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soil properties and herbaceous characteristics in an age sequence of Haloxylon ammodendron plantations in an oasis-desert ecotone of northwestern China

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Journal of Arid Land 2016年第6期8卷 960-972页

作者： ZHANG Ke SU Yongzhong WANG Ting LIU Tingna Linze Inland River Basin Research Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China University of Chinese Academy of Sciences Beijing 100049 China

Haloxylon ammodendron, a typical desert shrub with C4 pathway of photosynthesis, possessing a strong ability to adapt to an extreme drought environment, has a rapid growth rate in sandy lands and is widely used in sand-fixing shelter-forest systems in oasis-desert ecotones. To assess the effects of H. ammodendron plantation on the soil, we measured soil properties and herbaceous characteristics along a nearly 40-year chronosequence after H. ammodendron was planted in shifting sand dunes in an oasis-desert ecotone. Results showed that silt and clay fractions increased significantly in the topsoil. The accumulation rates of soil organic carbon （SOC）, total nitrogen （TN） and total phosphorus （TP） were faster in the early stages （0-9 years） and slower in the late stages （9-39 years）. The soil pH and electrical conductivity （EC） were higher than those in the non-vegetation dunes. Moreover, the soil properties in the topsoil （0-5 cm） showed larger variation scope than those in the deeper soil layers （5-20 cm）. The significant relationships of the soil silt＋clay content with the chemical properties mainly appeared in the topsoil. The wind erosion susceptibility of the soil, evaluated by erodible fraction （EF）, decreased significantly with increasing H. ammodendron plantation age. Additionally, the annual pioneer herb, Agriophyllum squarrosum, was gradually substituted by the annual salt-tolerant herb, Bassia dasyphylla, with increasing plantation age. These results showed beneficial effects of H. ammodendron plantation on improving soil conditions. However, the dynamics of the herbaceous species also reminded us that the long- term effects of H. ammodendron plantation, especially on changes in vegetation composition, still need further evaluation.

关键词： Haloxylon ammodendron soil properties herbaceous erodible fraction oasis-desert ecotone

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soil properties for Earthen Building Construction in Najran City,Saudi Arabia

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Computers, Materials & Continua 2021年第4期67卷 127-140页

作者： Yaser Khaled Al-Sakkaf Gamil M.S.Abdullah Department of Architectural Engineering Najran UniversityNajranSaudi Arabia Department of Civil Engineering Najran UniversityNajranSaudi Arabia

:Earth is the most common and important building material used in the construction industry,since it is found in almost every country in the *** earthen construction is alive and well,and is spread over an enormous geographical *** technique utilizes various earthen materials and numerous methods,and features many benefits for both construction in general and buildings in ***,a city located in the south of Saudi Arabia,is distinguished by its heritage of earthen architecture,which displays many advantages and a marvelous variety of types and exterior *** weaknesses of the material,however,along with a lack of knowledge and rapid development have caused the uplifting and destruction of many of Najran’s mud and heritage buildings during the last few *** all soil types are suitable for every building *** specification is thus very important in order to ensure that the materials used in construction meet all *** main goal of this study was to invistegate the suitability of local soils for the earthen building ***,available local materials of common quality were taken from local sites in *** experimentation and testing was then performed to determine the properties of those *** results showed that local soil properties are suitable for using in the earthen block construction since they satisified the *** results were then recorded for use in further studies,as well as to explore heritage building and rehabilitation,and to improve modern earthen building materials and techniques.

关键词： Najran earthen building local earthen material soil suitability standards soil properties

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soil properties and Characteristics of soil Aggregate in Marginal Farmlands of Oasis in the Middle of Hexi Corridor Region, Northwest China

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Agricultural Sciences in China 2007年第6期6卷 706-714页

作者： SUYong-zhong WANG Fang ZHANG Zhi-hui DU Ming-wu Laboratory of Watershed Hydrology and Applied Ecology Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 P.R.China Linze Inland River Basin Research Station Chinese Ecosystem Research Network Lanzhou 730000 P.R.China

