Search

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology 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.)

Copyright of World Nuclear Geoscience is the property of World Nuclear Geoscience Editorial Office 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.)

Vapor-water exchange among atmosphere, soil and groundwater plays an important role in the surface ecological restoration in the vadose zones of arid and semiarid regions. However, it is limited to in-situ monitoring of water vapor flux, due to the complex and uncertain process. The simulation of water vapor cannot be fully verified by the measurement. It is still lacking in the vapor-water migration at different spatial and temporal scales. This study aims to clarify the spatiotemporal variation and migration of vapor-water exchange in the vadose zone of Mu Us Sandy Land by in-situ vapor-water monitoring, isotope tracer and numerical analysis. The results showed that the δDL and δ18OL of precipitation were enriched in spring and summer, but depleted in autumn and winter, due to the atmospheric water vapor source and local circulation. Soil evaporation was enriched in the oxygen isotope (δ18Oa ) of surface soil vapor-water in summer more than that of soil freezing in winter. Moreover, there was a significant positive correlation (P<0.01) in the δ18O profile of the soil vapor-water and liquid water at different depths. The reason was that the evaporation intensity source and migration mode of soil vapor-water varied greatly in seasons. The δ18O values of vapor water in spring and summer showed an extremely significant linear positive correlation with the liquid water (P<0.01), while there was no significant correlation in winter (P=0.12). Moreover, there was a positive linear relationship between water vapor flux and δ18Oa . Furthermore, the δ18Oawas enriched in the surface layer at the large water vapor flux, including both downward and upward migration. The surfaceδ18Oa was enriched in the period of soil freezing in winter, particularly with the decrease of water vapor density (November-March). But the surface layer δ18Oa increased in summer (May-October) as well with the increase of surface water vapor density. Driven by the gradient of soil temperature in the vadose zone, the replenishment relationship of water vapor throughout the profile varied greatly at different periods. The water vapor of shallow soil was the supply source of deep vapor-water in summer, while the recharge was received from the deep layer in winter. But there were the temperature convergence and divergence zero flux planes in spring and autumn, respectively. The recharge characteristics caused the complicated relationship of vapor recharge in the profile. The soil δ18Oa was controlled by the water vapor migration, atmospheric evaporation and soil freeze-thaw in the vadose zone. In winter, the reduced evaporation and upward transport of water vapor can concurrently cause to enrich the surfaceδ18Oa, thus resulting in a decrease in the correlation between soil water vaporδ18Oa and liquid water δ18OL. While in summer, the dominant effect can be from the diurnal evaporation and condensation cycle of soil water. The findings can provide a scientific basis to clarify the migration of soil water vapor in the water circulation. [ABSTRACT FROM AUTHOR]

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS 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.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS 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.)

"Tobacco-free" or synthetic nicotine products have been favored by the majority of young people, which undoubtedly increase the potential health risks and regulatory challenges. Currently, there are few reliable methods for the determination of authenticity of natural nicotine and synthetic nicotine. The analytical techniques based on mass spectrometry have broad application prospects in component sequence analysis. structure analysis, molecular weight determination and component content determination. The synthesis processes of natural nicotine and synthetic nicotine are different, and their isotopic fractionations are also different. Here, a method of tandem mass spectrometry based on isotope model peak was developed using this feature. The source or naturalness of nicotine is verified by comparing the abundance and area ratio of [M + H]+ and [M+H+1]+ peaks of nicotine, and the abundance ratio of [M+H]+ and [M+H+1]+ peaks as fragments of parent ions. A total of 47 experimental results showed that the m/z 164. 1. 163. 1 peak abundance ratios and the area ratios of natural nicotine and synthetic nicotine in MS spectra were significantly different. In addition, in MS/MS spectra, the abundance ratios of fragment ions of m/z 163. 1. 164. 1 also had significant differences. Among the variables with significant differences. the overall abundance ratio of synthetic nicotine was higher than that of natural nicotine. The evaluation model for the identification of natural nicotine and synthetic nicotine was further constructed by combining chemometric methods. Using OPLS-DA modeling, the discriminant accuracy was 97. 87%. Moreover, rankings of importance of variables differed depending on the model of the evaluation. 164. 1-85. 1/84. 1, 164. 1-85. 1/(84. 1+85. 1), 163. 1-131. 1/131. 1. 163. 1-131. 1/(130.1+131. 1) were the key discriminant variables. This method has the advantages of simple operation, rapid operation and no need for quantitative analysis, which will help to accurately identify, label and supervise tobacco products from different nicotine sources on the market. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience 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.)

