Basins In China Research Articles

Hydrochemical processes and fluoride enrichment patterns in high-fluoride geothermal water in the Weihe Basin, China.

The enrichment of fluoride in the deep geothermal water of the Lantian - Bahe Formation in parts of the Weihe Basin in China is a potential health hazard for the millions of inhabitants of this region. We conducted hydrochemical and hydrogeological analyses of water samples from 31 geothermal wells in the Weihe Basin, with the aims of determining the distribution characteristics, enrichment patterns, hydrochemical processes, and the factors influencing the geochemistry of deep geothermal fluids. We also evaluated the potential health hazards of fluoride ions in these fluids. Our results show that geothermal fluids with high fluoride content are widely distributed in the deep aquifers of the Weihe Basin. The principal hydrochemical types are: HCO3-Na and SO4⋅HCO3⋅Cl-Na. We used hydrodynamic simulation and regression analysis to show that the high proportion of HCO3- in the geothermal water facilitates the precipitation of Ca2+ and the dissolution of fluorine-bearing minerals. The high temperature, alkaline environment, cation exchange reactions, and dissolution and precipitation processes lead to Ca2+ depletion, which facilitates the release of fluoride ions from the surrounding rocks into the geothermal fluids. A human health risk assessment shows that the hazard quotient (HQ) values of geothermal water for adult males, adult females, children, and infants are: 3.96 - 14.41 (median 6.55), 3.32 - 12.08 (median 4.50), 4.63 - 16.84 (median 5.50), and 7.48 - 27.22 (median 9.00), respectively. Infants are the most susceptible to the effects of high fluoride in groundwater due to their physiological characteristics. while the potential health risks of F- for children and adult women/men are relatively low. Therefore, in the process of developing deep geothermal water, it is necessary to prevent it from mixing into shallow drinking water as much as possible. If the fluoride ion content in the shallow water exceeds the standard, it may have an impact on the local environment and residents' health. These findings provide a scientific foundation for the effective management of high fluoride groundwater in the Weihe Basin and analogous regions elsewhere.

Unveiling mid-century conservation priorities: Co-occurrence of biodiversity, climate change exposure, and carbon storage in the Middle and Lower Yangtze River Basin, China

The global challenges of biodiversity loss and climate change necessitate the implementation of integrated conservation strategies. A forward-looking framework is necessary to reconcile climate change adaptation and mitigation efforts with biodiversity goals, supporting effective long-term planning and management of protected areas (PAs) network. This study develops a comprehensive approach to identify priority areas for biodiversity conservation until 2050, integrating assessments of species distributions, climate change exposure and carbon storage under distinct shared socioeconomic pathways. The Middle and Lower Yangtze River Basin (MLYRB) in China serves as a case study. Using an ensemble species distribution modeling (ESDM) method, we predicted the distributions of 435 threatened terrestrial vertebrate species and plants. We then mapped their richness in the MLYRB. Distance-based climate velocity analysis was performed to identify climate change coldspots and hotspots. The patch-generating land use simulation (PLUS) model and InVEST model were coupled to simulate carbon storage changes. Systematic conservation planning tool, Zonation, was used to prioritize species conservation hotspots. By examining the co-occurrence of these hotspots with climate change coldspots/hotspots and areas of high carbon storage, conservation priorities for the MLYRB were revealed. Our findings indicate that 18.27–24.94% of the MLYRB risks over 20% species richness declines by 2050 under various scenarios, while increases over 10% are projected for only 0.81–1.75% of the area. Co-occurrence analysis highlights significant associations, such as a 32.26% overlap between species conservation hotspots and climate change hotspots in SSP1-2.6. Particularly noteworthy is the substantial co-occurrence (57.93–59.50% across scenarios) between areas maximizing species conservation and carbon storage. The identified conservation priority areas, covering 41.95% of the MLYRB (441554km2), hold potential for long-term species conservation, climate resilience, and nature-based climate solutions by 2050. However, only 6.08% of these priorities currently benefit from protection. These results offer valuable guidance for region-specific landscape management and conservation policy aligned with international goals. The presented methodology provides a broader application, serving as a valuable resource for prioritizing conservation efforts in other regions integrating biodiversity, climate change adaptation, and mitigation goals.

