the region's agricultural economy. One of the biggest problems is soil erosion, which is made worse by the steep terrain and abundant rainfall in the area. This results in the loss of topsoil and decreased fertility. Deforestation, overgrazing, and unsustainable farming methods all contribute to land degradation, which further reduces biodiversity and soil quality. Furthermore, crop development is impacted by soil acidity in high-altitude regions, which restricts nutrient availability. However, these issues need efficient conservation measures and soil management techniques. In order to maintain Himachal Pradesh's rich biodiversity and agricultural potential for future generations, sustainable agricultural development and environmental protection in this ecologically sensitive area depend on an understanding of the complex soil dynamics. Addressing these interconnected issues requires a comprehensive approach, emphasizing sustainable land management practices, community engagement, and restoration efforts to preserve the vital soil resources of this ecologically sensitive region.

Comparative assessment of SoilGrids system with regional soil data for advancing ecosystem reporting in Bulgaria

The aim of this study is to test the suitability of the SoilGrids system for ecosystem reporting, research and monitoring. The study is conducted in the Rila Mountains in Bulgaria, an area characterised by diverse ecological factors. We propose a methodological approach to compare SoilGrids predictions with independent point observations, addressing issues of inconsistency across survey layers when combining data from different sources. The comparative analysis is discussed in respect to point data, soil type, altitude and climate. The results show that the SoilGrids represents the main soil parameters well in terms of their dynamics over the altitudinal range. There is a good agreement between the observed and predicted values for the averages of the parameters - bulk density, coarse fraction, soil organic carbon (SOC) content and SOC stock. The average measured SOC stock (0-30 cm) is 58.54 t/ha, while the average predicted SOC stock (0-30 cm) is 55.38 t/ha. However, the study also showed that the predicted values for nitrogen content are almost two times higher than the observed figures and the pH values from the SoilGrids are less acidic than those measured in the field.

Spider waste enhances soil nutrient content, soil respiration, and plant growth

Abstract Predators can alter the movement of nutrients through ecosystems by depositing waste products following predation. Whilst the benefits of predator waste for large predators (e.g. bears) or dense accumulations of predators (e.g. seabirds on islands) seem clear, less is known about whether smaller, solitary predators can have measurable effects on local ecosystem processes. In separate experiments with web‐building and wandering spiders, we tested if the presence of predators affected soil nutrient content, soil respiration, soil microbial communities, and plant growth. In the first experiment with black widow spiders, total nitrogen and nitrate were not affected by spider presence, but ammonia and phosphorus were higher from soil under the edge of the spider web than soil away from the spider. Soil respiration and plant growth were both higher in soil collected from under the spider retreat compared with soil collected away from the spider web. In a second experiment with wolf spiders, we tested for interactions between spiders and soil microbial communities. There were positive effects of wolf spider presence on all soil nutrients and there were interactions between spiders and soil type (i.e. field‐collected versus autoclaved) for total carbon, total nitrogen, nitrate, and pH. Spider presence and soil type also affected soil respiration and spider presence had a large effect on the composition of the microbial community of the soil. There were also positive effects of wolf spider presence on plant biomass and plant height, with a significant interaction between spiders and soil type for plant height. Overall, our results show that two spiders with different life histories (i.e. web‐building and wandering) both have significant positive effects on plant growth through the deposition of their waste products. These effects may occur through the direct deposition of nutrients and changes in soil microbial communities. Although, further work is needed to resolve these interactions. Read the free Plain Language Summary for this article on the Journal blog.

Soil available phosphorous and potassium stocks related to environmental properties, land uses and soils

Abstract Soil available phosphorus (SAP) and potassium (SAK) are indispensable for crops, and their stocks are important for food production needed for a growing global population. This study analysed 991 soil profiles across a large part of Romania covering forestland, grassland and cropland in almost all ecological regions. This study investigated SAP and SAK stocks for different soil depths and characterized their magnitude and variability within land uses under different environmental ecosystems, soil classes and soil types, for a better soil and land management under a temperate-continental climate. Cropland soils present the highest SAP and SAK stocks. Chernozems, Phaeozems and Vertosols possess the highest SAP and SAK stocks in Romania, representing the largest country's pool. Both SAP stocks and SAK stocks are significantly correlated with basic environmental properties, existing direct correlations between SAP, SAK, soil organic carbon (SOC) and total nitrogen (TN) stocks. For all land uses, SAP and SAK stocks correlated significantly and directly with each other, as well as with annual temperature, clay content, pH and sum of base cations, and inversely with altitude, slope and annual precipitation. The best predictive values using multiple regression models and basic environmental driving factors were found for forestland stocks of SAP and SAK, followed by grassland stocks, while the lowest prediction occurred for cropland stocks, probably due to the long-term additional nutrient input performed by farmers in cropland that changed the natural conditions otherwise present in grassland, and especially in forestland. Based on these results some management measures are discussed.