The composition and stability of soil aggregate are closely related to soil quality, soil erosion, and agricultural sustainability. In this study, 49 soil samples at the 0-10 cm surface layer were collected from four soil types （i.e., Ari-Sandic Primosols, Calci-Orthic Aridosols, Siltigi-Otrthic Anthrosols, and Ustic Cambosols） in the marginal farmland in the oasis of the middle Hexi Corridor region and was used to determine the characteristics of soil aggregates. The composition of dry- and wet- sieved aggregates and the physical and chemical properties （including soil particle distribution, soil organic carbon （SOC）, calcium carbonate （CaCO3）, and oxides of Fe^3＋ and Al^3＋） of the selected soils were analyzed. The results show that soil particle size distribution is dominated by fine sand fraction in most of soils except Ustic Cambosols. soil organic carbon concentration is 5.88 ± 2.52 g kg^-1 on average, ranging from 4.75 g kg^-1 in Ari-Sandic Primosols to 10.51 g kg^-1 in Ustic Cambosols. The soils have high calcium carbonate （CaCO3） concentration, ranging from 84.7 to 164.8 g kg^-1, which is increased with soil fine particle and organic carbon content. The percentage of 〉0.25 mm dry aggregates ranges from 65.2% in Ari-Sandic Primosols to 94.6% in Ustic Cambosols, and large dry blocky aggregates （〉5 mm） is dominant in all soils. The mean weight diameter of dry aggregates （DMWD） ranges from 3.2 mm to 5.5 mm. The percentage of 〉0.25 mm water-stable aggregate is from 23.8% to 45.4%. The percentage of aggregate destruction （PAD） is from 52.4% to 66.8%, which shows a weak aggregate stability. Ari-Sandic Primosols has the highest PAD. The distribution and characteristics of soil aggregates are in favor of controlling soil wind erosion. However, the stability of aggregate of all soils is weak and soils are prone to disperse and harden after irrigation. The mass of macro-aggregates and DMWD are positively significantly correlated with the contents of soil clay and silt,

关键词： soil aggregate soil properties returning cropland to grassland marginal oasis Hexi Corridor region

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Simultaneous estimation of surface soil moisture and soil properties with a dual ensemble Kalman smoother

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Science China Earth Sciences 2015年第12期58卷 2327-2339页

作者： CHU Nan HUANG ChunLin LI Xin DU PeiJun School of Environment Science and Spatial Informatics China University of Mining and Technology Key Laboratory of Remote Sensing of Gansu Province Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences Heihe Remote Sensing Experimental Research Station Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of Sciences

In this paper, a new state-parameter estimation approach is presented based on the dual ensemble Kalman smoother(DEn KS) and simple biosphere model(Si B2) to sequentially estimate both the soil properties and soil moisture profile by assimilating surface soil moisture observations. The Arou observation station, located in the upper reaches of the Heihe River in northwestern China, was selected to test the proposed method. Three numeric experiments were designed and performed to analyze the influence of uncertainties in model parameters, atmospheric forcing, and the model's physical mechanics on soil moisture estimates. Several assimilation schemes based on the ensemble Kalman filter(En KF), ensemble Kalman smoother(En KS), and dual En KF(DEn KF) were also compared in this study. The results demonstrate that soil moisture and soil properties can be simultaneously estimated by state-parameter estimation methods, which can provide more accurate estimation of soil moisture than traditional filter methods such as En KF and En KS. The estimation accuracy of the model parameters decreased with increasing error sources. DEn KS outperformed DEn KF in estimating soil moisture in most cases, especially where few observations were available. This study demonstrates that the DEn KS approach is a useful and practical way to improve soil moisture estimation.

关键词： soil moisture soil properties data assimilation state-parameter estimation dual ensemble Kalman smoother

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Relationships between humic substance-bound mercury contents and soil properties in subtropical zone

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Journal of Environmental Sciences 2006年第5期18卷 951-957页

作者： YU Gui-fen WU Hong-tao JIANG Xin HE Wen-xiang QING Chang-le Institute-of soil Science Chinese Academy of Sciences Nanjing 210008 China College of Environmental Sciences Southwest Agricultural University Chongqing 400716 China

The bioavailability of humic substance-bound mercury （HS-Hg） has been established, while the distribution of HS-Hg in soils in relation to soil properties remains obscure. Path analysis and principal component analysis were employed in present study to investigate how soil factors influence the contents of HS-Hg in soils. Results showed that HS-Hg ranged from 0.0192 to 0.2051 mg/kg in soils. The two fractions existed in soils as humic acid-bound mercury （HA-Hg）〉 fulvic acid-bound mercury （FA-Hg） and the ratio of HA-Hg/FA-Hg was 1.61 on the average. soil organic carbon （OC） and HS favorably determined soil HS-Hg and the two fractions. The mercury source forming HS-Hg derived from soil total mercury and HS-Hg. FA-Hg and HA-Hg served as mercury source for each other. In acidic soils, FA-Hg and HA-Hg consistently rose with the increase of OC, and generally HA-Hg increased more dramatically. soils with lower pH and lighter texture contained more HS-Hg, particularly fraction of FA-Hg. Among all influencing factors, organic material source showed the strongest effect, followed by other soil properties and soil mercury source.

