Mountainous Areas Of China Research Articles

Understanding cropland abandonment from economics within a representative village and its empirical analysis in Chinese mountainous areas

China has been experiencing "Lewis Turning-Point", which means rural labor has been continuously transmitting to manufacturing sector and urban areas, ended up with old or female labor left in agricultural sector. One immediate result from agricultural labor shortage, some pieces of farmland will be abandoned, especially in mountainous area where large-farming-machinery cannot be applied due to terrain restrictions, and labor loss from agriculture cannot be supplemented. In this context, understanding land abandonment is critical for land planning and management. Specifically, it is necessary to figure out which cropland is more likely to be abandoned? To what scale of the land will be abandoned in the future? This article aims to figure out the basic rules behind land use or abandonment decision from a perspective of economics. In China, village is the basic unit for land use and land use rights transferring, thus we introduced a representative village, featured by an average farmland size with distribution pattern following questionnaire survey carried out in Wulong district, Chongqing city. We developed a theoretical land use decision-making model with its objective of maximizing land use incomes among ‘representative village’. This model is employed to simulate land abandonment rate in the year of 2011 and 2020 by changing the external variables given by the market survey, with a result of 9.25% and 33.40% respectively. The simulated land abandonment rate shows only 3.84 percentage point difference with the official data, which certified that this model is reasonable and applicable for land use decision in mountain areas in China. The model also shows a rise of labor wage will lead to huge land abandonment. To counter land abandonment, government should take some measures, such as rise of agricultural product sale price or decline the chemical fertilizer price, to alleviate land abandonment effectively.

Stability Prediction of Rainfall-Induced Shallow Landslides: A Case Study of Mountainous Area in China

Heavy rainfall induces shallow landslides in the mountainous areas of China. There is a need for regional slope stability prediction to reduce the damage to infrastructure, residents, and the economy. This study attempts to demarcate areas prone to rainfall-induced shallow landslides using the transient rainfall infiltration and grid-based slope stability (TRIGRS) model under different rainfall conditions. After inputting the engineering geological and geotechnical characteristic data of the area in China, the slope stability was simulated and verified by a deformation monitoring landslide. The slope stability gradually declined under the influence of precipitation from 5–8 July 2021. Slope stability gradually decreased under the predicted rainfall intensity of 60 mm/d for 6 days. The percentage of the slope area with a factor of safety (FS) less than 1.0 increased from 0.00% (1 d) to 3.18% (6 d). The study results could be used for hazards mitigation in this region.

Application of intergenic sequence between ND5 and ND6 as novel target for authentication and quantification of Oviductus Ranae

Oviductus Ranae (OR), dried oviducts from Rana dybowskii (RD), is a valuable food and medicine included by Chinese pharmacopeia, mainly produced in Changbai Mountain area of China. Economically motivated adulteration with oviducts from unclear species has become one of the most concerned food safety issues. Existing methods based on DNA sequencing are cost and time consuming, making them unfit for rapid authentication and quantification. Here, we developed a PCR/RT-PCR method targeting a RD specific intergenic sequence region termed IGS56 in mtDNA (Genbank NC_023528.1, 17059–17154 bp). Common primers in RD close species (F1-ND5/R1-ND6), RD specific primers (F2-IGS56/R2-ND6) and universal primers (F0–18 s/R0–18 s) were used for authentication by PCR, while RD specific primers (F3-IGS56-RT/R3-ND6-RT) and reference primers (F0–18 s-RT/R0–18 s-RT) were used for quantification by RT-PCR. For authentication, standard OR sample together with 19 batches OR samples obtained from different sites of Changbai mountain area were all identified to be RD. For RT-PCR based quantification, calibration curve with a good linear correlation (R2 =0.9915), was plotted with Ct ratio (Specificity Ct /Reference Ct) and OR percentage mixed by oviducts of R.nigromaculata. The accuracy of RT-PCR method established was verified to be high, with an average recovery rate of 106.744%.