Changes in soil mechanical and hydraulic properties through regenerative cultivation measures in long-term and farm experiments in Germany

Regenerative agriculture has been associated with improved soil structure and soil fertility. However, conclusive evidence of its efficacy has remained elusive owing to a lack of long-term experimental studies. In this study, we assessed the impact of diverse regenerative agricultural measures on soil mechanical and hydraulic properties and indicators. Tested treatment factors included reduced tillage versus plowing, along with different levels of compost, mulch, and the application of ferments and compost tea. We measured in situ soil strength via soil penetration (from 0 to 0.8 m depth) and shear resistance (at 0.08 and 0.23 m depth) and assessed field-saturated hydraulic conductivity and ex situ soil aggregate stability (at 0.07 and 0.23 m depth). The experiments were conducted at five sites in Hesse, Germany, including one organic long-term experiment (LTE, since 2010) in Neu-Eichenberg and three organic and one conventional on-farm experiments to cover different soil types, weather conditions, and field practices. The soil types are classified as Luvisol and Vertic Cambisols, and the soil texture ranges from silt loam to silty clay loam. In the LTE, significant differences in aggregate stability and shear resistance were noted between treatments, with a higher geometric mean aggregate diameter at 0.07 m depth in 2021 and 2022 and a higher shear resistance at 0.19 m and 0.23 m in 2020 and in 2021, respectively, in the reduced tillage systems. However, no significant differences were observed among treatments for field-saturated hydraulic conductivity, which was overall very high, showing that reduced tillage did not negatively influence saturated infiltration, albeit bulk density is higher than in the conventionally plowed system. The soil penetration resistance was generally higher for the reduced tillage treatments across depths of 0.0–0.30 m, albeit not statistically significant (p > 0.05). Significantly higher water-stable aggregates and geometric mean diameters were observed for regenerative agricultural treatments in three of the on-farm experiments at a depth of 0.07 m. The shear resistance was significantly higher in regenerative agriculture units in specific years and depths. Although the outcomes are encouraging, the variability of the effects of reduced tillage and organic amendments in affecting soil properties highlights the need for further long-term research including farm trials. This is essential to fully understand the effects of regenerative practices on soil physical quality.

The Effect of Varying Compaction Levels on Soil Dynamic Properties and the Growth of Canola (Brassica napus L.)

Extremely low field emergence rates for canola are primarily attributed to soil compaction from field traffic during and after planting. This study aimed to determine the critical compaction level for canola emergence across different soil types. A laboratory experiment was conducted using sandy loam, silt clay, and clay soils, compacted to five levels (zero to four) using Proctor hammer drops after sowing canola (Brassica napus L.). The lab results were validated through two years of field experiments in sandy loam, applying four compaction levels (zero to three) using a tractor. Soil properties (bulk density and surface resistance) and canola growth parameters (plant emergence rate, count, height, and above-ground biomass) were measured. Zero compaction resulted in lower bulk density and surface resistance across all soil types. Laboratory results showed maximum emergence rates of 95% for sandy loam, 100% for silt clay, and 60% for clay, while field emergence rates were 63% and 87.59% in the first and second years, respectively, both at zero compaction. Recommendations include light or no compaction for sandy loam, and zero compaction for silt clay, while clay soil did not achieve the 80% emergence target at any compaction level. These results can assist agricultural producers in optimizing their seeding equipment setup and managing field traffic for canola production.

