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Factors determining soil water heterogeneity on the Chinese loess plateau as based on an empirical mode decomposition method

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Journal of Arid Land 2020年第3期12卷 462-472页

作者： GONG Yidan XING Xuguang WANG Weihua Faculty of Agriculture and Food Kunming University of Science and TechnologyKunming 650500China Key Laboratory for Agricultural Soil and Water Engineering in Arid Area of Ministry of Education Northwest A&F UniversityYangling 712100China

Soil water is a critical resource,and as such is the focus of considerable physical *** of the distribution and spatial variability of soil water content(SWC)offers important agronomic and environmental *** of non-stationary and non-linear SWC distribution at different scales is a research *** on this context,we performed a case study on the Chinese loess plateau,with objectives of investigating spatial variability of SWC and soil properties(i.e.,soil particle composition,organic matter and bulk density),and determining multi-scale correlations between SWC and soil properties.A total of 86 in situ sampling sites were selected and 516 soil samples(0–60 cm depth with an interval of 10 cm)were collected in May and June of 2019 along the Yangling-Wugong-Qianxian transect,with a length of 25.5 km,in a typical wheat-corn rotation region of the Chinese loess *** statistics and empirical mode decomposition(EMD)method were applied to evaluate characteristics of the overall and scale-specific spatial variation of SWC,and to explore scale-specific correlations between SWC and soil *** showed that the spatial variability of SWC along the Yangling-Wugong-Qianxian transect was medium to weak,with a variability coefficient range of 0.06–0.18,and it was gradually decreased as scale *** categorized the overall SWC for each soil layer under an intrinsic mode function(IMF)number based on the scale of occurrence,and found that the component IMF1 exhibited the largest contribution rates of 36.45%–56.70%.Additionally,by using EMD method,we categorized the general variation of SWC under different numbers of IMFs according to occurrence scale,and the results showed that the calculated scales among SWC for each soil layer increased in correspondence with higher IMF *** 78.00%of the total variance of SWC was extracted in IMF1 and ***,soil texture was the dominant control on

关键词： bulk density loess plateau soil water soil organic matter soil texture spatial variability

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Effects of a check dam system on the runoff generation and concentration processes of a catchment on the loess plateau

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International Soil and Water Conservation Research 2022年第1期10卷 86-98页

作者： Shuilong Yuan Zhanbin Li Li Chen Peng Li Zeyu Zhang Junzheng Zhang Anna Wang kunxia Yu State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China Xi'an University of TechnologyXi'an710048ShaanxiChina Key Laboratory of National Forestry Administration on Ecological Hydrology and Disaster Prevention in Arid Regions Xi'an University of TechnologyXi'an710048ShaanxiChina Desert Research Institute Las VegasNV89012USA Institute of Soil and Water Conservation Investigation and Planning of Shaanxi Province Xi'an710100ShaanxiChina

As an important soil and water conservation engineering measure,more than 100,000 check dams are constructed across the loess plateau;these dams play a vital role in reducing floods and sediment in the ***,the effects of check dams on hydrologic process are still unclear,particularly when they are deployed as a system for watershed soil and water *** study examined the watershed hydrologic process modulated by the check dam system in a typical loess plateau *** simulating scenarios with various numbers of check dams using a distributed physically-based hydro-logical model,the effects of the number of check dams on runoff generation and concentration were analyzed for the study *** results showed that the presence of check dams reduced the peak discharge and the flood volume and extended the flood duration;the reduction effect on peak discharge was most significant among the three *** system of check dams substantially decreased the runoff coefficient,and the runoff coefficient reduction rate was greater for rainstorms with shorter return periods than for rainstorms with longer return *** check dams increased the capacity of the catchment regulating and storing floods and extended the average runoff concentration time in the catchment that flattened the instantaneous unit *** study reveals the influencing mech-anism of check dam system on the watershed hydrological process under heavy rainstorm conditions and provides a theoretical basis for evaluating the effects of numerous check dams on regional hydrology and water resources on the loess plateau.

