Search Results (618)

Accurate mapping of terraces is important for farmland protection, food security, and the management of terrace abandonment. However, extracting terraces from high-resolution remote sensing imagery remains challenging because of complex backgrounds, fragmented ridge structures, weak boundary contrast, and high similarity between terraces and surrounding land-cover types. This study proposes AMF-Deep, an Attention Multi-scale Fusion DeepLabv3+ model, for binary terrace extraction across representative terrace regions and morphologies. AMF-Deep was evaluated using 0.61 m high-resolution remote-sensing imagery from five representative terrace regions in China, encompassing diverse terrace morphologies and background conditions. In the proposed model, MobileNetV2 is adopted as the backbone to reduce computational cost, a modified multi-scale ASPP module is used to capture terrace morphology at different spatial scales, CBAM enhances low-level boundary and texture features, ECA refines high-level channel responses before ASPP, and NAM recalibrates semantic features after ASPP. A residual decoder is further introduced to support low-level feature transfer and boundary recovery. Experimental results show that AMF-Deep achieved the highest regional performance in Huangling, with mIoU, mPA, Accuracy, Recall, and Precision of 89.47%, 95.17%, 96.70%, 94.99%, and 93.68%, respectively. Stepwise ablation experiments further indicated that the modified ASPP module, the differentiated attention arrangement, and the residual decoder contributed to the final performance. Qualitative seasonal visualization suggests that winter images and dryland terraces in Shexian remain more challenging because of weak texture contrast and high background similarity. These results indicate that AMF-Deep has potential for terrace extraction across representative regions, although further quantitative seasonal evaluation and cross-region validation are still needed. Full article

Many transmission tower foundations in Northeast China are built in paddy fields, requiring construction during the wet season. Currently, no temporary bridge can be quickly installed and removed to transport people, materials, and machines without destroying the fields. To solve this problem, this study designs a prefabricated steel temporary bridge. The dynamic response of the bridge under a 25-ton moving crawler vehicle was studied using both field tests and numerical simulations. This work analyzes how the whole structure and its local parts respond to moving loads on soft paddy soil and calculates its maximum load capacity. The results indicate that: (1) empirical field measurements demonstrate that under the worst condition when the vehicle enters and leaves the bridge (end eccentric loading), the bridge does not lift or overturn; (2) numerical extrapolations indicate that when the 25 t vehicle passes at 1–10 m/s, the dynamic response is stable without resonance, and the dynamic stresses and displacements are always kept within safe limits; (3) the bridge exhibits reliable load capacity and resistance to deformation, with numerical extrapolations indicating that the theoretical ultimate bearing boundary of the system approaches 100 t. However, practical operational loads must incorporate appropriate safety factors and remain significantly below this extreme limit. This system allows heavy equipment to pass quickly and move frequently, while protecting the farmland from damage. Full article

Clarifying SOC sequestration via physical and microbial processes is key for improving farmland fertility, yet the relative contributions of agronomic practices to carbon fractions and aggregate sizes remain unclear. This study (2010–2019, rice–wheat rotation, Funiu Mountain eastern plain, central China) examined tillage and organic amendment effects on SOC dynamics and underlying mechanisms across aggregate sizes under six treatments (conventional/reduced tillage with no fertilizer, chemical fertilizer, or organic manure). SOC, particulate organic carbon (POC), and mineral-incorporated organic carbon (MOC) were measured in bulk soil and water-stable aggregates (>2000, 250–2000, 53–250, <53 μm), and physical fractionation and phospholipid fatty acid (PLFA) analysis were conducted to assess interactions among aggregates, carbon quality, and microbial communities. Results showed that, compared with conventional tillage without fertilization, both conventional tillage and reduced tillage with organic manure significantly increased bulk SOC by 92–122% and macroaggregate (>250 μm) mass by 15–110%. The combined application of organic manure and reduced tillage redirected SOC from micro- to macroaggregates. Moreover, POC and MOC were the primary contributors to bulk SOC, with POC showing a strong direct effect on SOC accumulation. Furthermore, a positive priming effect was detected exclusively in macroaggregates, identifying them as key sites for SOC turnover and confirming that optimized tillage with manure shifts aggregates to larger sizes and boosts SOC through physical protection. The micro-to-macro cascade offers a robust framework for SOC dynamics, and its persistence under diverse climates warrants future research for sustainable management. Full article

