Search Results (1,113)

Soil compaction is considered as one of the main factors limiting plant growth. Understanding the variation in sap flow affected by soil compaction is of vital importance for precision agriculture. In this study, a two-year field experiment with three levels of soil compaction (i.e., NC, no compaction; MC, moderate compaction; and SC, severe compaction) was conducted in the black soil region of Northeast China. Results revealed that soil compaction had a significant impact on soil properties, soil water content, and plant growth parameters, which ultimately affected the sap flow rate of maize. The average daily sap flow rates of MC and SC decreased by 15.89% and 29.12% in comparison to those of NC in 2023, and decreased by 51.53% and 57.11% in comparison to those of NC in 2024, respectively. Net radiation and vapor pressure deficit were the two most important meteorological variables affecting sap flow rate. In addition, the relationship between sap flow rate and meteorological variables was independent of the level of soil compaction stress. Daily sap flow rate exhibited a strong linear relationship with leaf area index and stem diameter, but showed no significant correlation with plant height. Additionally, daily sap flow rate was well correlated with root length density in the 0–60 cm soil layer. Furthermore, daily sap flow rate was significantly affected by soil water content of the 0–60 cm soil layer, but there was no significant correlation between daily sap flow rate and penetration resistance. Moreover, cumulative sap flow rate was negatively correlated with soil bulk density in both the top layer (0–20 cm) and sub-layer (20–40 cm). Our results provide a scientific basis for understanding the relationship between maize sap flow and soil compaction. More precise and systematic characterization of soil compaction, especially in relation to root growth, is needed to explore the underlying mechanisms of soil compaction on plant sap flow in the future. Full article

Centella asiatica (L.) Urban or Asiatic pennywort is an important medicinal plant used in traditional medicine, cosmetic and pharmaceutical industries; it is also an indigenous vegetable in Asian countries. A total of 169 Centella accessions were collected from all regions of Thailand and assessed for 29 traits, including morphological traits, plant biomass, and centelloside contents. Experiments were conducted in two growing systems, soil and hydroponics, with two harvests every month. The centelloside concentrations were determined by high-performance thin-layer chromatography (HPTLC) procedure. Analysis of variance (ANOVA), correlation matrix, genetic parameters, principal component analysis (PCA), and hierarchical clustering were determined both across all environments and for each growing system separately. The ANOVA revealed significant differences in genotypes and growing systems, along with their interactions. Hydroponic culture produced three- to four-fold higher biomass than soil system while triterpenoid sapogenin concentrations were notably greater in hydroponics. Biomass-related traits showed strong positive correlations with centelloside yields, and genetic analyses revealed moderate to high heritability for these characteristics. PCA and cluster analyses classified accessions into four distinct groups, identifying elite genotypes with both high biomass and centelloside yield. These findings provide a solid foundation for targeted selection in Centella breeding programs. Full article

This study aimed to investigate vertical variations in dissolved organic matter (DOM) properties, humus (HS) composition, humic acid (HA) characteristics, and clay mineral dynamics, with a particular focus on the vertical distribution of HS components and mineral composition across Dark-brown, Meadow, and Paddy soil profiles. Results indicated that: (1) DOM in all three soil types was predominantly endogenous, primarily derived from microbial metabolism with minimal contributions from plant residues. (2) Vertical trends in DOM carbon content (C_DOM) were specific to soil type: in Dark-brown soil, C_DOM slightly increased from the Ap to Bt layer, followed by a sharp increase in the C layer; Meadow soil exhibited a significant decrease in C_DOM in the AB layer but remained relatively stable in other layers; Paddy soil showed a consistent decline in C_DOM with increasing depth. (3) HS and its fractions exhibited vertical variability: Paddy soil showed higher HS content in surface layers; carbon contents of water-soluble substances, HA, and humic-extracted acid (C_WSS, C_HA, and C_HE) decreased with depth in Dark-brown and Paddy soils, whereas they remained relatively stable in deeper layers of Meadow soil. (4) HA characteristics, including C/N ratio, functional groups, and aromaticity, were influenced by both depth and soil type: the Ap2 layer of Paddy soil effectively restricted the downward movement of organic matter; Fe³⁺ complexation played a key role in HA stabilization in Dark-brown soil; Meadow soil exhibited transitional HS properties. (5) Clay mineral assemblages were dominated by 2:1 type minerals (illite, smectite, illite–smectite interstratifications), showing distinct vertical weathering patterns: illite content decreased with depth due to hydrolysis, while proton-driven dissolution promoted kaolinite formation in surface layers, particularly in Dark-brown soil 2:1 minerals enhancing organic–mineral complexation in Meadow soil. The findings of this study provided a scientific basis for optimizing soil carbon pool management and offer insights into organic–mineral interactions that can enhance organic matter sequestration in agricultural soils. Full article