关键词： Check dam system Runoff generation Runoff concentration Instantaneous unit hydrograph loess plateau

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Cavernous Weathering in Aeolian Sandstones: An Example from the Yongningshan Hill of the loess plateau, Northwest China

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Acta Geologica Sinica(English Edition) 2022年第5期96卷 1764-1777页

作者： CHEN Liuqin Piotr MIGOŃ GUO Fusheng PAN Zhixin WU Hao State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China School of Earth Sciences East China University of TechnologyNanchang 330013China Institute of Geography and Regional Development University of Wrocławpl.Uniwersytecki 150-137 WrocławPoland School of Tourism Hainan UniversityHaikou 570228China Shaanxi Mineral Resources and Geological Survey Xi’an 710068China

Cavernous weathering is commonly found on sandstone slopes in different environments. Either a single dominant process or polygenetic agents require to be invoked in order to interpret the development. The Yongningshan hill of the central loess plateau is representative of cliff dwellings in Northwest China, which is characterized by well-developed cavernous weathering features and provides a good opportunity for the better understanding of sandstone weathering in the loess plateau. Multiple methods, including field survey, in-situ rock strength measurement, along with experiments on samples for microscopic observation, element composition and salt chemistry, were employed to investigate the controlling factors of cavernous weathering. The results show that cavern development is different on the four slopes with the western slope hosting massive honeycombs, tafoni and hardened surfaces. The porous and permeable aeolian sandstones are fundamental, because they provide space and pathways for the transportation of water and salt, honeycombs dominantly aligning within the lamination of cross-beds. The environmental factors such as the seasonal wetting and drying cycle, aeolian salt, moisture and water vapor are key factors for the development of cavernous weathering forms. The northern and northwestern wind-blown dust storms have brought abundant salts, the lengthier dry periods of the wetting and drying cycle being beneficial for salt accumulation within caverns, favoring salt weathering.

关键词： cavernous weathering honeycomb tafone salt weathering loess plateau

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Check dam extraction from remote sensing images using deep learning and geospatial analysis:A case study in the Yanhe River Basin of the loess plateau,China

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Journal of Arid Land 2023年第1期15卷 34-51页

作者： SUN Liquan GUO Huili CHEN Ziyu YIN Ziming FENG Hao WU Shufang Kadambot H M SIDDIQUE Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas Ministry of EducationNorthwest A&F UniversityYangling 712100China Institute of Water-Saving Agriculture in Arid Areas of China Northwest A&F UniversityYangling 712100China College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China College of Natural Resources and Environment Northwest A&F UniversityYangling 712100China The UWA Institute of Agriculture and School of Agriculture&Environment The University of Western AustraliaPerth 6001Australia

Check dams are widely used on the loess plateau in China to control soil and water losses,develop agricultural land,and improve watershed *** information on the number and spatial distribution of check dams is critical for quantitatively evaluating hydrological and ecological effects and planning the construction of new ***,this study developed a check dam detection framework for broad areas from high-resolution remote sensing images using an ensemble approach of deep learning and geospatial ***,we made a sample dataset of check dams using GaoFen-2(GF-2)and Google Earth ***,we evaluated five popular deep-learning-based object detectors,including Faster R-CNN,You Only Look Once(version 3)(YOLOv3),Cascade R-CNN,YOLOX,and VarifocalNet(VFNet),to identify the best one for check dam ***,we analyzed the location characteristics of the check dams and used geographical constraints to optimize the detection ***,recall,average precision at intersection over union(IoU)threshold of 0.50(AP_(50)),IoU threshold of 0.75(AP_(75)),and average value for 10 IoU thresholds ranging from 0.50-0.95 with a 0.05 step(AP_(50-95)),and inference time were used to evaluate model *** the five deep learning networks could identify check dams quickly and accurately,with AP_(50-95),AP_(50),and AP_(75)values higher than 60.0%,90.0%,and 70.0%,respectively,except for *** VFNet had the best performance,followed by *** proposed framework was tested in the Yanhe River Basin and yielded promising results,with a recall rate of 87.0%for 521 check ***,the geographic analysis deleted about 50%of the false detection boxes,increasing the identification accuracy of check dams from 78.6%to 87.6%.Simultaneously,this framework recognized 568 recently constructed check dams and small check dams not recorded in the known check dam survey *** extraction results will support efficient watershed management and

关键词： check dam deep learning geospatial analysis remote sensing Faster R-CNN loess plateau

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Soil surface roughness change and its effect on runoff and erosion on the loess plateau of China

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Journal of Arid Land 2014年第4期6卷 400-409页

作者： LongShan ZHAO XinLan LIANG FaQi WU College of Natural Resources and Environment Northwest A&F University

