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The study of the spatial-temporal heterogeneity characteristics of flash flood disasters is an important basis for formulating policies and measures for flash flood disaster prevention and control. In order to strengthen the pertinence of flash flood prevention and control in Shaanxi Province, this paper used standard deviation ellipse and gravity model to analyze the spatial and temporal distribution characteristics of flash flood disasters, and used geographic detectors to quantitatively evaluate the driving factors and interactions of flash flood disasters in northern Shaanxi, Guanzhong and southern Shaanxi. The results show that the high incidence period of flash floods in northern Shaanxi has been advanced from August to July. The center of gravity of flash flood disaster is gradually moved from Guanzhong to southeastern Shaanxi. The driving factors of the strongest rainfall in northern Shaanxi, Guanzhong and southern Shaanxi are rainstorm, heavy rain and moderate rain, respectively, and decision-makers should consider the differences in the driving forces of flash flood disasters among different regions and formulate flood control measures according to local conditions. [ABSTRACT FROM AUTHOR]

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In order to understand the community structure and distribution characteristics of macrobenthic shellfish in the coastal waters of Zhejiang, the fixed-point bottom trawl fishery resources survey was conducted from August 2020 to April 2021. The surveyed sea was divided into two areas, the northern and the southern part in Zhejiang, with 29°N as the boundary. A total of 41 species of shellfish belonging to 25 genera, 25 families and 6 orders were collected and identified. The absolute dominant species in all seasons were Bursa rana and Turritella terebra bacillum. There were obvious regional differences in number of species and shellfish biomass distribution in the north and the south areas during different seasons. The shellfish biomass for spring and autumn was higher than that for summer and winter, and it decreased from the north to south area in other seasons except summer. In summer, differences in the average biomass of shellfish were not found in the north region and the south areas. In terms of diversity analysis, The richness index (D) and the diversity index (H') were the highest in spring and the lowest in summer, and the evenness index (J') was the highest in winter and the lowest in spring. Hierarchical Cluster analysis (Cluster) results showed that the shellfish communities were divided into 3 groups at 60% similarity level in Zhejiang coastal waters. Group Ⅰ was in the southern area in spring, summer and autumn, Group Ⅱ was in the northern area in spring, summer and autumn, and Group Ⅲ was the whole area in the winter, and there were differences in the north and the south areas in spring, summer and autumn. The stress value of non-metric multidimensional analysis was 0.08, which had explanatory significance. CCA analysis showed that depth and bottom sea temperature had significant effects on benthic shellfish distribution. This study can provide some reference for shellfish biodiversity conservation and sustainable use for shellfish resources in the coastal waters of Zhejiang. [ABSTRACT FROM AUTHOR]

Using the surface meteorological observation data of 76 national meteorological stations in Hubei Province from 1961 to 2022, the drought and flood processes based on the meteorological drought composite index (MCI) and effective precipitation index (EP) are first identified. Then we analyze the spatial-temporal distribution of the frequency of the drought-flood processes, the characteristics of the drought-flood year, the drought-flood transitions over the past 62 years, and the characteristics of drought and flood processes since 2010. The results show that the frequent occurrence area of droughts and floods in Hubei Province is generally characterized by the flaky distribution with floods in the east and droughts in the west, while floods in the south and droughts in the north. The occurrence frequency of droughts and rainstorm floods shows a fluctuating decreasing and increasing trend, respectively. The droughts mainly occur in spring and summer-autumn with a decreasing trend in frequency, but an increasing trend is found in the summer-autumn droughts and extreme droughts. Comparatively, the rainstorms mainly concentrate in summer and show an increasing trend in frequency. The annual variation of drought-flood year is characterized by continuous droughts for 2-4 years, continuous floods for 2-3 years, or alternation of droughts and floods. In some years, droughts and floods coexist in the same year, while abrupt drought-flood transitions are also found. However, there has been no drought-flood coexistence in the same year since 2010. The annual variation of the number of stations with drought-flood transition fluctuates greatly, showing a five-stage increasing characteristic with the maximum value of each stage decreasing. Since 2010, the drought and flood events show characteristics of extreme enhancement, sudden increases, and successive droughts and floods.

For the problems of unreasonable layout location and low charging utilization rate of electric vehicle (EV) charging stations, this paper proposed a spatial-temporal demand model (STDM) for location optimization of charging stations under spatial-temporal demand. By mining the spatial-temporal distribution characteristics of EV travel data and combining the travel and charging behaviors of EVs, a charging demand prediction model is to obtain the spatial-temporal demand distribution in the region. The method based on spatial-temporal statistics obtained the demand hotspot areas, and the charging coverage rate as the model evaluation parameter considered the service coverage of charging stations. A comprehensive model included the perspectives of users, operators and society with EV distance cost to the station, charging station construction and operation cost and carbon emission cost. Finally, simulation results based on actual data show the feasibility and validity of the model. The results show that the model has set up 12charging stations in the region to reduce the comprehensive cost, while determining the layout location and the number of charging piles. The optimization model results effectively reduce the EV arrival distance and improve the arrival coverage compared with other methods. [ABSTRACT FROM AUTHOR]

【Objective】The spatial-temporal variation characteristics of soil pH and its driving factors were clarified to provide a basis for the improvement of soil acidification in southwest cigar area.【Method】Based on soil pH data of 26 sample points of the second general soil survey in Sichuan Province in 1984, 391 sample points of soil testing and fertilizer recommendation survey in Sichuan Province in 2009, and 164 sample points of cultivated land quality survey in Sichuan Province in 2019, Multi-statistics and Geostatistics were used to analyze the spatial-temporal variation characteristics of soil pH, and Random Forest model was used to explore the main driving factors of soil pH change.【Result】The mean values of pH in Shifang City in 1984, 2009 and 2019 were 6.40, 6.24 and 5.97, respectively, and the average annual value decreased by 0.01 from 1984 to 2009 and by 0.02 from 2009 to 2019. From 1984 to 2019, except for Jiandi Town and Yinghua Town, where the average soil pH value showed an upward trend, the rest of the towns were on the decline, with the largest decrease of 30.62% in Hefeng Town and the smallest decrease of 0.30% in Shigu Town. The overall soil pH in 1984 was dominated by weakly acidic and neutral properties, with alkaline soils accounting for 2.59% of the total area planted with tobacco, and the spatial distribution was characterized by higher soil pH in three areas: Luoshui Town, Hefeng Town and Majing Town. In 2009, only weakly acidic and neutral soils existed in the study area, and soil pH was spatially high in the centre and low in the north and south. In 2019, the area of weakly acidic and neutral soils accounted for 95.25%, and the area of acidic soils (pH < 5.5) accounted for 4.75%, which were mainly distributed in the towns of Majing, Mazu, Hefeng, Nanquan and Shigu. And soil pH in the south was spatially lower than that in the north. Soils planted with tobacco over the past 35 years have generally shown changes in acidification, with about 53.51% of the soil was acidified (ΔpH < -0.3), mainly distributed in the towns of Majing, Hefeng and Mazu, and about 11.63% of the soil was alkaline (ΔpH > 0.3), mainly in the towns of Yinghua and Jiandi; The pH of 44.98% tobacco growing soils ranged from -1.0 to -0.3, 34.86% ranged from -0.3 to 0.3, and tobacco growing soils with ΔpH ≤ -1.0 accounted for 8.54%. The random forest results showed that mean annual precipitation and soil organic matter were the main factors causing soil acidification.【Conclusion】Over the past 35 years, the acidification of tobacco growing soils in Shifang City was aggravated. Some measures should be taken to adjust the situation in production, such as creating new special fertilizer and applying soil conditioner.