Management of soil phosphorous using phosphate solubilizing microorganisms: A sustainable approach

Phosphorus is crucial for plant growth and productivity, and its scarcity in soil negatively affects crop yields. A major portion of chemical phosphate fertilizer precipitates with soil minerals, making it unavailable for plant growth. Phosphate-solubilizing microorganisms play a pivotal role in enhancing phosphorus availability, facilitating better nutrient absorption, and ultimately boosting plant growth. This article presents a brief overview of the phosphorus status in Indian soil, discusses the various forms of phosphorus and its dynamics across different soil types, and analyses the factors involved, highlighting the importance of phosphorus management for sustainable agriculture. Physiological and molecular mechanisms of microbial phosphate solubilization provide deep insights into exploring PSMs for managing phosphorous in different soil types. It also provides a path for the necessity to explore the multifarious plant growth-promoting traits of PSMs underscoring its applicability for sustainable agricultural practices with viable economy. The mechanism of solubilization of phosphorus has been discussed to understand the role of microorganisms in different soils. The study highlights the role of significant microorganisms in developing tailored consortia of PSMs and other plant growth-promoting rhizobacteria (PGPR) based on the chemical composition of the soil, along with an integrated nutrient approach incorporating PSMs. This review offers valuable insights into harnessing PSMs and their practical applications, facilitating their broader adoption in agricultural systems to maintain soil health.

Investigating environmental and geographical factors affecting iodine concentrations in Australian wheat (Triticum aestivum L.) grain

Iodine is an essential micronutrient for human nutrition, though it is found in relatively low concentrations in many important crop species. Wheat (Triticum aestivum L.) is a common staple crop worldwide, and as such could be an important source of dietary iodine due to its widespread consumption. However, little is known about iodine concentrations in wheat grain grown under rainfed field conditions, nor the impact of growing region or environment on these concentrations. Therefore, this paper had three objectives; (1) quantify the iodine concentration in a popular variety of wheat cultivated across the wheat belt of three Australian States (Western Australia, South Australia and Victoria) over two winter seasons (2) determine the influence of distance from the coast, rainfall, elevation, soil type and pH and grain yield on wheat grain iodine concentrations and (3) identify geographical areas where iodine concentrations of wheat grains are low enough that biofortification with iodine would be advantageous for human health outcomes. We sampled iodine concentrations of a single cv. Scepter at 125 sites from the winter season 2020 (65 sites) and 2021(60 sites), to investigate environmental and geographical effects on wheat grain iodine concentrations. Iodine concentrations were measured using triple quadrupole inductively coupled plasma mass spectrometer (ICP MS/MS). We found that the elevation and the region (State) of growing sites were the most significant predictors of iodine concentration, along with the interaction between rainfall and topsoil texture. However, very low concentrations of iodine (5–24 μg/kg) were detected in all samples tested, indicating that even wheat grown under advantageous environmental and geographic conditions in southern Australia would be unlikely to represent an important source of dietary iodine. This emphasises the need to consider biofortification strategies to improve iodine concentrations in Australian grown wheat to improve the dietary uptake of this essential micronutrient by human consumers.

Growth trends of loblolly pine age five or less in relation to soil type and management intensity

We evaluated three objectives for loblolly pine (Pinus taeda L.) trees age five or less: 1) how height growth varies by soil type and silvicultural intensity, 2) the accuracy of predicted base-age 25 site index (SI25) using age one to five heights, and 3) if height dominance exhibited early in the rotation is maintained throughout the rotation. Data from 42 sites across the southeastern United States with an array of soil textures and management intensities (optimal, intensive, and operational) were used. Management intensity and soils significantly affected tree height. Coarse loamy soils were the most responsive to increasing management intensity. At age four, tree heights were greatest in the optimal group (4.63 m), followed by the intensive (4.31 m), and then the operational (3.06 m). Organic soils do not appear to respond to maximum management intensity. Predictability of SI25 was high especially starting at age four, with R2 values ranging from 0.27 for the age four intensive group to 0.78 for the age four operational group. The optimal group had the greatest slope with an expected increase of 2.61, 2.75, 1.88, and 1.78 m in site index per additional meter of height at ages two, three, four, or five, respectively. Data from six different study sites indicate, the tallest (class one) and smallest (class five) trees changed percentile class the least often over time. As early as age two, over 40 % of observations in classes one and five had zero changes in class through age 13. Young tree data were effective in predicting SI25, and height dominance appeared generally set early in the rotation.

