Yuzhong County Research Articles

First Report of Basal Stem Rot of Achnatherum inebrians Caused by Fusarium pseudograminearum in China.

Drunken horse grass (Achnatherum inebrians) is a perennial bunchgrass that is widely distributed in arid and semi-arid grasslands in northwest China (Zhang et al., 2021). In July 2023, Basal stem rot was found in artificially grown drunken horse grass plots in Yuzhong County (35.85° N, 104.12° E), Gansu Province, China, with an average incidence of 5.2%. Diseased plants showed crown and basal stem rot with chocolate brown discoloration at the base of the stem and slight constriction of some basal stems. Five field's foci were surveyed and at least 6 basal stems per focus were collected. Infected basal stems were surface-sterilized (75% ethanol for 30 s and 1% NaClO for 90 s), rinsed three times with sterilized water, placed on potato dextrose agar (PDA), and incubated at 22°C in the dark for 3 days. Isolates were purified by single spore cultures (Leslie and Summerell, 2006). The average mycelial growth rate was 4.8 to 7.5 mm/day at 25°C on PDA, and the colonies produced aerial mycelium varying from rose to yellow white, and rose to burgundy pigment diffused into the agar. Macroconidia of the isolates were produced on carnation leaf agar (CLA) incubated under black light and observed to be abundant, but no microconidia were found. Macroconidia were relatively slender, curved to almost straight, commonly 3-6 septate, averaging 30.1 × 3.8 μm (n=50). The morphological characteristics of this fungus fully fit the description of F. pseudograminearum (Aoki and O'Donnell, 1999). To obtain the phylogenetic support, DNA of three representative isolates YZ-Y-1, YZ-Y-2 and YZ-Y-3 was extracted by using an HP Fungal DNA Kit (D3195), and a portion of the RNA polymerase II second largest subunit (RPB2) gene and elongation factor 1 alpha (EF1-α) gene were amplified using primers RPB2-5f2 and RPB2-7cr (O'Donnell et al. 2010) and EF1 and EF2 (O'Donnell et al. 1998), respectively. Results of sequences were deposited in GenBank (accession nos. PP179044 to PP179049). A nucleotide BLAST search revealed RPB2 and EF1-α sequences to be 99.8 and 100% similar to the corresponding sequences of the ex-type strain NRRL 28062 F. pseudograminearum accessions numbers MW233433 and MW233090, respectively. For pathogenicity tests, 15 μl of conidia suspension (1×106 conidia/ml) was inoculated into the stem bases of 10 healthy drunken horse grass seedlings (around 3 weeks old) using a sterile syringe, then wrapped with moistened sterile gauze, while the other 10 drunken horse grass seedlings were injected with sterile water as a control. All seedlings were placed in a greenhouse with a plastic cover at 15-22°C and 90-100% relative humidity. All inoculated drunken horse grass seedlings showed symptoms similar to those of natural infection with stem basal rot, whereas uninoculated drunken horse grass seedlings remained healthy after 15 days. Fungi re-isolated from the basal stems of inoculated plants were confirmed phenotypically and molecularly as F. pseudograminearum. To our knowledge, this is the first report of F. pseudograminearum causing crown rot of drunken horse grass in China. The disease has become a potential threat to the growth of drunken horse grass in China.

Non-Linear Relationships between Fine Root Functional Traits and Biomass in Different Semi-Arid Ecosystems on the Loess Plateau of China

