Table of Content

15 June 2025, Volume 42 Issue 6 Previous Issue    Next Issue

Weather and Climate

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Precipitation retrieval for Xinjiang region based on radar and remote sensing satellites GUO Jianmao, WU Dengguo, HAN Jinlong, ZHANG Rushui, WANG Yong 2025, 42 (6):  957-969.  doi: 10.13866/j.azr.2025.06.01 Abstract ( 287 )   HTML ( 26 )   PDF (13017KB) ( 125 )   To more accurately obtain precipitation distributions in remote areas, this study combined the high-resolution advantages of radar and the wide-coverage detection of satellites. By integrating radar and satellite-derived precipitation, we generated high-precision quantitative precipitation estimation products. Using the strong convective events in Xinjiang on August 12 and 13, 2023, as an example, we used radar reflectivity for precipitation inversion based on cloud classification and Z-R relationships. We fed the Himawari 9 satellite brightness temperature and IMERG precipitation into a BP neural network model to establish the relationship between the average brightness temperature and the average rainfall intensity. Subsequently, we used the instantaneous brightness temperature of the Himawari 9 satellite to invert the momentary precipitation through the BP neural network model. We also proposed two precipitation data fusion schemes: Scheme I uses a uniform correction value to integrate radar and satellite precipitation, whereas Scheme Ⅱ further considers the precipitation intensity levels for comparison. Finally, we obtained high-precision precipitation inversion products for Xinjiang. The results showed that: (1) Cloud classification based on brightness temperature can finely estimate precipitation within the radar range, and brightness temperature differences can reduce the impact of non-precipitating clouds to some extent. (2) The root mean square error (RMSE) of the satellite precipitation inversion was 1.793 mm·h-1, with a coefficient of determination (R2) of 0.572, indicating reasonable model accuracy. The binary classification score indicated that the model can accurately invert precipitation in over 70% of the areas. (3) The fusion of precipitation by the two schemes slightly improved the accuracy of short-duration light rain distributions. Scheme Ⅱ outperformed Scheme I for short-duration moderate rain but showed a slight decline for short-duration heavy rain compared with Scheme I, indicating that the asynchrony between satellite observation and near-surface precipitation had some impact. (4) Under a 95% confidence interval, the P-values for the RMSE and R2 differences between the two schemes and satellite inversion were all less than 0.005, while the P-value for Scheme Ⅱ compared with Scheme I was greater than 0.05. Both fusion schemes significantly improved the accuracy of the satellite precipitation; however, the improvement of Scheme Ⅱ, which considers the precipitation intensity levels, over Scheme I was minimal. Figures and Tables | References | Related Articles | Metrics

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Characteristics of regional heavy rain showers in eastern Gansu Province KONG Xiangwei, LI Chenrui, DI Wenjing, Yang Yi, FU Zhengxu, YANG Xiumei 2025, 42 (6):  970-980.  doi: 10.13866/j.azr.2025.06.02 Abstract ( 280 )   HTML ( 27 )   PDF (18564KB) ( 127 )   Using hourly precipitation data collected from automatic weather stations (AWS) in eastern Gansu Province during the summer months from 2010 to 2021, a total of 50 regional heavy rain showers were identified. An analysis was then conducted to examine the spatiotemporal distribution and intensity of such events in eastern Gansu Province. The obtained results can be summarized as follows: (1) The intensity of the heavy rain showers primarily ranged between 20 and 30 mm·h-1, which accounted for more than 60% of such events. Intensities exceeding 40 mm·h-1 represented less than 10% of such events. Notably, short bouts of intense precipitation with intensities exceeding 50 mm·h-1 occurred in 74% of the heavy rain showers in the studied region. (2) In the studied region, heavy rain showers mainly occur from mid-June to late August, peaking in the period from late July to mid-August. While such events occur throughout the year, the interannual variability in their occurrence is significant and closely associated with the position of the Western Pacific subtropical high, the transport of abnormally warm water vapor from the South China Sea or East China Sea, and significant baroclinic features resulting from the interaction of weather systems at mid- and low latitudes. (3) The area typically affected by heavy rain showers in eastern Gansu Province accounts for only 3.17% of its total area. However, there are notable regional variations in the spatial distribution of these events, with areas struck by high-intensity rainfall being primarily located in the Taizishan region, the western section of the Qinling Mountain, Liupan Mountain, and Ziwu Mountain. Additionally, areas affected by rainfall of extreme intensity, exceeding 40 mm·h-1, are concentrated in these high-incidence centers. (4) There is a clear pattern in the distribution of stations recording heavy rain showers under different circulation patterns. Stations associated with the eastward-moving plateau trough type are dispersed and most abundant. Meanwhile, stations related to the subtropical high’s southwestern airflow type record the lowest median number of such events. Finally, stations experiencing shear between two high-pressure systems are concentrated, while those associated with the northwest airflow type are the least numerous. There was no significant difference in the distribution of the events with heavy rainfall intensity among these circulation types. However, rainfall intensities between 30 and 50 mm·h-1 are more likely to occur in the two high-shear types. Figures and Tables | References | Related Articles | Metrics