To quantify the consumption of water resources for winter wheat, the spatial-temporal distribution and variation of water footprint for winter wheat were quantitatively analyzed based on the water footprint theory and method at the county scale in the Huang-Huai-Hai farming region from 1985 to 2015, and the distribution of cold and hot spot of water footprint were analyzed. The results showed that the total water footprint of winter wheat was 1 168.54X108 m³, and its spatial distribution was high in the south and low in the north. The blue water footprint of winter wheat was high in the north and low in the south, while the green water footprint and gray water footprint were high in the south and low in the north. From 1985 to 2015, the total water footprint for winter wheat increased by 54.8%. The blue and green water footprint changed little, while the grey water increased by 29.1%. The spatial distribution of blue, green and grey water footprints decreased in the north and increased in the south. The gravity center of the total water footprint for winter wheat moved to the southwest, while the overall change of which was small. In recent 30 years, the water footprint for winter wheat showed a spatial agglomeration trend in the global and local areas. The hot spot area expanded in the 2.5 sub-zone, and the cold spot area expanded in the 2.2 sub-zone. These results provided scientific basis for optimizing winter wheat distribution and efficient utilization and management of agricultural water resources in Huang-Huai-Hai farming region. [ABSTRACT FROM AUTHOR]

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Copyright of Guangdong Agricultural Sciences is the property of South China Agricultural University, Guangdong Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] The landscape ecological risk of the Qinling-Daba Mountains was scientifically assessed in order to provide a scientific basis for ecological security construction and for sustainable development in the region. [Methods] The spatial analysis method and the topographic distribution index method were used with land surface cover data for the Qinling-Daba Mountains from 2000 to 2020 to quantitatively analyze the temporal and spatial characteristics of the Qinling-Daba Mountains landscape ecological risk, and its dynamic changes on geographical terrain gradients. [Results] ① The overall ecological risk of the Qinling-Daba Mountains landscape was low, with significant spatial differences. There was an obvious spatial agglomeration effect, presenting a spatial distribution pattern of east and west sides, high in the middle, and low in the north and south. ② From 2000 to 2020, the ecological risk of the Qinling-Daba Mountains landscapes showed a downward trend, with low ecological risk areas expanding significantly, and high ecological risk areas shrinking significantly. ③ High ecological risk values were mostly concentrated in areas with high altitude, complex terrain, or low altitude and flat terrain. Low ecological risk values were predominantly located in areas with medium terrain gradients. [Conclusion] The overall landscape ecological risk in the Qinling-Daba Mountains showed a downward trend, indicating that the quality of the ecological environment in the region had improved. The distribution pattern of landscape ecological risk in the Qinling-Daba Mountains was greatly affected by topography and was relatively stable.

Fushun west open-pit mine, which has a history of 100 years of mining, entered the pit-closing period. Due to the exploitation of resources, the west open-pit mine was threatened by geological disasters for a long time. In order to summarize the occurrence regularity of geological disasters in the west open-pit mine, ensure the safety of production and life in the mining area and near-mining city, and provide reference cases for disaster analysis and safety protection of other similar open-pit mines, the distribution law and influencing factors of landslides and ground fissures in west open-pit mine are studied and analyzed from time and space scale, based on the DPSR model, the corresponding measures of chain break disaster reduction and safety protection are put forward from three aspects: driving force response, pressure response and state response. Spatial-temporal distribution characteristics of landslide: in space, it first appeared in the western part of the southern slope in 1927. In recent hundred years, due to the driving influence of open-pit mining and underground mining, the main location of landslide developed from the western part of the southern slope to the western part of the northern slope, the western part of the northern slope, the central part of the northern slope and the eastern part of the northern slope. In recent years, large-scale rock slope sliding deformation occurred in the southern slope. Actually, from 1970 to 2000, landslide disasters occurred most frequently. After 2000, the frequency of landslide disasters decreased, and most of them occurred from May to September. Spatial-temporal distribution of ground fissures: the ground fissures near the north slope appeared after 1960, and accelerated in 1970s and 1980s, with the strike basically consistent with that of F1 and F1A faults; the ground fissures in the southern slope are distributed in the rear edge of the huge slip deformation body in the southern slope, which are arc-fan shaped and appeared in 2009 and developed rapidly after 2012. Through the analysis of disaster influencing factors, it is found that there is a chain relationship of homology and mutual causality between landslides and ground fissures, and the main factors affecting the occurrence of geological disasters in mining areas are geological structure and control of unfavorable engineering geological environment, driving of mining activities and inducing of rainfall.

In order to analyze the spatio-temporal distribution and species characteristics of red tide in the coastal waters of Ningde, all red tide events occurred in this study area were collected from 2010 to 2020. The important conclusions were as follows: Firstly, a total of 16 red tides occurred in Ningde coastal waters, with an annual average of 1.5 times in the past 11 years. The total area of red tides was as high as 1468 km2, with an annual average of 133.5 km2. The duration of red tides was 169 days, with an annual average of 15.4 days. Secondly, red tide occurred from April to June, with a high frequency in May. Thirdly, red tide species included dinoflagellates and diatoms. In terms of frequency and area of red tide, Prorocentrum donghaiense ranked first, followed by Karenia mikimotoi, and the last one was Skeletonema costatum. Fourthly, in terms of spatial distribution, the locations with the highest frequency of red tide and the longest duration were in Funing Bay and its surrounding waters (Zone A), while the largest area of red tide was scattered in Sansha outer Bay (Zone D), and the largest number of red tide species was located in Sansha inner Bay (Zone C). Fifthly, there were four times of toxic red tides caused by Karenia mikimotoi, mainly concentrated in the waters around Xiapu coastal waters. Appropriate temperature and salinity, rich nutrients and good weather were the prerequisite conditions for the formation of red tide of Karenia mikimotoi.