Influence of tectonic evolution processes on burial, thermal maturation and gas generation histories of the Wufeng-Longmaxi shale in the Sichuan Basin and adjacent areas

The Wufeng-Longmaxi (WL) shale is widely distributed in the Sichuan Basin and adjacent areas in southwest China. The basin experienced multiple-stage complex tectonic movements, whose influences on burial, thermal maturation and gas generation histories in different areas are poorly understood. Based on a detailed study of the denudation stages, strata thickness, and thermal history of the basin, burial and thermal maturation histories of seven wells in different areas were modelled using PetroMod software. Due to the high maturity of the WL shale, a low-maturity Silurian Polish Llandovery shale was used for gold tube closed-system pyrolysis experiments to obtain kinetic parameters for evaluating methane generation history. The Polish shale was selected due to its depositional age, sedimentary environment and organic type, which are similar to the WL shale. The burial history of the WL shale can be divided into five stages: I. Early to Middle Silurian rapid burial; II. Caledonian uplift and denudation; III. Permian to Triassic sustained burial and denudation; IV. sustained burial since the Late Triassic; and V. Late Cretaceous to present sustained uplift and denudation. The thermal maturity of the WL shale in all wells increased with burial depth during stage IV. In addition, high calculated reflectance increments in wells JY1 and N201 during stage III occurred due to the relatively high basal heat flow and deep burial depth, resulting in higher current thermal maturities than in the other wells. The late Permian–Early Triassic and the Middle Jurassic–Early (or Late) Cretaceous were the key methane generation periods for wells JY1 and N201. In contrast, the other five wells had a single methane generation stage, mainly determined by burial and thermal maturation processes. The time of uplift and the amount of denudation during stage V, the current burial depth, the development of faults and fractures, high proportion of retention and the seal capacity of the overlying caprock are key factors for shale gas preservation. Hence, this study will help guide future shale gas development in the Sichuan Basin.

Multi-Scale Evaluation of ERA5 Air Temperature and Precipitation Data over the Poyang Lake Basin of China

Multi-Scale Evaluation of ERA5 Air Temperature and Precipitation Data over the Poyang Lake Basin of China

Identification of thresholds and key drivers on Water Use Efficiency in different maize ecoregions in Yellow River Basin of China

Identifying the constrains on water use efficiency (WUE) of crops along a wet-to-dry gradient is important due to irrigation water scarcity, as well as the increasing drought risk under climate change in China. This study coupled five high-resolution climate models from Coupled Model Intercomparison Project Phase 6 (CMIP6) with the Decision Support System for Agrotechnology Transfer (DSSAT)-CERES-Maize model to quantify drought risk and the drivers affecting WUE in five major maize ecoregions of the Yellow River Basin (YRB) under three future scenarios (SSP126, SSP370, and SSP585) for both the historical baseline (1985-2014) and three future periods: 2021-2040 (2030s), 2041-2070 (2050s), and 2071-2100 (2080s). And a bias correction method was implemented for the crop model to analyze optimal WUE thresholds for maize across varying dry-wet gradients. The results indicated that future drought risk will likely persist in the YRB under all scenarios, but with regional differences in drought severity and frequency. The southwestern region (V) experienced the highest frequency of drought (62.50%-SSP126), while the northwestern region (III) exhibited the lowest frequency (33.00%-SSP585) in 2030s, and 83.30% of areas in the southwestern (V) showed significant wetting in the 2080s under SSP126. The bias-corrected CERES-Maize model effectively simulated crop yield and evapotranspiration (ET), resulting in an average reduction of 4.00% and 9.73% in normalized root mean square error (nRMSE) respectively. Distinct WUE thresholds ranging from 1.96 to 8.41 kg ha−1 mm-1 were observed across various scenarios-periods in the maize regions, mostly under slight and moderate dry/wet conditions. Notably, all SSP585 scenarios demonstrated a decrease in WUE thresholds compared to the baseline. Across all scenarios and periods, WUE was mainly driven by yield in the eastern regions (I and II) but by ET in the western regions (III, IV, and V). These findings suggest that regions experiencing varying degrees of drought severity should undergo differentiated management and optimization of agricultural practices to improve WUE under future climate scenarios.