As a key soil carbon process, changes in plant root growth may have a dramatic impact on the global ecosystem’s carbon cycle. Fine root functional traits and fine root biomass can be used as important indexes of plant root growth. Compared with the much better understood relationships between aboveground plant functional traits and aboveground biomass, knowledge on the relationships between fine root functional traits and belowground biomass still remains limited. In this study, plant fine roots in 30 abandoned lands, 9 woodlands, 29 alfalfa grasslands, 30 Caragana shrublands and 29 croplands were sampled at 0–20 and 20–40 cm soil depths in Zhonglianchuan, Yuzhong County, Gansu Province, China (36°02′ N, 104°24′ E), to clarify the characteristics of the relationships between fine root functional traits (e.g., diameter, specific root area (SRA) and specific root length (SRL)) and fine root biomass at 0–20 and 20–40 cm soil depths. The results showed that the relationships between the fine root functional traits and fine root biomass in these ecosystems were robust, allowing for the use of an allometric growth model at both 0–20 and 20–40 cm soil depths (p < 0.05). Specifically, the relationship between root diameter and fine root biomass was consistent with highly significant positive power, while highly significant negative power relationships of SRA and SRL with fine root biomass were observed (p < 0.01, except the root diameter–biomass models in the woodlands in the 0–20 cm soil layer (p = 0.017) and 20–40 cm soil layer (p = 0.025)). The results can provide some parameters for these terrestrial ecosystem process models. From this perspective, our study is beneficial in the construction of suitable strategies to increase plant biomass, which will help with the restoration of the semi-arid region of the Loess Plateau of China.

Extraction of Lilium davidii var. unicolor Planting Information Based on Deep Learning and Multi-Source Data.

Accurate extraction of crop acreage is an important element of digital agriculture. This study uses Sentinel-2A, Sentinel-1, and DEM as data sources to construct a multidimensional feature dataset encompassing spectral features, vegetation index, texture features, terrain features, and radar features. The Relief-F algorithm is applied for feature selection to identify the optimal feature dataset. And the combination of deep learning and the random forest (RF) classification method is utilized to identify lilies in Qilihe District and Yuzhong County of Lanzhou City, obtain their planting structure, and analyze their spatial distribution characteristics in Gansu Province. The findings indicate that terrain features significantly contribute to ground object classification, with the highest classification accuracy when the number of features in the feature dataset is 36. The precision of the deep learning classification method exceeds that of RF, with an overall classification accuracy and kappa coefficient of 95.9% and 0.934, respectively. The Lanzhou lily planting area is 137.24 km2, and it primarily presents a concentrated and contiguous distribution feature. The study's findings can serve as a solid scientific foundation for Lanzhou City's lily planting structure adjustment and optimization and a basis of data for local lily yield forecasting, development, and application.

Luobuma Leaf Spot Disease Caused by Alternaria tenuissima in China.

Luobuma (Apocynum venetum and Poacynum hendersonni) is widely cultivated for environmental conservation, medicinal purposes and the textile industry. In 2018, a severe leaf spot disease that attacked the leaves of Luobuma was observed in plants cultivated in Yuzhong County, Gansu Province, China. Symptoms of the disease appeared as white or off-white spots surrounded by brown margins on the leaves of A. venetum. The spots expanded and covered a large area of the leaf, presenting as "cankers" with progression of the disease, leading to leaf death. The initial symptoms of the disease on P. hendersonni were similar to the symptoms of A. venetum, with a larger disease spot than A. venetum, and the spot was black and thicker. The aim of this study was to identify the fungal species and evaluate the effectiveness of fungicides (hymexazol and zhongshengmycin) against the pathogen in vitro. The fungi species that caused the new disease was identified as Alternaria tenuissima based on the morphological characteristics, pathogenicity tests, and phylogenetic analysis of the internal transcribed spacer (ITS) region, glyceraldehyde 3-phosphate dehydrogenase (gpd), translation elongation factor 1-alpha (TEF) and the histone 3 (H3) gene sequences. The findings showed that hymexazol fungicide can be used to control leaf spot disease. This is the first report on Luobuma leaf spot disease caused by A. tenuissima in China.

Analysis of the spatial and temporal distribution characteristics of AOD in typical industrial cities in northwest China and the influence of meteorological factors

The spatiotemporal distribution characteristics of AOD in Lanzhou City over the past decade, as well as the influence of meteorological factors, were analyzed using the MODIS MCD19A2 dataset from 2011 to 2022. Spatial Distribution: The annual average AOD in the study area was found to be 0.278. High AOD values were observed in the main urban area and surrounding low-altitude regions, while low AOD values were observed in the high-altitude mountainous areas in the northwest and southeast. The main urban area exhibited significantly higher AOD levels compared to the three surrounding counties. Temporal Trends: Influenced by air pollution control policies, the AOD in Lanzhou City started decreasing notably from 2014, with a total decrease of −27.18%. The overall trend displayed fluctuations and a downward pattern. The seasonal variation of AOD in Lanzhou City was evident, with the order of magnitude being spring > winter > autumn > summer. The AOD in Yuzhong County was particularly high in spring. There is spatial heterogeneity in the impact of meteorological factors on AOD in Lanzhou. Temperature exhibits greater significance in the central part of Lanzhou, while precipitation shows greater significance in the eastern part of the city, and wind speed is notably significant in the western and eastern parts of Lanzhou. Temperature, relative humidity, and wind speed are positively correlated with AOD, while precipitation and atmospheric pressure are negatively correlated with AOD. Three primary sets of interacting factors were identified: temperature and wind speed, temperature and relative humidity, and temperature and precipitation.

