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Study of elemental distribution in soil on the loess plateau of China

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Journal of Environmental Sciences 1993年第1期5卷 37-44页

作者： Tian Junliang, Li Yaqi Liu Pulingnorthwestern inst.tute of soil and water conservation, Chinese Academy of Sciences, Shaanxi 712100, China northwestern inst. of soil & water conservation Chinese Academy of Sciences Shaanxi 712 100 China

inst.ument neutron activation analysis (INAA) has been employed in this study to determine 32 elements in soil on the loess plateau. The preliminary results suggest that geochemical characteristics of elements in the soil mainly retained those in the parent materials (loess). It has been found that fractional deposition among grain sizes in the process of loess transportation as well as the bioclimate in which the soil developed are main factors affecting the regional variations of elemental distribution in soil on the plateau. Contour maps of element concentrations plotted from the trend analyses exhibit the major patterns of the distributions and variations on the plateau. Furthermore, the study also provides evidence for the aeolian theory of the loess transportation in China.

关键词： elements soil loess plateau variation patterns.

Identification and distribution of 13003 landslides in the northwest margin of Qinghai-Tibet Plateau based on human-computer interaction remote sensing interpretation

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China Geology 2024年第2期7卷 171-187页

作者： Wei Wang Yuan-dong Huang Chong Xu Xiao-yi Shao Lei Li Li-ye Feng Hui-ran Gao Yu-long Cui Shuai Wu Zhi-qiang Yang Kai Ma National inst.tute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Key Laboratory of Compound and Chained Natural Hazards Dynamics Ministry of Emergency Management of Chin12eijing 100085China School of Emergency Management Science and Engineering University of Chinese Academy of SciencesBeijing 100049China School of soil and water conservation Beijing Forestry UniversityBeijing 100083China School of Civil Engineering and Architecture Anhui University of Science and TechnologyHuainan 232001China No.3 Bureau of China Metallurgical Geology Bureau Taiyuan 030031China

The periphery of the Qinghai-Tibet Plateau is renowned for its susceptibility to ***,the northwestern margin of this region,characterised by limited human activities and challenging transportation,remains insufficiently explored concerning landslide occurrence and *** the planning and construction of the Xinjiang-Tibet Railway,a comprehensive investigation into disastrous landslides in this area is essential for effective disaster preparedness and mitigation *** using the human-computer interaction interpretation approach,the authors established a landslide database encompassing 13003 landslides,collectively spanning an area of 3351.24 km^(2)(36°N-40°N,73°E-78°E).The database incorporates diverse topographical and environmental parameters,including regional elevation,slope angle,slope aspect,distance to faults,distance to roads,distance to rivers,annual precipitation,and *** statistical characteristics of number and area of landslides,landslide number density(LND),and landslide area percentage(LAP)are *** authors found that a predominant concentration of landslide origins within high slope angle regions,with the highest incidence observed in intervals characterised by average slopes of 20°to 30°,maximum slope angle above 80°,along with orientations towards the north(N),northeast(NE),and southwest(SW).Additionally,elevations above 4.5 km,distance to rivers below 1 km,rainfall between 20-30 mm and 30-40 mm emerge as particularly susceptible to landslide *** study area’s geological composition primarily comprises Mesozoic and Upper Paleozoic *** fault and human engineering activities have different degrees of influence on landslide ***,the significance of the landslide database,the relationship between landslide distribution and environmental factors,and the geometric and morphological characteristics of landslides are *** landslide H/L ratios in the study area are

关键词： Landslides Human-computer interaction interpretation Landslide database Spatial distribution Earthquake Rainfall Human engineering activity Qinghai-Tibet Plateau Geological hazards survey engineering

N,P,and K characteristics of different age groups of temperate coniferous tree species in northwestern China

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Journal of Forestry Research 2018年第2期29卷 465-472页

作者： Simin Liu Hao Wang School of soil and water conservation Beijing Forestry University

This study chose dominant tree species including Picea crassifolia,Pinus armandii and Pinus tabuliformis which are distributed in Qilian Mountains,Xiaolongshan Mountains,and Bailongjiang *** to the different tree species,ages and components,we sampled leaves,branches,stems,and roots,and measured the contents of Nitrogen,Phosphorus,Potassium,along with soil *** changes of N,P,and K contents in the different tree species were studied,and the relationship between nutrient content and environmental factors was *** results indicated that the content of P in all three species was the lowest(0.039–0.28 g kg),while N content was the highest(0.095–1.72 g kg).As the terminal organ of nutrient transport,the nutrient content of leaves was the ***(0.45 g kg) had a higher nutrient concentration than ***(0.19 g kg) and ***(0.29 g kg).The nutrient content of each species was highest in a young forest,but lowest in a mature *** nutrient content of all three tree species was significantly affected by soil nutrient content,and negatively correlated with available soil nutrients.