Multidimensional patterns of bird diversity and its driving forces in the Yangtze river basin of China

Biodiversity is fundamental to human well-being and economic development. The Yangtze River, the largest river in China, faces biodiversity loss due to habitat degradation, climate change, and other anthropogenic threats. However, the long-term changes in the region's biodiversity remain poorly understood. Here, we constructed an optimized living planet index (LPIO) by combining Partial Least Squares Structural Equation Modeling and Random Forest Modeling. Using data from a monitoring network of 536 sites, we observed an increasing trend in terrestrial bird diversity and functional complexity across the entire watershed from 2011 to 2020. Our findings indicate that a large-scale ecological restoration program has contributed to increases in terrestrial and aquatic bird diversity in the Yangtze River Basin. In contrast, bird diversity in the downstream area has decreased by 2.83 ​%, largely due to a rapid decline in wetland birds. The degradation of wetland habitats and insufficient conservation measures have negatively impacted bird diversity in the downstream region. This suggests that although there have been significant improvements in terrestrial bird diversity, more effective wetland restoration is necessary for biodiversity conservation. We recommend optimizing the national large-scale biodiversity monitoring network and increasing the number of upstream monitoring sites.

Respective Advantages of Growing Different Green Manure With Nitrogen Fertilization in Cotton‐Based Cropping Systems: Insights From a Three‐Year Field Study

ABSTRACTPlanting green manure to improve cash crop yield and soil health has been widely recognized, and understanding cash crop performance after green manure integration is pivotal for determining its potential to bolster and enhance crop productivity and sustainable production. However, it is unclear whether the effects of different types of green manure on subsequent cash crops are uniform. In order to clarify this issue, we systematically analyzed the effects of green manure types and nitrogen (N) application rates on succeeding cotton agronomic performance, yield, biomass, yield stability, and nutrient uptake. A split‐plot experiment with two factors was designed, main factor includes four cover cropping systems monoculture cotton (MC), February orchid/cotton cover cropping (FoC), hairy vetch/cotton cover cropping (HvC), and a mixture of February orchid and hairy vetch/cotton cover cropping (FHC), and sub‐main factor include four N application levels (0 (N0), 112.5 (N1), 168.75 (N2), and 225 (N3) kg N ha−1). Results suggests that nonlegume green manure (February orchid) accumulated more biomass, N, P, and K nutrients than the legume green manure (hairy vetch) and green manure mixture. Compared with cotton yield of MC, the FoC, HvC, and FHC system increased by 5.8%, 7.6%, and 15%, respectively. N use efficiency was more significantly influenced by the N application rates than by cropping systems. Specifically, as N application rates increased, N use efficiency decreased under MC, HvC, and FHC systems, while it increased under the FoC system. Additionally, we observed a trade‐off between cotton yield and yield stability, with the highest yield stability when cotton yield reached 2633 kg ha−1. This study provides evidence that nonlegume green manure (February orchid) with greater advantages on cotton vegetative organ growth, legume green manure (hairy vetch) can promote nutrient uptake compared to other green manure, while green manure mixture (February orchid and hairy vetch mixture) significantly increased cotton yield and yield stability. These findings provide evidence‐based insights highlighting the respective benefits of incorporating diverse species of green manure into cotton‐based cropping systems in the Yellow River Basin of China.

Isotopic and Geophysical Investigations of Groundwater in Laiyuan Basin, China.