First Report of Fusarium solani and Fusarium oxysporum Causing Basal Stem Rot on Celery in China.

Celery (Apium graveolens L.) is an economically important vegetable crop in China. In recent years, celery has been widely planted in Yuzhong county, Gansu province. From 11 April to 24 May, 2019-2021, basal stem rot of celery was observed with incidences up to 15% in the Yuzhong region (35°49'N, 104°16'E, 1865 m a.s.l.), which caused serious economic losses to local farmers. Typical symptoms of the disease included wilting and darkening of the basal stem, leading to plant death. To identify the cause of the disease, small pieces (5mm×5mm) of the margin of asymptomatic and rotting basal stem tissues were sterilized with 70% ethanol for 30 s and 3% NaClO for 5 min, then placed on potato dextrose agar (PDA) plates, and incubated at 25℃ (Zhao et al. 2021). Twenty-seven single-conidium isolates with morphological characteristics similar to Fusarium spp. were obtained (Ma et al. 2022), which displayed two kinds of colony morphology. On PDA, seven isolates developed white, fluffy aerial mycelium and twenty isolates developed light pink abundant aerial mycelium. Isolate F5 and F55 from each distinct morphological group were cultured on PDA and synthetic low nutrient agar (SNA) for pathogenicity tests, morphological and molecular identification. The macroconidia (18.3 to 29.6 × 3.6 to 5.3 μm, n=50) with 1 to 2 septa and microconidia (7.5 to 11.6 × 2.6 to 3.5 μm, n=50) with 0 to 1 septum were observed in F5. For F55, the size of macroconidia was 14.2 to 19.5 × 3.3 to 4.2 μm (n = 50) with 1 to 2 septa; Microconidia were mostly 0 to 1 septum and measured 7.3 to 12.8 × 2.2 to 4.2 μm (n = 50). To confirm the identity of the isolates, the internal transcribed spacer region (ITS) and the translation elongation factor-1 alpha (TEF-1α) gene were amplified using primers ITS1/ITS4 and EF-1/EF-2 (Uwaremwe et al. 2020), respectively. The sequence similarities of isolate F5 (GenBank No. OL616048 and OP186480) and F55 (GenBank No. OL616049 and OP186481) with the corresponding sequences of F. solani (MT447508 and MN650097) and F. oxysporum (MG461555 and OQ632904) ranged from 99.22% to 100.00%, with matching base pairs of 531/532, 416/416, 511/515 and 394/395, respectively. The voucher samples were deposited in the sample center of Northwest Institute of Ecological Environment and Resources, Chinese Academy of Sciences. Morphological and molecular results confirmed the species of F5 and F55 as F. solani and F. oxysporum, respectively. A pathogenicity test was conducted under greenhouse conditions (19-31°C, avg. 26°C). Conidial suspension (105 spores/mL) of isolates F5 and F55 were poured onto the basal stems of healthy celery seedlings at the age of 1 month and mock-inoculated control treatments with sterile water. Ten plants were inoculated for each treatment. After 21 days, all plants inoculated with both fungal isolates developed symptoms similar to those observed in the field, whereas the mock-inoculated plants remained healthy. The pathogen was successfully reisolated from the inoculated symptomatic plants onto PDA medium and had morphology as described above, confirming Koch's postulates. F. solani and F. oxysporum have been reported to infect many plant species, including carrot (Zhang et al. 2014) and Angelica sinensis (Liu et al. 2022). To our knowledge, this is the first report that F. solani and F. oxysporum cause basal stem rot on celery in China. The identification of pathogens of the observed basal stem rot on celery provides a clear target for the prevention and management of this disease.