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Spatio-temporal variation characteristics of integrated temperatures of ≥0 ℃ and ≥10 ℃ on the Loess Plateau under global climate warming AN Bin, CHEN Wenjing, XIAO Weiwei 2025, 42 (6):  981-992.  doi: 10.13866/j.azr.2025.06.03 Abstract ( 223 )   HTML ( 25 )   PDF (15879KB) ( 113 )   The Loess Plateau (LP) in China is highly sensitive to climate change, making it an ideal region for understanding temperature dynamics under global warming. This study analyzed the spatio-temporal variations of integrated temperature indicators for ≥0 ℃ and ≥10 ℃—including the first date (FD), ending data (ED), duration (DD), and active integrated temperature (AIT)—using daily average temperature data from 55 meteorological stations on the LP spanning 1960 to 2019. Methods such as linear fitting, mutation tests, and dominance analysis were employed. The results indicate that, from 1960 to 2019, the indicators for both thresholds changed synchronously, with an advancing FD, a delayed ED, a prolonged DD, and an increasing AIT (P<0.01). Notably, most interdecadal shifts occurred in the 1990s, with abrupt changes concentrated from the late 1990s to the early 2000s. The spatial distribution of mean values for both thresholds was similar, showing that FD advanced, ED delayed, DD prolonged, and AIT increased from northwest to southeast. However, the spatial trends differed: the magnitude of the ED delay followed an east-west pattern with alternating phases, while the increase in AIT was higher in the east and lower in the west. For the ≥0 ℃ threshold, changes in FD, ED, and DD were influenced jointly by latitude and altitude, whereas changes in the other indicators were mainly driven by altitude, with contribution rates between 65.59% and 72.17%. The contribution of FD changes to DD changes was 65.1% for ≥0 ℃ and 68.4% for ≥10 ℃, each exhibiting opposite spatial distribution patterns. Compared with 1960-1989, most indicators—except DD and AIT for ≥0 ℃ and FD for ≥10 ℃—showed significant shifts (in terms of earlier or delayed timing, extended duration, or increased magnitude) during 1990-2019, with more pronounced changes at the ≥0 ℃ threshold. Furthermore, the contribution of FD change to DD change decreased by 2.3% for ≥0 ℃ but increased by 15.2% for ≥10 ℃. Spatially, the variation in contribution rates exhibited a “higher-lower-higher” pattern along the south-to-west axis and a contrast with higher values in the southeast and lower in the northwest. Overall, the integrated temperature indicators for both thresholds on the LP show significant responses to climate warming, with distinct regional and temporal characteristics. Figures and Tables | References | Related Articles | Metrics

Land and Water Resources

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Sustainable dynamics and driving factors of the global virtual water trade in crops DI Yanfeng, DUAN Weili, ZHOU Yiqi, HE Chao 2025, 42 (6):  993-1003.  doi: 10.13866/j.azr.2025.06.04 Abstract ( 274 )   HTML ( 16 )   PDF (39090KB) ( 68 )   Incorporating agricultural irrigation water into the global trade chain and determining its sustainability is vital for ensuring water and food security. However, the issue of sustainability in the virtual water of crop trade has received limited attention, due to the conflict between economic benefits and water resource utilization. Thus, based on the crop production and trade matrix data from the Food and Agriculture Organization, this study conducted physical trade flow and spatial correlation analyses as well as multiscale geographically weighted regression to systematically analyze the spatiotemporal distribution, the spatial correlation characteristics, and the driving factors of net exported virtual water sustainability in global crop trade from 2000 to 2019. Based on the findings, the sustainable and unsustainable net exported virtual water volumes in global crop trade (especially cotton) exhibited a fluctuating upward trend (approximately 0.20 Gm3 per year) over the past two decades. However, due to agricultural technological advancements, the proportion of unsustainable virtual water in the total virtual water trade volume decreased from 42.31% to 41.40%. Although the spatial analysis revealed considerable spatial clustering of unsustainable net exported virtual water volumes between 2000 and 2009, as shown by global and local Moran’s I statistics, this clustering trend weakened and became more dispersed over the past decade. Moreover, the increase in net exported virtual water was mainly driven by changes in cultivated land area, with agricultural value-added having a significant negative impact on virtual water in trade. Overall, these results highlight the importance of implementing stringent food security policies in order to facilitate the sustainable development of the global virtual water trade in crops and to further reduce the proportion of unsustainable water use. Figures and Tables | References | Related Articles | Metrics