Land-cover-based ecosystem service valuation commonly assigns a uniform value coefficient to pixels within the same land-cover class, thereby overlooking ecological heterogeneity in mountainous protected areas. This study developed an improved remote sensing ecological index (IRSEI) and applied it as a spatial adjustment factor in the equivalent factor method to assess ecosystem service value (ESV) changes in the Qionglai Mountains section of Giant Panda National Park, China, between 2017 and 2022. IRSEI integrated the normalized difference vegetation index, wetness, normalized difference built-up and soil index, land surface temperature, and cumulative dynamic habitat index derived from the fraction of absorbed photosynthetically active radiation. DHI-cum was included as a proxy for annual cumulative vegetation productivity and habitat energy availability rather than a direct measure of biodiversity or giant panda habitat quality. Total ESV increased from 3.27 × 10⁸ CNY in 2017 to 4.25 × 10⁸ CNY in 2022, representing an increase of 9.79 × 10⁷ CNY, or 29.98%. Water bodies contributed the largest absolute increase, rising by 4.79 × 10⁷ CNY, or 42.45%, whereas farmland showed the highest relative increase of 45.35%. Woodland remained the dominant contributor to total ESV. Spatially, ESV was higher in the northern and southern parts and lower in the central region. All corrected sensitivity coefficients were below one, indicating that total ESV responded inelastically to ±50% perturbations of individual land-cover value coefficients. The framework improves within-class spatial differentiation of ESV and may support targeted management of mountainous protected areas, although field-based habitat and biodiversity data are needed for further validation. Full article

Water conservation is among the most important ecosystem service functions, and its dynamic changes can reflect the health of regional ecosystems. As one of the ten major tributaries of the Yellow River, the Yi–Luo River in Henan Province plays a significant role in maintaining regional ecological health through the ecosystem water conservation functions of its basin. To explore the characteristics of these functions, this study employed ecosystem transfer matrix and water balance methods to analyze the changes in ecosystem types in the basin and the dynamic changes in the corresponding water conservation functions from 2010 to 2020. The results showed that from 2010 to 2020, the dominant ecosystem types were farmland, forestland, and shrubland, and the main transformations between different ecosystem types were from farmland to urban areas and wetland, from grassland to shrubland, and from shrubland to forestland. The water conservation functions of the different ecosystem types varied significantly, with the average water conservation capacities ranked as follows: forestland > wetland > shrubland > grassland > farmland > others > urban areas. Due to the decreased water conservation depths in the forestland and shrubland ecosystems, the overall water conservation depth decreased over the study period. In addition, the water conservation capacities of the farmland, forestland, and shrubland ecosystems were the highest, reaching 12.94 × 10⁸, 12.15 × 10⁸ and 9.73 × 10⁸ tons, respectively, accounting for 34.47%, 32.35%, and 25.91% of the total water conservation capacity, respectively. Overall, water conservation in the study area was high in the south and low in the north, and there was an overall decreasing trend over time. Moreover, the regions with critical and important water conservation functions accounted for the largest proportion (47.2%). The critical and important regions were mainly located in the higher altitudes of Luanchuan County and Lushi county, while the moderate and average regions were primarily located in the plains, and weak regions were distributed mainly in the urban area of Luoyang city. Through analysis of the spatiotemporal changes and degree of importance of water conservation functions in the Yi–Luo River Basin, the key regions for ecological protection and construction were identified. The study results can be used to help enhance ecological security in the Yellow River Basin of Henan Province and play a significant role in promoting the regional economy as well as the health and sustainable development of the ecological environment. Full article