As an important parameter in the soil erosion model, soil surface roughness（SSR） is used to quantitatively describe the micro-relief on agricultural land. SSR has been extensively studied both experimentally and theoretically; however, no studies have focused on understanding SSR on the loess plateau of China. This study investigated changes in SSR for three different tillage practices on the loess plateau of China and the effects of SSR on runoff and erosion yield during simulated rainfall. The tillage practices used were zero tillage（ZT）, shallow hoeing（SH） and contour ploughing（CP）. Two rainfall intensities were applied, and three stages of water erosion processes（splash erosion（I）, sheet erosion（II） and rill erosion（III）） were analyzed for each rainfall intensity. The chain method was used to measure changes in SSR both initially and after each stage of rainfall. A splash board was used to measure the splash erosion at stage I. Runoff and sediment data were collected continuously at 2-min intervals during rainfall erosion stages II and III. We found that SSR of the tilled surfaces ranged from 1.0% to 21.9% under the three tillage practices, and the order of the initial SSR for the three treatments was ZT〈SH〈CP. For the ZT treatment, SSR increased slightly from stage I to III, whereas for the SH and CP treatments, SSR decreased by 44.5% and 61.5% after the three water erosion stages, respectively, and the greatest reduction in SSR occurred in stage I. Regression analysis showed that the changes in SSR with increasing cumulative rainfall could be described by a power function（R2〉0.49） for the ZT, SH and CP treatments. The runoff initiation time was longer in the SH and CP treatments than in the ZT treatment. There were no significant differences in the total runoff yields among the ZT, SH and CP treatments. Sediment loss was significantly smaller（P〈0.05） in the SH and CP treatments than in the ZT treatment.

关键词： tillage practice soil surface roughness overland flow water erosion loess plateau

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An Indicator System for Assessing Soil Erosion in the loess plateau Gully Regions:A Case Study in the Wangdonggou Watershed,China

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Pedosphere 2004年第1期14卷 37-44页

作者： NIShao-Xiang MAGuo-Bin WEIYu-Chun JIANGHai-Fu CollegeofGeographicalScience NanjingNormalUniversityNanjing210097（China）

The Wangdonggou Watershed on the loess plateau in China was selected as the study area to develop a model for soil erosion assessments. Using the data collected at 20 sampling sites all tentatively selected indicators were assessed against their corresponding erosion intensity through a correlation analysis. Eight highly correlated indicators were then chosen for the soil erosion assessment. In addition, threshold limits to delineate the class size for these indicators and weights to rank them were determined. Next, a grading model incorporating the selected indicators class rating and their associated weights was developed and verified by an on site evaluation of the soil erosion intensity in the study area. Results of the verification showed that the overall accuracy of the indicator system for assessing soil erosion in the loess plateau gully regions could reach 85%.

关键词： assessment indicator loess plateau soil erosion watershed

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Impacts of land disturbance and restoration on runoff production and sediment yield in the Chinese loess plateau

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Journal of Arid Land 2017年第1期9卷 76-86页

作者： AI Ning WEI Tianxing ZHU Qingke QIANG Fangfang MA Huan QIN Wei School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China College of Life Science Yan'an UniversityYan'an 716000China China Institute of Water Resources and Hydropower Research Beijing 100048China International Research and Training Center on Erosion and Sedimentation Beijing 100048China

Land disturbance and land restoration are important factors influencing runoff production and sediment yield in the semi-arid loess regions of China. This study compared the runoff production and sediment yield during the early stage after land disturbance（ESLD） with those during restoring stage after land disturbance（RSLD）. Grey relational analysis was used to analyse the importance of each one of the influencing factors（vegetation, rainfall, soil and topography） in affecting the runoff production and sediment yield. Our results showed that during ESLD, topography was the most critical factor controlling the runoff production, while soil was the most important factor controlling the sediment yield. During RSLD, vegetation was more important in affecting runoff production, while rainfall was more important in affecting sediment yield. In additional, this study demonstrated that both the runoff production and the sediment yield can be effectively reduced by restoring vegetation on severely-disturbed lands, thus providing an important theoretical basis for better implementations of the Grain for Green Program. Our results revealed that the vegetation types of Hippophae rhamnoides＋Pinus tabulaeformis and H. rhamnoides are better plant selections for land restoration in this area, especially for relatively gentle slopes（i.e., less than 20 degrees）.

关键词： land disturbance/ restoration grey relational analysis runoff sediment yield loess plateau

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Response of sediment yield to vegetation restoration at a large spatial scale in the loess plateau

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Science China(Technological Sciences) 2014年第8期57卷 1482-1489页

作者： LIU XiaoYan YANG ShengTian DANG SuZhen LUO Ya LI XiaoYu ZHOU Xu Yellow River Conservancy Commission School of Geography Beijing Normal University Yellow River Institute of Hydraulic Research Yellow River Conservancy Commission Yellow River Institute of Hydrology and Water Resources

