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Critical thresholds for stage division of water erosion process in different ridge systems in mollisol region of Northeast China

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Journal of Mountain Science 2023年第6期20卷 1540-1560页

作者： JIAO Jian QIN Wei LI Kun-heng XU Hai-chao YIN Zhe HOU Shu-yan State Key Laboratory of Simulation and Regulation of water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Research Center on soil and water conservation of the Ministry of water Resources Beijing 100048China School of soil and water conservation Beijing Forestry UniversityBeijing 100083China Heilongjiang province Hydropower Research Institute Harbin 150070China

Extreme rainfall events on a slope under ridge tillage systems cause concentrated stream soil loss.To analyse the critical thresholds for different stages of water erosion process of ridge systems,simulated rainfall-erosion experiments for the contour wide ridge(CWR),contour narrow ridge(CNR),longitudinal wide ridge(LWR),and longitudinal narrow ridge(LNR)were conducted under four rainfall intensities,with slope gradients of 3°and 5°.For the runoff event,the runoff depth order was LNR>LWR>CWR>CNR;the soil loss order was CNR>LNR>CWR>LWR.The product of slope factor(S)and rainfall erosivity(R)or runoff depth(D),can be adopted as critical thresholds for different stages of runoff and soil erosion process.For the longitudinal ridge systems,R values were provided for LWR and LNR and were the beginning of sheet flow,whereas the product of rainfall erosivity and slope factor(RS)values were provided for LWR and LNR as the beginning of the accelerated concentrated flow.For the contour ridge systems,R values were provided for CWR and CNR as critical thresholds for the beginning of overflow.The product of runoff depth and slope factor(DS)values were 9.98 and 7.73 mm for CWR and CNR,respectively,and were critical thresholds for the beginning of ridge failure;the DS values were 18.45 and 12.75 mm for CWR and CNR,respectively,and were critical thresholds for the beginning of the formation of ephemeral gully erosion.The critical thresholds can distinguish different stages of soil erosion process modelling.

关键词： Runoff soil loss Threshold Ridge failure Artificial rainfall simulation

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Estimating water distribution of the rotating sprinkler with pulsating pressure on sloping land

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International Journal of Agricultural and Biological Engineering 2022年第27期15卷 39-47页

作者： Boyang Fu Yu Huang Lin Zhang College of water Resource and Architectural Engineering Northwest A&F UniversityYangling 712100ShaanxiChina Institute of soil and water conservation Northwest A&F UniversityYangling 712100ShaanxiChina

Pulsating pressure plays an important role in improving the poor irrigation quality and the uneven water distribution caused by the terrain slope.water distribution is one of the key factors in design of the sprinkler irrigation system,however,it is difficult to measure in practice.To provide appropriate technical parameters for the design of sprinkler irrigation system with pulsating pressure on sloping land,a mathematical model was established according to the water conservation principle and finite element idea,and its accuracy was experimentally verified.The model was applied to study the effects of terrain slope,sprinkler arrangement,sprinkler spacing and average pulsating pressure on water distribution on sloping land.The results showed that the water distribution was more favorable under the gentle terrain slope,when slope decreased from 25%to 5%,the uniformity increased from 74.47%to 86.22%.Sprinklers arranged in equilateral triangle and with the spacing close to R_(0)had the best water distribution uniformity,the uniformity coefficient(CU)of which was 11.43%and 8.75%higher than that in square and rectangular arrangement,respectively.The CU increased with the increase of the average pulsating pressure.However,the effect of increasing water pressure on promoting the uniformity of water distribution gradually decreases.Therefore,when using the Rainbird R5000 sprinkler on sloping land with pulsating pressure,it is suggested that the sprinkler irrigation systems should be arranged below the terrain slope of 20%,and operated at the average pulsating pressure of 300 kPa.The suitable sprinkler arrangement is the equilateral triangle,and with the spacing of 0.8R_(0)to 1.0R_(0).