Naturally Deposited Charcoal Enhances Water Retention Capacity of Subtropical Forest Soils

Charcoal, a byproduct resulting from incomplete combustion of biomass in fire events, can modify the physical properties of soil due to its high porosity and large surface area. To evaluate the impact of fire-deposited charcoal on soil hydraulic characteristics, soil–charcoal mixtures were analyzed to investigate the effects of different application doses (wt%: 0, 1%, 3%, 5%, 10% and 20%) of charcoal on soil bulk density (BD), porosity (total, capillary, and non-capillary), residual moisture after free drainage (RM), saturated water content (SC), and saturated hydraulic conductivity (Ks) of loamy and sandy soils collected from subtropical forests in south China. The results showed that the impact of charcoal on soil’s physical and hydraulic properties depends on the soil type and the application dose. The incorporation of charcoal significantly decreased the BD of sandy soil (p < 0.001), while a significant decrease in BD in loamy soil was only observed as a result of the higher application doses (10% and 20%) (p < 0.001). Charcoal application doses of 5% or higher led to a significant increase in the total porosity (TP) of sandy soil (p < 0.001) and doses of 3% and 20% resulted in a significant increase in the TP of loamy soil (p < 0.001). The capillary porosity (CP) of both sand and loamy soils significantly increased when charcoal was applied at doses of 3% or higher (p < 0.001). The minimum charcoal application dose that significantly increased the RM in sandy soil was 5%, while for loamy soil, the minimum effective dose was 10%. Charcoal applied at a dose of 3% significantly increased the Ks of sandy soil (p < 0.001), while no significant effect on Ks was observed for loamy soil (p > 0.05). Collectively, our findings suggest that fire-derived charcoal enhances the soil water-retention capacity in subtropical forests, with the effects becoming more pronounced at higher application doses and being particularly notable in sandy soil compared to loamy soil.

Can neotectonic faults influence soil air radon levels in the Upper Rhine Graben? An exploratory machine learning assessment

Radon (Rn) is a naturally occurring radioactive gas that poses a significant lung cancer risk. Subsurface fault zones can act as pathways for fluid and gas migration, potentially amplifying Rn accumulation. This study investigates the impact of fault zones on Rn concentrations within a 25 km2 area in the Northern Upper Rhine Graben, Germany — a region with available detailed geophysical exploration data and active neotectonic faulting. We conducted 597 Rn soil air measurements along precisely located fault zones, integrating a comprehensive range of environmental parameters. Utilizing the advanced machine learning model eXtreme Gradient Boosting (XGBoost) in conjunction with SHapley Additive exPlanations (SHAP) values, we dissected the influence of soil types, environmental factors, and proximity to fault zones on soil air Rn concentrations at a 1-meter depth. Our results reveal that clay-rich soils and cumulative 30-day precipitation are the primary drivers of elevated Rn levels. Proximity to fault zones also significantly influences Rn concentrations, though its impact is less pronounced than the factors mentioned above. Additionally, environmental factors such as wind speed, air pressure, and temperature exhibited lesser effects on Rn levels. The negligible influence of measuring devices and operating personnel increases confidence in data integrity in extensive environmental studies. This study demonstrates the effectiveness of integrating XGBoost with SHAP values to identify and quantify key factors influencing Rn concentrations. By providing a robust framework for enhancing Rn prediction models through machine learning, our findings contribute to improved risk assessments and mitigation strategies, thereby advancing public health and environmental management.

Enhanced remediation of acetochlor-contaminated soils using phosphate-modified biochar: Impacts on environmental fate, microbial communities, and plant health