Temperate grazing systems require advanced management strategies to simultaneously enhance both productivity and resilience. Multispecies pasture (MSS) mixtures offer a promising alternative to conventional Lolium perenne-Trifolium repens (LP-TR) systems by leveraging niche complementarity through diverse and deeper rooting profiles that enhance drought tolerance and optimize nutrient acquisition from heterogeneous soil layers. In a field study, we compared LP-TR pastures with three functionally distinct MSS pastures subjected to varying rotation lengths (RL) and defoliation intensities (DIs). Seasonal and annual dry matter (DM) yield and botanical composition were assessed. MSS consistently outperformed LP-TR in total DM production, especially under shorter RL, which had a more pronounced effect on annual and spring biomass than DI. An 8 cm defoliation height generally enhances DM accumulation across systems. Species interactions significantly influenced botanical composition, with Plantago lanceolata contributing to greater pasture stability under environmental stress, accounting for 24–61% of total herbage DM. Furthermore, RL and DI interactions affected species prevalence, underscoring the need for adaptive, species-specific management strategies. These findings demonstrate that integrating strategic species selection with tailored defoliation practices in MSS mixtures can substantially enhance pasture productivity, compositional stability, and long-term sustainability of temperate grazing systems. Full article

Seasonal drought and nitrogen loss through runoff are two critical problems in the sloping land with shallow soils in southwest China. Irrigation is an effective way to alleviate drought and increase crop yields. Although irrigation is a proven strategy to mitigate drought stress and enhance yields, increased soil moisture under irrigation may exacerbate water and nitrogen losses. Therefore, this study aimed to investigate the long-term effects of irrigation regimes on crop yield, surface runoff, leaching, and nitrogen loss in shallow soil systems. Three experimental treatments were implemented: rainfed control (RF), single irrigation at a flowering stage (SI), and full irrigation (FI). The annual crop yield under SI and FI treatments was 16.4% and 43.5% higher than treatment RF, respectively. The surface runoff in RF was 46.2% and 52.8% higher than the values in SI and FI, respectively. Conversely, the leaching water volume in RF was 13.7% and 13.6% lower than in SI and FI, respectively. The total runoff did not differ significantly, as reduced surface runoff offset elevated leaching. The annual nitrogen loss was 35.4, 30.5, and 22.0 kg N ha⁻¹ in RF, SI, and FI treatments, respectively. Irrigation can significantly decrease the nitrogen loss. Leaching accounted for 96% of the total nitrogen loss. Enhanced crop nitrogen uptake under irrigation reduced total nitrogen concentrations in both soil and leaching water solution, which was the main factor for the decrease in total nitrogen loss under irrigation. These results indicate that in sloping land with shallow soil layers, optimal irrigation scheduling can effectively enhance crop yield without elevating nitrogen leaching risks. The study provides a scientific basis for formulating irrigation strategies in the study region. Full article