Microplastic contamination is an emerging global concern, but its occurrence in high-altitude protected areas has been understudied. This study systematically assessed microplastic abundance, morphology, and spatial distribution in Sagarmatha National Park (SNP), Nepal, a UNESCO World Heritage Site. Soil samples were collected from 25 sites across four land-use types, including settlement, farmland, forest, and floodplain, at two depths along the Lukla–Phortse trekking corridor during the pre-monsoon season of 2023. Samples were pretreated by density separation and Fenton’s reagent digestion, and microplastics were then detected using a YOLOv11n-seg instance segmentation model. A subset of extracted particles was chemically confirmed by optical photothermal infrared (O-PTIR) spectroscopy. Microplastics were present in all samples, with concentrations ranging from 80 to 960 particles·kg⁻¹. Fragments were the dominant morphological type, accounting for 65.7% of all particles, followed by fibers and films. Negative binomial regression revealed significant effects of land use and soil depth and their interaction on microplastic abundance. Settlement soils showed the highest concentrations with significant surface enrichment, while farmland soils showed no significant depth effect, consistent with human-dominated plastic sources and tillage-driven redistribution. Elevation was not a significant predictor of contamination. Hotspot analysis identified statistically significant clustering around Lukla and Namche, the two primary tourism hubs. The baseline established in this study provides a foundation for long-term monitoring and targeted waste management in SNP and offers insights to other protected high-altitude environments. Meanwhile, the application of deep learning and O-PTIR to balance the counting efficiency and accuracy is a novel approach that could be adopted by other researchers. Full article

Sustainable urbanization requires reconciling rapid land development with ecological security, a challenge particularly acute in mountainous megacities. While land-use/cover change (LUCC) substantially reshapes regional carbon storage, conventional whole-region assessments often mask critical spatiotemporal dynamics and subregional heterogeneity. Taking Chongqing, China, as a representative case, this study integrates the Future Land-Use Simulation (FLUS) and Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) models to decode historical carbon-storage dynamics (2000–2020) and simulate future spatial trajectories (2035) under four multi-scenario land-use pathways: Integrated Development Priority Scenario (IDPS), Ecological Conservation Priority Scenario (ECPS), Farmland Conservation Priority Scenario (FCPS), and Economic Priority Scenario (EPS). Results show a net decline of 8.49 × 10⁶ t in total carbon storage during 2000–2020, primarily driven by the often-overlooked degradation of high-carbon-density grasslands alongside construction-land expansion. Scenario simulations reveal that the ECPS is the only pathway achieving a net carbon-storage increase (+4.26 × 10⁶ t), although the resulting land-use pattern was jointly shaped by ecological protection constraints, land suitability, and scenario-specific land-demand allocation. Crucially, subregional analysis highlights distinct spatial roles: the Northeastern Urban Agglomeration (NUA) emerges as the core for ecological restoration, the Main Urban Area (MUA) remains highly sensitive to development-driven carbon loss, and the Southeastern Urban Agglomeration (SUA) acts as a buffer requiring a delicate development balance. By linking coupled spatial modeling with subregional constraints, this framework advocates for a shift from “one-size-fits-all” land management to precise spatial governance, providing a scalable scientific reference for carbon-oriented sustainable planning in mountainous megacities worldwide. Full article