Plenty of organic waste has been produced from agriculture and rural areas in Beijing suburbs over the last decade, with the rapid development of urban agriculture. It is still lacking in the dynamics of the quantity, nutrient content, and the relationship between supply and demand over time. This paper aims to estimate the quantities and nutrient resources of straw, vegetable waste, abandoned branches of fruit trees, livestock/poultry solid and liquid manure, and kitchen waste in Beijing suburbs, according to the statistical yearbooks and literature. A systematic investigation was also made on the relationship between organic fertilizer nutrient inputs and crop nutrient demand. The results show that the production of organic waste and its nutrient production was declined yearly from 2010 to 2019, with 1.30×107 t and 2.18×105 t in 2010, respectively, while declining by and 62.3% and 71.8% in 2019, respectively. The ratio of specific organic waste and nutrients was ranked in the descending order of the livestock/poultry solid and liquid manure, straw, vegetable waste, abandoned branches of fruit trees and kitchen waste, but varied in different regions. Specifically, the Daxing, Shunyi, Pinggu, and Tongzhou districts shared the highest proportion of plant production waste and its nutrients in 2010, whereas, the Daxing and Miyun districts presented the highest proportion of breeding waste and its nutrients. Furthermore, the Pinggu, Shunyi, Daxing and Miyun districts showed the highest proportion of plant production waste and the corresponding nutrients in 2019, whereas, the Shunyi and Pinggu districts shared the highest proportion of breeding waste and the corresponding nutrients. The main producing areas of rural domestic waste were always in the Changping, Daxing, and Tongzhou districts. The amount of organic waste and nutrients in the Daxing district was the highest in 2010, at 2.45×106 and 5.10×104 t, respectively, the Pinggu district had the highest amount of nutrients, at 1.37×104 t, and the Mentougou district produced the least amount of organic waste. The amount of organic waste returned to the field gradually decreased over the decade, where the total amount of organic waste returned to the field in 2010 was 5.55×106 t and the total organic nutrient input was 1.51×105 t. The amount of waste and its nutrients returned to the field decreased by about 76.8% and 72.3% in 2019, compared with the distribution in 2010. The organic waste returned to the field was concentrated in the southeastern region in 2010, while the amount of organic waste returned to the field tended to be evenly distributed in 2019. There was a staggered trend in the matching between effective nutrient supply and crop demand in the returning fields under 50% chemical fertilizer rationing conditions. Specifically, the nutrient surplus was exacerbated in the Changping and Fangshan districts between 2010 and 2015, whereas, the nutrient deficit was found in the Huairou and Miyun districts in 2019. The nutrient overload of nitrogen and potassium was the most serious in the Mentougou district, while the phosphorus overload was serious in the Changping district. The nutrient overload areas should be controlled by the scale of the agriculture industry, considering the diversified high-value use of organic waste and the outward transportation of organic fertilizers, while the nutrient deficit areas can appropriately expand the scale of production for the nutrient utilization rate of organic waste. This finding can provide a scientific basis for green agricultural development, rational layout, and organic waste resource utilization. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology / Shuisheng Shengwu Xuebao is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Based on conventional observation data, NCEP reanalysis data, lightning locating data and radar data, we have conducted the analysis on weather types, spatial-temporal distribution and environment condition of thunderstorm gales in Hubei from 2007 to 2015. Moreover, according to the results in boxplots, we have discussed the environmental parameter characteristics for the different types of thunderstorm gales in different regions and seasons. The main results are as follow. (1) Thunderstorm gales in Hubei, which occur between March and August, can be divided into high-level cold advection forcing (HCAF), low-level warm advection forcing (LWAF), baroclinic frontogenesis (BCF), and quasi-barotropic (QBT) types, with 78% of them occurring in the summer (from June to August). Most of thunderstorm gales occur from 15∶00 BT to 19∶00 BT in a day, whose peak value is at 16:00 BT. The spatial distributions of thunderstorm gales are uneven, whose high frequency regions are located near Yichang of southwestern Hubei and Huangshi of east Hubei. (2) There are seasonal and regional differences in the spatial-temporal distribution of the different types of thunderstorm gales. Among those types, the BCF type occur mostly in spring, and most of HCAF, LWAF and QBT types occur in summer. The HCAF type occurs mostly in the northwest Hubei, and the LWAF type occurs more in Yichang area, Jianghan plain and eastern Hubei, while both the QBT type and the BCF type occur mostly in the eastern Hubei. (3) When the HCAF type thunderstorm gales occur, both the temperature difference (ΔT85) between 850 hPa and 500 hPa and the wind vertical shear (S95) in the mid- and low-level (925-500 hPa) are greater, while the dew-point at 850 hPa is lower. For the QBT type thunderstorm gales, both S95 and K index are greater. For the QBT type, the convective available potential energy (CAPE) is greater, and both S95 and the wind vertical shear (S97) in the low-level (925-700 hPa) is less. For the BCF type, both S95 and S97 are greater. (4) When the thunderstorm gales in Hubei occur, the thresholds of convection parameters of K index, ΔT85 and CAPE are 35 ℃, 25 ℃ and 925 J·kg-1, respec tively. The dispersion of convection parameters is greater in the northwestern Hubei and eastern Hubei, therefore, summing up the thresholds of convection parameters in region has more indicative significance to the forecasting and warning of thunderstorm gales in Hubei.

Based on DEM terrain elevation data and ADTD lightning location data of Chongqing from 2008 to 2020, the temporal and spatial distribution characteristics of cloud-to-ground (CG) lightning activities under the influence of complex terrain in Chongqing were studied. The results showed that: (1) The spatial distribution of CG lightning activities in Chongqing exhibited significant differences, and it was closely related to topography and altitude. From west to east, the CG lightning activities in Chongqing gradually weakened from basins to hills and to the mountainous areas with high altitudes, and the proportion of positive CG lightning gradually increased. (2) The inter-annual variation of CG lightning activities was unevenly distributed. The monthly variation of CG lightning activity was unimodal. The peak was in July, and the lightning activities mainly occurred from April to September, accounting for 96.3% of all the activities in the whole year. The diurnal variation of lightning activity was characterized by double peaks. The peak at night was concentrated at 00: 00-04: 00, and the peak at daytime was concentrated at 14:00-18:00. The number of CG lightning activity during 08:00-12:00 was the lowest. The monthly and seasonal changes in CG lightning activity were mainly dominated by large-scale weather systems. (3) The influence of topography and altitude on CG lightning activity was mainly reflected in the significant differences in diurnal changes. In basins, hills, and low mountainous areas with an altitude less than 1000 m, the frequency of CG lightning at nighttime was significantly higher than that in the daytime. In high mountainous areas with an altitude more than 1000 m above sea level, the frequency of CG lightning during the day was more than that at night. The higher the altitude, the more likely lightning would occur during the day. (4) The current intensity of the positive CG lightning was obviously greater than that of negative CG lightning, and the influence of terrain and altitude changes on the current intensity of the CG lightning was not obvious. [ABSTRACT FROM AUTHOR]