Zoning and Management of Ecological Restoration from the Perspective of Ecosystem Service Supply and Demand: A Case Study of Yuzhong County in Longzhong Loess Hilly Region, China

The loess hilly region is a typical ecologically fragile and sensitive area. It is of great significance when measuring the balance between supply and demand of ecosystem services and clarify the relationship between supply and demand of ecosystem services for scientific ecological restoration zoning and realizing regional ecological security and social and economic sustainable development. We take Yuzhong County in the loess hilly region of Longzhong, China as an example; by constructing the matching and coordinating relationship between ecosystem service supply and demand and following the idea of “problem diagnosis—strategic orientation—key optimization”, this paper delimits the ecological restoration zones and proposes corresponding governance strategies. The results show that: (1) The supply and demand of ecosystem services were mainly at a low and medium level, with significant spatial heterogeneity. Overall, the spatial pattern of ecosystem services showed high supply and low demand in the southwest mountainous areas and showed low supply and high demand in the urban gully areas of Yuzhong. (2) There were four types of spatial matching of ecosystem service supply and demand: HH type, LH type, LL type, and HL type. The local spatial autocorrelation of supply and demand was dominated by high-low or low-high spatial misadjustment. The average degree of coordination between supply and demand of ecosystem services was 0.629, indicating that supply and demand were basically coordinated. (3) The ecological restoration zones in Yuzhong County can be divided into six categories: the ecological core protection area, ecological potential restoration area, key ecological restoration area, soil and water conservation restoration area, ecological agriculture development area, and ecological innovation promotion area. The results of this study can provide ideas for the refined management and targeted restoration practice of regional ecosystem services. It provides a strong guarantee for ecosystem management and decision-making in the loess hilly region.

Renovation Potential Evaluation and Type Identification of Rural Idle Residential Land: A Case Study of Yuzhong County, Longzhong Loess Hilly Region, China

The land problem is the key to the implementation of the rural revitalization strategy, and the land suitability evaluation is the basis for the renovation and classification of idle rural residential areas. Taking Yuzhong County in the Loess Hilly region of Longzhong, China as the research area, this study constructed an idle residential identification matrix by combining the evaluation results of ecological protection suitability, agricultural production suitability, and construction and development suitability, and realizing renovation zoning of rural residents through the advantage type identification method. The results show that: (1) The waste in rural residential is serious, and there are significant phenomena of “one household with two houses” and “one household with multiple houses.” The renovation potential of 1700 idle rural residential patches is 1.18 km2. (2) The spatial differences in the suitability of rural residents in Yuzhong County are significant, and through the rational guidance and planning layout of rural residential renovation, it can provide an important decision-making basis for the rational utilization of rural residents and national land–space planning. (3) The renovation of rural residential should be guided by national land–space planning; make a solid plan for the renovation of rural residential areas; formulate a scientific plan for the renovation, relocation, and reuse of rural “hollow houses”; stimulate the vitality of rural land resources; and promote the revitalization of the countryside and the improvement of the rural living environment.

Characterization of Boeremia exigua causing stem necrotic lesions on Luobuma in northwest China

Luobuma (Apocynum venetum, Poacynum pictum, and P. hendersonni) are perennial herbs widely used in the textile and medical industries and ecological restoration. In the summer of 2020, reddish-brown or off-white sunken shape necrotic lesions were observed on the stems and shoots of seven Luobuma ecotypes grown in the field in Yuzhong County, Gansu province of China, which is a limiting factor that affects the growth, function and application of Luobuma. To make clear whether the new symptoms were caused by a novel pathogen, a combined research in field and greenhouse was conducted. Based on the morphological and molecular analysis results, the pathogen causing the necrotic lesions was identified as Boeremia exigua var. rhapontica. The incidence and disease index of the seven ecotypes in the field ranged from 11.49 to 33.68% and 6.63 to 23.01, respectively, from 2020 to 2021. The results showed that the disease severity gradually increased with the growing season. According to the pathogenicity analysis of the eight ecotypes in the greenhouse, the ecotypes Pp-BMK and Pp-BMH were susceptible, while ecotype Pp-BMQ was resistant to Boeremia exigua var. rhapontica infection. Thus, the present study provides a theoretical basis for preventing and controlling the stem and leaf necrotic lesions disease on Luobuma by planting resistant varieties/ecotypes. To our knowledge, this is the first report of stem necrotic lesions and leaf spots on Luobuma caused by B. exigua var. rhapontica.