Copyright of Carsologica Sinica is the property of Institute of Karst Geology, CAGS 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.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office 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.)

Copyright of Steel Pipe is the property of Steel Pipe Magazine 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.)

BACKGROUND: With mining activities taking place on a global scale, the concern for environmental issues within and around mines continues to increase. The advent of multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) has promoted the geochemical study of isotopes and has led to the widespread use of isotope tracing techniques to investigate various issues in the mining environment. OBJECTIVES: To systematically summarize the various types of studies currently conducted on the application of isotope tracing technology in mining environments, with the aim of highlighting the importance of the application of isotope tracing technology in complex mining environments and the diversity of scientific problems it can solve. METHODS: Data published by scholars at home and abroad by July 2022 has been collected and compiled on testing and analyzing the supply source/ connection of mine water body, sulfate/ carbonate source and the cause of acid mine wastewater (AMD), migration and transformation of mining elements, different sources and contribution rates of heavy metal pollution with the help of isotope tracer technology. The study area covers more than 40 regions in 20 countries. RESULTS: It is found that hydrogen and oxygen isotope tracing techniques in water bodies are effective tools for mine water source analysis, hydraulic linkage studies and AMD source identification. Sulfate sulfur and oxygen isotope tracing techniques provide important support for the study of sulfate sources in mine environments, AMD acidification processes and pollution, bacterial sulfate reduction and elemental migration transformation. Heavy metal isotope (Pb, Cd, Zn, Hg isotopes) tracing technology is an effective way to investigate the sources of metal pollution in mines and nearby environments and the contribution of different sources. CONCLUSIONS: Although isotope techniques play an important role in resolving the sources of environmental pollutants in mines and the mechanisms of migration and transformation of characteristic pollutants and revealing the hydrogeochemical processes in mines, most of the current studies are limited to the application of single/ few isotopes for short time tracing studies of environmental media in mines. Therefore, further development of multiisotope tracing technology is needed in the future, as well as long-term and continuous monitoring and investigation of various problems in the mine environment. New and effective methods for pollution prevention and control are also proposed. [ABSTRACT FROM AUTHOR]