Study on water vapor transport is beneficial for better understanding the process of extreme precipitation. However, the precipitation system is complex and precipitation isotopes exhibit randomness, which makes it large uncertainty to use precipitation isotopes to trace water vapor transport. Information entropy has been employed to study the probability distribution characteristics of precipitation isotopic compositions in China, and it shows a strong linear relationship between hydrogen and oxygen precipitation isotopic information entropies, with a slope that is close to one. The spatial and temporal distributions of precipitation isotope information entropy were compared with the mean value of precipitation isotopes. Results showed that the spatial distribution of precipitation isotopic information entropy can suitably reveal the movement of water vapor from the ocean to continents, but this feature is not reflected by the spatial distribution of the mean value of precipitation isotopes. Precipitation isotope information entropy was applied to trace the three moisture corridors driven by monsoon system in China. Results showed that the spatial distribution of precipitation isotope information entropy can accurately reflect the vapor source and movement of the three moisture corridors and their seasonal changes. [ABSTRACT FROM AUTHOR]

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In order to understand the spatial-temporal distribution and ecological risk of antibiotics in the soil of an agricultural watershed in the Three Gorges Reservoir area, the topsoil samples were collected at 26 sites in the Wangjiagou small watershed, Fuling District, Chongqing in spring, summer, autumn, and winter of 2022, and 21 antibiotics with five classes were determined using solid phase extraction and ultra-performance liquid chromatography-tandem mass spectrometry. The content levels and spatial-temporal distribution of antibiotics were analyzed, the correlations between antibiotic contents and soil physicochemical factors were discussed, and the potential ecological risk of antibiotics in the soil was evaluated using the risk quotient method. The results showed that the detection rates of 21 antibiotics were 0-100% with the range of ND-219.5 μg·kg -1 , and those of tetracyclines （TCs）, quinolones （FQs）, and chloramphenicols （CAPs） reached 100% in all four seasons. The total antibiotic content ranged from 14.35 to 504.1 μg·kg -1 with the average value of 149.7 μg·kg -1 , and the average contents of the five classes of antibiotics showed a decreasing trend of TCs （77.95 μg·kg -1 ）, FQs （34.96 μg·kg -1 ）, CAPs （28.14 μg·kg -1 ）, sulfonamides （SAs, 7.15 μg·kg -1 ）, and macrolides （MLs, 1.48 μg·kg -1 ）. The antibiotic contents of soils during autumn and winter were significantly higher than those in summer （ P &lt; 0.05） and showed an overall variation trend of first decreasing and then increasing with the season and a distribution situation of "low in the west and high in the east." The sites with high antibiotic contents were mainly concentrated in vegetable fields, residential areas, and dry lands. In spring soils, the contents of tylosin （TYL） （ P &lt; 0.01）, tetracycline （TC） （ P &lt; 0.01）, doxycycline （DXC）, and sulfamethodiazine （SMR） （ P &lt; 0.05） were significantly negatively correlated with soil pH. In summer soils, total phosphorus （TP） had significantly positive effects on the contents of sulfamethoxazole （SFZ） and TC （ P &lt; 0.05） and had extremely significant positive effects on sulfamethoxazole （SMX）, SMR, and ofloxacin （OFL） （ P &lt; 0.01）. Total nitrogen （TN） had significantly positive effects on the contents of SMX （ P &lt; 0.01） and SMR （ P &lt; 0.05）, and soil organic matter （SOM） had significantly positive effects on the contents of TC and enrofloxacin （ENR） （ P &lt; 0.05）. However, ciprofloxacin （CIP） （ P &lt; 0.001）, sulfampyridine （SPD）, norfloxacin （NOR）, and TYL contents （ P &lt; 0.05） were significantly negatively correlated with soil pH. In autumn soils, TN significantly negatively affected CIP content （ P &lt; 0.05）； the contents of sulfadiazine （SDZ）, TC, and DXC were negatively affected by soil pH （ P &lt; 0.05）； and cation exchange capacity （CEC） significantly positively affected the contents of TC and SFZ （ P &lt; 0.05）. In winter soils, TP had a significantly positive effect on TYL content, and TN had a significantly positive effect on SFZ content （ P &lt; 0.05） and an extremely positive effect on sulfamethoxine （SMM） （ P &lt; 0.001）. Chlorotetracycline （CTC） （ P &lt; 0.01）, CIP （ P &lt; 0.01）, thiamphenicol （TAP） （ P &lt; 0.001）, chloramphenicol （CAP） （ P &lt; 0.001）, oxytetracycline （OTC） （ P &lt; 0.001）, and sulfadimidine （SM2） （ P &lt; 0.05） were significantly negatively correlated with soil pH, and CEC had a significantly negative effect on SDZ content （ P &lt; 0.05）. The soils in the Wangjiagou agricultural small watershed were mainly threatened by SMX, SDZ, TC, DXC, erythromycin, NOR, OFL, CIP, and ENR, and their ecological risks should not be ignored.

According to the data sets of fine particulate matter （PM 2.5 ） and its components in 35 cities in the Huaihe River Basin from 2015 to 2021, the temporal and spatial distribution patterns of pollutants were analyzed. The influence of meteorological factors on PM 2.5 concentrations was examined using a random forest model. The original series of PM 2.5 , sulfate （SO 4 2- ）, nitrate （NO 3 - ）, ammonium salt （NH 4 + ）, organic matter （OM）, and black carbon （BC） were rebuilt using KZ （Kolmogorov-Zurbenko） filtering and multiple linear regression （MLR） to quantify the effects of meteorological conditions. The results demonstrated that from 2015 to 2021, the declining rates of PM 2.5 , SO 4 2- , NO 3 - , NH 4 + , OM, and BC in the Huaihe River Basin were 4.71, 0.99, 1.05, 0.77, 1.01, and 0.19 μg·（m 3 ·a） -1 , respectively. The high mass concentrations of PM 2.5 and its components were concentrated in the central and western regions of the HRB, whereas those in coastal and southern cities were lower. The variance contributions of the short-term, seasonal, and long-term components of PM 2.5 to the original PM 2.5 sequences in 35 cities were 51.6%, 35.9%, and 7.0%, respectively. The PM 2.5 in coastal cities were more affected by the short-term components. The meteorological conditions were unfavorable for PM 2.5 reduction in the HRB from 2015 to 2018, whereas the meteorological conditions supported the PM 2.5 decrease from 2019 to 2021. From 2015 to 2021, the contribution rates of meteorological conditions to the long-term component reductions of PM 2.5 , SO 4 2- , NO 3 - , NH 4 + , OM, and BC were 28.3%, 29.1%, 31.0%, 29.3%, 27.8%, and 28.6%, respectively. The contribution rates of meteorological conditions to the long-term PM 2.5 reduction were 43.4%, 25.6%, 25.5%, and 20.6% in the HRB cities in Anhui, Shandong, Jiangsu, and Henan Provinces, respectively. With the decrease in PM 2.5 concentration in the HRB, the sulfur oxidation rate （SOR） increased significantly, while the nitrogen oxide oxidation rate （NOR） changed little.

