Search Results (16)

Rural tourism plays a crucial role in promoting industrial revitalization in mountainous regions. Drawing inspiration from the site selection mechanisms of nature reserves, this study constructs a gap analysis framework tailored to rural tourism destinations, aiming to provide technical support for their spatial layout and systematic planning. By integrating a potential evaluation system based on tourism resources, market demand, and synergistic factors, the study identifies rural tourism priority zones and proposes a development typology and spatial optimization strategy across five provinces in Southwest China. The findings reveal: (1) First- and second-priority zones are primarily located in the core and periphery of provincial capitals and prefecture-level cities, while third-priority zones are concentrated in resource-rich areas of Yunnan and Guizhou and market-oriented areas of Sichuan, Chongqing, and Guangxi. (2) The Chengdu Plain emerges as the core region for rural tourism development, with hotspots clustered around Chengdu, northern and western Guizhou, central Chongqing, eastern Guangxi, and northwestern Yunnan, whereas cold spots are mainly situated in the western Sichuan Plateau and the Leshan–Liangshan–Zhaotong–Panzhihua–Chuxiong–Pu’er belt. (3) The alignment between tourism resources and rural tourism destinations is highest in Yunnan and Guizhou, while Chongqing exhibits the strongest match between destinations and tourism market potential and synergistic development conditions. Overall, 79.35% of rural tourism destinations in the region are situated within identified priority zones, with Chongqing, Guizhou, and Sichuan exhibiting the highest proportions. Based on the spatial mismatch between potential and existing destinations, the study delineates four development types—maintenance and enhancement, supplementation and upgrading, expansion, and reserve development—and offers regionally tailored planning recommendations. The proposed framework provides a replicable approach for spatial planning of rural tourism destinations in complex mountainous settings. Full article

The content of the watercore in apples plays a decisive role in their taste and selling price, but there is a lack of methods to accurately assess it. Therefore, this paper proposes an OCRNet-based method for apple watercore content evaluation. A total of 720 watercores of apples from Mengzi, Lijiang, and Zhaotong City in Yunnan Province were used as experimental samples. An appropriate watercore extraction model was selected based on different evaluation indicators. The watercore feature images extracted using the optimal model were stacked, and the watercore content of apples in different regions was evaluated by calculating the fitted area of the stacked watercore region. The results show that the OCRNet model is optimal in all evaluation metrics when facing different datasets. The error of OCRNet is also minimized when extracting overexposed as well as underexposed images with 0.15% and 0.38%, respectively, and it can be used to extract the characteristics of the apple watercore. The evaluation result of the watercore content of apples in different regions is that Lijiang apples have the highest watercore content, followed by Mengzi apples, and Zhaotong apples have the least watercore content. Full article

The Baihetan Reservoir is built for hydropower in China. The rise of the reservoir water leads to a series of earthquakes in the surrounding area. This study proposes fully coupled equations of pore-viscoelasticity and a parallel partition mesh model to study the short- and long-term effects of the Baihetan Reservoir and further calculate the changes in stress, pore pressure, and Coulomb failure stress with time on the major faults. Based on the calculation results, impoundment increases regional seismicity, which is consistent with the seismic catalog. The reservoir impoundment causes an increase in pore pressure in the crust, primarily enhancing Coulomb failure stress beneath the reservoir center. This effect extends to approximately 60 km in length and 20 km in width at a depth layer of 5–10 km. Seismicity varies greatly among different faults. Coulomb failure stress increases on the northern part of the Xiaojiang Fault and Zhaotong-Ludian Fault, and decreases on the southern part of the Xiaojiang Fault and Zemuhe Fault. The Coulomb failure stress is highly correlated with the number of earthquakes along the Xiaojiang Fault. The influence of the reservoir on the local seismicity is mainly limited to several months, and it has a slight effect later on. The focal depth of the induced earthquakes increases while the magnitude decreases. The earthquakes caused by the impoundment all have a small magnitude, and the $M_{s}4.3$ Qiaojia earthquake on 30 March 2022, was more likely a natural event. Full article