Given that acetochlor (ACT) persists in soil for extended periods, disrupting microbial community structure and causing phytotoxicity to sensitive crops, this study investigated the potential of phosphate-modified biochar (PBC-800) to remediate ACT-contaminated soil. Incorporating 0.5 % PBC-800 into fluvo-aquic, red, and black soils increased their adsorption capacities by 80.4 mg g−1, 76.6 mg g−1, and 76.0 mg g−1, respectively. Even after six months of aging, the Kf values remained 1.6 to 5.1 times higher than in untreated soils. PBC-800 also accelerated ACT degradation across all three soil types, reducing residual ACT levels by 34.3 % to 76.4 % after 60 days, and shortening the degradation half-life by 5 to 7 days. High-throughput sequencing revealed that ACT reduced soil microbial diversity and disrupted community structure, while 0.5 % PBC-800 amendments promoted the growth of degradation-capable genera such as Rhodococcus, Lysobacter, and Gemmatimonas, enhancing microbial ecosystem stability. Furthermore, the amendment of soil with 0.5 % PBC-800 reduced ACT residue concentrations in maize and soybeans by 76.5 % to 82.9 %, and restored plant biomass, leaf chlorophyll content, and mesophyll cell ultrastructure to levels comparable to the control. Therefore, amending ACT-contaminated soil with PBC-800 mitigates ecological and environmental risks, boosts microbial activity, and safeguards plant health.

Isolation, Characterization, and Optimization of Culture Medium for Local Straw-Degrading Bacteria from Northeastern Black Soils of China

In order to solve the problem of low and poor straw degradation in typical black soil areas of Northeast China, the present study was carried out to screen the potential of in situ strains with cellulose degradation ability from black soils of Northeast China to play a role in the resourceful utilization of straw and the development of sustainable agriculture. The straw degradation potential of the strains was evaluated by combining sodium carboxymethyl cellulose plate screening and cellulase viability assay; the species identification of the strains was carried out by morphology, physiology, biochemistry, and molecular biology; and the basic medium formulation of the strains was optimized by Box–Behnken response surface methodology. Ten cellulose-degrading strains were identified: ZL-5, ZL-69, ZL-88, ZL-95, ZL-111, ZL-137, ZL-139, ZL-140, ZL-187, and ZL-216, of which ZL-139 had the highest cellulase production capacity, with a cellulase secretion of 7.8781 U/mL in the enzyme-producing medium. ZL-139 was identified as Bacillus cereus; the optimized best formulation was glucose—4.284 g/L, yeast extract—1.454 g/L, MgSO4—0.417 g/L, KH2PO4—0.5 g/L, KH2PO4—0.5 g/L, K2HPO4—1.5 g/L, and NaCl—1.0 g/L. In conclusion, strain ZL-139 has good potential for crop straw degradation and can be a candidate strain for a straw-rotting agent in northeast China, with promising prospects for development and utilization.

A Method to Determine the Optimal Period for Field-Scale Yield Prediction Using Sentinel-2 Vegetation Indices

This study proposes a method for determining the optimal period for crop yield prediction using Sentinel-2 Vegetation Index (VI) measurements. The method operates at the single-field scale to minimize the influence of external factors, such as soil type, topography, microclimate variations, and agricultural practices, which can significantly affect yield predictions. By analyzing historical VI data, the method identifies the best time window for yield prediction for specific crops and fields. It allows adjustments for different space–time intervals, crop types, cloud probability thresholds, and variable time composites. As a practical example, this method is applied to a wheat field in the Po River Valley, Italy, using NDVI data to illustrate how the approach can be implemented. Although applied in this specific context, the method is exportable and can be adapted to various agricultural settings. A key feature of the approach is its ability to classify variable-length periods, leveraging historical Sentinel-2 VI compositions to identify the optimal window for yield prediction. If applied in regions with frequent cloud cover, the method can also identify the most effective cloud probability threshold for improving prediction accuracy. This approach provides a tool for enhancing yield forecasting over fragmented agricultural landscapes.

Impact of Site Conditions on Quercus robur and Quercus petraea Growth and Distribution Under Global Climate Change

Climate change has significant natural and economic implications, but its extent is particularly challenging to assess in forest management, a field which combines both of the previous aspects and requires the evaluation of the impact of climate change on tree species over a 100-year timeframe. Oaks are among the tree species of significant natural and economic value in Europe. Therefore, the aim of this study was to analyze all oak stands in Poland and verify the hypothesis regarding differences between Quercus robur and Quercus petraea stands in terms of soil type, annual total precipitation, average annual air temperature, and the length of the growing season. Additionally, this study aimed to analyze the impact of these differences on the growth rates of both oak species and test whether climate change may affect oak stands. A database containing 195,241 tree stands, including different oak species with varying shares in the stand (from 10% to 100%), was analyzed. A particular emphasis was placed on Q. robur and Q. petraea. The results show that, although both oak species have a wide common range of occurrence, there are clear differences in their habitat preferences. Based on the ordinal regression analysis of selected oak stands, it was concluded that an increase in air temperature of 1 °C could impair the growth of Q. robur and slightly improve the growth of Q. petraea. This may indicate the possibility of expanding the geographic range of sessile oaks towards the east and northeast under warming climatic conditions, provided that appropriate moisture conditions are maintained.