Responses of soil biochemical and microbial properties to vegetation combinations of quarry restoration strategies in mountainous areas in China

The growing concern about the effectiveness of restoration strategies has spurred an evaluation of soil properties under different vegetation combinations. The restoration of underground microbial communities is critical to the success of restoration, however, the responses of biochemical and microbial properties to reclamation remain unknown. In this study, soil nutrients, enzyme activities and the characteristics of microbial communities of four restoration modes, CK1 (a non-restored mode) and CK2 (an original habitat mode) in a mining area of Sanhe City of Hebei Province were measured. Soil bacteria and fungi communities were analyzed by high-throughput sequencing of 16S rRNA gene fragment and internal transcribed spacer (ITS) to assess the recovery effects of different ecological restorations. Our results showed that: (1) The improved effect on soil available phosphorus (AP), available potassium (AK) and organic matter (OM) was obvious. Also, artificial and native plant combinations of Medicago sativa + local dominant natural vegetation (Nr) had the most obvious effect on soil nutrients. (2) The activities of soil urease, soil sucrase and soil phosphatase in Nr were considerably higher than those in other restoration modes (p < 0.05), while the soil catalase activity was the highest in the vegetation combinations of Medicago sativa + artificial miscellaneous grass (Mg) (p < 0.05). (3) Bacterial community structures in Nr were closest with those in CK2, whereas fungal community structures in Mg recovered the best. On the whole, the recovery rates of different indicators were ranked as follows: soil nutrients > bacteria > fungi. These results indicated that in the short term, native vegetation incorporating the planting of alfalfa significantly increased ecological restoration effects, however, a longer restoration history was required to restore the soil microbial diversity level similar to that of the original habitat.

Moderate scale and realization potential of new citrus-planting business entities in hilly and mountainous areas in China

Moderate scale and realization potential of new citrus-planting business entities in hilly and mountainous areas in China

Towards differentiated development policies for mountainous areas: A spatial analysis of mountain distribution and characteristics in a geographic region

AbstractScientifically defining the scope of mountain distribution and understanding the spatial patterns of mountainous areas in China is critical for formulating development policies tailored to the diverse needs of different regions and promoting rural revitalization in mountainous areas. This study aims to scientifically define the scope of mountain distribution and understand the spatial pattern characteristics of mountainous areas in China to aid in the formulation of differentiated development policies and support the rural revitalization strategies of mountainous areas. Using measurements of the areas of mountains and hills in Mainland China, and drawing on European scholars' definitions of mountain cities, a classification system of mountainous areas was constructed based on the proportion differences between hills and mountains within counties. The results showed that hills and mountains were widely distributed across 81.52% and 85.35% of the 2847 total counties in China, respectively. Moreover, 14 provinces accounted for over 90% of the mountainous area, and 5 provinces accounted for 100%. These findings indicate that China's provinces have obvious mountainous characteristics, which need to be considered in policy‐making for regional development.

Quantitative law and scenario-based forecasting of different land use expansion, based on reliability analysis in mountainous areas.

The continuous high-intensity and disorderly expansion of construction land in mountainous areas threatens city development; consequently, the scientific guidance of its sustainable development has become a research hotspot. This work aimed to develop a new theoretical framework for predicting land expansion. Based on DMSP/OLS-Landsat 7 data correction from 2000 to 2019, to ensure data reliability, this study quantitatively analysed the expansion law of land-use and land-cover (LULC) in Huayuan, a typical mountainous area in China. Based on the land expansion law, the patch-generating land use simulation (PLUS) model was used to predict various types of LULCs in different scenarios. The results showed that (1) the reliability of LULC under multi-source spatio-temporal data correction reached more than 0.97. (2) The expansion law of industrial and mining land, urban living land, and traffic land is sprawl, while rural living land is enclaved and the expansion direction and intensity are obviously different. (3) The scale of land expansion in the natural-oriented scenario was significantly higher than that in the humanism-oriented scenario, with a higher value of 199.33 hm2. This study expands the case study of land use analysis and prediction, and provides scientific guidance for different land expansion planning, which can avoid the mismatch and waste of land resources. Furthermore, it also deepens the exploration of LULC identification reliability method and enriches the theory of different land use prediction in mountainous areas.