To understand the spatial distribution of NO 2 near the surface, we utilized measured data from NO 2 monitoring stations and combined it with column concentration data from the Tropospheric Monitoring Instrument （TROPOMI）, taking the Yangtze River Delta region as the study area. We considered the impact of factors such as population, elevation, and meteorological conditions on NO 2 levels. We used automated machine learning to select five machine-learning algorithms with high simulation accuracy, namely ET, RF, XGBoost, LightGBM, and Catboost, and then integrated these five algorithms using the Stacking model to simulate the daily NO 2 concentration in the Yangtze River Delta region from March 2020 to February 2021. The results indicated that the RMAE and MAE values of the Stacking ensemble model were 7.078 and 5.270, respectively, which outperformed the single algorithms of ET, RF, XGBoost, LightGBM, and Catboost. The spatial distribution of high NO 2 concentrations in the Yangtze River Delta region, consisting of three provinces and one municipality, exhibited a U-shaped pattern with the convergence point located at the intersection of the three provinces, extending towards the southwest. Notably, urban pollution was particularly significant in the urban agglomerations centered around Shanghai, Hangzhou, Nanjing, and Hefei. There were 27 cities that exceeded the national standard daily limit. Changzhou was the city with the most serious NO 2 pollution, with the NO 2 concentration exceeding the standard for 14 d, followed by Shanghai, with 13 d. In terms of seasonal variation, the order of severity was as follows： winter, autumn, spring, and summer, with the least NO 2 pollution occurring on July 9th during the summer, and the most severe NO 2 pollution was observed on December 23rd during the winter.

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In the past, the studies on the operation characteristics of urban vehicles were mostly aimed at single type of vehicles, which was difficult to reflect the differences and comparative characteristics between current taxis and online ride-hailing. In order to accurately analyze the operation efficiency and spatial-temporal changes of urban operating vehicles, the GPS trajectory data of taxis and online car-hailing in Xiamen and Baidu Interest Point (POI) data are taken as the research objects. On the basis of constructing the operation characteristic index system, the weighted time capacity utilization index is introduced, and the operation efficiency and spatial-temporal changes of two types of operating vehicles at different time points, different administrative regions and different functional areas are compared. The results show that the two types of vehicles have obvious and unbalanced daily change trends, but the proportion of orders in different administrative areas and different functional areas is roughly the same. The operation intensity of taxis is significantly higher than that of online ride-hailing, but the service scope of online ride-hailing is much larger than that of taxis. The weighted time capacity utilization rate of taxis is significantly related to the ratio of GDP and taxi number in the administrative area. Therefore, the planning and management of taxis and online car-hailing should be strengthened in Tongan District and other economically underdeveloped areas. The research results can provide reference and data support for the supervision and scientific services of traditional taxis and online car-hailing. [ABSTRACT FROM AUTHOR]

This paper summarizes the research progress on extreme hourly precipitation (EXHP) over China in the past decade. The main results are as follows. (1) Thresholds of EXHP are usually defined using the percentile method or the empirical distribution function method. The thresholds of EXHP in China show substantial regional variations, with the most intense centers over the coastal South China, Hainan and Taiwan islands, and North China Plain, and two secondary ones in the Sichuan Basin and the middle-lower-reaches of the Yangtze River. (2) The EXHP records are classified into four types according to the synoptic situations under which they occur, i.e., the tropical cyclone, surface front, low-level vortex/shear line, and weak-synoptic forcing types. Each type presents distinctive characteristics in regional distribution and seasonal or diurnal variations. (3) An extreme hourly rainfall event (EXRE) is defined as a continuous time period with hourly rainfall rates at a station ≥ 0.1 mm·h-1, with at least one EXHP record and at most 1 h intermittence. The average duration of EXREs exceeds 12 h in the southeast coastal regions and the Yangtze River valley, but is relatively short (< 6 h) in northern China. The rainfall evolution of EXREs is asymmetric, i.e., rainfall rates increase rapidly from the beginning of an event to the extreme value, but more slowly afterwards to the end of the event, especially over the complex terrains in western China. (4) Over the past 50 years, the positive trends of EXHP in China are scattered. Significant increasing trends of EXHP are observed in Shanghai megacity and the urban cluster over the Pearl River Delta during the rapid urbanization period, which differ from their surrounding areas. Both the observation and modeling studies suggest that the strong urban heat island effect in Beijing is conductive to intensification of hourly precipitation.

In order to analyze the variation of pan evaporation and the influencing factors of the Yellow River basin in the context of climate change, this paper used linear regression, Mann-Kendall and EOF to analyze the pan evaporations of 95 meteorological stations in the Yellow River basin from 1961 to 2019. The results show that the pan evaporation has shown a significant downward trend in the past 59 years. The climate inclination rate of the whole basin is -60.4 mm/10 a. However, the decline in evaporation has been accelerated, with an evaporation value of -219.4 mm / 10 a since 2004. For seasonal variation, the climate inclination rates in spring, summer, autumn and winter are -12.7, -24.5, -10.4 and -1.9 mm/10 a respectively. The climate inclination rate in the upper reaches (-59.3 mm/10 a) is the highest, followed by the middle reaches (-49.2 mm/10 a) and the lower reaches (-74.9 mm/10 a). Two spatial distribution modes in the basin are identified, including consistent distribution and the anti-phase distribution of central and eastern and western. Based on partial correlation, grey correlation and multiple regression analysis, the main factors influencing the pan evaporation in the Yellow River basin are the annual mean daily temperature range, annual sunshine duration, annual precipitation and relative humidity. [ABSTRACT FROM AUTHOR]