Effect of Palm Oil Mill Effluent (Pome) Concentration and Soil Type on the Growth of Oil Palm (Elaeis guinensis Jacq) in Pre-Nursery

The place of research was carried out at Educational and Research Garden of the STIPER Agricultural Institute which is located in Maguwoharjo Village, Depok District, Sleman Regency, Yogyakarta, Indonesia. The research location is located 118 meters above sea level. This research was conducted between March to June 2024. Two components make up the factorial experiment used in the Complete Randomized Design (CRD). The soil type had three levels: A1 = latosol soil, A2 = regusol soil, and A3 = grumusol soil, was the first factor. Palm Oil Mill Effluent (POME) concentration was the second factor. It was consisted into four levels: X1 was the control (NPK fertilizer), X2 was 150 ml per polybag, X3 was 300 ml per polybag, and X4 was 450 ml per polybag. So there were 12 treatment combinations (3 x 4 = 12) with 4 repetitions, so all the experiment 48 plants. Analysis of variance (ANOVA) was applied at the significant level of 5% to check the observation data. Duncan's Multiple Range Test (DMRT) was then used at a noticeable 5% level if there was significant difference. The weight parameters of fresh roots and the amount of chlorophyll in the leaves are influenced by the interaction of the soil and POME concentration. The composition, regusol soil and POME 450 ml/polybag provide an optimal combination of treatments. The type of soil has an impact on the weight of fresh and dry crowns, the number of leaves, the chlorophyll content in the leaves, the volume of roots, and the height of the plant. The best type of soil is regusol soil. Plant height, root volume, fresh and dry crown weight, and leaf chlorophyll content are all affected by POME concentration. The concentration of POME 450 ml/polybag showed the best results.

Research on identification and zoning control of territorial spatial risk pattern based on deep learning: A case study of Shenzhen, China

In the era of globalization, digitalization, and diversification, currently societal cities face risks intertwined by uncertainty and complexity. Thus, it is crucial to address risks concerns to achieve modernization of spatial management. Moreover, how to scientifically identify the risk pattern of territorial space and how to map and control it in space becomes a critical and urgent issue to be addressed for achieving modernization of spatial management. Understanding the intricate relationship between land use, environmental factors, and population density is essential for identifying risk patterns that can inform effective disaster management strategies. By employing advanced analytical methods, this study aims to provide a comprehensive framework for recognizing and mitigating territorial spatial risks in an increasingly complex urban landscape. This study used a case study to conduct the unsupervised algorithm of stack autoencoder self-organizing map to analyze the distribution and spatial clustering of Shenzhen's land spatial risk pattern and reveal the driving mechanism of its risk pattern formation in detail. It was found that: (1) The overall territorial spatial risk pattern of Shenzhen presents a distribution trend of "high in the west and low in the east, high in the south and low in the north"; that is, I and II risk areas are clustered in the hilly areas in the northeast and IV and V risk areas in the coastal areas in the southwest; (2) Population density, land use intensity, seawater intrusion, geological disasters, relief amplitude, soil type, soil erosion intensity are the main driving forces for the formation of Shenzhen's territorial spatial risk pattern. In particular, seawater intrusion, population density and land use intensity, soil type were found having significantly synergistic impact on the risk pattern.