The Integrated Impact of Drought on Crop Yield and Farmers’ Livelihood in Semi-Arid Rural Areas in China

Drought has a profound impact on crop yield and the subsistence farming economy in arid and semi-arid lands of developing countries. It creates insecurity in the food supply and livelihood of rural farmers, leading to different livelihood trajectories and transformations. However, a primary challenge is to examine the complexity and location-specificity of drought impact. This study proposes a conceptual framework to understand the integrated drought impact on Yuzhong County in Gansu Province, China. Specifically, the study applies the standardized precipitation index at different time scales to observe drought changes from 1960 to 2017 and estimates the correlation with crop yield. Then, farmers in the northern, central, and southern regions of Yuzhong County were categorized using two-step cluster analysis, based on survey data collected from 1013 interviews conducted in the three regions. The study explores the impact of drought on the livelihood and food security of different clusters of farmers and analyzes their livelihood trajectories and transformations. The results showed that the drastic years with moderate and severe droughts were 1981–1983, 1997, and 2011–2012. Drought was significantly correlated with crop yield, and the effect of SPI12 was more severe. Five clusters of farmers in the southern regions of Yuzhong county were affected by drought with large drought disaster areas and serious economic losses, leading to high rates of affordability deficit and food insecurity, especially in the southern region. As a result, farmers have been adapting their livelihoods to drought, transforming toward mixed livelihoods in the northern region and part-time agricultural livelihoods in the central and southern regions. This study recommends an increase in public investment in water conservancy and irrigation facilities and suggests that locations and policies be utilized to promote the transformation of farmers’ livelihoods to make them more resilient.

Risk Assessment and Attribution Analysis of "Five Toxic" Heavy Metals in Cultivated Land in Lanzhou

Heavy metals in cultivated soil may migrate and transform through the food chain to harm the ecological environment and human health. At present, the ecological environment and human health risks of heavy metals in cultivated soil in Lanzhou city remain unclear, which impacts the effective management and control of heavy metals. The potential ecological risk hazard index was used to evaluate the ecological environmental risks of As, Cd, Cr, Hg, and Pb in the surface soil of cultivated land in Lanzhou, and the health risk model proposed by USEPA and the recommended standard were used to evaluate their human health risk. The main factors influencing the spatial differentiation of human health risk were explored by using geographic detectors. The risk of heavy metals to the ecological environment of the cultivated land surface soil in the study area was mainly medium (65.25%), and small portions were low (13.80%) and high (20.95%). The low-risk areas were mainly located in the southeast of Yongdeng County, the middle and north of Yuzhong County, and the southwest of Gaolan County. Moderate risk areas were distributed in three counties and five districts. The high-risk areas were located in the north and southeast of Yongdeng County, the south of Chengguan District, the northeast of Qilihe, the east of Xigu District, and the middle of Yuzhong County. The non-carcinogenic and carcinogenic risks of five types of heavy metal exposure pathways were as follows:oral ingestion>skin contact>respiratory ingestion; generally speaking, children were at higher risk than adults. The non-carcinogenic risk in children was higher than that in adults; however, there was no such risk for local residents, as they were all less than 1. At the same time, the carcinogenic risk of As was greater than 1×10-5 (children 2.04×10-5) and less than 1×10-4 (adults 1.91×10-5), respectively. This indicated an acceptable medium risk to the local residents, and the risk to children was again greater than that to adults. Geographical detector analysis showed that average precipitation during the sampling season had the greatest impact on the spatial differentiation of human health risks of As and Cd, GDP had the greatest impact on the spatial differentiation of human health risks of Cr, and distance from the railway had the greatest impact on the spatial differentiation of human health risks of Hg and Pb. Interaction detection showed that all factors were enhanced by double factors. In addition to leading factors, other factors such as pH, slope, and altitude also enhanced the influence of leading factors on the spatial differentiation of heavy metal risk in cultivated soil.