The Zhaotong area in Yunnan Province stands out as one of the most susceptible areas to landslide disasters. The landslide susceptibility of the Zhaotong area can be attributed to its steep terrain, fractured rock formations and strong rainfall, compounded by its frequent seismic activity. This study utilized landslide data provided by the Zhaotong City Natural Resources and Planning Bureau and visually interpreted from high-resolution satellite images of Google Earth to establish the landslide database of the Zhaotong area, including 161 landslides and 3646 potential geological disasters. The distribution characteristics and possible influencing factors of landslides within the Zhaotong area were analyzed using the aforementioned data. The results show that the spatial distribution of landslides and potential geological disasters is roughly consistent; the most concentrated landslides occurred at the junction of Yiliang County, Zhaotong City, and Daguan County, indicating the necessity to enhance surveillance of these landslide-prone areas. The relationship of landslide locations and different influencing factors suggests that elevation, slope angle, and distance to rivers are closely related to landslide occurrence. Landslides are more likely to occur in areas with lower elevations with slope angles ranging from 10° to 40° and near river channels. Full article

Micro- and nano-scale pores develop in shale reservoirs, and the associated pore structure controls the occurrence state, gas content, seepage capacity, and micro-migration and accumulation mechanisms of shale gas. For this study, we mainly conducted tests, using field emission-scanning electron microscopy, of the isothermal methane adsorption of powder-sized samples under high temperatures (60–130 °C) and pressures (0–45 MPa), along with methane-saturated nuclear magnetic resonance tests of plug-sized samples under different temperatures (60–100 °C) and pressures (0–35 MPa). These samples were from Longmaxi shale cores from strata at different burial depths from the Zhaotong, Weiyuan, and Luzhou areas. As the burial depth increases, organic pores transform from complex networks to relatively isolated and circular pore-like structures, and the proportion of organic matter-hosted pores increases from 25.0% to 61.2%. The pore size is influenced by the pressure difference inside and outside the pores, as well as the surface tension of organic matter in situ. As the burial depth increases to 4200 m, the main peak of the pore size first increases from 5–30 nm to 200–400 nm and then decreases to 50–200 nm. This work establishes an NMR method of saturated methane on plug-sized samples to test the free gas content and develop a prediction model of shale reservoirs at different burial depths. The gas content of a shale reservoir is influenced by both burial depths and pore structure. When the burial depth of the shale gas reservoir is less than 2000 m, inorganic pores and microfractures develop, and the self-sealing ability of the reservoir in terms of retaining shale gas is weak, resulting in low gas content. However, due to the small pore size of organic pores and the low formation temperature, the content of adsorbed gas increases, accounting for up to 60%. As the burial depth increases, the free gas and total gas content increase; at 4500 m, the total gas content of shale reservoirs is 18.9 m³/t, and the proportion of free gas can be as high as 80%. The total gas content predicted by our method is consistent with the results of the pressure-holding coring technique, which is about twice our original understanding of gas content, greatly enhancing our confidence in the possibility of accelerating the exploration and development of deep shale gas. Full article

Estimating the effectiveness of hydraulic fracturing in the context of the incrfease in the shale gas demand is of great significance for enhancing shale gas production, which aims to substantially reduce fossil energy consumption and CO₂ emissions. The Zhaotong national shale gas demonstration zone has complex stress structures and well-developed fracture zones, and thus it is challenging to achieve targeted reservoir segment transformation. In this paper, we construct and optimize the geometry of hydraulic fractures at different pressures considering the upper and lower barriers in hydraulic fracturing simulation experiments and numerical modeling. The numerical simulation results show that the pore pressure exhibits a stepped pattern around the fracture and an elliptical pattern near the fracture tip. During the first time of injection, the pore pressure rapidly increases to 76 MPa, dropping sharply afterward, indicating that the fracture initiation pressure is 76 MPa. During the fracture propagation, the fracture length is much greater than the fracture height and width. The fracture width is larger in the middle than on the two sides, whereas the fracture height gradually decreases at the fracture tip in the longitudinal direction until it closes and is smaller near the wellbore than at the far end. The results revealed that the fracture width at the injection point reached the maximum value of 9.05 mm, and then it gradually decreased until the fracture width at the injection point dropped to 6.33 mm at the final simulation time. The fracture broke through the upper and lower barriers due to the dominance of the effect of the interlayer principal stress difference on the fracture propagation shape, causing the hydraulic fracture to break through the upper and lower barriers. The results of the physical simulation experiment revealed that after hydraulic fracturing, multiple primary fractures were generated on the side surface of the specimen. The primary fractures extended, inducing the generation of secondary fractures. After hydraulic fracturing, the width of the primary fractures on the surface of the specimen was 0.382–0.802 mm, with maximum fracture widths of 0.802 mm and 0.239 mm, representing a decrease of 70.19% in the maximum fracture width. This work yielded an important finding, i.e., the urgent need for hydraulic fracturing adaptation promotes the three-dimensional development of a gas shale play. Full article