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Research advances and arid zone applications of coupled models for water resources carrying capacity WANG Yixuan, DENG Xiaohong, FAN Huiwenqing, HAN Jiangzhe, LI Zongxing 2025, 42 (6):  1004-1020.  doi: 10.13866/j.azr.2025.06.05 Abstract ( 265 )   HTML ( 14 )   PDF (6263KB) ( 337 )   As the scarcity of global water intensifies, accurate assessments of water resource carrying capacity (WRCC) have become essential for sustainably managing regional water resources and combating the adverse effects of climate change. However, the water resources-ecology-society system is highly complex, involving multidimensional interactions anddynamic internal changes that cannot be fully captured by a single evaluation method. This paper reviews the application status and research progress of coupled-model methods for WRCC evaluation. A systematic comparative analysis reveals the strengths and limitations of the major evaluation methods—systems analysis, comprehensive evaluation, and machine learning—in WRCC evaluation. Particular attention is devoted to the challenges of these methods in arid regions. The dynamic feedback mechanisms, nonlinear modeling capabilities, data-driven characteristics, and applicabilities of different methods are analyzed through a horizontal comparison study. The review also analyzes the suitabilities and limitations of each method in arid regions and explores the feasibility of coupled models, providing new insights for resolving WRCC issues in these areas. Multimodel integration and data-driven optimization will enhance the generalizability and applicability of models in future, facilitating the transition of water resource management from static evaluation to dynamic simulation and precise prediction. These developments will offer scientific support for sustainable water resource utilization in arid regions and worldwide. Figures and Tables | References | Related Articles | Metrics

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Applicability analysis of hydrological models for different types of watersheds in the eastern section of the agro-pastoral transitional zone in northern China ZHANG Yajing, HAO Ruifang 2025, 42 (6):  1021-1031.  doi: 10.13866/j.azr.2025.06.06 Abstract ( 170 )   HTML ( 8 )   PDF (5841KB) ( 224 )   Water resources form the foundation for maintaining ecosystem balance and ensuring human life and economic development. Simulating hydrological processes in arid and semi-arid ecosystems promotes the effective utilization of local water resources. This paper analyzed the applicability of two models—the Distributed Hydrology Soil Vegetation Model (DHSVM) and the Soil and Water Assessment Tool (SWAT)—in different types of watersheds in semi-arid regions by performing: Sensitivity analysis and parameter calibration. simulation of monthly runoff for the upper reaches of the Xar Moron River and the Laoha River during the growing seasons of 2011-2012 and 2017-2019. The upper reaches of the Xar Moron River are dominated by grasslands, while those of the Laoha River are dominated by forestland and farmland. The results show that DHSVM exhibits 7 primary sensitive parameters in the Xar Moron River and 6 in the Laoha River, whereas SWAT identifies 11 and 12 sensitive parameters, respectively. Following parameter calibration, in the upper reaches of the Xar Moron River the Nash-Sutcliffe efficiency coefficient for DHSVM is 0.70 during calibration and 0.11 during validation, while for SWAT it is 0.43 and 0.04, respectively. In the upper reaches of the Laoha River, the Nash-Sutcliffe efficiency coefficients for DHSVM are 0.56 and 0.70 during the two periods, compared with 0.86 and 0.54 for SWAT. The findings indicate that both models are applicable for simulating hydrological processes in the study area, with DHSVM more accurately simulating overall runoff and SWAT more accurately simulating peak monthly runoff. Figures and Tables | References | Related Articles | Metrics

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Object-based glacier boundary extraction utilizing multi-feature fusion LIN Zhouyan, WANG Xiaying, XIA Yuanping 2025, 42 (6):  1032-1042.  doi: 10.13866/j.azr.2025.06.07 Abstract ( 190 )   HTML ( 8 )   PDF (17763KB) ( 37 )   Pixel-based classification struggles with the accurate identification of glacier changes in areas with similar spectral characteristics, particularly in debris-covered areas where spectral features closely resemble the surrounding mountains and rocks, thereby resulting in low extraction accuracy. This study investigates the Yinsugaiti and Yalong Glaciers using Google Earth Engine to integrate spectral indices, microwave texture features, and topographic data. An object-based (OB) machine learning algorithm is applied for automated glacier extraction and compared to pixel-based (PB) classification methods. The results show the following. (1) The OB classification approach, integrating multi-feature fusion, significantly improved the glacier extraction accuracy. The OB_RF classifier achieved an overall accuracy of 98.1%, a Kappa coefficient of 0.97, and an F1-score of 98.67%, outperforming the OB_CART and OB_GTB classifiers. When compared to PB_RF, the overall accuracy, Kappa coefficient, and F1-score increased by 1.7%, 0.024, and 5.57%, respectively. (2) Between 2001-2022, the Yinsugaiti and Yalong Glaciers retreated at average annual rates of 0.08% and 0.13%, respectively. (3) Supraglacial debris was primarily distributed below 5000 and 4800 m on the Yinsugaiti and Yalong Glacier, respectively. Over the same period, debris-covered areas on both glaciers expanded upward. Figures and Tables | References | Related Articles | Metrics