Man-land relationship based on the spatial coupling of population and residential land – A case study of Yuzhong County in Longzhong Loess Hilly Region, China

Population and residential land use are the core elements of the rural man-land relationship system. The relationship between the rural population and residential land is of great significance to the study of the man-land relationship in rural regions. The Longzhong loess hilly region is one of the most vulnerable areas of social ecology and economy in China, with relatively poor natural conditions and economic development. In this paper, 268 administrative villages in Yuzhong County, Longzhong Loess Hilly Region, were used as evaluation units with spatial dislocation analysis methods to analyze the spatial distribution of population and residential land from a micro-spatial perspective. This shows the coupling relationship between population and residential land, and altitude gradient characteristics. Following conclusions are obtained: (1) Rural permanent residents, migrants, residential land area and idle homesteads show high spatial similarity. The areas with high density and geographic concentration are mainly concentrated in the central Chuanyuan area, and the areas with low ones are mainly distributed in the northern mountainous regions. (2) There is a highly coupled relationship between population and residential land in Yuzhong County. For the permanent population and residential land area, 89.18% of the administrative villages are in coordination, and 10.82% of the administrative villages are not coordinated. In terms of the proportion of the migrant population and the proportion of idle homesteads, 55.97% of the administrative villages are coordinated, and 44.03% of the administrative villages are not coordinated. (3) The altitude gradient effect on the “population-residential land” coupling relationship is significant. The permanent population and residential land area are mainly “H-H” type villages in low-altitude gradient areas, and “L-L” type villages in medium-high altitude gradient areas. The proportion of the outflow population and the proportion of idle homesteads of “L-L” type villages are the largest in low-altitude gradient areas, and that of “H-L” type villages are the largest in the middle and high-altitude gradient areas. This paper explored a new model of man-land relationship, and improved the theory of rural man-land relationship regional system. It is of great significance to promote the coordinated and sustainable development of loess hilly region and even the entire Loess Plateau in China.

Spatiotemporal evolution and mechanism of rural transformation: A case study of Yuzhong County in Gansu Province

Spatiotemporal evolution and mechanism of rural transformation: A case study of Yuzhong County in Gansu Province

Trends in Corneal Transplantation and Characteristics of Donors in the Chongqing Eye Bank, China: A Retrospective Study, 1999-2018.

Aim: This study aimed to analyze corneal transplantation trends and voluntary donor characteristics at the Chongqing Eye Bank in China.Methods: We retrospectively reviewed and analyzed data from January 1, 1999, to December 31, 2018, covering 5,397 preregistered voluntary donors, 1,955 actual donors, 3,910 donated tissues, and 2,374 corneal transplantations.Results: The 5,397 preregistered donors included 13 ethnic groups, with an overall mean age of 39.6 years (SD 21.5) and 3,010 were women (55.8%). The most prevalent education level was college and above (2,546, 47.2%), and the most common ethnic group was Han (5,335, 98.85%). Of the 1,955 actual donors, the male-to-female ratio was 3.3, and the mean age was 57.1 (SD 23.0 years). Based on population size in 2018, Jiangbei county was the most active in donation willingness, with ~60 × 10−6 per capita, and the Yuzhong county was the most active in cornea donations, with ~451 × 0−6 per capita. Of the 3,910 donated corneas, 2,540 (65.0%) were clinically used. Of those not used, 978 (71.4%) were rejected for poor corneal quality. The 2,374 (93.5%) corneal transplantation procedures were done at the Department of Ophthalmology of the First Affiliated Hospital of Chongqing Medical University and the rest (n = 166, 6.5%) were performed in other centers. Of those 2,374 corneal transplantations, there were 1,671 penetrating keratoplasty (70.39%), 700 anterior lamellar keratoplasty (29.49%), and three corneal endothelial transplantations in our center (0.13%). The number of annual corneal transplantations increased by nearly 10 times, from 35 cases in 1999 to 327 cases in 2018. Among them, cases of penetrating keratoplasty and anterior lamellar keratoplasty increased from 27, and eight cases in 1999 to 230 and 94 cases in 2018, respectively. Infectious keratitis (37.0%) was the leading indication for keratoplasty, followed by corneal scar (19.8%). Over the study period, corneal scars dropped from the first (41.1% in 1999–2003) to the second indication (20.5% in 2014–2018), while infectious keratitis advanced to take the lead, ranging from 12.2% in 1999–2003 to 26.3% in 2014–2018.Conclusion: Our study reports corneal donation and transplantation trends in Chongqing over 20 years, showing that infectious keratitis is a leading indication for keratoplasty and that penetrating keratoplasty and anterior lamellar keratoplasty show upward trends. The analysis further suggests that a potential preregistered cornea donor is a female Han, with a higher education level.