Soil compaction is a pivotal factor influencing crop growth and yield, and its accurate assessment is imperative for precision agricultural management. Soil mechanical resistance is the key indicator of soil compaction, with accurate measurement enabling precise assessment. Dynamic soil mechanical resistance measurement outperforms conventional manual fixed-point sampling in data acquisition efficiency. In this paper, a methodology is proposed for the dynamic acquisition of soil mechanical resistance using a flexible thin-film pressure sensor. This study dynamically captures soil mechanical resistance at three depths (5 cm, 10 cm, and 15 cm) under dynamic machinery operating conditions. A device was designed for the detection of soil mechanical resistance, and a prediction model for soil mechanical resistance was developed based on the Kalman filter algorithm. Tests were conducted under steady-state and variable-load conditions, and the predicted values accurately tracked the reference pressure. Soil tank trials showed that at an operating speed of 0.69–0.72 km/h, the average prediction errors for the three soil layers were 2.03%, 1.48%, and 6.27%, with the coefficient of determination (R²) between predicted and measured values reaching 0.96. The system effectively predicts multi-depth soil resistance, providing novel theoretical and technical approaches for dynamic acquisition. Full article

The Zigui Basin, located in the Three Gorges Reservoir Area, has developed numerous landslides due to its interlayering of sandstone and mudstone, geological structure, and reservoir operations. This study identifies a fourth type of landslide failure mode: an oblique-dip slope wedge (OdSW) landslide, based on the Wanshuitian landslide. Following four heavy rainfall events from 3 to 13 July 2024, this landslide exhibited significant deformation on the 17th and was completely destroyed within 40 min. The dimensions of the landslide were 350 m in length, 160 m in width, and 20 m in thickness, with a volume estimated at 8.0 × 10⁵ m³. The characteristics of landslide deformation and the changes in moisture content within the shallow slide body were ascertained using unmanned aerial vehicles, moisture meters, and mobile phone photography. The landslide was identified to have occurred within the weathered residual layer of mudstone, situated between two sandstone layers, with the eastern boundary defined by an inclined rock layer. Upon transitioning into the accelerated deformation stage, the landslide initially exhibited uniform overall sliding deformation, culminating in accelerated deformation destruction. The dip structure created terrain disparities, resulting in a step-like terrain on the left bank and gentler slopes on the right bank, with interbedded soil and rock in a shallow layer, because the interlayered soft and hard geological conditions caused varied weathering and erosion patterns on the riverbank slopes. The interbedded weak–hard stratum layer fostered the development of the oblique-dip slope wedge landslide. Based on the improved Green–Ampt model, we developed a stability prediction methodology for an oblique-dip slope wedge landslide and determined the rainfall infiltration depth threshold of the Wanshuitian landslide (9.8 m). This study aimed not merely to sharpen the evolution mechanism and stability prediction of the Wanshuitian landslide but also to formulate more effective landslide-monitoring strategies and emergency management measures. Full article

Designing deep foundations in densely urbanized areas presents significant challenges due to complex soil conditions, high groundwater levels, and the proximity of sensitive infrastructure. This study addresses these challenges through the development and numerical analysis of a combined pile–raft foundation (CPRF) system for a 75 m tall hotel tower in Frankfurt am Main, Germany. The construction site is characterized by heterogeneous soil layers and is located adjacent to a historic quay wall and bridge abutments, necessitating strict deformation control and robust structural performance. A comprehensive three-dimensional finite element model was developed using P_LAXIS 3D to simulate staged construction and soil–structure interaction (SSI). The CPRF system comprises a 2 m thick triangular raft and 34 large-diameter bored piles (1.5 m in diameter, 40–45 m in length), designed to achieve a load-sharing ratio of 0.89. The raft contributes significantly to the overall bearing capacity, reducing bending moments and settlement. The predicted settlement of the high-rise structure remains within 45 mm, while displacement of adjacent heritage structures does not exceed critical thresholds (≤30 mm), ensuring compliance with serviceability criteria. The study provides validated stiffness parameters for superstructure design and demonstrates the effectiveness of CPRF systems in mitigating geotechnical risks in historically sensitive urban environments. By integrating advanced numerical modeling with staged construction simulation and heritage preservation criteria, the research contributes to the evolving practice of performance-based foundation design. The findings support the broader applicability of CPRFs in infrastructure-dense settings and offer a methodological framework for future projects involving complex SSI and cultural heritage constraints. Full article