An assessment of sustainable wellbeing and coordination of mountain areas: A case study of Qinba Mountain Area in China

Old economic development theories no longer adequately explain development issues as the world moves toward the Sustainable Development Goals (SDGs). The key to solving this problem lies in shifting from economic wellbeing with wealth at its core to sustainable wellbeing with equitable development at its core. However, there is a lack of systematic methods and applications for assessing sustainable wellbeing, which leaves policy makers unsure of how to optimize policies for sustainable wellbeing enhancement. Therefore, this research aims to establish a sustainable wellbeing measurement system connection with the SDGs, to value and index sustainable wellbeing, and to explore the progress of sustainable wellbeing in 46 counties in the Qinba Mountain Area from 2009 to 2020, taking the Qinba Mountain Area, which is the most concerned area in China. Methodologically, Genuine Progress Indicator (GPI), Ecosystem Services Vuale (ESV), and Life Satisfaction (LS) are valorized separately to represent economic capital, ecological capital, and social capital, thus valorizing sustainable wellbeing, and get the Sustainable Wellbeing Value (SWV). Based on this, we follow the principle of “the best system is one that achieves a simultaneously prosperous” advocated by the theory of sustainable wellbeing, and calculate the Sustainable Wellbeing Index (SWI) by the method of coupling coordination, so as to build up the interconnection of the three capital accounts of sustainable wellbeing: economic, ecological and social. We investigate the spatial and temporal dynamics dynamic changes of sustainable wellbeing in the Qinba Mountain Area based on the valuation and indexation of sustainable wellbeing. The results of the research show that, first, the value of sustainable wellbeing in the Qinba Mountain Area fluctuates upward, with economic capital contributing the most, ecological capital fluctuating the most, and social capital contributing most smoothly. Although economic capital is necessary for the development of all counties, it is obvious that developing counties rely on it more. The SWI in the Qinba Mountain Area fluctuates and rises, and it is overall in a stage of coordinated transition, showing strong social and economic capital and weak ecological capital. By county, the proportion of dysfunctional economic, ecological, and social capital interrelationships declined significantly in all counties. However, some counties still suffer from ecological lag, mainly stemming from an imbalance between human activities and the required ecosystem services. Therefore, it is crucial to clarify the functional territorial zoning of regions and promote the structural transformation of development. This research will provide a valuable reference for the refinement research of Sustainable Development Goals and the optimization of rural development policies in mountainous areas.

Spatial differences of specialty agriculture development in the mountainous areas of China -- "one village, one product" as an example

With the rapid development of urbanization, the rate of abandonment of arable land in China's mountainous areas has accelerated. Solving the phenomenon of abandonment of arable land has become an important issue in managing the use of China’s arable land, the key to which lies in the development of specialty agriculture using the unique natural environment of mountainous areas. This paper scrutinizes both the horizontal and vertical distribution of specialty agriculture in these areas, drawing upon the “One Village, One Product” dataset provided by the Chinese Ministry of Agriculture and Rural Development. The findings reveal that the horizontal distribution pattern of specialty agriculture exhibits the formation of eight primary clusters. It is intriguing to observe that a majority of these clusters are situated at the intersection of two or three provincial administrative units, with the largest cluster occurring at the border of Chengdu and Chongqing. In terms of the vertical distribution pattern, the specialty agriculture in China’s mountainous areas are mainly distributed at low altitudes, i.e., below 500 m, and at gentle slopes of 4°–8°, and with increases in altitude or slope, the overall amount of specialty agriculture declines rapidly.

Spatiotemporal Evolution of Land Use Efficiency in Southwest Mountain Area of China: A Case Study of Yunnan Province