Due to the complex intersection and control of multiple structural systems, the hydrogeological conditions of the Laiyuan Basin in China are complex. The depth of research on the relationship between geological structure and groundwater migration needs to be improved. The supply relationship of each aquifer is still uncertain. This paper systematically conducts research on the characteristics of hydrogen and oxygen isotopes, and combines magnetotelluric impedance tensor decomposition and two-dimensional fine inversion technology to carry out fine exploration of the strata and structures in the Laiyuan Basin, as well as comprehensive characteristics of groundwater migration and replenishment. The results indicate the following: (i) The hydrogen and oxygen values all fall near the local meteoric water line, indicating that precipitation is the main groundwater recharge source. (ii) The excess deuterium decreased gradually from karst mountain to basin, and karst water and pore water experienced different flow processes. (iii) The structure characteristics of three main runoff channels are described by MT fine processing and inversion techniques. Finally, it is concluded that limestone water moved from the recharge to the discharge area, mixed with the deep dolomite water along the fault under the control of fault F2, and eventually rose to the surface of the unconsolidated sediment blocked by fault F1 to emerge into an ascending spring.

First report of leaf blight of water chestnut (Trapa natans L.) caused by Sclerotium hydrophilum in central China.

Trapa natans L., or water chestnut, is a currently globally distributed aquatic plant. The Yangtze River basin in China, a site origin of water chestnut (Fan et al., 2022), has extensive cultivation as a vegetable. In June 2021, a survey at the National Aquatic Vegetable Resource Garden in Wuhan, Hubei, China, revealed browning and wilting of water chestnut plants, with abundant white mycelia and brown to black sclerotia on leaves, indicative of southern blight (Sclerotium rolfsii). Field disease incidence a 1 ha area reached 70%, reducing fruit yield by 50%. About 10% of diseased plants showed blackening and rot from petioles to leaves. White sclerotial primordia and small brown to black sclerotia formed on the plant surfaces. By late August, symptoms exceeded 60%. To identify the pathogen, isolations were made from 243 sclerotial samples using 75% alcohol to disinfect, rinsed three times with water, and then incubated on potato dextrose agar (PDA) at 25℃. A total of 129 isolates were obtained, most of which exhibited characteristics of S. rolfsii. However, 21 isolates had sclerotia significantly smaller than those of S. rolfsii (1 to 1.5 mm in diameter). These isolates, cultured on PDA, produced abundant fluffy white aerial hyphae, 3 to 6 μm wide. Optimal mycelium growth was between 25 °C to 30 °C, with an average daily rate of 10 mm. White to light brown sclerotia appeared after 5 days and turned black within 10 to 14 days, averaging 0.34 mm in diameter (n=50). Some isolates produced a light brown pigment. These traits matched the description of S. hydrophilum (Bashyal et al. 2021). Isolates 221 and 238 were selected for molecular identification, with genomic DNA extracted from mycelia using the CTAB method. PCR amplification was conducted using ITS1/ITS4 and NS1/NS6 primers to target the internal transcribed spacer (ITS) and the small subunit ribosomal RNA gene (ssrRNA). Sequence analysis showed that the ITS sequence of isolate 221 (GenBank Acc. No. OR512512) had 99.84% sequence identity with S. hydrophilum Msh6 (GenBank Acc. No. FJ595946), and isolate 238 (GenBank Acc. No. PP035993) had 99.72% identity with S. hydrophilum Whcc-4 (GenBank Acc. No. PP035994). The ssrRNA sequences of both isolates (GenBank Acc. No. PP237261) had 99.69% identity with S. hydrophilum strain Hbq001 (GenBank Acc. No. KY995575), confirming their identification as S. hydrophilum. To assess pathogenicity, 16 water chestnut plants (cultivar Jia-yu Ling) at the rosette stage were placed individually in 32 cm diameter, 10 cm deep containers with fresh water. Eight plants were inoculated with 50 mature sclerotia from PDA cultures of isolates 221 and 238, and incubated at 25 °C for 14 days, with four plants per isolate. The remaining eight plants served as controls. Containers were covered to maintain 100% relative humidity at 25 °C to 32 °C for 3 days. This procedure was repeated twice. After 7 days, inoculated plants developed dark brown lesions on petioles that spread to leaves by 15 days post-inoculation. Fungi isolated from diseased leaves resembled isolates 221 and 238, fulfilling Koch's postulates. S. hydrophilum infecting at least 19 genera of plants, including rice (Zhong et al. 2018), wild rice, water lily (Kernkamp et al. 1977) and watershield (Fu et al. 2024). This is the first report of S. hydrophilum infecting water chestnut (T. natans) in central China, identifying it as a co-pathogen with S. rolfsii. Their combined presence may heighten plant mortality and threaten water chestnut cultivation.