关键词： sprinkler irrigation water distribution on sloping land estimation model pulsating pressure

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Nutrient coordination mechanism of tiger nut induced by rhizosphere soil nutrient variation in an arid area, China

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干旱区科学:英文版 2023年第10期15卷 1216-1230页

作者： TAN Jin WU Xiuqin LI Yaning SHI Jieyu LI Xu School of soil and water conservation Beijing Forestry UniversityBeijing 100083China

Tiger nut is a bioenergy crop planted in arid areas of northern China to supply oil and adjust the planting structure.However,in the western region of Inner Mongolia Autonomous Region,China,less water resources have resulted in a scarcity of available farmland,which has posed a huge obstacle to planting tiger nut.Cultivation of tiger nut on marginal land can effectively solve this problem.To fully unlock the production potential of tiger nut on marginal land,it is crucial for managers to have comprehensive information on the adaptive mechanism and nutrient requirement of tiger nut in different growth periods.This study aims to explore these key information from the perspective of nutrient coordination strategy of tiger nut in different growth periods and their relationship with rhizosphere soil nutrients.Three fertilization treatments including no fertilization(N:P(nitrogen:phosphorous)=0:0),traditional fertilization(N:P=15:15),and additional N fertilizer(N:P=60:15)were implemented on marginal land in the Dengkou County.Plant and soil samples were collected in three growth periods,including stolon tillering period,tuber expanding period,and tuber mature period.Under no fertilization,there was a significant correlation between N and P contents of tiger nut roots and tubers and the same nutrients in the rhizosphere soil(Psoil prompts tiger nut to increase the C:N ratio,improving N utilization efficiency,and maintaining N:P ratio in tube

关键词： tiger nut stoichiometry rhizosphere soil nitrogen addition marginal land

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Semi-automated detection of rangeland runoff and erosion control berms using high-resolution topography data

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International soil and water conservation Research 2024年第1期12卷 217-226页

作者： Li Li Changjiang River Scientific Research Institute of Changjiang water Resources Commission Wuhan430010China Research Center on Mountain Torrent&Geologic Disaster Prevention Ministry of Water ResourcesWuhan430010China University of Arizona School of Natural Resources and the EnvironmentTucsonAZ85719USA

An inventory of topographic modifications is essential to addressing their impacts on hydrological and morphological processes in human-altered watersheds.However,such inventories are generally lacking.This study presents two workflows for semi-automatic detection of linear earthen runoff and erosion control berms in rangelands using high-resolution topographic data.The workflows consist of initial object identification by applying either morphological grayscale reconstruction(MGR)or the Geomorphon(GEO)method,followed by identification refinements through filters based on objects’horizontal and vertical information.Three sites were selected within the Altar Valley,Arizona,in the southwestern United States.One site was used for developing workflows and optimizing filter thresholds,and the other two sites were used to validate workflows.The results showed that:1)The MGR-based workflow methodology could produce final precision and detection rates of up to 92%and 75%,respectively,and take less than 5 s for a 10.1 km^(2) site;2)The workflow based on the MGR method yielded greater identification accuracy than did the GEO workflow;3)Object length,orientation,and eccentricity were important characteristics for identifying earthen berms,and are sensitive to general channel flow direction and berm shape;4)Manual interrogation of topographic data and imagery can significantly improve identification precision rates.The proposed workflows will be useful for developing inventories of runoff and erosion control structures in support of sustainable rangeland management.

关键词： Earthen berm Rangeland Grayscale morphological reconstruction Geomorphon LiDAR

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Spatial distribution of trace elements associated with organic carbon along the Beiyun River basin, Beijing, China

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International Journal of Sediment Research 2022年第3期37卷 335-345页

作者： Farhan Iftikhar Shiliang Liu Yongxiu Sun Yixuan Liu Muhammad Imran School of Environment State Key Laboratory of Water Environment Simulation Beijing Normal University Department of soil and Environmental Science Ghazi University Key Laboratory of soil Resource & Biotech Application Shaanxi Academy of Sciences Xi'an Botanical Garden of Shaanxi Province Institute of Botany of Shaanxi Province