Ecological restoration has been one of the most important strategies for the ever-increasing ecosystem degradation and environmental pollution in the world. A great challenge can be also posed on the Baiyangdian Lake, the largest fresh water lake in the North China Plain, particularly for the water deterioration, biodiversity decline, and ecological function disorder. In this study, a comprehensive restoration project was implemented to restore the fishery resources in the ecosystem of Baiyangdian Lake. Some ecological restoration techniques were utilized to create habitats for the aquatic animals, aquatic plant diversity, and stock benthic organisms during the change of the bottom. A systematic evaluation was conducted to determine the regulation effect of the project on the community structure of fishery resources and the nutritional relationship between species. An investigation was also performed on the fishery resources, food web structure, and nutritional level, where the Shihoudian Lake (restoration area) was selected as the research object, and Dabaiyangdian Lake as the control. Six sampling points were set in the two areas at the same time. The results showed that the ecological restoration project increased the catch species, abundance and biomass by 35.29%, 58.60%, and 200.00%, respectively, in the restoration area, compared with the control. The fish’s physical signs in the restoration area (the total length of (125.04±54.97) mm, the body length (100.22±44.44) mm, and body weight (44.02±331.45) g on average) were much higher than those in the control area (the total length 106.94±35.47mm, the body length (85.79±29.66) mm, and the body weight (19.77±82.30) g on the average). The average physical characteristics for the six types of fish (Carassius auratus, Pseudobagrus fulvidraco, Cultrichthys erythropterus, Toxabramis swinhonis, Protosalanxh yalocranius, and Rhinogobius giurinus) in the restoration area were significantly higher than those in the control area (P<0.05).The C/N stable isotope analysis showed that the mean value of δ13C and δ15N in the restoration area was higher than that of the control area, regardless of the whole catch, fish population, or invertebrate population. The one-way analysis of variance (ANOVA) of δ13C and δ15N between the two areas showed that there were significant differences (P<0.05) among the whole catch, while the fish population only had significant differences in δ15N (P<0.05) and invertebrate population only had significant differences (P<0.05) in δ13C. In addition, the δ13C span of the restoration area (6.30‰) was significantly higher than that of the control area (4.47 ‰), indicating the more abundant food organisms and the more complex food web structure in the restoration area. The trophic level analysis demonstrated that the trophic level range, the total span, and average (1.93-3.96, 2.03, and 2.99±0.66) of the main fishery organisms in the restoration area were higher than those in the control area (1.94-3.89, 1.95, and 2.76±0.70). The species with the highest trophic level in the restoration and control area were Cultrichthys erythropterus (3.96), and Silurus asotus (3.89), respectively. Meanwhile, the species number with a trophic level between 3-3.5 in the restoration area was the highest (30.43%), while the species number with a trophic level between 2.5-3 in the control area was the highest (41.18 %). Therefore, the ecological restoration project can be expected to effectively improve the biodiversity, the stable ecosystem structure, and the rapid restoration of ecological functions and fishery resources in the Baiyangdian Lake. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office 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.)