Contrasting effects of increasing irrigation efficiency on hydrological drought based on hydrological scenario simulations

Over-exploitation of water resources leads to water scarcity and aggravation of hydrological drought. An approach to addressing the problem is to invest in increasing irrigation efficiency (IE). However, higher IE may lead to the paradox of IE, that is, after increasing IE, irrigation water consumption (IWC) could increase rather than decrease. An important cause of the paradox of IE is that increasing IE may lead to an increase in irrigation area (IA). Therefore, an improved understanding of the impacts of such practices on hydrological drought is needed. This study used the PCR-GLOBWB 2.0 model to investigate the effects of increasing IE on hydrological drought for the catchment above Bengbu in the Huaihe River Basin in central eastern China. The hydrological drought was simulated under three scenarios, i.e., a baseline scenario in which IE remains unchanged, an IE increases scenario, and an IE & IA increase scenario. The results show that increasing IE has two contrasting effects: aggravation and alleviation of hydrological drought. For instance, the increase in IE (from 0.562 to 0.601 in Henan, 0.482 to 0.544 in Anhui, and 0.464 to 0.522 in Hubei province) from 2009 to 2019 reduced standardized drought streamflow deficit (SDSD) by about 5 ∼ 60 % in the central parts of the study area, whereas in the northern edge of the study area, it intensified SDSD even by more than 80 %. When water availability (WA) is high and can meet most of the crop water demand, increasing IE will lead to a situation in which the increase of IWC is less than the decrease of irrigation water withdrawal (IWW). In this situation, increasing IE alleviates the hydrological drought as intended. However, when water resources are relatively scarce with limited WA and cannot meet most of the crop water demand, increasing IE could lead to a paradoxical situation where the increase of IWC is higher than the decrease of IWW and thereby aggravates the hydrological drought. Also, increasing IE can aggravate the hydrological drought in water-receiving areas by reducing water supply from outside water supply regions. Results show that the impact of increasing IE and IA on hydrological drought is also two-sided, but the aggravating effect is dominant because the increase in IA leads to a significant increase in IWW and IWC. However, when the irrigation system restricts the increase of IA (the IA cannot increase or only slightly), the intensification effect of increasing IE and IA on hydrological drought will be weakened, and may even alleviate the hydrological drought. These results underline the importance of considering consequences at both local and basin scales, particularly for periods during and following drought, when policy makers consider the promotion of water-saving measures at irrigation-system level.

The spatiotemporal distribution and environmental suitability evaluation of Neolithic settlements in the Western Guanzhong Basin of China

Illustrating the relationship between past settlement changes and human-land could help us to understand the complex interactions among climate, human activities, and the environment. Based on archeological literature and fieldworks, this paper combines dating techniques and GIS analysis to explore the spatial and temporal distribution characteristics and human diffusion of Neolithic settlements in the Western Guanzhong Basin (WGB), and to quantitatively analyzes the relationship between human activities and natural geographic factors by index model. The results show that: (1) There was a continuity of Neolithic cultures in the WGB and the absolute chronological sequence of human activities ranges from 7500 to 3900 a BP; (2) The distribution of settlements tends to be on river terraces and Loess tableland, and with the evolution of Neolithic cultures, human activities shifted from near-water to far-water distributions and expanded to areas of high gradient. The center of activity of the settlement spreads from a single nucleus (the Wei River) to multiple nuclei (the Wei River, the Qian Rivers, and the Qishui River) and back to a single nucleus on the northern bank of the Wei River in the area of present Qishan-Fufeng, laying the foundation for the development and strength of the Western Zhou Dynasty Cultures in this area; (3) The suitability level of the natural geographic environment in the WGB gradually decreased from the Wei River to the north and south, and settlements were mainly distributed in the highly and moderately suitable zones; (4) It was found that as early as the Neolithic period, mankind had already grasped certain laws of nature, and the spatial distribution of settlements reflected mankind’s awareness of disaster avoidance and “compromise and reconciliation.”