The study of land use efficiency (LUE) evaluation and coupled coordination (CC) relationships under the perspective of urbanization can reasonably allocate land resources and contribute to the solution for agriculture, rural areas, and farmers. The LUE evaluation index system is constructed in three aspects: economy, society, and ecology. Then the LUE and CC degrees of Yunnan Province from 2010 to 2020 are measured, and the characteristics of LUE and the relationship of CC in each administrative region at each level are analyzed in space. Besides, the overall LUE and CC relationship in Yunnan Province is described. The study concludes that (1) The urbanization process in Yunnan Province is accelerating, unused land is decreasing, and construction land is increasing. (2) During the study period, the LUE of Kunming was much higher than that of other regions. The economic efficiency of the inner circle cities centered on Kunming is higher, while the economic efficiency of the outer circle cities is lower; social efficiency is increasing year by year except for Nujiang and Diqing, showing a higher pattern in the east than in the west; ecological efficiency is not increasing year by year except for Kunming, Qujing, and Lijiang, showing a higher pattern in the east than in the west; comprehensive efficiency is on the rise, with Kunming and Qujing leading the way with the overall pattern of “east &gt; central &gt; west”. The high-value area is relatively stable, and the low-value area has a clear tendency to shift eastward. (3) The coupling level of economic, social, and ecological efficiency of land use in administrative regions of Yunnan Province is low, but the coupling relationship is gradually optimized, showing the “contiguous effect” and realizing the state of extreme disorder to severe disorder in a large area. (4) The overall CC of three subsystems in Yunnan Province shows a fluctuating upward trend; the comprehensive efficiency index has an upward trend except for a slight decrease in 2017–2018; from 2010 to 2019, ecological and social efficiency is better than economic efficiency.

Tracking land use trajectory to map abandoned farmland in mountainous area

The strategy of recultivating abandoned farmland (AF) has been proposed as an effective response to the current global food crisis, it could increase food production without damaging the ecological environment. However, accurately identifying the spatial-temporal distribution of AF is a prerequisite for its successful implementation. Since abandonment is more likely to occur in mountainous areas than in plains, it is difficult to develop reliable methods to obtain long-time series information due to data source constraints and complex algorithms. In this study, we present a method to identify abandoned farmland based on tracking land use change trajectory in mountainous areas. Using Google Earth Engine (GEE), we mapped the land use classification of mountainous areas year by year and analyzed the land change at pixel level to obtain abandonment data through time series recursion. We applied this method to Tongjiang County, a mountainous area in China, and verified its accuracy, which turned out to be 82%. Our results indicate that the change in abandonment rate from 2001 to 2015 showed a phased characteristics that were likely determined by the interaction between policy, economics, and the rational choice of operators in different periods. Additionally, the Kernel Density Estimation (KDE) of AF distribution in Tongjiang County presented an agglomeration and stability pattern of “southwest> central> northeast”. Land transformation model (LTM) simulations further indicated that the future contraction or expansion of AF would have the greatest impact on the critical areas (southwest region of Tongjiang County). Our findings suggest that improving the precision of preferential agricultural policies, promoting the transfer of rural land management rights, and improving farming conditions in key areas could effectively address the problem of abandonment.

Hydrochemical formation mechanism of mineral springs in Changbai Mountain (China)

Changbai Mountain area is an important mineral water storage and development area in China. The hydrochemical composition of mineral water is the decisive factor for mineral–water quality. Based on the hydrochemical data of 74 mineral water samples collected from 2018 to 2020, the characteristics and formation mechanism of the hydrochemical components of the mineral water were analyzed. The results show that the formation of single-type mineral springs (metasilicate mineral water) is controlled by rock weathering; compound mineral springs (metasilicate mineral water with high CO2 content) are the product of CO2-rich, weakly acidic, confined hot groundwater with high salinity, which are mixed with shallow groundwater as rising along the fracture. The volcanic geological process greatly influences the formation of the hydrochemical components of mineral springs on the North slope of Changbai Mountain. The mineral springs on the Longgang Mountain are greatly affected by human activities. The results of cluster analysis only consider that hydrochemical components are consistent with the classification of the areas which concentrated distributions of mineral as determined by hydrogeological and geomorphological studies. The results of this study are useful for understanding the distribution, hydrochemical characteristics, and formation mechanism of mineral springs in the Changbai Mountain area of China and provide the theoretical basis for the protection and development of mineral spring.