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Effects of different land use types on soil N2O fluxes on the Loess Plateau DU Jun, LI Guang, DU Mengyin, YAO Yao, MA Weiwei, YUAN Jianyu 2025, 42 (6):  1043-1054.  doi: 10.13866/j.azr.2025.06.08 Abstract ( 198 )   HTML ( 23 )   PDF (10096KB) ( 64 )   Nitrous oxide (N2O) a remarkable greenhouse gas in the atmosphere, exerts a pronounced effect on global climate warming. Changes in land use types critically affects N2O emissions, particularly in ecologically fragile semiarid regions with more complex underlying mechanisms. However, there is still a lack of systematic research on how complex and diverse land use types affect soil N2O emissions in semiarid regions of China and the key driving factors involved. To address this, this study focused on four typical land use types in the semiarid Loess Plateau of central Gansu Province: Picea asperata forest, Medicago sativa grassland, abandoned land, and wheat field. Soil N2O fluxes were monitored using the static chamber-gas chromatography method, combined with soil physicochemical property data, to elucidate the key drivers regulating soil N2O emissions under different land use types. Compared to the abandoned land, the Picea asperata forest and Medicago sativa grassland had significantly increased soil water content, while wheat fields exhibited elevated ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) concentrations. Compared to the abandoned land, the Medicago sativa grassland and wheat fields exhibited markedly enhanced nitrate reductase and nitrite reductase activities, which decreased with an increase in soil depth across all treatments. Soil N2O fluxes under different land use types exhibited an initial increase followed by a decline during the vegetation growth stages. The total soil N2O emissions decreased by 34.2% and 23.3% in the Picea asperata forest and Medicago sativa grassland, respectively, and increased by 32.47% in the wheat fields, compared to the abandoned land. Random forest analysis identified soil temperature as the most influential factor affecting the soil N2O flux. Overall, compared to the abandoned land and wheat fields, the artificial forest and grassland systems in the study area demonstrated superior emission reduction effects. Therefore, future vegetation restoration and ecological rehabilitation efforts should prioritize optimizing the proportional allocation of “forest-grass-cropland” land use types and appropriately increasing the coverage of artificial forests and grasslands to achieve the dual objectives of ecological benefits and emission mitigation. Figures and Tables | References | Related Articles | Metrics

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Structure and functional group characteristics of generalized and specialized species of soil and root-associated fungi in Pinus sylvestris var. mongolica forests of the Hulunbuir Desert CHENG Yanlin, WANG Jiayuan, GAO Guanglei, DING Guodong, ZHANG Ying, ZHAO Peishan, ZHU Binbin 2025, 42 (6):  1055-1066.  doi: 10.13866/j.azr.2025.06.09 Abstract ( 140 )   HTML ( 3 )   PDF (7559KB) ( 30 )   This study investigated the community structure and function of generalized and specialized fungal species (GFS and SFS, respectively) in the soil and roots of Pinus sylvestris var. mongolica forests and their relationship with soil physicochemical properties, aiming to identify key microbial mechanisms affecting ecosystem functioning in P. sylvestris var. mongolica forests. Using high-throughput sequencing technology, we analyzed the differences in the community structure and functional groups of GFS and SFS in the soil and roots of natural forests and plantations (24 a, 35 a, 44 a) of P. sylvestris var. mongolica in the Hulunbuir Desert. The results were as follows: (1) The soil and root-associated GFS retained 169 operational taxonomic units (OTUs) in total, the soil SFS retained 603 OTUs, and the root-associated SFS retained 216 OTUs, including Tricholoma and Suillus in soil GFS; and Tricholoma, Suillus, and Cadophora in root-associated GFS; Penicillium in soil SFS; and Acephala in root-associated SFS. (2) The relative abundance of symbiotic nutritive fungi accounted for 28.49%-47.21% of soil GFS, and the dominant ecological functional group was ectomycorrhizal fungi, which showed a trend of increasing and then decreasing with forest age. Saprophytic nutritive fungi accounted for 17.01%-40.01% of soil SFS. The relative abundance of saprophytic nutritive fungi in plantation forests was lower than that in natural forests, and it showed a tendency of increasing and decreasing followed by increasing with forest age. Symbiotic trophic fungi accounted for 43.25%-54.45% of the root-associated GFS; the dominant ecological functional group was ectomycorrhizal fungi, which showed an increasing trend with increasing forest age, and the relative abundance of ectomycorrhizal fungi in natural forests was higher than that in plantation forests. (3) The soil organic matter and available phosphorus content of natural P. sylvestris var. mongolica forests were significantly higher than those of plantation forests (P<0.05). In plantation forests, with increasing forest age, the soil organic matter (SOM), total phosphorus (TP), available nitrogen (AN), and available phosphorus in the soil increased significantly (P<0.05), whereas the soil pH decreased but not significantly (P>0.05). GFS was mainly dominated by SOM, soil NH4+-N, and TP (P< 0.05). Furthermore, the community variability of root-associated SFS was regulated by total nitrogen (P<0.05), whereas soil SFS was significantly affected by only TP, AN, and NO3--N (P<0.05). The drivers of fungal community structure showed significant ecological niche differentiation. This study contributes to a deeper understanding of the ecological functions of fungi in the soil and roots of P. sylvestris var. mongolica forests, providing a basis for the sustainable management and protection of P. sylvestris var. mongolica forests in the Hulunbuir Desert. Figures and Tables | References | Related Articles | Metrics