Evaluation and driving factors of ecological environment quality in the Tarim River basin based on remote sensing ecological index.

Changes in the ecological environment quality (EEQ) in the main inland Tarim River Basin in China substantially impact the regional development. Indeed, comprehensive ecological environment measures have been implemented in the Tarim River Basin since 2000. In this context, the main objective of the present study was to investigate the spatiotemporal evolution of the EEQ and monitor the effectiveness of ecological restoration measures in the Tarim River Basin over the 2000-2020 period using remote sensing data. First, a Remote Sensing Ecological Index (RSEI) was constructed based on the Moderate Resolution Imaging Spectroradiometer remote sensing data. Second, the spatial distributions and factors of the RSEI were analyzed by using Moran's Index and Geodetector. The results indicated that the overall RSEI values for the Tarim River Basin increased from 0.22 in 2000 to 0.25 in 2020. Moreover, the values for areas with poor EEQ decreased from 50.7% to 44.73%, while those with moderate EEQ increased from 11.45% to 16.91%. Therefore, the results demonstrated a slight overall improvement in the EEQ of the study area over the 2000-2020 period. On the other hand, the EEQ in the Tarim River Basin exhibited a significant spatial autocorrelation in the 2000-2020 period, with a relatively stable overall spatial distribution. Areas with high-high aggregation were distributed in the high-elevation mountainous areas in the western, northern, and southern parts of the study area. In contrast, areas with low-low aggregation were observed in the central and eastern low-elevation desert areas. The EEQ in the Tarim River Basin was driven by the interactions of several factors, including the normalized difference vegetation index, land surface moisture, land surface temperature, normalized differential build-up and bare soil index, and elevation. In particular, heat was the main driving factor that severely impacted the EEQ in the study area. Indeed, increase in the heat values could directly enhance meltwater runoff from glaciers in the basin, thereby resulting in short-term improvement in the basin EEQ. Furthermore, rapid urbanization from 2015 to 2020 resulted in a decrease in the average RSEI value of the Tarim River Basin by 0.1 over this period, consequently, the EEQ level decreased slightly. Briefly, the EEQ in the Tarim River Basin showed an overall increasing trend from 2000 to 2020, further demonstrating the effectiveness of a series of implemented ecological restoration measures in the Tarim River Basin over this period.

Economic assessment of ecosystem services with a novel concept of elevation: An application of the discrete choice experiment method

AbstractThis research was conducted in the Hei River Basin of China to understand respondents' willingness to pay (WTP) for ecological services towards sustainable river system management. A discrete choice experiment is used to gauge respondents' preferences. In addition, elevation was introduced as a novel spatial attribute to account for heterogeneity. Primary data from 1680 respondents were collected across the Hei River Basin. The elevation of the river was categorized into five ad hoc elevation ranges to analyze the potential effects of elevation on environmental attributes. These samples were stratified as 1000–1600 m, 1601–2200 m, 2201–2800 m, 2801–3400 m, and 3401–4000 m. Pooled data results showed that the maximum WTP was for water quality, that is, 142.05 RMB, without considering the effect of elevation. However, when the interaction with elevation was included, the amount decreased to 133.52 RMB. Likewise, elevation‐based group estimates showed a varied pattern of spatial preference, with different preferences for each distinguishing attribute. Group A prioritized water quality (92.81 RMB) and the East Juyan area (4.12 RMB). In contrast, Group B preferred the guaranteed rate of irrigation of farmland (3.50 RMB) and reduced sandstorm frequency (17.90 RMB). Leisure and entertainment conditions had the lowest WTP across all groups (0.09–0.50 RMB). These findings highlight the importance of incorporating respondents' preferences in restoring and maintaining river systems. Additionally, it emphasized the need to consider respondents' socioeconomic characteristics when developing sustainable management policies.