A coupled study of ecological security and land use change based on GIS and entropy method-a typical region in Northwest China, Lanzhou.

Due to rapid population growth, industrialization, and urbanization, it is particularly important to address the increasingly serious ecological security issues in the process of urbanization, while it is important to grasp the impact of changes in land use structure on ecological security for scientific planning and to aid decision-making. As a typical valley basin industrialized city in northwest China, Lanzhou has complex geomorphology and climate with distinct regional characteristics, and the relationship between land use and ecological security is complex. In order to understand the current status and influencing factors of ecological security in various regions of Lanzhou, and to explore the intrinsic connection between ecological security and land use, this study constructed an ecological security evaluation index system based on the pressure-state-response (PSR) model with 14 secondary factors including natural, social, and economic factors. Based on the entropy method, GIS was used to analyze the trend of ecological security in each district and to clarify the coupling relationship between ecological security and land use change in Lanzhou City. The results show that the ecological security index (ESI) of Xigu District, a typical heavy industrial area, increased from 0.26 to 0.35, and the ESI of Yuzhong County, an agricultural development area, increased from 0.51 to 0.55 from 2000 to 2017. Low ESI was mainly distributed in areas with developed heavy industry, while high ESI was mainly found in areas with favorable natural conditions and mainly agricultural development. Economic factors were the leading factors affecting the ecological security of Lanzhou. In general, changes in land use structure and ecological security were inextricably linked, and the two influence and interact with each other. These results could provide some reference for the study of ecological security development and land use change in typical river valley cities and also provide a new path for other cities to study ecological security and the conservation of the ecological environment.

Gradient Difference of Structure of Rural Construction Land in Loess Hilly Region: A Case Study of Yuzhong County, Gansu Province, China

Studying the differences in the township gradient of rural construction land structures at the microscale is beneficial for the adjustment of rural construction land structure based on local conditions and differentiation, for the classification and guidance of the scientific planning and management of rural construction land, and for improving the level of intensive use of rural construction land. In this study, we took 268 administrative villages of Yuzhong County in the Loess Hilly Region as the research object and conducted research on the internal structure and gradient difference of rural construction land from two aspects: quantitative structure and spatial layout. The main conclusions are as follows: (1) the distribution of rural construction land has significant connection with the river and road. The land structure of the county is simple, with large differences in area and uneven quantities between different types; (2) the shape of a rural construction land patch is complicated, with a high degree of fragmentation. The spatial agglomeration is not significant, and there is a significant difference between “east-west-north-south” in space; (3) the rural construction land has a significant gradient effect at the township level. In terms of quantitative structure, the closer the construction land is to key towns and central towns, the more complex the construction land, the higher the information entropy as well as the equilibrium degree, and the lower the dominant degree. Moreover, the spatial layout shows an upward trend in the fractal dimension, fragmentation degree and separation degree when the level of the township decreases.

Simulation study of urban expansion under ecological constraint—Taking Yuzhong County, China as an example