Ecology and Environment

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Spatiotemporal changes in vegetation coverage in the arid regions of Northwest China over the past 30 years and their response to climatic factors ZHANG Xiuxia, HAN Lisha, DANG Xinghai, WANG Xiaoxian, LIN Qingrun, DENG Lingzhi, YANG Minghang, ZHANG Xilai 2025, 42 (6):  1067-1079.  doi: 10.13866/j.azr.2025.06.10 Abstract ( 209 )   HTML ( 38 )   PDF (26567KB) ( 131 )   The arid region of Northwest China is an area of notable vegetation vulnerability, where vegetation cover plays a crucial role in sustaining unique terrestrial ecosystems. This study utilized Landsat data and the pixel dichotomy model to analyze spatiotemporal variation patterns of Fractional Vegetation Cover (FVC) in the arid region of Northwest China from 1990-2022. Integrating land use data, the research employed Sen’s slope estimation, the Mann-Kendall test, and correlation analysis to investigate FVC characteristics across different vegetation types and their responses to climatic factors. The results indicate that: (1) FVC exhibited a fluctuating upward trend, with an annual increase rate of 0.98×10-4; spatial heterogeneity was significant, with areas predominantly characterized by very low vegetation coverage, while river basin regions displayed higher FVC values. (2) Land use transformation has driven the evolution of FVC patterns, with increases in forestland and cultivated land contributing to the expansion of areas with very high FVC coverage (increasing by 3.0% and 18.8%, respectively); grassland remains the dominant cover across all levels, with an average proportion exceeding 47.7%. (3) Average precipitation during the vegetation growing season ranks as follows: shrubland>forestland>grassland>cropland, whereas temperature trends are reversed; evapotranspiration follows the order: forestland>cropland>grassland>shrubland; the average annual humid area proportion is 61.03% in shrubland regions, compared to less than 5% in cropland regions. FVC shows negative correlations with precipitation (52.0%), temperature (60.2%), evapotranspiration, and aridity index (63%). Vegetation demonstrates significant sensitivity to climate change. The findings provide an important basis for ecological management and restoration in the arid regions of Northwest China. Figures and Tables | References | Related Articles | Metrics

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Dynamic simulation of land use change and habitat quality in the Three River Source Region based on the PLUS-InVEST models LIU Xiaoming, ZHENG Shiyan, QIAO Zhanming 2025, 42 (6):  1080-1092.  doi: 10.13866/j.azr.2025.06.11 Abstract ( 327 )   HTML ( 14 )   PDF (19723KB) ( 42 )   The ongoing decline in biodiversity adversely effects ecosystem services. Investigating spatiotemporal changes in land use and habitat quality in the Three River Source Region is crucial for ecological protection and restoration. This study, based on the PLUS model and the InVEST model’s habitat quality module, conducts multi-scenario simulations to predict land use changes and estimate habitat quality. The results are as follows: (1) During the historical period, 9663.53 km2 of grassland converted to unused land, represented the largest proportion of total land conversion, whereas unused land converted to grassland only covered 3659.27 km2, the grassland degraded into unused land to a relatively serious extent in the Three River Source Region. (2) Multi-scenario predictions for 2030 reveal that the biodiversity conservation scenario performs best, followed by the grassland protection scenario, then the water resources protection scenario, and finally the natural development scenario. (3) Among conversion types, the contribution rate of converting unused land to grassland in enhancing habitat quality is highest at 0.7167, followed by that of converting unused land to water bodies, at 0.2603. Implementing biodiversity protection strategies, resolving the grass-livestock conflict, and enhancing management of unused land, while reducing grassland-to-unused land conversion will help mitigate the decline in habitat quality. Figures and Tables | References | Related Articles | Metrics