关键词： Different ages northwestern China N,P,K Tree species

Study of Spatial and Temporal Processes of soil Erosion on Sloping Land Using Rare Earth Elements As Tracers

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Journal of Rare Earths 2004年第5期22卷 707-713页

作者：薛亚洲刘普灵杨明义琚彤军 inst.tute of soil and water conservation CAS and Ministry of Water Resources State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau Northwestern Science and Technology University of Agriculture and Forestry Yangling 712100 China

Rare earth elements (REE) were used to study the temporal and spatial processes of soil erosion from different depths and sections of a slope. Two simulated rainfall events were applied to a prepared plot with a slope of 22°. The total runoff and sediment yield were collected every minute during the rainfall events. During the first twenty minutes of the first rainfall event, the average rate of rill erosion and the accumulated sediment yield due to rill erosion was 0.5 and 0.3 times higher than for sheet erosion. During this time, most of the erosion occurred on the lower one third of the plot. After 20 min, rill erosion became the dominant process on the slope. The average acceleration in the rate of rill erosion, the rate of rill erosion and the accumulated sediment yield due to rill erosion were 42, 6 and 4 times higher than that of sheet erosion, respectively. During the first 35 minutes of the second rainfall event, the average acceleration in the rate of rill erosion was 6～9 times higher than that of sheet erosion. Afterwards, the slope became nearly stable with little change in either rill or sheet erosion rates. Initially, most of the rill erosion occurred in the lower third of the slope but later the preexisting rillhead in the middle section of the slope became reactivated and erosion in this section of the slope increased rapidly. These results indicate that REE tracer technology is a valuable tool for quantifying spatial and temporal changes in erosion from a soil slope.

关键词： soil and water loss erosion process REE tracer technology slope land erosion rare earths

Influence of vegetation parameters on runoff and sediment characteristics in patterned Artemisia capillaris plots

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Journal of Arid Land 2014年第3期6卷 352-360页

作者： GuanHua ZHANG GuoBin LIU PingCang ZHANG Liang YI Department of soil and water conservation Changjiang River Scientific Research Institute State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources inst.tute of soil and water conservation Northwest A&F University Hubei Academy of Environmental Sciences

Vegetation patterns are important in the regulation of earth surface hydrological processes in arid and semi-arid areas. Laboratory-simulated rainfall experiments were used at the State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau, Yangling, northwestern China, to quantify the effects of Artemisia capillaris patterns on runoff and soil loss. The quantitative relationships between runoff/sediment yield and vegetation parameters were also thoroughly analyzed using the path analysis method for identifying the reduction mechanism of vegetation on soil erosion. A simulated rainfall intensity of 90 mm/h was applied on a control plot without vegetation （Co） and on the other three different vegetation distribution patterns： a checkerboard pattern （CP）, a banded pattern perpendicular to the slope direction （BP）, and a single long strip parallel to the slope direction （LP）. Each patterned plot received two sets of experiments, i.e. intact plants and roots only, respectively. All treatments had three replicates. The results showed that all the three other different patterns （CP, BP and LP） of A. capillaris could effectively reduce the runoff and sediment yield. Compared with Co, the other three intact plant plots had a 12%-25% less runoff and 58%-92% less sediment. Roots contributed more to sediment reduction （46%-70%）, whereas shoots contributed more to runoff reduction （57%-81%）. BP and CP exhibited preferable controlling effects on soil erosion compared with LP. Path analysis indicated that root length density and plant number were key parameters influencing runoff rate, while root surface area density and root weight density were central indicators affecting sediment rate. The results indicated that an appropriate increase of sowing density has practical significance in conserving soil and water.

关键词： arid and semi-arid areas Artemisia capillaris patches runoff and sediment roots and shoots vegetation parameters

Machine learning-based identification for the main influencing factors of alluvial fan development in the Lhasa River Basin,Qinghai-Tibet Plateau

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Journal of Geographical Sciences 2022年第8期32卷 1557-1580页

作者： CHEN Tongde WEI Wei JIAO Juying ZHANG Ziqi LI Jianjun State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100ShaanxiChina School of Automation Northwestern Polytechnical UniversityXi'an 710072China inst.tute of soil and water conservation Chinese Academy of Sciences and Ministry of Water ResourcesYangling 712100ShaanxiChina

Alluvial fans are an important land resource in the Qinghai-Tibet Plateau with the expansion of human activities. However, the factors of alluvial fan development are poorly understood. According to our previous investigation and research, approximately 826 alluvial fans exist in the Lhasa River Basin(LRB). The main purpose of this work is to identify the main influencing factors by using machine learning. A development index(Di) of alluvial fan was created by combining its area, perimeter, height and gradient. The 72% of data, including Di, 11 types of environmental parameters of the matching catchment of alluvial fan and 10 commonly used machine learning algorithms were used to train and build *** 18% of data were used to validate models. The remaining 10% of data were used to test the model accuracy. The feature importance of the model was used to illustrate the significance of the 11 types of environmental parameters to Di. The primary modelling results showed that the accuracy of the ensemble models, including Gradient Boost Decision Tree,Random Forest and XGBoost, are not less than 0.5(R^(2)). The accuracy of the Gradient Boost Decision Tree and XGBoost improved after grid research, and their R^(2) values are 0.782 and 0.870, respectively. The XGBoost was selected as the final model due to its optimal accuracy and generalisation ability at the sites closest to the LRB. Morphology parameters are the main factors in alluvial fan development, with a cumulative value of relative feature importance of 74.60% in XGBoost. The final model will have better accuracy and generalisation ability after adding training samples in other regions.