关键词： humic acid-bound Hg fulvic acid-bound Hg soil properties

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Changes in soil properties and erodibility of gully heads induced by vegetation restoration on the Loess Plateau, China

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Journal of Arid Land 2018年第5期10卷 712-725页

作者： GUO Mingming WANG Wenlong KANG Hongliang YANG Bo State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Northwest A&F University Yangling 712100 China Institute of soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources Yangling 712100 China

soil erosion on the Loess Plateau of China is effectively controlled due to the implementation of several ecological restoration projects that improve soil properties and reduce soil erodibility. However, few studies have examined the effects of vegetation restoration on soil properties and erodibility of gully head in the gully regions of the Loess Plateau. The objectives of this study were to quantify the effects of vegetation restoration on soil properties and erodibility in this region. Specifically, a control site in a slope cropland and 9 sites in 3 restored land-use types （5 sites in grassland, 3 in woodland and 1 in shrubland） in the Nanxiaohegou watershed of a typical gully region on the Loess Plateau were selected, and soil and root samples were collected to assess soil properties and root characteristics. soil erodibility factor was calculated by the Erosion Productivity Impact Calculator method. Our results revealed that vegetation restoration increased soil sand content, soil saturated hydraulic conductivity, organic matter content and mean weight diameter of water-stable aggregate but decreased soil silt and clay contents and soil disintegration rate. A significant difference in soil erodibility was observed among different vegetation restoration patterns or land-use types. Compared with cropland, soil erodibility decreased in the restored lands by 3.99% to 21.43%. The restoration patterns of Cleistogenes caespitosa K. and Artemisia sacrorum L. in the grassland showed the lowest soil erodibility and can be considered as the optimal vegetation restoration pattern for improving soil anti-erodibility of the gully heads. Additionally, the negative linear change in soil erodibility for grassland with restoration time was faster than those of woodland and shrubland. soil erodibility was significantly correlated with soil particle size distribution, soil disintegration rate, soil saturated hydraulic conductivity, water-stable aggregate stability, organic matt

关键词： soil erosion land use soil properties revegetation root characteristics headcut retreat Loess Plateau

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The Response of Vegetation Biomass to soil properties along Degradation Gradients of Alpine Meadow at Zoige Plateau

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Chinese Geographical Science 2020年第3期30卷 446-455页

作者： LIU Miao ZHANG Zhenchao SUN Jian XU Ming MA Baibing TIJJANI Sadiy Baba CHEN You-jun ZHOU Qingping Synthesis Research Centre of Chinese Ecosystem Research Network Key Laboratory of Ecosystem Network Observation and Model-lingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-environmental SciencesChinese Academy of SciencesBei-jing 100085China Department of Ecology Evolutionand Natural ResourcesSchool of Environmental and Biological SciencesRutgers UniversityNew BrunswickNew Jersey 08901USA The College of Environment and Planning of Henan University Kaifeng 475004China University of Chinese Academy of Sciences Beijing 100049China Institute of Qinghai-Tibetan Plateau Southwest Minzu UniversityChengdu 610041China

Alpine grassland of the Tibetan Plateau has undergone severe degradation, even desertification. However, several questions remain to be answered, especially the response mechanisms of vegetation biomass to soil properties. In this study, an experiment on degradation gradients was conducted in an alpine meadow at the Zoige Plateau in 2017. Both vegetation characteristics and soil properties were observed during the peak season of plant growth. The classification and regression tree model(CART) and structural equation modelling(SEM) were applied to screen the main factors that govern the vegetation dynamics and explore the interaction of these screened factors. Both aboveground biomass(AGB) and belowground biomass(BGB) experienced a remarkable decrease along the degradation gradients. All soil properties experienced significant variations along the degradation gradients at the 0.05 significance level. soil physical and chemical properties explained 54.78% of the variation in vegetation biomass along the degradation gradients. AGB was mainly influenced by soil water content(SWC), soil bulk density(SBD), soil organic carbon(SOC), soil total nitrogen(STN), and pH. soil available nitrogen(SAN), SOC and p H, had significant influence on BGB. Most soil properties had positive effects on AGB and BGB, while SBD and p H had a slightly negative effect on AGB and BGB. The correlations of SWC with AGB and BGB were relatively less significant than those of other soil properties. Our results highlighted that the soil properties played important roles in regulating vegetation dynamics along the degradation gradients and that SWC is not the main factor limiting plant growth in the humid Zoige region. Our results can provide guidance for the restoration and improvement of degraded alpine grasslands on the Tibetan Plateau.