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Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rivers are important reservoirs of antibiotic resistance genes (ARGs). However, most current studies have focused on the temporal and spatial distribution, and data on the differences in the species and abundance of ARGs between urban and rural rivers is still lacking for certain areas. In view of this, two rural rivers and three urban rivers were selected in Shijiazhuang City. In both December 2020 and April 2021, sediments were collected at 15 sampling sites. Metagenomic sequencing technology was used to compare the differences in temporal-spatial variation for ARGs in sediments. The results showed that:① 162 and 79 ARGs were detected in urban (4 776 ±4 452) and rural rivers (1 043 ±632), respectively. The abundance and species of ARGs in urban rivers were higher than those in rural rivers. ② The relative abundances of sulfonamide (SAs,27 %), aminoglycoside (AGs,26 %), and multidrug (MDs,15 %) ARGs had the highest abundance in urban rivers, whereas the relative abundance of MDs ARGs was highest in rural rivers (65 %). On the whole, the complexity of ARGs in urban rivers was higher than that in rural rivers. ③ There was a significant positive correlation between SAs, AGs, MDs, tetracycline, phenicol, macrolides-lincosamids-streptogramins (MLS), β -lactams, and diaminopyrimidine ARGs in urban rivers ( P &lt; 0.01); however, there was a significant negative correlation between glycopeptide ARGs and all types of ARGs ( P &lt; 0.05 and P &lt; 0.01). There was a significant positive correlation between MDs and SAs ARGs in rural rivers ( P &lt; 0.05), but there was a significant negative correlation between amino aminocoumarin, peptide, rifamycin, and fosfomycin ARGs ( P &lt; 0.05 and P &lt; 0.01). ④ For the temporal variation in urban rivers, 162 ARGs (4 776 ±4 452) and 148 ARGs (5 673 ±5 626) were detected in December and April, respectively. For the temporal variation in rural rivers, 79 species (1 043 ±632) and 46 species (467 ±183) were detected in December and April, respectively. ⑤ RDA analysis results showed that the spatial-temporal distributions of ARGs in urban and rural rivers were different. Correlation analysis showed that the ARGs in urban rivers were significantly correlated with the number of industrial enterprises, whereas the ARGs in rural rivers were significantly correlated with the output value of animal husbandry. In general, this study identified the main influencing factors for ARGs in different rivers and provided data support for ARGs risk management in different rivers.

Based on the traditional Mann-Kendall method,this paper analyzes the spatial-temporal precipitation distribution by the cloud model according to the monthly precipitation data (1990—2020) from 38 stations in Qingyuan City,Guangdong province.The results show that:①In the last 30 years,the precipitation in Qingyuan showed an upward trend in the whole year,flood season and non-flood season,especially in the whole year and flood season.②The stability of precipitation was best in non-flood season,less in whole year,and the worst in flood season.The distribution of precipitation was the most discrete throughout the year,followed by flood season,and more concentrated in non-flood season.③The precipitation showed similar spatial distribution in whole year and flood season,increased from northwest to southeast in general,among them the precipitation in Lianzhou City is small,concentrated and stable.In non-flood season,the distribution of precipitation increased from southeast to northwest,among them the precipitation in the south of Qingcheng District is the least and unstable but concentrated;while that in the northeast of Yingde City is large and stable but not concentrated.

As an important parameter of aerosols, mass density affects the complex chemical reactions in the atmosphere, and is closely related to the transport process and spatial distribution of aerosols. In This paper, column mass densities of dust aerosols and dust PM2.5 aerosols in the Tarim Basin are studied over period of 1980-2018 based on the MERRA-2 data. Generally, the column mass densities of dust aerosols and dust PM2.5 aerosols over the Tarim Basin show large variations with average values of 0.33g/m² and 0.086 g/m², respectively, as well as distinctive annual, monthly and seasonal patterns. The annual average column mass densities of dust aerosols and dust PM 2.5aerosols in the Tarim Basin vary in ranges of 0.24-0.41 g/m² and 0.06-0.11 g/m², respectively .As for their seasonal and monthly variations, the column mass densities are large in spring (0.47g/m² and 0.12 g/ m²) and small in winter (0.13g/m² and 0.04g/m²), which peak in May with values of 0.57 g/m² and 0.14 g/m², and lowest in January with values of 0.1g/m² and 0.03 g/m², for dust aerosols and dust PM2.5 aerosols, respectively. [ABSTRACT FROM AUTHOR]

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The severe over-exploitation of groundwater led to the problems of extreme water shortage and restricted irrigation in the Heilonggang Basin. Effective use of natural precipitation was one of the key approaches to solve the problem of water requirement for maize production in the Heilonggang Basin. The objective of this study was to analyze spatial-temporal distribution characteristics of effective precipitation and water requirement for maize production and define the water deficit region. Daily meteorological data from 18 surface meteorology stations from 1966 to 2015 were collected and phenological data of summer maize in 5 typical regions of the Heilonggang Basin were observed. The calculated index included effective precipitation, water requirement, the Crop Water Deficit Index (CWDI), the frequency of drought, and the correlation between water demand and meteorological factors during the maize whole growing period and 4 important stages. The water requirement of maize was estimated by using the Penman-Monteith equation of the Food and Agriculture Organization and crop coefficient method, and the crop coefficient of summer maize was identified by previous research of Hebei Province. The spatial distribution and evolution trend of drought for summer maize in different growth stages were analyzed by using the CWDI. Furthermore, analyzing the temporal and spatial distribution characteristics of the all calculated index in the whole growing period and each growth stage of maize was drew by the Inverse Distance Weighted (IDW) method of ArcGIS. The results showed that the range of annual effective precipitation in the summer maize growth period was from 292.89 mm to 361.56 mm, an average of the whole growth period was 326.46 mm, and the spatial distribution of effective precipitation during the whole growth period was showed a trend of ‘high in northeast and low in the southwest’. The annual average water requirement for maize ranged from 362.82 mm to 444.04 mm with an average of 395.45 mm during the whole growing period, and the spatial distribution of water requirement showed a trend of ‘higher in the south and lower in the north’. Total effective precipitation and water requirement during the whole growth period showed a downward trend year by year, and the climate tendency rates were -11.76 mm/10a and -6.26 mm/10a, respectively. Correlation analysis showed that the reduction in water requirement was related to a significant reduction in average sunshine hours and average wind speed. In the past 50 years, the drought frequency of summer maize during the whole growth period in the Heilonggang Basin was 48.30%. Among them, the proportion of drought-prone years of all the 4 growth stages were more than 33.3% in the southern regions and more than 66.6% during the kernel formation stage and grain filling stage both in the central and northern regions. The values of CWDI were less than 0.35 from the seedling stage to the ear developing stage and the water deficit regions were mainly concentrated in the central and southern regions. The average values of CWDI during the kernel formation stage and the grain filling stage were 0.49 and 0.41 respectively. The southern region of the Heilonggang basin was prone to light drought during the kernel development stage. The kernel formation stage and the grain filling stage were prone to occur drought in central and northern regions of the Heilonggang Basin, and the highest drought level reached moderate drought. Hybrid cultivars with higher drought resistance, shortened growth period and a higher rate of grain filling were recommended in the Heilonggang Basin to improve the drought resistance of summer maize, and soil water supply capacity could be increased through techniques such as subsoiling and straw-returning. This study could provide a theoretical basis for the efficient use of precipitation resources for summer maize in the Heilonggang Basin. [ABSTRACT FROM AUTHOR]