Spatiotemporal variation of nitrate (NO3 ¯ ) and isotope components were investigated in the karst and non-karst sub-basins, to clarify the influence of hydrogeological conditions and underlying surface properties on the source and migration of nitrate in water. The research areas were selected as the Mudong and the Jingui sub-basin in the Qingshitan Reservoir Irrigation District of Lijiang River Basin in southwest China. Both small karst watersheds were also dominated by agricultural activity. Multiple isotopes (δD-H2O, δ18O-H2O, δ15N-NO3 ¯, and δ18O-NO3 ¯ ) and the Bayesian Model Stable Isotope Analysis in the R (SIAR) model were applied to compare the multiple potential nitrate sources in the water. The results indicated that the spatial and temporal variation of nitrate in water depended on the hydrogeological conditions and the associated topography, soil characteristics, and land use types of the sub-basin. Total nitrogen (TN) was mainly formed by NO3 ¯ and NH4 + in the river, where the proportion of NO3‾ was slightly higher while decreasing along the river. TN was overwhelmingly dominated by NO3‾ in the shallow groundwater. Nitrification was the dominant process of NO3 ¯ formation and transformation. The Jingui sub-basin included the woodland with a thicker soil layer, while the Mudong sub-basin was mainly agricultural land with the karst development and the discontinuous thin soil layer. The ranges of mean NO3 ¯ concentration (0.19-15.84 mg/L), and the isotope values of δD-H2O (from -44.08‰ to -19.63‰), δ18O-H3O (from -7.24‰ to -1.55‰), δ15N-NO3 ¯ (from -1.65‰ to 53.98‰), and δ18O-NO3 ¯ (from 0.04‰ to 13.74‰) in the Mudong sub-basin, were all greater than those in the Jingui sub-basin. In terms of spatial distribution, the mixing of nitrogen fertilizer infiltration from the orchard of exposed karst stone mountain in the north recharge area and manure & septic waste infiltration from the village groups were not smoothly dispersed and discharged in the central tectonic basin region, resulting in the high concentration of NO3 ¯ (the mean concentration range from 11.96 to 15.84 mg/L) and the high isotope value of δ15N-NO3 ¯ (from 0.65‰ to 28.23‰) and δ18O-NO3 ¯ (from 2.46‰ to 14.43‰) in the water of G4-G7 wells. The contributions of NO3 ¯ sourced from the soil nitrogen in the dry season, as well as the manure and septic waste in the wet season in the Mudong sub-basin, were less than those in the Jingui sub-basin. The reason was the low capacity of water storage in the thin soil layer that was formed by the weathering of carbonate rocks, together with the strong permeability of the shallow soil layer in the Mudong sub-basin. Consequently, spatial and temporal variations of nitrate pollution and migration in water were achieved under karst hydrogeological conditions and underlying surface properties. The finding can provide decision support for the control of agricultural non-point source pollution and the improvement of the water environment in karst and non-karst areas. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) is an important greenhouse gas. High input of water and fertilizer in vegetable production results in large N2O emission. Though drip irrigation is the most commonly used irrigation method in vegetable production, it is still unclear how water and fertilizer interaction under drip irrigation affects N2O emission. Therefore, the objective of this study was to analyze the effects of different fertilizer treatments under drip irrigation on N2O emission and isotopic signatures, and thus provide a theoretical support for reducing N2O emission in vegetable production mainly driven by microbial activity that included Bacterial Nitrification (BN), Bacterial Denitrification (BD), Nitrifier Denitrification (ND), Fungal Denitrification (FD) and N2O reduction to N2. The study was conducted in at the environmental research station of the Chinese Academy of Agricultural Sciences, situated in the Shunyi District, Beijing, China (40°15′N, 116°55′E). The soil of the experiment field was classified as calcareous fluvo–aquic. The Chinese cabbage was sown on 7 August 2015. Under drip irrigation, four fertilizer treatments were evaluated, including inorganic NPK compound fertilizer (NPK), organic fertilizer of sheep manure (M), water-soluble fertilizer of amino acid (WS), and no-fertilizer (NF). Gas and soil samples were collected throughout the study phase. The concentration and isotopic signature values (δ15NbulkN2O and δ18ON2O of N2O), ammonium (NH4+) and nitrate (NO3-) content of soil, soil C/N, and yield of Chinese cabbage were analyzed. Net isotope effect between N2O and H2O and 15N site preference in N2O molecule (SP) were also analyzed and used to distinguish BN/FD and BD/ND and to calculate the extent of N2O reduction to N2. The results showed that the SP had significant positive correlation with both δ15NbulkN2O and δ18ON2O (P<0.01), and significant negative correlation with N2O emission fluxes (P<0.01) and Water Filled Pore Space (WFPS, P <0.05). It indicated that using SP vs. δ18ON2O to quantitatively analyze production and consumption pathways of N2O was feasible and water content significantly affected the activity of soil microorganisms. Under approximately 60% WFPS condition, for the NPK, M, WS and NF treatments, the N2O emission were 1 074, 146.5, 116.2 and 112.9 μg/(m²·h), respectively. The Nitrogen Use Efficiency (NUE) of the NPK, M and WS were 45.1%, 22% and 45.2%, respectively. The yield of Chinese cabbage of the NPK, M, WS and NF were 147.9, 116.5, 127.5 and 86.4 t/hm², respectively, and the contribution of nitrification were 38%, 46%, 54% and 49%, respectively, and the extent of N2O reduction were 14%, 71% 46%, and 70%, respectively. The water-soluble fertilizer treatment showed the highest NUE and relatively low N2O emission, and both inorganic fertilizer treatments showed the low extent of N2O reduction, which was unfavorable for reducing N2O emission during denitrification. In contrast, organic fertilizer treatment had the highest the extent of N2O reduction, which was the main pathway to reduce N2O emission during denitrification. Therefore, this study suggests that organic fertilizer may be used as the base fertilizer with water and fertilizer integration technology as a management practice during the growing season for reducing N2O emission and enhancing NUE. [ABSTRACT FROM AUTHOR]