Divergent responses of forest canopy height to environmental conditions across China

As major components of terrestrial ecosystems, forest ecosystems play an important role in sequestering carbon and hence mitigating climate change. Canopy height is a crucial factor characterizing the structure and function of forest ecosystems, yet the driving mechanism of forest canopy height receives less attentions in China. Here, we utilize the satellite-based forest canopy height product with several environmental and climate factors (e.g. forest age, temperature, etc.) to delineate the spatial distributions of forest canopy height and its drivers in China at 1 km spatial resolution during the period of 2014 to 2018. The random forest is employed for identifying the dominant factors at province level, while Shapley additive explanations (SHAP) analysis is further incorporated at pixel-level to dig into the specific contributions of each driver. The results show that forest age primarily dominates the spatial distributions of forest canopy height across different forest ecosystems of China, followed by mean annual precipitation, soil type, and aspect. SHAP analysis further indicates that other factors, such as soil moisture and wind speed, also play critical roles to shape the spatial patterns of forest canopy height in China, which could not be revealed from province-level random forest analyses. Such results emphasize the priority of incorporating SHAP analysis with random forest to advance our understanding of forest canopy height distributions and benefit future projections. Our study highlights the necessity to characterize the spatial heterogeneity of forest canopy height, which is critical for accurate estimations of forest and even terrestrial carbon sink in China, facilitating the achievement of the goal of “carbon peak in 2030 and carbon neutrality in 2060”.

Comparative study of fenpropathrin and its main metabolite in soil-earthworm microcosms: Toxicity, degradation, transcriptome, and oxidative stress

This study comprehensively investigated the comparative acute toxicities, degradation, transcriptome, and oxidative stress induction of fenpropathrin (FEN) and its main metabolite 3-phenoxybenzoic acid (3-PBA)in soil-earthworm microcosms. FEN degradation half-life ranged from 19.09 to 28.52 days, and the peak-shaped trends of 3-PBA were also observed in different soil types. The LC50 values of FEN and 3-PBA were 12.75 and 7.49 μg/cm2, respectively, suggesting that 3-PBA was more toxic to earthworms. Furthermore, the sub-lethal toxicities indicated that 3-PBA exerted more prominent alterations in protein content, enzyme activity, lipid peroxidation, and oxidative stress in earthworms. Additionally, integrated biomarker response evaluations indicated that 3-PBA induced more prominent sub-lethal toxicity in earthworms than FEN. Finally, exposure to FEN and 3-PBA resulted in distinct differentially expressed genes (DEGs) in earthworms. Enrichment analysis revealed that these DEGs were predominantly enriched in purine metabolism and bile secretion pathways in earthworms. Moreover, the p53 signaling pathway, cell cycle, DNA replication, drug metabolism, and pyrimidine metabolism were also enriched in earthworms after exposure to FEN and 3-PBA. These results suggested that FEN and 3-PBA induced varying toxicities in earthworms. This study highlighted the systemic differences in the toxicities, degradation, transcriptome, and oxidative stress induction between FEN and 3-PBA in soil-earthworm microcosms. Our findings could be used for a comprehensive risk assessment of FEN and 3-PBA in the soil ecosystem.

Optimizing Voltage for Effective X-ray Computed Tomography Scan: A Study on Varied Soil Bulk Densities and Container Sizes

Numerous studies have highlighted the role of X-ray computed tomography (X-ray CT) in understanding root architecture. Nevertheless, setting definitive scanning parameters for diverse soils in varied container sizes remains challenging. This study investigates the influence of X-ray CT system voltage on the penetration capability in diverse soils and container sizes, focusing on two key parameters: (1) gray values, which indicate X-ray attenuation and contribute to image contrast, and (2) signal-to-noise ratio, a measure of image clarity. Five soil samples were collected from various depths within a soil profile to encompass bulk density values ranging from 1.34 to 1.84 g·cm−3 to conduct the experiment. Containers with dimensions of 6 × 6 × 6 cm³, 8 × 8 × 6 cm³, 10 × 10 × 6 cm³, 12 × 12 × 6 cm³, 14 × 14 × 6 cm³, and 16 × 16 × 6 cm³ were used. Voltage levels spanning 75 to 225 kV, in 25-kV increments, were applied to each sample. The observed gray values of the X-ray images were fitted using a logistic model of three parameters. Results showed that increasing voltage leads to enhanced penetration up to a plateau point, irrespective of soil density or container size. This plateau could potentially yield higher quality scans, given that lower voltages result in subdued gray values and reduced image contrast. Notably, it was observed that soil properties, including mineral composition, directly affect image gray values. This study established optimal voltage settings for specific soil types at fixed densities, offering valuable insights for researchers investigating soil–root interactions. Although the current findings are based on five soils, a more extensive sampling encompassing diverse soil textures and densities is necessary for a comprehensive understanding of X-ray penetration behavior across various soil types.