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In order to research spatial-temporal distribution characteristic of freezing damage risk for wine grape during overwintering in Ningxia,reasonable buried soil makes full use of temperature resources to ensure wine grape safe overwintering and reduce losses. Based on the various temperature observations in meteorological station of wine grape growth area in Ningxia during 1980-2018,verify by freezing damage data,19°Cextreme minimum temperature as the index critical value of freeze injury, researching of the spatial distribution and the interannual variation characteristic.Using mathematical statistical methods, linear trend fitting,Mann-kendall mutation test,Morlet wavelet analysis, the results showed that freezing damage risk is the highest in the north of main wine-growing areas in Ningxia,the freezing damage risk reduced gradually from north to south. The risk of freezing damage is higher in the north, east and west of the planting area; wintering days with freezing damage in Ningxia wine grape growing areas decreased.The number offreezing damage days during overwintering of Majorwine grape growth region in Ningxia decreased during 1980-2018.The decrease was obvious after 2007,the largest number offreezing damage was the winter of 2007, and 1992, 1988, 2002, 2010 and 1984 were the years with serious freezing damage in the actual investigation, the freezing damage with long duration occurred in all planting areas. In 1989、1990、2001 and 2006,there were not freezing injury days in the main wine-growing areas, the number of freezing injury days had periodic changes of 3a and 21a,and there was a trend mutation in 1988, 2002 and 2013. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central China Normal University is the property of Huazhong Normal University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Soil erosion and ecological degradation are the most important ecological environment problems for the Chinese Loess Plateau in recent years, which have seriously hindered the sustainable development of the economy of the Chinese Loess Plateau. Based on the remote sensing image data of the Landsat TM and OLI, the remote sensing ecological index (RSEI) of the tableland protected regions of the Gansu, Shaanxi and Shanxi in the Chinese Loess Plateau were estimated during the period of 2002, 2009 and 2017 in this paper, and the influences of the change of the ecological restoration were also quantitatively evaluated. Besides, the locations of the regions of main ecological degradation were also screened out in this study. The results show that: (1) compared with the results of 2002, the remote sensing ecological index of the Gansu tableland region in 2017 showed a slightly increasing trend (increased by 0.04). Besides, the RSEI of the Shaanxi tableland region in 2017 also showed an obviously increasing trend, and the RSEI increased from 0.45 (in 2002) to 0.56 (in 2017), which indicated that the ecological environment of the Shaanxi tableland region has been improved. The RSEI of the Shanxi tableland region decreased from 0.54 (in 2002) to 0.46 (in 2017), which indicated that the ecological environment of this region has been degraded. (2) Compared the results of 2017 with 2002, the areas of the poor ecological conditions and relatively poor ecological conditions in the Gansu tableland region reduced obviously, while the areas of the good and excellent ecological conditions showed an increasing trend. In the Shaanxi tableland region, the areas of the poor ecological conditions and the relatively poor ecological conditions also demonstrated a decreasing trend, while the areas of the medium ecological conditions and the good ecological conditions increased significantly, the excellent areas presented a fairly stable status. In the Shanxi tableland region, the areas of the poor ecological conditions, the relatively poor ecological conditions and the medium ecological conditions presented increasing trend, while the areas of the good ecological conditions and the excellent ecological conditions showed a decreasing trend. (3) In the Gansu tableland region, the degradation of ecological environment mainly located in the Puhe and the Honghe river basins. In the Shaanxi tableland region, the degradation of ecological environment mainly distributed in the Juhe, Sanshuihe, Ganhe and Qishuihe river basins. In the Shanxi tableland region, the ecological environment degradation areas concentrically located in the Zhouchuanhe and Ehe river basin. (4) Compared the three tableland regions, the ecological conditions in the Gansu tableland regions and the Shaanxi tableland region have been remarkable improved during the period of 2002-2017. Although the ecological conditions in the Shanxi tableland region have declined, the improvement trend of ecological conditions has emerged in this study area. With the continuous implementation of various soil and water conservation and ecological restoration measures, the ecological environment in these three tableland regions of the Chinese Loess Plateau will be effectively improved. The research results of remote sensing ecological security in this paper have a far-reaching significance for the ecological restoration of the tableland regions of the Chinese Loess Plateau, and it is informative for the comprehensive control of regional soil erosion. [ABSTRACT FROM AUTHOR]

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The gold deposits in Qinghai can be divided into fractured alteration rock-type, marine volcanic rock-type, skarn-type, overlay-type and sand-type. The forming ages of deposit are continuous, ranging from Early Paleozoic to Cenozoic. The peaks of deposit development appear at Late Paleozoic and Mesozoic. Late Paleozoic deposits are mainly located in the northern margin of Qaidam Basin, and Mesozoic deposits mainly distribute in East Kunlun, West Qinling and North Bayankala. The rock gold deposits mainly distribute to the north of 35°N. The fractured alteration rock-type gold deposits are the main in Qinghai, and are strictly controlled by structures. The output and distribution of gold orefields and deposits are controlled by regional deep fractures and secondary structural units as well. Based on the information of gold orefields, deposits and metallogenic characteristics, there are 19 gold ore-concentrated areas divided. According to the ore-concentrated areas, mineralization information and regional metallogenic conditions, the 10 gold metallogenic prospects were proposed. Considering several factors such as regional geological background, information integration and research level, the 5 gold metallogenic prospects including Suganhu-Xitieshan, Saishikenan-Chachalongwa, Qimantage, Citieshan-Zhiyu and Tongde-Tongren are most promising. The above 5 gold metallogenic prospects mainly distribute in the northern and central Qinghai, and are related to the northern margin of Qaidam mineralization belt (Ⅲ-6), the East Kunlun metallogenic belt (Ⅲ-8) and the West Qinling metallogenic belt (Ⅲ-9). [ABSTRACT FROM AUTHOR]

Wind waves are a ubiquitous characteristic of aquatic environments and also an intrinsic feature of planktonic habitats, in lakes, especially in large and shallow lakes, wind waves greatly influence the physico-chemical properties of the water column, and directly or indirectly play a crucial role in plankton ecology. This paper reviewed studies of the effects of wind waves on the zooplankton, phytoplankton, and bacterioplankton in lakes. Accumulating studies showed that wind waves affect the spatial-temporal distribution of plankton and play a crucial role in shaping the structure and function of planktonic systems. In particular, it strongly affects the behaviour, nutrient uptake rate and flux, predation, growth, competition and succession of planktonic organisms, which in turn significantly influence the structure of aquatic food webs, potentially affecting the overall structure and function of lake ecosystems. This paper highlights the major future research directions to further reveal the ecological effects of hydrodynamics in lakes under global climate change scneario, which could provide new insights and support for decision making in terms of management and control of eutrophic lakes. [ABSTRACT FROM AUTHOR]