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Evaluation of climate comfort for red tourism in the Shaanxi-Gansu-Ningxia Region based on GIS JIN Shuang, REN Jiahui, FENG Fang, HUANG Qiaohua, HE Ping 2025, 42 (6):  1093-1102.  doi: 10.13866/j.azr.2025.06.12 Abstract ( 168 )   HTML ( 7 )   PDF (6194KB) ( 275 )   Assessing climate comfort in the Shaanxi-Gansu-Ningxia region is essential for the development of red tourism and the promotion of ecological sustainability. Using daily meteorological data from 1953 to 2020, including average temperature, wind speed, and relative humidity, this study applies a comprehensive climate comfort evaluation model integrated with GIS-based spatial interpolation and zoning methods to systematically analyze the spatiotemporal distribution of climate comfort in the region. The results show that, temporally, the climate is generally comfortable from May to September, while discomfort prevails from December to February. Spatially, northern Shaanxi exhibits relatively favorable climatic conditions, whereas the southwestern Xihaigu region is less suitable in terms of climate comfort. Under the influence of global warming, the annual average number of comfortable days has increased, whereas the number of uncomfortable days has significantly decreased since 2000. Comprehensive zoning results indicate that southwestern and central high-altitude areas experience lower comfort levels, while other regions remain relatively favorable. Further analysis reveals that for each unit change in the climate comfort index, the red tourism visitor flow index changes by 0.593%. Notably, Yan’an, due to its rich red tourism resources and favorable climate, has a significantly higher attractiveness index than other regions. Future red tourism planning should be dynamically optimized to address climate change and evolving tourist preferences. This study offers a scientific basis for regional tourism development and the sustainable advancement of red tourism. A scientific reference for regional tourism development and the sustainable advancement of red tourism activities. Figures and Tables | References | Related Articles | Metrics

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Spatiotemporal evolution of the ecological security pattern in Longnan City based on the MSPA-InVEST model LI Zhiming, ZHANG Guofei, XING Jie, YANG Lei, WANG Weidong, CAO Juan 2025, 42 (6):  1103-1113.  doi: 10.13866/j.azr.2025.06.13 Abstract ( 189 )   HTML ( 14 )   PDF (20551KB) ( 40 )   Accurate identification for ecological restoration is essential for promoting sustainable ecological development. Longnan City, as a crucial water source conservation area and ecological security barrier in the upper reaches of the Yangtze River, plays a critical role in maintaining the regional ecological balance. This study used the InVEST model to evaluate ecosystem services and combined the morphological spatial pattern analysis (MSPA) method with circuit theory to construct the ecological security pattern of Longnan City, then analyze its evolution. The results showed: (1) From 2000 to 2022, the number of ecological source areas increased, primarily distributed in the Kang County, Hui County, and Cheng County. The spatial distribution exhibited a pattern of higher density in the south and lower in the north. (2) The average resistance value first decreased then increased, while the length of ecological corridors initially increased and later decreased, during the study period with a net reduction of approximately 508.94 km. Spatially, the corridors shifted from central to southeastern regions. (3) Ecological bottleneck areas, primarily dominated by forests, croplands, and grasslands, were concentrated in low-resistance zones. Their total area decreased annually, with a net reduction of about 144.84 km2 over the study period. Ecological obstacles also decreased in both number and area, mainly clustered in Wudu County, Li County, and Tanchang District. Thus, the research results provide a scientific foundation for the formulation of ecological restoration plans and promotion of high-quality regional economic development in Longnan City. The findings provide scientific support for formulating ecological restoration plans and promoting high-quality economic development in Longnan City. Figures and Tables | References | Related Articles | Metrics