As one of the rivers with the highest elevation in the world, the Yarlung Zangbo River concentrates more than half of the water resources in Tibet. With the development of cascade hydropower stations in the Yarlung Zangbo River, human activities have changed the ecological environment and affected the nitrogen cycle in the river. In order to clarify the distribution characteristics of nitrogenous compounds and quantitatively analyze their sources, eleven sampling points were set up in the middle and lower reaches of the Yarlung Zangbo River and its main tributaries (Nianchu River, Lhasa River and Niyang River), and water samples were collected in March (the dry season) and August (the wet season) of 2018. The concentrations of dissolved oxygen (DO), total dissolved nitrogen (TDN), NO3 - , NO2 - and NH4 + were measured. Dissolved organic nitrogen (DON) was calculated as the difference between TDN and inorganic N. The occurrences and spatial-temporal distribution of nitrogenous compounds in the water samples of the rivers were analyzed, and the main sources of NO3 - in the wet season were determined by the dual isotope analyses. The results showed that the DON was the main form of TDN. The concentrations of TDN ranged from 1.3 to 2.5 mg/L in the dry season and from 1.1 to 2.0 mg/L in the wet season, and showed a downward trend along the river. The NO3 - -N was the main form of inorganic nitrogen in the water, with an average proportion of 25.6% in TDN, and NH4 + -N accounted for 17.5% in TDN, while NO2 - -N was not detected at the most sampling sites. The results of nitrogen and oxygen isotope analyses showed that the values of δ15N-NO3 - ranged from -9.17‰ to 22.68‰, and δ18O-NO3 - from -13.25‰ to 8.24‰ in the wet season. The NO3 - mainly came from rainfall and fertilizer, organic nitrogen in soil, and sewage and feces. Based on the Stable Isotope Analysis in R (SIAR) model, the contribution rates of nitrate from different sources were quantitatively calculated. In the Shigatse and Lhasa sections, NO3 - in the water body mainly came from the organic nitrogen in soil and the NH4 + in rainfall and fertilizer, with more than 70% of contribution rate. The main sources of NO3 - in the water in the upstream and downstream of the cascade power stations were NH4 + in rainfall and fertilizer, as well as sewage and feces, which accounted for a similar proportion, totally contributing more than 80% of the sources of NO3 - . In the Nyingchi section, the NH4 + in rainfall and fertilizer contributed the most to NO3 -, accounting for 60%-70%, followed by the organic nitrogen in soil with 22%-28% of contribution rate. A large amount of farmland was distributed along the Yarlung Zangbo River and its tributaries. The nitrogen fertilizer applied in the farmland flowed into the river along with the surface runoff through rainfall, which was an important source of nitrogen in the water body of the Yarlung Zangbo River. Due to the reclamation of gentle slopes along the river and the erosion of cultivated soil, the organic nitrogen in soil was another important source of NO3 - in the water of the Yarlung Zangbo River, especially in the wide valley section. Higher contribution rate of sewage and feces to NO3 - in the canyon reach may be related to the development and construction of the cascade hydropower stations in the region. According to the change of DO contents and theoretical and measured values of δ18O-NO3 -, nitrification and denitrification in the Yarlung Zangbo River are the main factors affecting the forms of nitrogen and the composition of nitrogen and oxygen isotopes. The results in the present study can provide data for the pollution control of nitrogenous compounds in the rivers in plateaus and drinking water security in Tibet. [ABSTRACT FROM AUTHOR]