Forest ecological security is related to national ecological security. Yunnan Province has a significantly stereoscopic climate characterized by diverse and complex vegetation. Therefore, the ecological security of Yunnan Province’s forests, which span multiple climate zones, must be carefully considered. The purpose of this study is to evaluate the forest ecological security situation and influencing factors in Yunnan Province in 2017. Utilizing data from remote sensing, the Yunnan Province Yearbooks, socioeconomic statistical data, and better pressure-state-response modeling, this work produced an index system containing state and societal pressure. The evaluation indicators were weighted using a combination of entropy weighting and expert weighting, using 16 prefectures in Yunnan Province as samples. Using the fuzzy matter-element technique, the forest ecological security situation in Yunnan Province in 2017 was assessed, and the contributing causes were examined. Results indicate that there are spatial distribution differences in ecological security in various regions of Yunnan Province. The regions with the greatest indices of forest ecological security were found in Xishuangbanna in the south and Nujiang and Diqing in the northwest of Yunnan Province, while those areas with the lowest indices were distributed in Qujing and Zhaotong in the northeast and Baoshan in the west. Results of the grey relation analysis show that those factors that influence forest ecological security across different prefectures showed significant diversity. In Yunnan Province, the main influencing factors include days when the air quality reaches Level 2 or higher, the percentage of natural forest acreage and accumulation, the value of forest ecological service function per unit area, the annual average temperature, and forest coverage. The influence of the forest status index was greater than that of the forest pressure index. The findings of this work can guide decisions related to regional forest ecological security construction across multiple climate zones. In view of the differences in ecological security status and influencing factors in different regions, ecological environment governance should be adapted to local conditions to ensure the coordinated development of nature, the economy, and the ecological environment. Full article

Zhaotong City in Yunnan Province is one of the largest apple growing bases in China. However, the terrain of Zhaotong City is complicated, and the rainy weather is more frequent, which brings difficulties to the identification of apple orchards by remote sensing. In this paper, an improved spectral angle feature is proposed by combining the Spectral Angle Mapper and Sentinel-1 data. Based on the Google Earth Engine and Sentinel image, a random forest classifier was used to extract apple orchards in the Ganhe Reservoir area, Zhaoyang District, Zhaotong City, which provides a theoretical basis for extracting the spatial distribution and sustainable development of the local apple industry. The classification results show that the improved spectral angle characteristics can improve the overall accuracy and F1 score of apple orchards. The RGB band combined with NDVI, GLCM, and improved spectral angle features obtained the most favorable results, and the F1 score and overall accuracy were 88.89% and 84.44%, respectively, which proved the reliability of the method in identifying apple orchards in Zhaotong City. Full article