Water-surface photovoltaic systems have affected water physical and chemical properties and biodiversity

The implementation of water-surface photovoltaic systems as a source of renewable power has expanded rapidly worldwide in recent decades. Water-surface photovoltaic avoids negative impacts on terrestrial ecosystems, while the impacts on aquatic physical and chemical properties and biodiversity are unclear. To understand the ecological and environmental impacts of water-surface photovoltaic systems, here we conducted a field survey on water physical and chemical properties, plankton and bird communities of 26 water-surface photovoltaic systems in the Yangtze River basin in China during the winter and summer of 2022. We found that water-surface photovoltaic systems decreased water temperature, dissolved oxygen saturation and uncovered area of the water surface, which caused a reduction in plankton species and individual density, altering the community composition. Water-surface photovoltaic systems also caused an overall decrease in bird diversity and changed bird community compositions. These findings suggested that water-surface photovoltaic systems have impacts on the water environment and ecology. Since water-surface photovoltaic systems will continue to expand in the future, our results emphasize that rational planning is critical for the sustainable development of water-surface photovoltaic systems and the protection of the aquatic environment and biodiversity.

Study on the Damage Characteristics of Red Sandstone Foundation Under Rainfall Infiltration in the Red-Bed Area of the Sichuan Basin—Taking Zhongjiang County as an Example

The Sichuan Basin in China is one of the most concentrated areas of red beds in China. In the red-bed area, abundant rainfall can easily cause natural disasters, such as landslides, mudslides, collapses, and subsidence. This has had a great impact on the safety of people and property and sustainable modernization in the area. Zhongjiang County of Sichuan Province is a typical red-bed area, and red sandstone is one of the main foundation rocks in this area. Under the influence of rainfall, the strength of red sandstone foundation easily decays, causing disasters such as house collapse. Therefore, in order to explore the influence of rainfall on the mechanical properties of red sandstone, this paper takes the red sandstone in Zhongjiang County, Sichuan Province, China, as the research object and conducts acoustic-emission uniaxial compression experiments under different water contents. The strength characteristics, instability precursor characteristics, fracture types, and damage characteristics of red sandstone in different water-bearing states are obtained. The abovementioned results provide a reference for the Zhongjiang County Government to consider the impact of rainfall on the red sandstone foundation during modernization and emergency management.

Territorial Spatial Evolution and Driving Mechanisms in Economically Developed Watershed Areas: A Case Study of Hanjiang River Basin in China

Territorial Spatial Evolution and Driving Mechanisms in Economically Developed Watershed Areas: A Case Study of Hanjiang River Basin in China

Study on Shear Strength of Soil-Root Systems of Different Vegetation Types.

The root systems of vegetation significantly contribute to enhancing slope stability. The shear strength of soil-root systems is a crucial parameter for assessing slope stability. This study focuses on six types of vegetation in the Yellow River Basin of China (woodland: Populus przewalskii and Broussonetia papyrifera; shrubland: Periploca sepium and Ziziphus jujuba; grassland: Artemisia hedinii and Setaria viridis), employing in situ shear tests and the Wu-Waldron model (Wu model) to investigate the shear strength of soil-root systems. The results show that the shear stress-displacement curves for P. przewalskii, B. papyrifera, and Z. jujuba are higher and steeper, with clear inflection points. The tensile strength of the roots from the six vegetation types decreases as the root diameter increases. According to the Wu model, the additional root cohesion is ranked as follows: A. hedinii > B. papyrifera > P. przewalskii > Z. jujuba > P. sepium > S. viridis. Based on the in situ shear tests, the shear strength increments are ranked as follows: Z. jujuba > B. papyrifera > P. przewalskii > A. hedinii > P. sepium > S. viridis. Overall, the additional root cohesion obtained by the Wu model in each soil layer is greater than the shear strength increment measured from the in situ shear tests. In the 0-30 cm soil layers, the soil-root systems of Z. jujuba, B. papyrifera, P. przewalskii, and A. hedinii exhibit a better shear strength, whereas P. sepium and S. viridis perform poorly. A principal component analysis reveals that the shear strength of the soil-root systems of different vegetation types is primarily influenced by the soil moisture content and root mass density. Z. jujuba, B. papyrifera, P. przewalskii, and A. hedinii are recommended for ecological restoration projects in the Yellow River Basin of China.