关键词： alluvial fan machine learning feature importance XGBoost Lhasa River Basin

ON TIME CONSTANT VARIABILITY OF ELECTRIC ANALOGY OF water FLOW IN soil-PLANT SYSTEM

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Chinese Science Bulletin 1992年第14期37卷 1208-1211页

作者：邵明安 northwestern inst.tute of soil and water conservation Academia Sinica and Ministry of Water Resources Yangling Shaanxi 712100 PRC

There are two different models of water flow in soil-plant system, i. e. the linear model and the non-linear *** linear model is based on an analogy with Ohm’s Law. A difference in water potential is analogous to the electrical potential difference, and the flow rate analogous to current intensity. Hydraulic resistance R(constant)is defined by the ratio of water potential difference

关键词： time constant hydraulic resistance hydraulic capacitance

Combining conservation tillage with nitrogen fertilization promotes maize straw decomposition by regulating soil microbial community and enzyme activities

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Pedosphere 2024年第4期34卷 783-796页

作者： Houping ZHANG Xueqin TANG Quanming HOU Yuanpeng ZHU Zhangheng REN Huanxin XIE Yuncheng LIAO Weiyan WANG Xiaoxia WEN College of Agronomy Northwest A&F UniversityYangling 712100China Key Laboratory of Crop Physi-ecology and Tillage Science in northwestern Loess Plateau Ministry of AgricultureNorthwest A&F UniversityYangling 712100China Key Laboratory of water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Straw return can effectively improve farmland soil microenvironment and ***,excessive straw in the topsoil adversely affects seed germination and crop *** present,the characteristics and key driving factors of straw decomposition in dry farmlands are *** on the interactions between tillage practices including zero tillage(ZT),chisel tillage(CT),and plow tillage(PT)and nitrogen(N)fertilization,i.e.,low N(N1,180 kg ha^(-1)),normal N(N2,240 kg ha^(-1)),and high N(N3,300 kg ha^(-1)),quantitative polymerase chain reaction technology and an enzymatic detection kit were used to investigate the effects of key straw C-degrading enzyme activities and microbial abundance in soil on maize straw decomposition during the growth period of winter wheat in the winter wheat/summer maize double cropping system in a dry farmland of the Loess Plateau,*** 2018 and 2020,ZT and CT significantly increased winter wheat yield(by 10.94%and 12.79%,respectively)and straw decomposition velocity(by 20%and 26.67%,respectively),compared with *** to N1 and N3,N2 significantly increased wheat yield(by 4.65%and 5.31%,respectively)and straw decomposition velocity(by 26.33%and 13.21%,respectively).The partial least squares pathway modelling showed significant positive direct effects of soil moisture,NO3-,NH4+,total N,bacteria,and cellulase,laccase,and xylanase activities on straw decomposition,while soil pH,fungi,and Actinomycetes had significant negative direct ***,conservation tillage(ZT and CT)combined with N2 was beneficial for straw decomposition in the drylands of the Loess Plateau and improved straw resource utilization and basic soil *** results of the study clarified the key drivers of straw decomposition in dry farmlands and provided new ideas for developing updated soil management practices and adaptive N application strategies to promote the resource utilization of straw and achieve the goals of carbon peaking and carbon ne

关键词： hydrolytic enzyme microbial biomass oxidative enzyme straw decomposition velocity tillage practice

Evaluating the necessity of autumn irrigation on salinized soil by considering changes in soil physicochemical properties

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Pedosphere 2024年第4期34卷 837-842页

作者： Hang ZHAO Jingwei WU Changsen LI Yawen LIU Rui ZHANG Qiang ZHAO State Key Laboratory of water Resources Engineering and Management Wuhan UniversityWuhan 430072China

Dear Editor,soil salinization is one of the main forms of global soil degradation,which seriously threatens food security production (Liu et al.,2022).Proper irrigation is the main management measure to control soil salinization (Aragüés et al.,2015;Machado and Serralheiro,2017).For example,in Hetao Irrigation District in Inner Mongolia of northwestern China,the effects of irrigation,seasonal freezing-thawing,and evaporation have led to serious soil salinization *** the 1980s,autumn irrigation (AI) has typically been implemented widely in Hetao Irrigation District before soil freezing (Li et al.,2010;Lu et al.,2019),to leach the salts accumulated on the surface and maintain sufficient soil moisture to create a suitable environment for the next spring sowing.

关键词： soil freezing irrigation