Conventional ridge tillage has triggered severe soil organic carbon depletion and soil erosion in sloping maize fields of humid northeast China, posing a persistent threat to black soil health and regional grain security. As representative conservation tillage systems integrated with full straw residue retention, no tillage and strip tillage exhibit prominent potential in soil protection, and their soil-improving benefits are inseparable from continuous straw carbon input; however, their regulatory effects on humus fractions and humic acid molecular properties in erosion-prone sloping farmlands remain largely unclarified. This study aimed to screen the optimal integrated tillage–cultivation mode for sloping farmlands in the northeast China black soil region and to reveal how tillage systems coupled with incremental agronomic practices affect maize yield, humus composition, and humic acid molecular characteristics in Albic soil, a representative degraded soil type of the regional black soil system. A 2-year field experiment was conducted in a typical sloping farmland of Jilin Province, with conventional ridge tillage set as the control. Five incremental integrated management practices (from baseline practice to fertilizer reduction, straw decomposition promotion, and 5–10% higher planting density) were arranged under both under no-tillage and strip-tillage systems. We analyzed dissolved organic matter fluorescence properties, carbon content of humus fractions, and humic acid molecular structural features, and performed principal component analysis for comprehensive performance evaluation of all treatments. This study demonstrates that optimized strip tillage, supported by full straw C input as an indispensable prerequisite, combined with straw decomposition promotion and a 10% planting density increase can synchronously boost soil fertility and maize yield, providing a scientific and practical tillage strategy for sustainable black soil conservation of sloping Albic farmlands in humid northeast China. Strip tillage achieved a 6.78% higher average maize yield than NT, and the maximum yield was recorded with ST5 (strip tillage combined with straw decomposition promotion and 10% planting density increase). Both no tillage and strip tillage significantly increased C_DOM content, humification index and autochthonous contribution, optimized humus component distribution with elevated humic acid carbon content, humic acid carbon-to-fulvic acid carbon ratio and humic acid carbon-to-total organic carbon ratio, and enhanced humic acid aromaticity, thermal stability, and hydrophobicity. The principal component analysis results indicated that ST5 ranked first in comprehensive performance, while conventional ridge tillage ranked the lowest among all treatments. Strip tillage integrated with straw decomposition promotion and 10% increased planting density effectively modulated humus fractions, improved humic acid molecular stability, and synchronously increased maize yield. This integrated management regime provides a scientific and practical tillage strategy for sustainable black soil conservation and high-efficiency maize production in sloping Albic farmlands of humid northeast China. Full article

Global urbanization has caused widespread ecological degradation, yet habitat quality in agricultural plains remains understudied. This study addresses this gap by assessing and predicting land use and habitat quality changes in the Northern Anhui Plain from 2000 to 2030 using the PLUS and InVEST models under four scenarios (natural development, farmland protection, economic development, and sustainable development). The optimal parameters-based geographical detector (OPGD) was employed to identify driving factors. Results show that farmland continuously shrank while built-up land expanded, and habitat quality remained low and declined over time, with low-grade areas expanding. All four 2030 scenarios exhibited declines, with the farmland protection scenario yielding the highest habitat quality and the economic development scenario the lowest. The optimal spatial scale was 4 km, and discretization algorithms and break numbers significantly influenced driver analysis. Locational factors had relatively higher explanatory power, though the overall q-statistic was moderately low, indicating limited single-factor explanation. The study reveals the spatiotemporal dynamics and driving mechanisms of habitat quality in this farmland-dominated plain, providing useful insights for spatial planning and policy-making to support sustainable development in agricultural regions. Full article