Environmental impacts and nitrogen-carbon-energy nexus of vegetable production in subtropical plateau lake basins.

Vegetables are important economic crops globally, and their production has approximately doubled over the past 20 years. Globally, vegetables account for 13% of the harvested area but consume 25% of the fertilizer, leading to serious environmental impacts. However, the quantitative evaluation of vegetable production systems in subtropical plateau lake basins and the establishment of optimal management practices to further reduce environmental risks are still lacking. Using the life cycle assessment method, this study quantified the global warming, eutrophication, acidification, and energy depletion potential of vegetable production in a subtropical plateau lake basin in China based on data from 183 farmer surveys. Our results indicated that vegetable production in the study area, the Erhai Lake Basin, was high but came at a high environmental cost, mainly due to low fertilizer efficiency and high nutrient loss. Root vegetables have relatively high environmental costs due to the significant environmental impacts of fertilizer production, transportation, and application. A comprehensive analysis showed that the vegetable production in this region exhibited low economic and net ecosystem economic benefits, with ranges of 7.88-8.91 × 103 and 7.35-8.69 × 103 $ ha-1, respectively. Scenario analysis showed that adopting strategies that comprehensively consider soil, crop, and nutrient conditions for vegetable production can reduce environmental costs (with reductions in global warming potential (GWP), eutrophication potential (EP), acidification potential (AP), and energy depletion potential (EDP) by 10.6-28.2%, 65.1-73.5%, 64.5-71.9%, 47.8-70.4%, respectively) compared with the current practices of farmers. This study highlighted the importance of optimizing nutrient management in vegetable production based on farmers' practices, which can achieve more yield with less environmental impacts and thereby avoid the "trade-off" effect between productivity and environmental sustainability.

Correlation change analysis and NDVI prediction in the Yellow River Basin of China using complex networks and GRNN-PSRLSTM.

The Normalized Difference Vegetation Index (NDVI) is affected by various environmental factors, and its relationship with these factors is complex. In order to explore the complex relationship between NDVI and environmental factors, this paper adopts the complex network method to construct a correlation fluctuation network and analyze the interaction between them. It is found that temperature, precipitation, soil moisture, sunshine duration, and PM2.5 are all correlated with NDVI to varying degrees, and their combined correlation with NDVI varies over time. The correlation typically takes 3 to 6months to change, and it tends to persist to some extent. Moreover, we fuse a generalized regression neural network (GRNN) with a long-short-term memory (LSTM) network combining phase space reconstruction (PSR) to propose a GRNN-PSRLSTM prediction model. The model achieves the prediction of monthly NDVI using the five environmental factors of the fluctuation network. The results indicate that the averages of root mean squared error (RMSE) and mean absolute percentage error (MAPE) predicted by the GRNN-PSRLSTM model in the nine provinces are 0.0232 and 0.0564 respectively. This model performs better in the assessment metrics for monthly NDVI forecasts. These findings are significant for evaluating vegetation changes and have some theoretical value for the ecological protection of the Yellow River Basin.

Meteorological–hydrological coupling flood forecast and error propagation characteristics based on radar data assimilation in small- to medium sized River Basin: a case study of Zhanghe River Basin in China

Meteorological–hydrological coupling flood forecast and error propagation characteristics based on radar data assimilation in small- to medium sized River Basin: a case study of Zhanghe River Basin in China