Aiming at the problems of intensified soil compaction under the conditions of no-tillage operations and machine blockage caused by large-scale straw returning to the field, an operation mode of “straw strip collecting-strip subsoiling” was proposed, and a Monomer Profiling Strip Tillage Machine (MPSTM) with Straw-Strip-Collecting and Subsoiling Functions was designed to achieve anti-blocking operation and three-dimensional soil compaction reduction. The principle and mechanism parameters of monomer profiling in strip tillage are analyzed, and the effective profiling conditions are clarified. It is determined that the deflection angle, inclination angle, and installation spacing have a key influence on the straw clearance effect. The theory of soil failure and soil compaction reduction under the operation of the subsoiling and strip tillage mechanism is studied, and a combination of a medium-sized Subsoiler shovel handle and a 150 mm double-wing shovel is adopted. Using the EDEM discrete element method, taking the spatial parameters of the stubble clean disc (SCD) as the test factors and the straw removal rate (SRR) as the test indicator, a quadratic orthogonal rotation test is conducted to clarify the influence of each parameter on the straw clearance. The optimal SCD spatial parameters were determined as a deflection angle of 16.5°, an inclination angle of 25°, and an installation spacing of 100 mm, achieving a maximum SRR of 95.34%. Field test results demonstrated stable machine operation. Post-operation measurements yielded the following results: the width of the straw-cleaning band (WSCB) in the sowing strip is 193.7 mm; the overall straw removal rate (OSRR) is 84.82%, which is basically consistent with the simulation results; the subsoiling depth (SD) is 271.7 mm; the subsoiling depth stability (SDS) is 91.85%; the soil fragmentation rate (SFR) is 81.19%; and the reduction of soil compaction in the 0–10, 10–20, and 20–30 cm soil layer is 50.08%, 21.78%, and 40.83%, respectively. These results confirm that the machine effectively cleaned straw within the seeding band and reduced soil compaction, meeting the agronomic and technical requirements for strip tillage. Full article

Global climate change has intensified the frequency and severity of drought events, posing significant threats to agricultural sustainability, particularly for water-sensitive crops such as tea. In northern China, where precipitation is unevenly distributed and evapotranspiration rates are high, tea plantations frequently experience water stress, leading to reduced yields and declining quality. Therefore, accurately simulating soil water content (SWC) is essential for drought forecasting, soil moisture management, and the development of precision irrigation strategies. However, due to the high complexity of soil–vegetation–atmosphere interactions in field conditions, the practical application of the HYDRUS-1D model in northern China remains relatively limited. To address this issue, a three-year continuous monitoring campaign (2021–2023) was conducted in a coastal area of northern China, covering both young tea plantations and adjacent grasslands. Based on the measured meteorological and soil data, the HYDRUS-1D model was used to simulate SWC dynamics across 10 soil layers (0–100 cm). The model was calibrated and validated against observed SWC data to evaluate its accuracy and applicability. The simulation results showed that the model performed reasonably well, achieving an R² of 0.739 for the tea plantation and 0.878 for the grassland, indicating good agreement with the measured values. These findings demonstrate the potential of physics-based modeling for understanding vertical soil water processes under different land cover types and provide a scientific basis for improving irrigation strategies and water use efficiency in tea-growing regions. Full article