Characteristics of Raindrop Size Distributions in the Southwest Mountain Areas of China According to Seasonal Variation and Rain Types

The precipitation and raindrop size distribution (RSD) characteristics of the four seasons and different rain types were studied using a PARSIVEL2 raindrop disdrometer set in the southwest mountain areas of China from 2019 to 2021. The seasonal precipitation in the southwest mountain areas was mainly stratiform rain. The peaks of the RSD were about 1–2 orders of magnitude higher than those in the plains. The convective rain in spring and autumn was very close to the ocean-like convective mass. The local shape–slope (μ–Λ), radar reflectivity–rain rate (Z–R), and kinetic energy–rain rate (KE–R) relationships were further derived, and the diversity of these relationships was mainly due to the variability of the RSDs. In addition, the differences in the RSD characteristics between the top and the foot of the mountain during a typical precipitation process in the summer of 2020 were further compared. It was found that the number density of the small particles at the top of the mountain was higher than that at the foot of the mountain due to the broken large raindrops caused by the high wind speed, while the high evaporation rate, strong convective available potential energy (CPAE), and water vapor content at the foot of the mountain could strengthen the RSD, making the number density of the large raindrops at the foot of the mountain higher than that at the top.

Mapping Cropland Abandonment in Mountainous Areas in China Using the Google Earth Engine Platform

Knowledge about the spatial-temporal pattern of cropland abandonment is the premise for the management of abandoned croplands. Traditional mapping approaches of abandoned croplands usually utilize a multi-date classification-based land cover change trajectory. It requires quality training samples for land cover classification at each epoch, which is challenging in regions of smallholder agriculture in the absence of high-resolution imagery. Facing these challenges, a theoretical model is proposed to recognize abandoned croplands based on post-abandonment secondary succession. It applies the continuous change detection and classification (CCDC) temporal segmentation algorithm to Landsat time series (1986~2021) to obtain disjoint segments, representing croplands’ status. The post-abandonment secondary succession showing a greening trend is recognized using NDVI-based harmonic analysis, so as to capture its preceding abandonment. This algorithm is applied to a mountainous area in southwest China, where cropland abandonments are widespread. Validation based on stratified random samples referenced by a vegetation index time series and satellite images shows that the detected abandoned croplands have user accuracy, producer accuracy and an F1 score ranging from 43% to 71%, with variation among abandonment year. The study area has a potential cropland extent of 22,294 km2, within which 9252 km2 of the cropland was abandoned. The three peak years of abandonment were 1994, 2000, and 2011. The algorithm is suitable to be applied to large-scale mapping due to its automatic manner.

The development characteristics and mechanisms of the Xigou debris flow in the Three Gorges Reservoir Region

Debris flow is a common geological hazard in mountainous areas of China, often causing secondary disasters and seriously threatening residents and infrastructure. This paper uses the Xigou debris flow in the Three Gorges Reservoir Region (TGRR) as an example case study, the development characteristics and initiation pattern of which were analyzed based on field investigation. The disaster dynamics software DAN-W was then used to simulate the entire initiation-movement-accumulation process of the debris flow and conduct the debris flow dynamics analysis. The paper also simulated and predicted the movements of landslides in the formation area of a debris flow after its initiation. The results show that the movement duration of the Xigou debris flow was approximately 40 s, the maximum velocity was 37.1 m/s, the maximum thickness of the accumulation was 18.7 m, and the farthest movement distance was 930 m, which are consistent with the field investigation. When the volumes of landslide transformed into a new source material of debris flow are 5 × 104, 10 × 104, 15 × 104, 20 × 104, and 26 × 104 m3, the movement distances of the debris flows are 250, 280, 300, 340, and 375 m, respectively. When the volume of the source material exceeds 20 × 104 m3, debris flow movement can seriously impact the residential houses at the entrance of the gully. This paper can provide a scientific basis for the prevention and mitigation of the Xigou debris flow.