The coastal wetlands of Yancheng, Jiangsu Province, serve as a crucial overwintering and stopover site for rare waterbirds such as red-crowned cranes. The changes in their landscape pattern are directly related to the protection of regional wetland ecological functions and biodiversity. Using land use data from 2010 to 2022 to extract landscape pattern indicators for each period, this study adopts the Covariance–Analytic Hierarchy Process (Cov-AHP) to construct a comprehensive Landscape Fragmentation Index (LFI) for coastal wetlands, considering aspects including patch density, boundary complexity, spatial connectivity, and landscape diversity. Combined with multi-source indicators of Ecology–Economy–Society (EES), the Generalized Additive Model (GAM) and Geographically Weighted Regression (GWR) are adopted to systematically analyze the nonlinear response relationships and spatially heterogeneous driving mechanisms of landscape fragmentation. GWR is employed to reveal the spatial heterogeneity of the influence of each driving factor on fragmentation by mapping local regression coefficients. The results show that: (1) During the study period, the overall landscape fragmentation of the coastal wetlands in Yancheng, Jiangsu Province, exhibited a slow increase trend, with a spatial gradient pattern of “higher in the north and lower in the south, and higher in coastal areas than in inland areas,” reflecting the combined effects of varying levels of economic development and human activity intensity across different administrative regions and along the coast-inland gradient. (2) Based on the deviance explained by the GAMs, social factors generally had higher explanatory power for LFI than ecological and economic factors. Specifically, human population density and the proportion of construction land showed a significant positive correlation with LFI, while NDVI and the proportion of farmland exhibited obvious nonlinear effects under different fragmentation levels. (3) The GWR results indicated that the regression coefficients of the main driving factors were highly spatially non-stationary, and regions with high coastal development intensity had the most significant promoting effect on landscape fragmentation. The local coefficient maps further reveal that GDP and NDVI exhibit the strongest spatial heterogeneity, with their effects shifting from positive to negative across different sub-regions. The study demonstrates that the integrated framework of Cov-AHP combined with GAM and GWR can effectively characterize the spatiotemporal dynamics and multi-dimensional driving mechanisms of coastal wetland landscape fragmentation, providing a reference for the protection of coastal wetlands in Yancheng, Jiangsu Province, and the conservation of waterbird habitats represented by red-crowned cranes. Full article

Visitor access in linear defensive built heritage landscapes needs to balance historical interpretation, route accessibility, and current protection constraints. This issue is evident in the Laoniuwan section of the Ming Great Wall in Shanxi Province, China, where heritage nodes lie within a scenic area but access infrastructure and interpretive route organization remain underdeveloped. This study proposes a conservation-oriented trail planning method for Great Wall scenic areas by combining MaxEnt-based historical defensive landscape modeling with GIS-based contemporary resistance analysis. MaxEnt was used to model terrain- and visibility-related suitability for defensive node locations, including watchtowers, beacon towers, forts, and mamian. The output was treated as a historical landscape interpretation layer, not as a prediction of tourist movement or final route location. Contemporary resistance was built from terrain ruggedness, road and village disturbance, the Great Wall protection buffer, permanent basic farmland, and the ecological conservation redline. Three historical–contemporary weighting scenarios were compared using least-cost path analysis. A Conservation–Interpretation Balance Index (CIBI) was then used to support scenario selection. The 4:6 scenario achieved the highest CIBI score (0.606). It maintained connectivity among defensive nodes while reducing ecological and farmland conflicts. The recommended loop trail was further translated into a four-tier conservation management zoning scheme. The results offer a spatial decision support approach for organizing fragmented built heritage resources into controlled-access interpretation routes with reduced disturbance to heritage fabric and protected land. Full article

Beneficial microorganisms are an effective approach to ameliorate degraded soils and improve farmland productivity. At present, systematic research on the regulatory effects of plant growth-promoting bacteria on tomato growth in acidic soils is still lacking. In this study, pot experiments combined with microbiome technology were conducted to investigate the effects of Bacillus cereus BC-101, Bacillus methylotrophicus BM-25 and Bacillus amyloliquefaciens BA-11 on the growth of tomato seedlings and the structure of rhizosphere microbial communities in acidic soils. All the three tested plant growth-promoting bacteria significantly promoted the growth of tomato seedlings. The plant heights were increased by 43.01%, 94.38% and 99.20% under BC, BM and BA treatments, respectively. Meanwhile, the bacterial inoculation significantly increased plant biomass, improved leaf photosynthetic pigment contents, activated protective enzyme activities, and elevated the contents of osmotic adjustment substances and growth-promoting hormones. In addition, the bacteria could improve the physicochemical properties of acidic soils, enhance soil enzyme activities, and significantly increase the relative abundances of beneficial genera such as Pseudomonas and Bacillus in the rhizosphere. Rhizospheric inoculation of the three plant growth-promoting bacteria improved tomato growth and enhanced rhizosphere soil properties under naturally acidic soil conditions, suggesting their potential application in the biological improvement of acidic soils. This study provides practical evidence for the comprehensive improvement and application of acidic soils. Full article