Context: To revive the practice of planting legume green manure (GM) in the fallow period in rainfed agricultural areas, it is essential to demonstrate the benefits of this practice on the yields and water use efficiency (WUE) of subsequent crops, especially when integrating with optimized water and fertilizer management. Objectives: We conducted a field experiment to determine the positive effects of planting legume GM in the summer fallow on the yield, WUE, and nitrogen uptake efficiency (NupE) of subsequent winter wheat, which was grown with plastic film mulching and integrated fertilization in the Loess Plateau of China. Methods: A split-plot-designed experiment was arranged with two main treatments, namely (1) wheat planting followed by GM planting in the summer fallow (GM) and (2) conventional wheat monoculture followed by bare land summer fallow (BL), and three sub-treatments: (1) control treatment without any chemical fertilizer (Ct), (2) application of chemical N, P, and K as basal fertilizer (B), and (3) application of basal fertilizer plus wheat straw return (BS). Results: In the initial two years, even in a dry year, GM did not decrease the soil water content and storage (0–200 cm layer) during the subsequent winter wheat season, relative to BL. But in the third and fourth years, GM increased the grain yield of winter wheat by 3.2% and 3.8%, respectively. B and BS increased the grain yield of winter wheat by 14.4% and 22.2%, respectively, during the third experimental year, and by 12.7% and 19.4% during the fourth experimental year, primarily through increasing the population density of winter wheat. The increase in the grain yield contributed to a higher WUE of winter wheat. In the third year, GM increased the water consumption (WC) and WUE of wheat by 2.4% and 1.7%, respectively, though they were far lower than B (8.3% and 5.6%) and BS (10.4% and 10.7%). B and BS resulted in a higher yield and N nutrition than GM alone, but GM combined with B and BS resulted in the highest yield and N nutrition, thus greatly decreasing the NupE and increasing N productivity. Conclusions: Planting legume GM in the fallow can further increase the long-term yield, WUE, and N utilization of winter wheat when integrated with chemical fertilization and wheat straw return in rainfed agriculture. Implications: Our study yields new insights into the agronomic benefits of legume GM application in semi-arid or analogous rainfed agroecosystems and underscores the critical role of water conservation in ensuring dryland agricultural production, particularly in regions undergoing optimization of fertilization. Full article

Plastic mulch technology plays an important role in increasing agricultural productivity and economic returns. However, residual mulch remaining in agricultural fields poses significant challenges to both crop production and environmental sustainability. Effective recovery and recycling of residual plastic mulch requires accurate detection and identification of mulch fragments, which presents a substantial technical challenge. The detection of residual plastic film is complicated by several factors: the visual similarity between residual film fragments and soil in terms of color and texture, as well as the irregular shapes and variable sizes of the target objects. To address these challenges, this study develops FreqDyn-YOLO, a detection model for residual film identification in agricultural environments based on the YOLO11 architecture. The proposed methodology introduces three main technical contributions. First, a Frequency-C3k2 (FreqC3) feature extraction module is implemented, which employs a Frequency Feature Transposed Attention (FreqFTA) mechanism to improve discrimination between residual film and soil backgrounds. Second, a High-Performance Multi-Scale Feature Pyramid Network (HPMSFPN) is developed to enable effective cross-layer feature fusion, enhancing detection performance across different target scales. Third, a Dynamic Detection Head With DCNv4 (DWD4) is introduced to improve the model’s ability to adapt to varying film morphologies while maintaining computational efficiency. Experimental findings on a self-developed agricultural field residual film dataset confirm that FreqDyn-YOLO outperforms the baseline approach, achieving improvements of 5.37%, 1.97%, and 2.96% in mAP50, precision, and recall, respectively. The model also demonstrates superior performance compared to other recent detection methods. This work provides a technical foundation for precise residual film identification in agricultural applications and shows promise for integration into automated recovery systems. Full article

The sustainable utilization of saline water resources represents an effective strategy for alleviating water scarcity in arid regions. However, the mechanisms by which prolonged saline water irrigation influences soil salinization and dryland crop growth are not yet fully understood. This study examined the effects of six irrigation water salinity levels (CK: 0.87 g·L⁻¹, S1: 2 g·L⁻¹, S2: 4 g·L⁻¹, S3: 6 g·L⁻¹, S4: 8 g·L⁻¹, S5: 10 g·L⁻¹) on soil salinization dynamics and jujube growth during a three-year field experiment (2020–2022). The results showed that soil salinity within the 0–1 m profile significantly increased with rising irrigation water salinity and prolonged irrigation duration, with the 0–0.4 m layer accounting for 50.27–74.95% of the total salt accumulation. A distinct unimodal salt distribution was observed in the 0.3–0.6 m soil zone, with the salinity peak shifting downward from 0.4 to 0.5 m over time. Meanwhile, soil pH and sodium adsorption ratio (SAR) increased steadily over the study period. The dominant hydrochemical type shifted from SO₄²⁻-Ca²⁺·Mg²⁺ to Cl⁻-Na⁺·Mg²⁺. Crop performance exhibited a nonlinear response to irrigation salinity levels. Low salinity (2 g·L⁻¹) significantly enhanced plant height, stem diameter, leaf area index (LAI), vitamin C content, and yield, with improvements of up to 12.11%, 3.96%, 16.67%, 16.24%, and 16.52% in the early years. However, prolonged exposure to saline irrigation led to significant declines in both plant growth and water productivity (WP) by 2022. Under high-salinity conditions (S5), yield decreased by 16.75%, while WP declined by more than 30%. To comprehensively evaluate the trade-off between economic effects and soil environment, the entropy weight TOPSIS method was employed to identify S1 as the optimal irrigation treatment for the 2020–2021 period and control (CK) as the optimal treatment for 2022. Through fitting analysis, the optimal irrigation water salinity levels over 3 years were determined to be 2.75 g·L⁻¹, 2.49 g·L⁻¹, and 0.87 g·L⁻¹, respectively. These findings suggest that short-term irrigation of jujube trees with saline water at concentrations ≤ 3 g·L⁻¹ is agronomically feasible. Full article