Soil salinity analysis on a regional scale is of great significance for protecting agriculture production and maintaining eco-environmental health in arid and semi-arid irrigated areas. In this study, we explored the soil salinity distribution and its effect on crop growth in Hetal Irrigation Dsitrict based on field investigation and remote sensing inversion. The Hetao Irrigation District (Hetao) in Inner Mongolia Autonomous Region suffered long-term soil salinization problem. Field sampling experiments and investigations related to soil salinity, crop growth and yields were carried out at 281 different sampling points across the whole area during April to August in 2015. Spatial-temporal soil salinity characteristics were systematically analyzed as well as the corresponding impacts on crops. The remote sensing inversed soil salinity model had the accuracy of the determination coefficient of 0.75 (P<0.01) and the root mean square error of 0.10% at the validation process. The relationships between soil salinity and crops and groundwater depth were investigated. The results showed that the surface soil (0-10 cm) and the root zone soil (0-100 cm) had the mean of soil salinity 0.12%-0.20% and the mean of soil salinity was all below 0.40%. The salinity could be lower than 0.10% in some regions. The uncultivated land was mainly sever salinized. The soil salinity of the uncultivated land averaged 1.15% at 0-10 cm and 1.60% at 0-100 cm. The soil salinity had a good relationship with the total amount of irrigated water, the conditions of drainage system, and the groundwater depth. Mild salinization with the soil salinity less than 0.20% for all the investigated soil was founded when the depth of groundwater depth was about 2.0 m. Remotely sensed map of soil salinity distribution for surface soil was derived based on the Landsat OLI data with a 30 m resolution and showed that the spatial distribution of soil salinity based on remote sensing was consistent with the sample analysis, and the correlation coefficient was 0.87. Over 14% of the land with its salinization exceeded the level of heavy salinized soil in Hetao Irrigation District, and about 86% of the total area was nonsalinized or mildly salinized soil. Crops such as corn, wheat, fruits and vegetables were planted in the area with low salinity while sunflower was widely planted in the area with severe salinized soil or saline soil, and the leaf area index decreased with the increasing of soil salinity. Based on the investigation results, the corn field was classified into high level (yield>12 000 kg/hm2) and low level (yield <12 000 kg/hm2) and the sunflower field was high (yield>3 000 kg/hm2) and low level (yield<3 000 kg/hm2). The high yield level had relatively lower soil salinity than the field with low yield. So it is very important to minimize the salinity of root zone for sunflowers at the stage of filling period, especially for the lower reach of the Hetao. In addition, the strong spatial variability of salinization was clearly presented by the map of soil salinity. Overall, this paper can provide very useful information for salinization control and guidelines for agricultural production and soil-water management in Hetao. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To explore the pollution characteristics and sources of heavy metals in atmospheric deposition in a typical lead-zinc smelting city, 511 effective atmospheric deposition samples from 22 points in different functional areas of a city in Henan Province were collected monthly during 2021. The concentrations and spatial-temporal distribution of heavy metals were analyzed. The geo-accumulation index method and health risk assessment model were utilized to evaluate the heavy metal pollution degree. The sources of heavy metals were quantitatively analyzed using a positive matrix factorization (PMF) model. The results showed that the average concentrations of ω (Pb), ω (Cd), ω (As), ω (Cr), ω (Cu), ω (Mn), ω (Ni), and ω (Zn) in atmospheric deposition samples were 3185.77, 78.18, 273.67, 149.50, 453.60, 810.37, 54.38, and 2397.38 mg·kg -1 , respectively, which were all higher than the soil background values of Henan Province. All heavy metals except Mn had significant seasonal variation characteristics. The concentrations of Pb, Cd, As, and Cu in the industrial area with lead-zinc smelting were significantly higher than those in other functional areas, and the concentration of Zn was the highest in the residential mixed area. The results of the geo-accumulation index showed that the pollution of Cd and Pb were the most serious, followed by that of Zn, Cu, and As, which belonged to the serious-extreme pollution category. The main exposure route of non-carcinogenic risk was hand-mouth intake. Pb and As posed the greatest non-carcinogenic risk to children in all functional areas. The carcinogenic risks of Cr, As, Cd, and Ni through the respiratory system to humans were all below the threshold values. The analysis of the PMF model showed that the main sources of heavy metals in atmospheric deposition were industrial pollution sources (39.7%), transportation sources (28.9%), secondary dust sources (14.4%), incineration and coal combustion sources (9.3%), and natural sources (7.8%).

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Objective: To analyze the spatial-temporal distribution characteristics of Oncomelania hupensis snails in Anhui Province from 2011 to 2020, to provide insights into precision control of O. hupensis snails in Anhui Province., Methods: O. hupensis snail distribution data were collected in Anhui Province from 2011 to 2020 and descriptively analyzed, including actual area of snail habitats, area of emerging snail habitats and area of Schistosoma japonicum -infected snails. The actual area of snail habitats and area of emerging snail habitats were subjected to spatial autocorrelation analysis, hotspot analysis, standard deviation ellipse analysis and space-time scanning analysis, and the clusters of snail distribution and settings at high risk of snail spread were identified in Anhui Province from 2011 to 2020., Results: The actual area of snail habitats gradually decreased in Anhui Province from 2011 to 2020. The actual area of snail habitats were 26 238.85 hm 2 in Anhui Province in 2020, which were mainly distributed in marshland and lake regions. There was a large fluctuation in the area of emerging snail habitats in Anhui Province during the period from 2011 to 2020, with the largest area seen in 2016 (1 287.65 hm 2 ), and 1.96 hm 2 emerging infected snail habitats were detected in Guichi District, Chizhou City in 2020. Spatial autocorrelation and hotspot analyses showed spatial clusters in the distribution of actual areas of snail habitats in Anhui Province from 2011 to 2020 ( Z = 3.00 to 3.43, all P values < 0.01), and the hotspots were mainly concentrated in the marshland and lake regions and distributed along the south side of the Yangtze River, while the cold spots were mainly concentrated in the mountainous regions of southern Anhui Province. There were no overall spatial clusters in the distribution of areas of emerging snail habitats ( Z = -2.20 to 1.71, all P values > 0.05), and a scattered distribution was found in local regions. Standard deviation ellipse analysis showed relatively stable distributions of the actual areas of snail habitats in Anhui Province from 2011 to 2020, which was consistent with the flow direction of the Yangtze River, and the focus of the distribution of areas of emerging snail habitats shifted from the lower reaches to upper reaches of Anhui section of the Yangtze River. Space-time scanning analysis identified two high-value clusters in the distribution of actual areas of snail habitats in lower and middle reaches of Anhui section of the Yangtze River from 2011 to 2020, and two high-value clusters in the distribution of areas of emerging snail habitats were identified in mountainous and hilly regions., Conclusions: There were spatial clusters in the distribution of O. hupensis snails in Anhui Province from 2011 to 2020, which appeared a tendency of aggregation towards the south side and upper reaches of the Yangtze River; however, the spread of O. hupensis snails could not be neglected in mountainous and hilly regions. Monitoring of emerging snail habitats should be reinforced in mountainous and hilly regions and along the Yangtze River basin.