中国“平原-山地”地形过渡带NDVI时空变异与气候响应

PDF HTML阅读 XML下载 导出引用 引用提醒 中国“平原-山地”地形过渡带NDVI时空变异与气候响应 DOI: 10.5846/stxb202202190399 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金-河南区域创新发展重点资助项目（U21A20108）；河南省高校科技创新团队支持计划项目（22IRTSTHN008） Spatio-temporal variation and its response to climate change of NDVI in the terrain transition zone, China Author: Affiliation: Fund Project: Supported by the National Natural Science Foundation of China ( No. U21A20108), and Scientific and Technological Innovation Team of Universities in Henan Province (No. 22IRTSTHN008) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究地形过渡带植被的地形效应，边缘效应，及其对纬度、气候变化的响应，将为我国山地生态格局和资源禀赋的深层认知提供地学参考。利用1982-2015年第三代全球库存建模和制图研究归一化植被指数数据集（GIMMS NDVI3g v1）和年均气温、降水等气象数据，分别进行最大值合成、趋势分析、突变分析、变异分析和相关分析，揭示了中国近南北走向的"平原-山地"地形过渡带（简称"地形过渡带"）植被物候的时空变化规律及对气候变化的响应特征。研究表明：（1）"地形过渡带"跨越一年三熟的低纬度地区，到一年两熟的中纬度地区，再到一年一熟的高纬度地区的周期性植被物候特征区；（2）34年间，年际NDVI整体呈增长趋势，其中植被改善区域占58.84%；年内分析表明"地形过渡带"植被生长期（LOS）变化率-3.16 d/纬度；（3）34年间"地形过渡带"的年均气温呈现升高趋势，每10年上升速率为0.098-0.386℃之间；年均降水呈现减少趋势，每10年下降速率为8.29-31.82 mm；（4）34年间NDVI变异系数结果表明，研究区NDVI低波动变化和相对较低波动变化的面积占比达95.52%，说明研究区植被呈稳中向好趋势；（5） NDVI与年均气温的相关性随着纬度的升高而减弱，表明南方植被对气温变化敏感；NDVI与年均降水量的相关性随着纬度的升高而升高，表明北方植被对降水变化敏感。 Abstract:Due to its huge differences in longitude, latitude, and elevation, the transition zone between the second and third steps provides a unique natural profile for basic environmental research on physical geography and human settlements in mainland China. In terrain transition zone, the topographic and marginal effects of vegetation, and their responses to latitude and climate change will provide a geographical reference for in-depth understanding of the ecological pattern and resource endowment of mountainous areas in China. Based on the GIMMS NDVI3g v1 dataset, annual mean temperature and precipitation data from 1982 to 2015, combined with the maximum value synthesis, trend analysis, mutation analysis, variation analysis, and correlation analysis, this paper reveals the spatiotemporal variation trend and response characteristics to climate change of vegetation phenology in terrain transition zone of "plain-mountain" near the north-south direction between the second and third steps of China. The results show that:(1) The terrain transition zone is a periodical vegetation phenological characteristic region which spans the low-latitude region with three crops a year, the mid-latitude region with two crops a year, and the periodic vegetation phenology zone in the high-latitude region with one crop a year; (2) During 34 years, the inter-annual NDVI showed an increasing trend, of which the vegetation improvement area accounted for 58.84%; the inner-annual analysis showed that the vegetation growth period (LOS) change rate of the terrain transition zone was -3.16 d per latitude; (3) The annual average temperature of the terrain transition zone in the 34 years showed an increasing trend with an increase rate from 0.098℃ to 0.386℃ per 10 a, while the annual average precipitation showed a decreasing trend with a decrease rate from 8.29 mm to 31.82 mm per 10 a; (4) The NDVI variation coefficient analysis showed that low volatility change area and relatively low volatility change area accounted for 95.52%, presenting a stable and positive trend; (5) The correlation between NDVI and annual mean temperature decreased as latitude increased, indicating that southern vegetation was sensitive to temperature changes; while the correlation between NDVI and annual mean precipitation increased as latitude increased, indicating that northern vegetation was sensitive to precipitation changes. Vegetation distribution and climate change in terrain transition zone of "plain-mountain" have topographic effects; In the mountain-plain junction zone, due to the human-land conflict caused by urban expansion, the vegetation distribution around the city has a marginal effect. 参考文献 相似文献 引证文献

DCI-PGCN: Dual-Channel Interaction Portable Graph Convolutional Network for Landslide Detection