As an important ecological barrier and animal husbandry resource base in arid and semi-arid areas, grassland degradation directly affects regional ecological security and sustainable development. Ili Prefecture is located in the western part of Xinjiang, China, and is a typical grassland resource-rich area. However, in recent years, driven by climate change and human activities, grassland degradation has become increasingly serious. In view of the lack of comprehensive evaluation indicators and the inconsistency of grassland evaluation grade standards in remote sensing monitoring of grassland resource degradation, this study takes the current situation of grassland degradation in Ili Prefecture in the past 20 years as the research object and constructs a comprehensive evaluation index system covering three criteria layers of vegetation characteristics, environmental characteristics, and utilization characteristics. Net primary productivity (NPP), vegetation coverage, temperature, precipitation, soil erosion modulus, and grazing intensity were selected as multi-source indicators. Combined with data sources such as remote sensing inversion, sample survey, meteorological data, and farmer survey, the factor weight coefficient was determined by analytic hierarchy process. The Grassland Degeneration Comprehensive Index (GDCI) model was constructed to carry out remote sensing monitoring and evaluation of grassland degradation in Yili Prefecture. With reference to the classification threshold of the national standard for grassland degradation, the GDCI grassland degradation evaluation grade threshold (GDCI reduction rate) was determined by the method of weighted average of coefficients: non-degradation (0–10%), mild degradation (10–20%), moderate degradation (20–37.66%) and severe degradation (more than 37.66%). According to the results, between 2000 and 2022, non-degraded grasslands in Ili Prefecture covered an area of 27,200 km², representing 90.19% of the total grassland area. Slight, moderate, and severe degradation accounted for 4.34%, 3.33%, and 2.15%, respectively. Moderately and severely degraded areas are primarily distributed in agro-pastoral transition zones and economically developed urban regions, respectively. The results revealed the spatial and temporal distribution characteristics of grassland degradation in Yili Prefecture and provided data basis and technical support for regional grassland resource management, degradation prevention and control and ecological restoration. Full article

Natural hydrogen is generated by fairly deep processes and/or in low-permeability rocks. In such contexts, fluids circulate mainly through the network of faults and fractures. However, hydrogen flows from these hydrogen-generating layers can reach sedimentary rocks with more typical permeability and porosity, allowing H₂ flows to spread out rather than be concentrated in fractures. In that case, three different H₂ transport modes exist: advection (displacement of water carrying dissolved gas), diffusion, and free gas Darcy flow. Numerical models have been run to compare the efficiency of these different modes and the pathway they imply for the H₂ in a sedimentary basin with active aquifers. The results show the key roles of these aquifers but also the competition between free gas flow and the dissolved gas displacement which can go in opposite directions. Even with a conservative hypothesis on the H₂ charge, a gaseous phase exists at few kilometers deep as well as free gas accumulation. Gaseous phase displacement could be the faster and diffusion is neglectable. The modeling also allows us to predict where H₂ is expected in the soil: in fault zones, eventually above accumulations, and, more likely, due to exsolution, above shallow aquifers. Full article