Timely and quantitatively evaluating regional eco-environmental quality (EEQ) is of great significance for realizing regional sustainable development goals. Especially for cloudy areas, it was a great challenge to construct a regional EEQ dataset with high quality and high resolution. However, existing studies failed to consider the influence of land surface and season elements in evaluating regional EEQ. Therefore, this study aimed to promote an accurate EEQ-evaluating framework for cloudy areas. Zhaotong city, a typical karst and cloudy region, was chosen as the study area. First, we integrated multi-source spatiotemporal datasets and constructed a novel eco-environmental comprehensive evaluation index (ECEI) to assess its EEQ from 2000 to 2020. Next, standard deviation ellipse (SDE) and trend analysis methods were applied to investigate regional EEQ’s change trends. Finally, ecological index (EI) values for different years were calculated to validate the effectivity of the ECEI. The main findings were as follows: (1) The EEQ of Zhaotong showed an upward-fluctuating trend (0.0058 a⁻¹), with average ECEI values of 0.729, 0.693, 0.722, 0.749, and 0.730. (2) The spatial distribution pattern of the EEQ showed high values in the north and low values in the south, with Zhaoyang district having the lowest ECEI value. (3) From 2000 to 2020, the standard deviation of the major axis of the ellipse moved northeast of Zhaotong city with θ of SDE changing from 57.06° to 62.90°, thus, indicating the improvement of northeastern regions’ EEQ. (4) The coefficients of the determinant (R²) between the EI and ECEI were 0.84, which was higher than that of EI–RSEI (R² = 0.56). This indicated that our promoted framework and the ECEI could acquire more accurate EEQ results and provide suggestions for relevant policymakers. Full article

Village classification schemes and development strategies have important theoretical and practical significance for realizing rural revitalization. Mountainous villages account for a large proportion of China’s rural areas, which is a challenge to rural revitalization. This study takes the mountainous region of Zhaotong, Yunnan Province, and the “National Strategic Plan for Rural Revitalization (2018–2022)” to construct an evaluative index of village development potential and a village classification model, and proposes regulation strategies and the classification and stratification public service configuration scheme for different types of village. The research results show that (1) when evaluating development potential, terrain factors such as slope and geological hazards should be included; (2) the distribution of development potential in Zhaotong has obvious heterogeneity; (3) villages in Zhaotong are divided into five types for development: agglomeration and upgrading, suburban integrated, relocated and merged, characteristic conservation, and temporarily ambiguous types; and (4) the order of greatest to least number of village types is agglomeration and upgrading > suburban integrated > relocated and merged > temporarily ambiguous > characteristic conservation. The agglomeration and upgrading, relocated and merged, and suburban integrated types are relatively concentrated spatially. The characteristic conservation and temporarily ambiguous types are more scattered. Based on the above research results, it is suggested that villages be renovated and public service facilities be configured on different levels, according to the characteristics of different village types. During renovation, special emphasis is placed on preserving the original style of the village and protecting and respecting the will of the villagers. The strategy for developing village infrastructure and public service facilities should be dynamically adjusted according to village type. Full article

Pore and its structural characteristics are key parameters affecting shale gas reservoir development. Accurate quantitative characterization of shale pore and its structural characteristics is of great significance for evaluating shale reservoir state. In this study, 15 shallow marine shale samples were collected in Well Y108. X-ray diffraction results indicate that brittle minerals are the most common components in shale. In this paper, various pore types are classified and characterized by scanning electron microscope images. The total porosity of shale measured by the mercury intrusion method is between 3.2% and 6.5%. In addition, a petrophysical model is established to calculate matrix porosity and fracture. The results of this model are consistent with the measured porosity. Three key parameters (V_TOC > V_Bri > V_Clay) were obtained. The low-pressure N₂/CO₂ adsorption experiment allows for the analysis of pore volume, specific surface area, and pore size. Finally, it was determined that the primary pore types and primary shale gas reservoir space in shallow marine shale are mesopores and micropores. The impact of shale constituents on pores and their structural properties is also covered in this work. The results indicate that the enrichment of total organic carbon and brittle minerals is conducive to the development of shallow marine shale pore-fracture system. Additionally, there is a positive linear relationship between matrix porosity, pore volume, specific surface area, average pore diameter, and surface porosity. Full article

In order to study the characteristics and causes of ozone (O₃) pollution in 16 cities of Yunnan Plateau, the methods of COD, backward trajectory and potential source contribution function (PSCF) were used to analyze the O₃ concentrations from 2015 to 2020 of all state-controlled environmental monitoring stations in 16 cities of Yunnan. The results show that the O₃ concentrations in Yunnan gradually increased from 2015 to 2019, and the concentration in 2020 was the lowest due to the COVID-19 pandemic. The peak O₃ concentration appears in spring. The daily change trend is a typical single peak shape, the lowest value appears around 8: 00, and the highest value is between 15:00 and 16:00. High concentrations of O₃ are from the cities of Zhaotong and Kunming in northeastern Yunnan, while low concentrations of O₃ mainly occur in the southwest and northwest border areas. Temperature and relative humidity are two meteorological parameters that have significant effect on O₃ concentration. Temperature has the best correlation with O₃ in winter, and relative humidity has a better correlation with O₃ in autumn and winter than in spring and summer. Finally, source analysis of O₃ showed that local ozone precursor emission sources and long-distance transmission from South and Southeast Asia constituted the major contributions of O₃ in Yunnan. Full article