Urban expansion is the spreading process of urban construction land overcoming ecological resistance. In this paper, we introduced relative resistance factors on different source levels in the minimum cumulative resistance model (MCR), and considered the inherent constraints and epitaxial ecological resistance on town expansion. Then, we constructed an improved minimal cumulative resistance (IMCR) for urban expansion simulation. The ecological resistance surface of Yuzhong county was formed to simulate the spatial distribution and boundary of town expansion to 2030. The results show: (1) the spatial difference of comprehensive ecological resistance in Yuzhong County is significant, which is decreasing from south to north. The urban expansion is affected by the ecological environment. In addition, the ecological constraints of urban expansion are higher in the areas with better ecological quality. (2) When the ecological constraints are high, the simulated area of urban expansion is smaller than the planned area. On the contrary, when the ecological constraints are low, the simulated area of urban expansion is larger than the planned area. The urban expansion boundary under the planning scenario is relatively straight, simple and rigid, and the town boundary under the ecological constraint scenario is a curve, complex and irregular. (3) The simulation results based on the IMCR model are more in line with reality and reflect the requirements of ecological protection. From the perspective of urban expansion scale and intensity control, the simulation results are more in line with actual needs and reflect the direction of policy regulation.

A Study on the Music Characteristics of the Ceremony of "July Official God"

July official God is the second batch of intangible cultural heritage list published by Gansu Provincial People's government. The project is located in Yuzhong County, Lanzhou city. The ritual process and ritual music of "July Official God" are the main contents of this folk cultural space activity, which are closely connected and indispensable. Therefore, the study of ritual music is also one of the work of intangible cultural heritage protection. The combination of ritual music research and intangible cultural heritage protection will be one of the important orientations of future ritual music research.

Spatial Access to Medical Services in the Underdeveloped Region of Northwestern China: A Case Study in Lanzhou City

Research on the spatial access to medical services has become a hot topic in recent years. The representative provincial capital in the underdeveloped region of northwestern China, Lanzhou, was selected for the research area. In this paper, methods such as the two-step floating catchment area and ArcGIS network analysis are used to analyze the geographic spatial accessibility of medical services and differences of spatial access between urban and rural areas in Lanzhou city. The results show that 1. Areas in General and below grade of accessibility account for most of Lanzhou city. Therefore, the spatial accessibility of whole Lanzhou city is comparatively unsatisfactory. It shows a tendency of the north region to be worse than south region, and areas in parts of the main districts, parts of HG, and other tiny minority show Great grade of accessibility, and most of other areas distribute in poorer grade of accessibility, especially the surrounding mountainous region. 2. There are obvious differences in accessibility between urban and rural regions, mainly reflected in that residents and areas are basically districted in the Great and Good grade in the urban region, while almost 75% of the population and 35% of the areas are distributed in the Great and Good grade, and nearly 25% of the residents and 65% of the areas are still in the unsatisfactory accessibility grade in the rural region. According to the results, the researchers put forward corresponding suggestions to improve the current situation, which are roughly as follows: The construction of hospitals and primary health care should be strengthened in the rural region, especially the construction of township health centers and health stations. High-class hospitals are needed in Honggu district, Yongdeng county, Yuzhong county, and Gaolan county, while the medical capacity and facility grade of existing hospitals should be improved to satisfy the demand of local residents. Meanwhile, rural areas should strengthen the construction of road networks.

Inventory and Spatiotemporal Distribution of Ammonia Emission from Agriculture and Animal Husbandry in Lanzhou City

After obtaining data on the activity of agriculture and animal husbandry by field investigation and from statistical data, an inventory of ammonia emission from agriculture and animal husbandry in Lanzhou was established based on literature investigation to determine the emission factors. The emission factor related to the application of nitrogen fertilizer was calculated using the NARSES model. The spatiotemporal distribution of the amount of ammonia emission was also analyzed. The total amount of ammonia emission from agriculture and animal husbandry was 9356.90 t. Among this emission, the amount from livestock and poultry was 7584.03 t, accounting for 81.05%. Yongdeng County was the region with the largest amount of ammonia emission, which was 2820.59 t, accounting for 30.14%. Considering the sharing rate of ammonia emissions in all districts and counties, the sharing rates of livestock and poultry were between 65.83% and 97.38%; and the sharing rates for nitrogen fertilizer application were between 2.27% and 28.66%. From the perspective of spatial distribution, the sources of ammonia emissions from agriculture and animal husbandry were mainly concentrated in the northwest and central parts of Gaolan County, the southeast of Honggu District, the east and west of Qilihe District, and the east of Yuzhong County. From the perspective of temporal distribution, the ammonia emissions from livestock and poultry were higher from April to September. The emission from nitrogen fertilizer application was higher from March to September, except in August.