Pollution resulting from terrestrial and aquatic trace elements has become a severe problem across the world. Organic carbon(OC) content has a high affinity for metallic contaminants and it acts as a significant sink for trace elements. The decomposition of OC content directly influences the bioavailability of trace elements. The decomposition of OC content and OC distribution vary spatially, these processes affect the release of trace elements and need further research. In the current study, sediment samples from the surface sediment along Beiyun River(Section 1 to Section 4 from upper to lower reaches),which is situated in the rapidly urbanized Beijing metropolis, were measured for OC, moisture, hardness,and trace elements. The OC contents were found to have a substantial difference among all four river sections along the urbanized river gradient. Whereas the higher OC contents were found in Sections 2(Urbanized uplands) and 3(farmland) compared to those in Sections 1(forest) and 4(farmland and part of constructed areas). On the other hand, the highest value of the correlation coefficient was found among the different values of trace elements and OC content in the riverine zone of the Beiyun River basin. OC contents play a vital role in the transformation and origin of trace elements in the surface sediment of the Beiyun River basin. The One-way Analysis of Variance(ANOVA) was applied to compare the means of OC and trace elements at different sections indicating no significant difference. However,source identification of trace elements indicated that a geogenic source was responsible for higher contents of As and(69.95%). Simultaneously, the natural OC, agricultural activities, and industrial waste contributed about(21.10%) towards the Cd and Zn, and about 10% for Cr and Cu. The current study concludes that the absolute principle component analysis-multiple linear regression(APCA-MLR)method can be successfully used to investigate the trace elements(Zn, Ni, Pb, Mn, Cd, Cu, and As) interactions through OC content

关键词： Organic carbon content Trace element Spatial distribution Source apportionment Absolute principle component analysis–multiple linear regression (APCA-MLR)

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Decreasing magnitude of soil erosion along vegetation succession on sloping farmland in the Loess Plateau of China:5 years field monitoring evidence

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Journal of Mountain Science 2022年第8期19卷 2360-2373页

作者： LIANG Yue JIAO Ju-ying TANG Bing-zhe CAO Bin-ting LI Hang State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationAcademy of Sciences and Ministry of Water ResourcesYangling 712100China

The impacts of vegetation restoration on the soil erosion have been widely elucidated in the semi-arid regions.However,the magnitude of soil erosion on abandoned sloping farmland still remained unclear and their responses to vegetation succession were rarely addressed.The main objective of this study is to determine the magnitude of soil erosion along vegetation succession and explore the impact of vegetation succession on soil erosion from abandoned sloping farmland.Field observations were employed to monitor the rainfall,runoff,and soil erosion of seven sloping farmland plots with different abandoned ages and bare land from 2015 to 2019.The results indicated that the annual runoff depth and soil erosion modulus of vegetation types were in the range of 0.46 to 5.49 mm·a^(-1)and 1.3 to 24.5 t·km^(-2)·a^(-1),respectively.The vegetation effectively reduced the annual surface runoff and soil erosion with reduction of 73.8% to 97.8%and 98.0% to 99.9% as opposed to bare land.However,there were no significant differences in runoff and soil erosion for different vegetation types along succession.The largest event of vegetation types contributed to 38.7%-44.1% of the annual runoff and 42.5%-66.3% of the annual soil erosion,respectively.Vegetation restoration considerably alleviated the contribution of largest erosive event to annual soil erosion.The relationships between soil erosion,runoff and rainfall factors could be fitted well by linear functions,and the performances of regression models in predicting runoff were more satisfactory compared to predicting soil erosion.The Artemisia gmelinii(Agm)+Stipa bungeana(Sb)optimized the trade-off between sediment reduction and runoff maintenance,which should be selected as the suitable vegetation types to achieve the sustainability of socio-ecological systems.