The impact of vegetation coverage on erosion and sediment yield in the loess plateau has been extensively studied,but the research has been primarily based on observations from slope runoff plots or secondary forest regions;the scaling method remains unresolved when it is applied at a large spatial scale,and it is difficult to apply to regions with severe soil and water loss given the predominance of herbs and *** date,there is little data on the quantitative impact of changes to vegetation on sediment concentration at a large spatial *** paper is based on vegetation information from remote sensing images,measured rainfall and sediment data over nearly 60 years,and results from previous runoff and sediment variation research on the Yellow *** introduce the concepts of a sediment yield coefficient and the percentage of effective vegetation and erodible area,analyze the impact of different vegetation conditions on the flood sediment concentration and sediment yield,and evaluate the effect of rainfall intensity on sediment yield under different vegetation conditions at the watershed *** propose models to evaluate the impact of vegetation on sediment yield in the loess gully hilly region,which are based on remote sensing data and support an application at a large spatial *** models can be used to assess sediment reduction that results from the current significant improvement of vegetation in the loess plateau.

关键词： loess plateau large spatial scale forest and grass vegetation sediment concentration sediment yield

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Seasonal freezing-thawing process and hydrothermal characteristics of soil on the loess plateau, China

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Journal of Mountain Science 2021年第11期18卷 3082-3098页

作者： CHOU Ya-ling WANG Li-jie Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Lanzhou University of Technology Lanzhou 730050China

In seasonally frozen soil regions,freezing-thawing action and hydrothermal effect have strong influence on physical and mechanical behavior of shallow soil.A field experiment on the loess plateau in Northwest China was carried out to analyze the freezing-thawing process and hydrothermal characteristics of shallow soil considering the climate *** results show that the maximum seasonal freezing depth under bare ground surface in this area is from 20 cm to 50 *** ground temperature shows a similar changing trend with air temperature,but it has lagged behind the air temperature,and the ground temperature amplitude exponentially decreases with the increase of soil *** seasonally frozen soil has experienced four typical stages:unfrozen period,alternate freezing period,freezing period and alternate thawing *** freezing-thawing process is characterized by unidirectional freezing and bidirectional *** water content of shallow soil is significantly affected by air temperature,evaporation and precipitation,and the soil water content shows a"low-high-low"changing trend with the increase of *** soil temperature and water content interact with each other,and are often *** variation trend of soil moisture with time is consistent with the change trend of the ground temperature with time in each soil layer,andthe degree of consistency is higher in the near surface soil than that in the lower ***,the spatial-temporal characteristics of soil moisture and temperature is that the volumetric water content and ground temperatureof near surface soil have strong variability,and the range valueKa and coefficient of variation Cvof soil water content and ground temperaturein different seasons show a decreasing trend with the increase of depth.

关键词： Seasonally frozen soil Freezing-thawing process Hydrothermal characteristics loess plateau

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Toward Sustainable Revegetation in the loess plateau Using Coupled Water and Carbon Management

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Engineering 2022年第8期8卷 143-153页

作者： Fubo Zhao Yiping Wu Xiaowei Yin Georgii Alexandrov Linjing Qiu Department of Earth and Environmental Science School of Human Settlements and Civil EngineeringXi’an Jiaotong UniversityXi’an 710049China A.M.Obukhov Institute of Atmospheric Physics Russian Academy of SciencesMoscow 119017Russia

The"Grain-for-Green"project on the loess plateau is the largest revegetation program in the ***,revegetation-induced land use changes can influence both water and carbon cycles,and the diverse consequences were not well ***,the reasonability and sustainability of revegetation measures are in *** study quantifies the impacts of revegetation-induced land use conversions on the water and carbon cycles in a typical watershed on the loess plateau and identifies suitable areas where revegetation of forest or grassland could benefit both soil and water conservation and carbon *** used a coupled hydro-biogeochemical model to simulate the changes of a few key components in terms of water and carbon by designing a variety of hypothetical land use conversion scenarios derived from revegetation *** to the baseline condition(land use in 2000),both sediment yield and water yield decreased substantially when replacing steep cropland with forest or *** cropland with slopes larger than 25°,15°,and 6°to forest(CTF)would enhance the carbon sequestration with a negligible negative effect on soil water content,while replacing cropland with grassland(CTG)would result in a decline in net primary production but with a substantial increase in soil water content(3.8%-14.9%).Compared to the baseline,the soil organic carbon would increase by 0.9%-3.2% in CTF and keep relatively stable in *** testing a variety of hypothetical revegetation scenarios,we identified potential priority areas for CTF and CTG,where revegetation may be appropriate and potentially beneficial to conserving soil and water and enhancing carbon *** study highlights the challenges in future water and carbon coupling management under revegetation policy,and our quantitative results and identification of potential areas for revegetation could provide information to policy makers for seeking optimal management on the loess Plate

关键词： Carbon Land use change loess plateau Sediment SWAT-Day Cent Water resources

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