Soil water deficit is the main obstacle factor of plant reconstruction in rocky desertification area of Southwest China. Mycorrhizal mulberry (Morus alba L.) can cope with the main ecological barriers during the seasonal drought in the rocky desertification area. However, it is unclear the water resource of mulberry. In this study, we studied the water use strategy of mulberry root in different seasons by hydrogen and oxygen stable isotope technique. The mulberry was grown in typical rocky desertification area in Qingshuipu town, Qixingguan district, Bijie city (105°35′02′′E, 27°41′19′′N) in Guizhou Province. The precipitation was mainly concentrated in June-September. The mulberry was not irrigated. The annual growth of mulberry was in 2 seasons: from April to June and from September to November. The samples of rainfall water, soil and plant branch were collected from April to November of 2014. Soil was sampled at 0-60 cm depth with 10 cm as a sampling layer. The abundance of deuterium and oxygen stable isotope were measured. The correction analysis method was used to preliminarily evaluate water sources of mulberry. The contribution rate of water at each soil layer was also calculated. The results showed that in rainfall water, the abundance of deuterium from April to November averaged -25.9‰ and the oxygen stable isotope abundance averaged -4.82‰. In spring from April to June, the abundance of deuterium and oxygen stable isotope in rainfall water averaged -0.24‰ and -1.68‰, respectively. In autumn from September to November, the abundance of deuterium and oxygen stable isotope in rainfall water averaged -60.0‰ and -8.17‰, respectively. In spring, the abundance of deuterium and oxygen stable isotope in soil water averaged -29.4‰ and -4.77‰, respectively while the abundance of deuterium and oxygen stable isotope in xylem water averaged -33.2‰ and -5.39‰, respectively. In autumn, the abundance of deuterium and oxygen stable isotope in soil water averaged -70.1‰ and -9.27‰, respectively while the abundance of deuterium and oxygen stable isotope in xylem water averaged -55.7‰ and -7.92‰, respectively. The abundance of both stable isotopes in soil water and xylem water were below that in the rainfall water and that of xylem water were between soil water and rainfall water. It indicated that the mulberry mainly used soil water. Both isotopes in rainwater were more enriched in the early stage of mulberry growth (spring, from April to June) than in the late growth stages (autumn, from September to November). With the seasonal variation of rainfall, the both isotopes of soil water showed a downward trend. According to rainfall water equations, the mulberry absorbed mainly soil water. Both isotopes had clear seasonal trend. In spring, the isotopes in soil water decreased with the increase of soil depth. In autumn, isotopes in soil water decreased then increased with soil depth. Based on the correlation method, the mulberry absorbed water from different soil depth. In spring, it absorbed water from soil below 20 cm while it absorbed water from soil 0-20 cm. In September, it also absorbed water from 50-60 cm soil layer. Based on results from the IsoSource software, in spring, mulberry mainly used soil water from soil layers of 10-30 to 50-60 cm. In autumn, it mainly used soil water from soil layers of 50-60 to 0-10 cm. In spring, the contribution rate was 69.1% by 10-30 cm in soil, 31.8% and 66% by 50-60 cm layer in May and June, 70.2% by 50-60 cm in September and 94.3% and 71.9% by 0-10 cm in October and November, respectively. The study will be helpful to mulberry manage and application in rocky desertification area. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office 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.)

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office 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.)

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology 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.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal 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.)