Trade-offs and conflicts among different sectors of production, living, and ecology have become important issues in regional sustainable development planning due to both the versatility and limitation of land resources, especially in poverty-stricken mountainous areas. This study builds an optimization model to assist policymakers in simulating land demand and allocation in the future. The model takes socioeconomic and demographic development into consideration and couples local planning policy with land use data from the perspective of system integration. The model was employed for a case study of Zhaotong city to optimize production–living–ecological (PLE) space. The results show that the model provides a feasible method to explore the sustainable development pattern of territorial space, especially in distressed regions. Full article

Based on 243 current valid distribution records for six wild strawberry species in China and data on 20 environmental variables, the geographical distributions of and potentially suitable areas for the wild strawberry species in Yunnan Province (China) under the current climate scenario were explored using the MaxEnt model and ArcGIS software, and major environmental variables affecting their geographical distributions were evaluated. In addition, the spatio-temporal dynamic patterns of the suitable areas for the six wild strawberry species in Yunnan Province in the 2050s and 2070s under the two climate models of RCP2.6 and RCP8.5 were predicted. Under the current climate scenario, the six wild strawberry species have suitable areas in Yunnan Province, which were mainly distributed in the high-altitude and low-temperature regions in the northwest and northeast, such as Diqing and Zhaotong. In addition, the average size of the highly suitable area for diploid wild strawberry species was greater than that for tetraploid species. Under the future climate scenarios, the average size of the highly suitable area for diploid species showed a tendency to expand, while that of tetraploid species showed a tendency to shrink. Altitude was a critical variable affecting the distribution of tetraploid species. Under the two future climate models of RCP2.6 and RCP8.5, the suitable areas for wild strawberry species shifted to the regions of high latitude, high altitude, and low temperature. In addition, the average distance in the shift of the suitable area for tetraploid strawberry species was greater than that for the suitable area for diploid strawberry species. The above results provide valuable information for the management and protection of the germplasm resources of Fragaria. Full article

Rocky desertification is an important type of ecological degradation in southwest of China. The author uses the web crawler technology and obtained 9345 journal papers related to rocky desertification from 1950s to 2016 in China. The authors also constructed a technological process to extract research hot regions on rocky desertification and then a spatial distribution map of research hot regions on rocky desertification was formed. Finally, the authors compared the spatial distribution using the sensitivity map of rocky desertification to find the differences between two maps. The study shows that: (1) rocky desertification research hot regions in China are mainly distributed in Guizhou, Yunnan and Guangxi, especially in Bijie, Liupanshui, Guiyang, Anshun, Qianxinan Autonomous Prefecture, QianNan Autonomous Prefecture, Qiandongnan Autonomous Prefecture in Guizhou Province, Hechi, Baise, Nanning, Guilin in Guangxi Zhuang Autonomous Region and Zhaotong in Yunnan Province. (2) The research hot regions on rocky desertification have good spatial consistency with the sensitivity regions of rocky desertification. At the prefecture level, the overlap rate of the two regions reached 85%. Because of the influence of topography, vegetation coverage, population distribution, traffic accessibility and other factors, there were regions that consisted of combinations of high sensitivity but low research popularity regarding rocky desertification; these sites included Qionglai Mountain-Liangshan Area of Sichuan, Wushan-Shennongjia Area of Hubei, Hengduan Mountain Area of western Yunnan and Dupangling Area of southern Hunan. (3) The research hot regions and sensitive regions cannot be matched completely in time, space and concept. Therefore, we can use their spatial distribution differences to improve the pertinence of planning, governance and study of rocky desertification. Full article