关键词： vegetation biomass soil properties degradation gradients structural equation modelling Zoige Plateau

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Changes in soil properties of Paddy Fields Across a Cultivation Chronosequence in Subtropical China

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Pedosphere 2005年第1期15卷 110-119页

作者： LIZhong-Pei ZHANGTao-Lin LIDe-Cheng B.VELDE HANFeng-Xiang InstituteofsoilScience ChineseAcademyofSciencesNanjing210008China LaboratoiredeGéologie EcoleNormaleSupérieureCNRSParis75231France DiagnosticInstrumentationandAnalysisLaboratory MississippiStateUniversityStarkvilleMS39759USA

Rice production plays a crucial role in the food supply of China and a better understanding of the changes in paddy soil fertility and the management effects is of practical importance for increasing rice productivity. In this study, field sampling in a typical red soil region of subtropical China, Jiangxi Province, was used to observe changes in the soil physical, chemical, and biological properties in a cultivation chronosequence of paddy fields. After cultivation, clay (soil…

关键词： cultivation chronosequence paddy fields soil properties subtropical China

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Fine root morphology and soil properties under influence of different tree stands along an altitudinal climosequence in the Carpathian mountains

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Forest Ecosystems 2022年第5期9卷 692-700页

作者： Karolina Staszel Ewa Błonska Jarosław Lasota Department of Ecology and Silviculture Faculty of ForestryUniversity of Agriculture in Krakow29 Listopada 46 Str31-425KrakowPoland

In an era of climate change, understanding the factors that impact root systems can improve our understanding of carbon cycling in forest ecosystems. The study objective was to determine the impact of climatic conditions on the biomass and morphology of roots of different tree species along an elevation gradient, and consequently on properties of montane forest soils. The study plots were established at three different elevations(600, 800 and1000 m a.s.l.) along a slope with an inclination of 15°. The research plots were located in a beech stand(Fagus sylvatica L.) and fir stand(Abies alba Mill.). soil samples were collected from each study plot, for which basic physical and chemical properties were determined. Additionally, we determined the morphology, production and decomposition rate of fine roots. Our analyses confirmed the significance of climatic conditions in the formation of soil properties, in particular the amount of accumulated carbon and nitrogen content. A decrease of root biomass and reduced root growth were recorded with increasing elevation. The characteristics of roots were linked with the properties of the studied mountain soils, in particular p H, alkaline cation content and content of selected micronutrients. Limitation of root growth in higher elevations affected both study species. Additional research into the formation of tree root morphology is needed, especially in mountainous regions where changes may occur more dynamically. This will provide a better understanding of how stands can cope with different types of environmental stress.

关键词： Beech Fir Forest ecosystem Root biomass soil properties

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Influence of different soil properties on the failure behavior of deposit slope under earthquake after rainfall

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Journal of Mountain Science 2023年第1期20卷 65-77页

作者： YANG Bing HOU Jiang-rong ZHOU Zi-hong GOU Jin-cheng School of Civil Engineering Southwest Jiaotong UniversityChengdu610031China

In this study,the influence of soil properties on the failure behavior and mechanism of slope under earthquake after rainfall was studied with shaking table test in the laboratory,in which the failure process of slope and instant responses of water content and pore water pressure were *** on the principle of similarity,a model test was *** experimental results showed that soil properties exhibit significant influence on failure mode and failure mechanism of *** flowslide,local failure,and creep flowslide failure modes appear in the slope exposed to only ***,under earthquake after rainfall,the other three failure modes occur,i.e.,local slip failure,overall slip failure,and shallow scouring and creep flowslide *** spatial distribution of water content and pore water pressure are the two key factors leading to slope ***,due to the difference of permeability,the soil properties not only affect the spatial distribution of water content of the slope after rainfall,resulting in the peak pore water pressure which occurs mainly near the foot of the slope and near the bedrock interface in the middle and lower parts of the slope,but also affect the dissipation of excess pore water pressure in the process of ***,it is discovered that different types of soil lead to significant differences in the peak acceleration of slope *** critical acceleration of slope with coarse-grained soil is greater than that of slope with fine-grained *** critical acceleration of slope failure shows a close relationship with soil properties.

关键词： Failure mode Failure mechanism Deposit slope soil properties Earthquake after rainfall

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