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Change in the ecological environment quality in Babusha region in the Gulang County WEI Qian, MA Quanlin, ZHAO Ruifeng 2025, 42 (6):  1114-1125.  doi: 10.13866/j.azr.2025.06.14 Abstract ( 177 )   HTML ( 7 )   PDF (15110KB) ( 30 )   Located in the convergence zone of the Qinghai-Xizang Plateau Ecological Barrier and the Northern Sand Control Belt, the Babusha region acts as a frontline defense against the southward encroachment of the Tengger Desert. Assessing changes in the ecological environment quality in the Babusha region holds significant value for evaluating the effectiveness of regional desertification control and advancing the Three-North Shelterbelt Development Program. This study used data from the Google Earth Engine platform to investigate land use pattern changes in the Babusha region from 1986 to 2021. A comprehensive assessment of the spatiotemporal changes in the regional ecological environment quality was conducted using the normalized difference vegetation index (NDVI), desertification index (DI), and remote sensing ecological index (RSEI). The results were as follows: (1) Over time, the desert area in the Babusha region has continued to decrease, the grassland area has progressively increased, and the vegetation coverage has improved. From 1986 to 2021, NDVI and RSEI showed a fluctuating upward trend, with NDVI increasing from 0.14 to 0.31 (>50% increase) and RSEI increasing from 0.22 to 0.24 (9.39% increase). In contrast, DI exhibited a fluctuating downward trend, decreasing from 0.79 to 0.57 with a cumulative reduction of 27.85%. (2) Areas with high NDVI and RSEI values were concentrated in the southern and northwestern parts of the study region, dominated by woodland and cultivated land, whereas areas with low NDVI and RSEI values were distributed in the northern region characterized by extremely low vegetation coverage and desert. (3) The trend analysis primarily revealed a nonsignificant or significant increase in NDVI and RSEI values and a nonsignificant decrease in DI values. Specifically, 12.12% and 61.10% of the study area exhibited a nonsignificant and significant increase in NDVI, respectively, whereas 5.06% and 38.63% of the study area showed a nonsignificant and significant increase in RSEI, respectively. The ecological improvement areas were concentrated in the northwestern and southeastern regions with higher human activity levels. From 1986 to 2021, the Babusha region demonstrated marked vegetation restoration, sustained improvement in the ecological environment, and significantly effective desertification control, facilitating the establishment of a replicable Babusha model. Figures and Tables | References | Related Articles | Metrics

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Deformation monitoring and prediction of Xijitan giant landslide based on SBAS-InSAR technology and long short-term memory neural network LI Shuaifei, LIU Changyi, HU Xiasong, TANG Binyuan, WU Zhijie, DENG Taiguo, XING Guangyan, ZHAO Jimei, LEI Haochuan 2025, 42 (6):  1126-1137.  doi: 10.13866/j.azr.2025.06.15 Abstract ( 171 )   HTML ( 3 )   PDF (22861KB) ( 22 )   This study examines the surface deformation characteristics and deformation rate prediction of large-scale landslides in the upper regions of the Yellow River between the Longyang and Jishi Gorge riverbanks. The study area was the Xijitan giant landslide within the Guide region of the upper Yellow River. The Small Baseline Subset Interferometric Synthetic Aperture Rader（SBAS-InSAR）technology was employed to monitor the surface deformation of the Xijitan giant landslide and analyze, its deformation rates and variation characteristics for the period 2019-2022. The results show that the following. (1) The maximum surface deformation rate of the landslide body was -96 mm·a-1, with a maximum cumulative deformation of 464.71 mm. Distinct deformation zones were observed along the front and rear edges of the landslide body, with surface deformation rates ranging across -96-16 mm·a-1. (2) The cumulative deformation of characteristic points on a landslide body, determined using SBAS-InSAR technology, exhibited a maximum cumulative deformation of -140.50 mm. (3) The long short-term memory (LSTM) neural network model was used to predict the cumulative deformation of these points, and the results were compared with those obtained using Support Vector Machine（SVM） and Back Propagation（BP） neural network models. The LSTM model demonstrated high prediction accuracy, with an absolute error within 5 mm and a goodness-of-fit (R2) greater than 0.8. This confirmed the effectiveness of the LSTM model in predicting the cumulative surface deformation of landslides. Thus, the findings of this study provide data support and practical guidance for the enhanced monitoring of giant landslide deformation in the upper Yellow River region and the early detection of potential landslides. Figures and Tables | References | Related Articles | Metrics