Landslide, a kind of destructive natural disaster, often occurs in the mountainous areas of China. Landslide information instant collection plays an important role in taking appropriate remedial measures and personnel evacuation. In recent years, the use of Convolutional Neural Network (CNN) for landslide regional detection achieved good performance, however, most CNN-based methods had no regard for the internal connection of the cover materials in the disaster occurrence area. Moreover, the information revealed by the internal deformation features was ignored, and the same surface object in the image presents different features under different illumination, environment and resolution, which makes it difficult to extract the structural features of landslide images. In this paper, we propose a novel graph convolutional network for landslide detection, inspired by attention mechanism’s ability to focus on selective information supplemented with both different channels. The global maximum node connection strategy with positive and negative connectivity makes the Graph Convolution Network (GCN) more portable, which is used as the basic unit of graph feature propagation to construct a multi-layer residual connection module. In order to learn interactively and spread graph information, channel dimension is added to make the boundary of features between classes more discriminative. Extensive experiments on Sichuan province and Bijie landslide datasets show that our proposed method outperforms other detection models and achieves high precision and accuracy. In addition, we also carried out landslide detection for Zhaotong of Yunnan Province on GF-2 original images to prove the effectiveness and applicability of the algorithm.

Development Path of Digital Agriculture in Southwest Mountainous Areas of China in the Context of Chinese Path to Modernization

Development Path of Digital Agriculture in Southwest Mountainous Areas of China in the Context of Chinese Path to Modernization

Discrete element analysis of deformation features of slope controlled by karst fissures under the mining effect: a case study of Pusa landslide, China

Karst landforms are widely distributed in the southwestern mountain areas of China, and the continuous underground mining activities lead to frequent occurrence of catastrophic collapses and landslides. Revealing the relationship between the development characteristics of the controlling karst fissures and the slope deformation process is crucial to understand the collapse and landslide phenomena. The Pusa landslide is selected as the geological prototype of discrete element analysis, and the universal distinct element code (UDEC) is applied to simulate the overall deformation response of the mountain containing extensive karst fissure during the mining process. The results show that under the action of mining, the roof above the goaf bends and subsides, and the middle of the roof even breaks and collapses. The separation fractures effectively block the upward transmission of the collapse state of the rock stratum. The bottom of the karst fissure is susceptible to cracking first in the process of coal seam mining due to stress concentration, and the area of severe deformation in the slope coincides with the mining pressurization area. The morphology of the karst fissure controls and determines the deformation characteristics of the rock mass at the slope top, and only the karst fissure located within the mining influence range is the object to be considered in the slope stability analysis. The limit karst fracture depth, about 1/3 of the slope height, is the limit value to determine whether the rock mass at the slope top is toppled or slipped. The relationship between the karst fissure and the free surface gradually changes from the directional or co-directional to the reverse, the motion state of the rock mass at the slope top changes from slipping to toppling, and the role of karst fissure changes from a potential slip surface to the cracking boundary. Although the deformation damage of the reverse structural slope is not very serious, the influence of the karst fissure on the stability of the slope still cannot be ignored. This study aims to provide basic theoretical support for the subsequent research on the failure mechanism of karst mountains under the combined action of multi-structural planes.

Performance of a Tower-Shaped Integrated Ecological Purification Device for Pollutants Removal from Domestic Sewage in Rural Areas

With the continuous development of China's modern economy and agricultural society, the discharge of rural sewage has been recognized as a major threat to the safety of the rural ecological environment. This study discussed the purification efficiency of a tower-shaped integrated ecological purification device (TIEPD)-consisting of a measuring tank, detention tank and three-stage purification unit-towards various common pollutants in rural areas during operation and tested the stability and efficiency of the TIEPD under different rural life events (fair activity days and nonfair activity days) and different precipitation intensities (light rain, moderate rain and heavy rain). The results showed that the average removal efficiencies of the TIEPD towards chemical oxygen demand, ammonia nitrogen, total nitrogen and total phosphorus were 69%, 67%, 54% and 73%, respectively. The average effluent concentration of each pollutant can meet the standard of the discharge of pollutants in China. The system exhibited good stability in removing pollutants and good ecological and economic benefits. This study provides the treatment of domestic sewage in the upper reaches of the Yangtze River and in mountainous areas of China and strengthens the prevention and control of rural nonpoint source pollution.