How does state-led farmland protection reshape the industrial structure of cities? While farmland protection is widely understood as an ecological policy, its consequences for industrial transformation remain underexplored. This paper argues that farmland protection in China operates through a quantitative-target system enforced via land use regulation: a binding farmland retention target mechanically tightens the supply of construction land, making land use regulation the operative channel through which farmland protection reshapes urban industries. Drawing on the socio-ecological systems framework, we treat the 2010 incorporation of farmland protection into the bureaucratic performance evaluation system as a governance perturbation and apply a continuous difference-in-differences design to a long-term panel of Chinese prefecture-level cities spanning two decades. The estimates show that intensified regulation moves the industrial structure toward more rational and technology-intensive configurations. Mechanism analysis confirms that the policy operates through two complementary channels: restricting construction land supply and enhancing per-area output. Heterogeneity analysis reveals an asymmetric response: structural gains concentrate in non-eastern cities, where binding farmland protection forces a more decisive break with land-extensive growth, whereas eastern cities absorb the policy on the intensive margin, deepening within-sector productivity rather than reorganizing the cross-sector mix. The findings establish farmland protection as a policy lever for industrial upgrading and offer guidance on calibrating regulatory intensity across regions at different developmental stages. Full article

Modern agriculture in developing regions faces significant challenges due to labor scarcity and the health hazards associated with the manual application of chemical treatments. This study presents the design, development, and techno-economic evaluation of an experimental hexacopter unmanned ariel vehicle (UAV) platform specifically tailored for crop protection on fragmented, smallholder farmlands. The research aims to bridge the gap between expensive imported technology and the practical needs of small-scale farmers by providing a cost-effective, locally manufacturable solution. The methodology involved the integration of a modular spraying system and optimized control architecture into a high-stability hexacopter frame. Experimental evaluations focused on flight stability, payload capacity, and spray uniformity using water-sensitive media. The results indicate that the developed platform achieves high coverage efficiency while significantly reducing chemical waste compared to traditional manual methods. Furthermore, the economic analysis suggests that the operational costs are substantially lower than those of comparable imported systems, offering a favorable payback period within a few crop seasons. These findings demonstrate that an indigenous UAV spraying platform can enhance both operational safety and economic feasibility for smallholder agriculture. Full article

With the advancement of systematic ecological protection and restoration, ecosystem coordination assessment and multi-scale differentiation analysis have become increasingly important for regional ecological governance. In this context, this study develops a multi-scale coupling coordination evaluation framework for the mountain–water–forest–farmland–lake (MWFFL) system in Dangtu County, Anhui Province. The framework integrates 14 indicators across five subsystems, uses a combined weighting method based on the Entropy Weight Method and Analytic Hierarchy Process, and applies the coupling coordination degree (CCD) model and trend analysis to characterize inter-system coordination and its spatiotemporal patterns at the regional and ecosystem scales. The results indicate that land use is dominated by arable land, with water bodies forming the structural backbone and construction land distributed in clusters. From 2020 to 2024, the mean CCD remained stable around 0.675, indicating that the overall coupling coordination level was relatively stable. Spatially, the CCD pattern remained higher in the southwest and lower in the northwest, with a new high-value clustering zone emerging in the south. At the ecosystem scale, the four ecological restoration units showed distinct spatiotemporal patterns of coupling coordination. This multi-scale MWFFL evaluation framework supports regional ecological monitoring and provides a reference for restoration effectiveness assessment in similar regions under the life community concept. Full article