Since the initiation of the large-scale ecological rehabilitation project by the Chinese central government in 1999, jujube forest was widely cultivated in the loess hilly region, due to its ecological and economic benefits. Soil moisture is a key factor affecting jujube growth. Clarifying water use strategy of jujube trees of different stand ages can provide useful indications for the water management of jujube forest in this area. In 2016, we selected 4 different stand ages (4, 8, 17 and 22 years) of jujube forests in a rain-fed jujube (Ziziphus Jujube cv. Lizao) plantation in Qingjian County, Shaanxi Province (37°15′N, 118°18′E). In the study, the oxygen stable isotope tracer method was used to measure the oxygen isotope ratio (δ18O) of xylem water and soil water sources in jujube orchards with 4 different stand ages, and the contribution of soil water from different depths to water uptake was estimated by the MixSIR Bayesian mixing model. The results showed that soil moisture and soil water δ18O varied across soil depths and sampling dates, which were influenced by the rainfall and evaporation. The composition of soil water isotopes and rainfall isotopes showed the same temporal trend. In arid and semi-arid areas, with the variation of soil moisture, jujube trees of different stand ages could adjust the utilization structure of soil water to adapt to the soil water environment changes. Jujube tree mainly absorbed soil water from shallow soil (0-40 cm) when soil water was available. However, when shallow soil water was scarce, jujube tree mainly absorbed the soil water from middle layer (>40-120 cm) and deep layer (>120-200 cm) with the stand age increasing, leading to the middle and deep soil water content close to wilting point (7%). In germination stage (May 29th), jujube trees mainly absorbed shallow soil water. With the increase of stand age of jujube trees, the ratio of water absorption for jujube trees from shallow soil water gradually decreased, whereas the proportion of deep soil water absorption gradually increased during flowering and fruit setting stage (July 29th), and water absorption rates in shallow layer for the 4-, 8-, 17-, and 22-year-old jujube trees were 63.58%, 78.79%, 45.03% and 11.81%, respectively. However, water absorption rates in deep layer for the 17- and 22-year-old jujube trees were 39.22% and 72.25%, respectively. In fruit enlargement period (August 26th), 4-year-old jujube trees mainly absorbed middle layer soil water, and 8-year-old jujube trees absorbed deep soil water, with absorption rate as much as 94.30%, while 17- and 22-year-old jujube trees mainly absorbed shallow soil water. During the fruit ripening period (September 25th), 8-, 17- and 22-year-old jujube trees mainly absorbed shallow, deep and middle layer soil water, respectively. The results suggest that based on soil water utilization characteristics of jujube trees with different stand ages, water management should be carried out for reducing the non-productive water consumption for 4- and 8-year-old jujube trees and the luxury water consumption for 17- and 22-year-old jujube trees, so as to ensure the sustainability of the local jujube forest and soil water use. [ABSTRACT FROM AUTHOR]

In order to reduce soil erosion and improve ecological environment, the Chinese government implemented the Grain for Green Project in 1999, in which numerous croplands were converted to grasslands, forestlands, or free land for natural plant succession. The ecological construction not only significantly changes the vegetation cover conditions of the watershed, but also changes the hydrological processes of the watershed. In order to understand the changes of ecological and hydrological processes under different ecological construction conditions, 414 water samples were collected in the governance river basin of Jiuyuangou Watershed and 300 water samples were collected in the natural river basin of Peijiamao Watershed, which are sub basins of Wuding River. The water samples included precipitation, river water, well water, reservoir water and snow water. Each water samples had three replicates. Based on stable isotope technology, the hydrogen and oxygen isotope characteristics were analyzed in different water samples. The effects of ecological construction on water transmission process and transformation characteristics between different water bodies in different seasons were also evaluated in this research. The results showed that the amplitude of precipitation isotope values were greater than the river water and well water isotope values. In addition, the river water and reservoir water had stronger evaporation fractionation than other water samples and well water was relatively stable. The local meteoric water line was δD=7.09δ18O+1.29 in the governance river basin of Jiuyuangou watershed and δD=6.71δ18O-3.25 in the natural river basin of Peijiamao watershed. The slope and intercept of the local meteoric water line in Jiuyuangou watershed was greater than that in Peijiamao watershed. The water supply source of river water, well water and reservoir water were mostly from precipitation. At the same time, precipitation and snow water had similar sources. During the dry season (from December to June), the temperature was low and during the wet season (from July to November), it was high, and the precipitation was mainly distributed in June to November. The isotope values were low in the wet season, and dry season isotope values were high. The isotope values were positively correlated with the precipitation, and negatively correlated with the temperature. The isotope values of river water and well water showed a similar trend of variation, which became enrichment with the main channel flow. The oxygen isotope value was used to calculate the supply ratio of precipitation, river water and well water in dry season and wet season. In dry season, precipitation and well water supplied river water, and the supply ratio was 24.66%, 75.34% and 83.81%, 16.19%, respectively. In wet season, well water was supplied by precipitation and river water, and the supply ratio was 14.75%, 85.25% and 48.06%, 51.94%, respectively. Ecological construction had significantly changed the ecological and hydrological processes. The acceleration of ecological construction had a significant impact on the transformation of different water bodies in the river basin of Loess Plateau. The present research could provide technical support and theoretic foundation for the study of ecological and hydrological processes and ecological environment protection on the Loess Plateau. [ABSTRACT FROM AUTHOR]