Agricultural Ecology

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Simulation of soil hydrothermal distribution characteristics and analysis of the influencing factors of vertical tube surface drip irrigation FAN Yanwei, LYU Zijie, ZHANG Yao, WANG Lei, SHI Wen 2025, 42 (6):  1138-1150.  doi: 10.13866/j.azr.2025.06.16 Abstract ( 139 )   HTML ( 10 )   PDF (11268KB) ( 28 )   The success of sand fixation projects in deserts is dependent on soil hydrothermal conditions, which are essential for the healthy growth of sand fixation plants. Vertical pipe surface drip irrigation is a new water-saving and temperature-control conservation technology focused on combating soil drought and surface heat stress on seedlings. However, the mechanisms regulating hydrothermal distribution and migration status remain unclear, and its widespread application in sand-fixing areas lacks a theoretical formulation. Thus, this study constructed a mathematical model of soil water-heat migration for vertical tube surface drip irrigation using HYDRUS-2D software. The study investigated the effects of key irrigation parameters (drip head flow rate and irrigation water temperature) and vertical tube parameters (tube diameter and burial depth) on soil water-heat distribution and migration. The accuracy of the constructed model was confirmed through indoor experiments. Consequently, a single-factor analysis was conducted involving nine simulation scenarios to study the impacts of four influencing factors—drip head flow rate (1, 2, and 3 L·h-1), irrigation water temperatures (10, 20, and 30 ℃), riser diameter (9.6, 11.6, and 13.2 cm), and riser depth (15, 20, and 25 cm) to obtain the distributions and migration patterns of the soil hydrothermal properties. The results showed the following. (1) Soil hydrothermal changes during irrigation occurred through water-heat coupling influenced by irrigation water temperature. Dynamic changes were most pronounced in the early stage of irrigation, particularly in the inner surface layer of the tube. Over time, these changes stabilized. Water infiltration from the bottom holes of the tube into the surrounding soil increased the soil moisture rapidly before stabilizing. Further, the soil temperature was affected by the irrigation water temperature, exhibiting slight increases or decreases. (2) The diameter of the vertical tube had a minimal effect on the soil hydrothermal changes during drip irrigation. However, the burial depth had a significant influence on the soil moisture but minimal impact on the thermal environment. Outside the tube, the soil moisture distribution around the tube formed a distinct pattern, with the bottom of the tube functioning as a dividing line. Above this line, the soil moisture content at the same point decreased as the burial depth increased, while below this line, the soil moisture content increased with greater burial depth. (3) The drip head flow was a critical factor in determining the soil moisture status although its impact on the soil temperature distribution was limited. The larger the drip head flow, the higher the soil moisture content at the same points outside the pipe. (4) The influence of the irrigation water temperature on the soil moisture distribution was relatively weak; however, it directly influenced the soil temperature. Higher irrigation water temperatures resulted in increased soil temperature at the same points inside and outside the pipe. (5) When adjustments to the vertical tube’s diameter and burial depth were not feasible, soil hydrothermal conditions in the root zone could be effectively regulated by adjusting the drip head flow rate and irrigation water temperature. Thus, this study offers a scientific basis for the design, operation, and management of a vertical pipe surface drip irrigation project for sand fixation plants. Figures and Tables | References | Related Articles | Metrics

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Effect of soil temperature on cotton growth under phosphate fertilizer drip application conditions WANG Yiqi, MAI Wenxuan, ZHANG Wentai, WANG Yanyan, TIAN Changyan 2025, 42 (6):  1151-1158.  doi: 10.13866/j.azr.2025.06.17 Abstract ( 175 )   HTML ( 12 )   PDF (6193KB) ( 307 )   This study examines cotton growth affected by soil temperature under the condition of phosphate fertilizer drip application. It also explores the role and mechanism of soil temperature regulation of cotton root growth on improving the utilization rate of cotton phosphate fertilizer. Using potted tests, three soil temperature gradients were examined: low temperature (LT: 11-18 ℃), medium temperature (MT: 22-26 ℃), and high temperature (HT: 30-34 ℃). Single factor testing with water bath temperature control was utilized. The effects of various soil temperatures on the growth traits, biomass, root distribution, effective soil phosphorus distribution, and phosphate utilization efficiency in cotton were assessed. As soil temperature increased, cotton plant height, stem thickness, leaf number and biomass all showed parabolic changes that peaked in the medium temperature (22-26 ℃) group. Additionally, root length in the 0 to 5 cm soil layer increased with soil temperature, most notably with high temperature treatment, followed by low temperature and medium temperature treatments increasing by 5.2%-126.9% and 4.9%-62.3%, respectively. Below the 5 cm soil layer, root length decreased with increasing temperature, with the medium temperature treatment having the longest root length, 81.68%-98.43%, which was 170.17%-218.35% longer than the low temperature and high temperature treatment, respectively. The effective P content of each treatment increased with lower temperatures, with the medium and high temperature treatment content being 13.7% and 20.5% lower than the low temperature treatment, respectively. Phosphorus absorption and phosphate utilization were maximized in the medium temperature cotton, followed by the low temperature cotton. With the lowest high temperature, the total phosphorus absorption in the medium temperature cotton increased relatively by 49.69% and 89.36% compared with low temperature and high temperature treatments, respectively. Furthermore, the phosphate utilization rate was twice and 50% higher than the high and low temperature treatments, respectively. These findings indicate that based on the effects of soil temperature on cotton growth, root and soil effective phosphorus distribution, phosphorus absorption, and phosphate utilization, the most suitable soil temperature for cotton growth is 22-26 ℃. Figures and Tables | References | Related Articles | Metrics