关键词： Vegetation restoration Abandoned ages soil erosion Vegetation types Abandoned slope Loess Plateau

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Response of density-related fine root production to soil and leaf traits in coniferous and broad-leaved plantations in the semiarid loess hilly region of China

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Journal of Forestry Research 2022年第3期33卷 1071-1082页

作者： Meimei Sun Bo-Chao Zhai Qiu-Wen Chen Guoqing Li Sheng Du State Key Laboratory of soil Erosion and Dryland Farming On the Loess Plateau Northwest A&F UniversityYanglingShaanxi712100People’s Republic of China College of Forestry Northwest A&F UniversityYanglingShaanxi712100People’s Republic of China Institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water ResourcesYanglingShaanxi712100People’s Republic of China

Fine roots are the most active and functional component of root systems and play a significant role in the acquisition of soil resources. Density is an important structural factor in forest plantations but information on changes in fine roots along a density gradient is limited. In this study, plantations of black locust (Robinia pseudoacacia L.) and Chinese pine (Pinus tabuliformis Carr.) with four density classes were analyzed for the influence of soil and leaf traits on fine root growth. Fine root biomass increased with stand density. High fine root biomass was achieved through increases in the fine root production and turnover rate in the high-density black locust plantations and through an increase in fine root production in the pine plantations. In the high-density Chinese pine stand, there was a high fine root turnover which, coupled with high fine root production, contributed to a high fine root biomass. Overall, fine root production and turnover rate were closely related to soil volumetric water content in both kinds of plantations, while fine root biomass, especially the component of necromass, was related to soil nutrient status, which refers to phosphorous content in black locust plantations and nitrogen content in Chinese pine plantations. There was a close linkage between leaf area index and fine root dynamics in the black locust plantations but not in the pine plantations.

关键词： Fine roots Black locust Chinese pine Semiarid soil moisture Leaf area index

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Runoff-and erosion-reducing effects of vegetation on the loess hillslopes of China under concentrated flow

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International soil and water conservation Research 2022年第4期10卷 662-676页

作者： Wenzhao Guo Li Luo Hongwei Li Wenlong Wang Yun Bai State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Water and Soil ConservationNorthwest A&F UniversityYangling712100ShaanxiChina School of water Conservancy and Architectural Engineering Northwest A&F UniversityYangling712100ShaanxiChina Hanjiang-to-Weihe River Valley water Diversion Project Construction Co.Ltd. Xian710000ShaanxiChina Yulin University Yulin719000ShaanxiChina

Evaluating the effects of revegetation on runoff and erosion reduction is essential for studying soil and water conservation on the Loess Plateau after implementation of China's Grain for Green Project.However,quantifying the influence of revegetation on the erosion caused by concentrated runoff in extreme rainstorms is still challenging.To evaluate this influence,scouring-erosion experiments were implemented in situ on the vegetated hillslope plots(GR)and bare hillslope plots(CK).The runoffreducing effects of grass(GRR)averaged 31%,20%and 8%,and the erosion-reducing effects of grass(GER)averaged 93%,95%and 93%on the 5-plots,10-plots and 18-plots,respectively.The ratios of GRR to GER were 0.09e0.33,implying that the ability of vegetation to reduce erosion was greater than its ability to reduce runoff.The GRR and GER obviously decreased as the inflow rate increased,and the GRR decreased as the hillslope gradient increased,but there were no obvious differences in the GER between hillslope gradients.Vegetation could decrease the ability of the concentrated flow to carry and transport sediment and increase the energy consumption of the concentrated flow in response to hydraulic resistance.Vegetation also significantly reduced the degree of rill development.The degree of rill dissection on the GR(0.054e0.087 m^(2)m^(2))was lower than that on the CK(0.061e0.184 m^(2)m^(2)).Our findings provide an essential reference for ecological environment and vegetation restoration on loess hillslopes.

关键词： soil erosion Concentrated runoff China's grain for green project Vegetation Hydraulic parameters Chinese loess plateau

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Multiscale causes of the 2022 Yangtze mega-flash drought under climate change

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Science China Earth Sciences 2024年第8期67卷 2649-2660页

作者： Xing YUAN Yumiao WANG Shiyu ZHOU Hua LI Chenyuan LI School of Hydrology and water Resources Nanjing University of Information Science and Technology Institute of Atmospheric Physics Chinese Academy of Sciences Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of water Resources Nanjing University of Information Science and Technology

The 2022 Yangtze mega-flash drought is characterized by strong intensity and rapid development both in time and space, accompanied by a persistent anticyclonic circulation anomaly. However, the causes of the extreme event remain elusive given the multiscale nature of drought. Here we presented a brief overview for the oceanic and terrestrial causes of the megaflash drought during the summer of 2022, and estimated the risk in a changing climate. Using the soil moisture percentile as the drought index, it was found that the drought expanded to the entire Yangtze River basin within two months, with 80% of basin under severe drought conditions at the end of August. Both the intensity and onset speed of the 2022 mega-flash drought were ranked as the first during the past 62 years, with return periods of 86 and 259 years, respectively. The results of composite analysis showed that the spring La Ni?a can facilitate the abrupt change from a wet/normal condition in May–June to drought in July–August over the Yangtze River basin, which was beneficial for the increase of flash drought intensity and onset speed in2022. The analysis through the linear regression also indicated that the unprecedented intensity was associated with the negative phase of the Pacific Decadal Oscillation. Quantified by a coupling strength index for soil moisture and vapor pressure deficit, it was found that there was a strong land-atmosphere coupling over the Yangtze River basin during July–August 2022. The attribution by using CMIP6 climate models suggested that land-atmosphere coupling increased the risks of flash drought intensity and onset speed like 2022 by 61%±6% and 64%±7% under natural climate forcings, and the synergy of coupling and anthropogenic climate change would increase the risks by 75%±22% and 85%±12%. Our findings emphasized the role of landatmosphere coupling combined with anthropogenic climate change in intensifying flash droughts.

关键词： Flash drought Yangtze River basin Land-atmosphere coupling Climate change Attribution

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Electrochemical and colorimetric dual-signal detection of Staphylococcus aureus enterotoxin B based on AuPt bimetallic nanoparticles loaded Fe-N-C single atom nanocomposite

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Food Science and Human Wellness 2024年第4期13卷 2025-2035页

作者： Huan Liang Hongcheng Liu Haojian Lin Guobao Ning Xiaokang Lu Siying Ma Fei Liu Hui Zhao Canpeng Li School of Chemical Science and Technology Yunnan UniversityKey Laboratory of Medicinal Chemistry for Natural ResourceMinistry of EducationKunming 650091China Institute of Quality Standard and Testing Technology Yunnan Academy of Agricultural ScienceSupervision and Testing Center for Farm Product QualityMinistry of AgricultureKunming 650223China State Key Laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou 510275China Laboratory for conservation and Utilization of Bio-resource Yunnan UniversityKunming 650091China

Sensitive detection of Staphylococcus aureus enterotoxin B(SEB)is of importance for preventing food poisoning from threatening human health.In this work,an electrochemical and colorimetric dual-signal detection assay of SEB was developed.The probe(Ab2/AuPt@Fe-N-C)was bound to SEB captured by Ab1,where the Ab2/AuPt@Fe-N-C triggered methylene blue degradation and resulted in the decrease of electrochemical signal.Furthermore,the probe catalyzed the oxidation of 3,3’,5,5’-tetramethyl biphenyl to generate a colorimetric absorbance at 652 nm.Once the target was captured and formed a sandwich-like complex,the color changed from colorless to blue.SEB detection by colorimetric and electrochemical methods showed a linear relationship in the concentration ranges of 0.0002-10.0000 and 0.0005-10.0000 ng/mL,with limits of detection of 0.0667 and 0.1670 pg/mL,respectively.The dual-signal biosensor was successfully used to detect SEB in milk and water samples,which has great potential in toxin detection in food and the environment.

关键词： Staphylococcus aureus enterotoxin Electrochemical immunosensor Colorimetric assay MOF@borophene composite Dual-functional Fe-N-C signal atom catalyst

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