Journal articles: 'Loess soil'

1

Pierce, Kenneth L., Daniel R. Muhs, Maynard A. Fosberg, Shannon A. Mahan, Joseph G. Rosenbaum, Joseph M. Licciardi, and Milan J. Pavich. "A loess–paleosol record of climate and glacial history over the past two glacial–interglacial cycles (~ 150 ka), southern Jackson Hole, Wyoming." Quaternary Research 76, no. 1 (July 2011): 119–41. http://dx.doi.org/10.1016/j.yqres.2011.03.006.

Full text

Abstract:

AbstractLoess accumulated on a Bull Lake outwash terrace of Marine Oxygen Isotope Stage 6 (MIS 6) age in southern Jackson Hole, Wyoming. The 9 m section displays eight intervals of loess deposition (Loess 1 to Loess 8, oldest), each followed by soil development. Our age-depth model is constrained by thermoluminescence, meteoric 10Be accumulation in soils, and cosmogenic 10Be surface exposure ages. We use particle size, geochemical, mineral-magnetic, and clay mineralogical data to interpret loess sources and pedogenesis. Deposition of MIS 6 loess was followed by a tripartite soil/thin loess complex (Soils 8, 7, and 6) apparently reflecting the large climatic oscillations of MIS 5. Soil 8 (MIS 5e) shows the strongest development. Loess 5 accumulated during a glacial interval (~ 76–69 ka; MIS 4) followed by soil development under conditions wetter and probably colder than present. Deposition of thick Loess 3 (~ 43–51 ka, MIS 3) was followed by soil development comparable with that observed in Soil 1. Loess 1 (MIS 2) accumulated during the Pinedale glaciation and was followed by development of Soil 1 under a semiarid climate. This record of alternating loess deposition and soil development is compatible with the history of Yellowstone vegetation and the glacial flour record from the Sierra Nevada.

APA, Harvard, Vancouver, ISO, and other styles

2

Gajic, Grozdana, Nikola Zivanovic, and Luka Vukic. "Indicators and degradation mechanisam of loess soil." Bulletin of the Faculty of Forestry, no. 114 (2016): 45–54. http://dx.doi.org/10.2298/gsf1614045g.

Full text

Abstract:

Studies that are presented in this paper were carried out to define the formation criteria of loess soil degradation. Erosion stability analysis of this soil type will be carried out on the basis of its physical and mechanical characteristics. To describe the established relationships between the individual parameters of loess soil, the study uses mathematical model, that is based on experimentally obtained results of soils? physical and mechanical characteristics, From the presented results of geotechnical tests, mathematical models and functional relations between water regime and loess soils? resistant characteristics; indicators of internal erosion were defined as well as the mechanism of this process. Effects of the practical application of found results are also analyzed in this paper.

APA, Harvard, Vancouver, ISO, and other styles

3

FOLLMER, LEON R. "Loess." Soil Science 155, no. 5 (May 1993): 361–62. http://dx.doi.org/10.1097/00010694-199305000-00010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Wu, Xiyuan, Xingxiu Yu, Yujiao Gao, and Guirong Wang. "Different Impacts of Rainfall Intensity on Surface Runoff and Sediment Loss between Huang-mian Soil and Brown Soil." Journal of Environmental Science and Management 20, no. 2 (December 31, 2017): 1–8. http://dx.doi.org/10.47125/jesam/2017_2/01.

Full text

Abstract:

Huang-mian soil and brown soil are typical soils in Loess Plateau and Yimeng mountainous area, respectively. The differences of surface runoff and sediment loss between the two soils are important to special environmental protection management in two areas. In order to study the impacts of rainfall intensity on surface runoff and sediment from Huang-mian soil and brown soil, four simulated rainfalls were applied on fields with different soils on a laboratory scale. Huang-mian soil under 60×10-3 m hr-1 had the shortest runoff occurrence time, while brown soil under 30×10-3 m hr-1had the longest time; Huang-mian soil under 30×10-3 m hr-1 had the most sediments; Huang-mian soil has less loss of phosphorus (P) in concentration than brown soil, which explains why Loess Plateau has more soil and water loss but less eutrophication than the Yimeng mountainous area. Under the same rainfall intensity, Huang-mian soil had more runoff volume than brown soil; however, higher rainfall intensity decreased the difference. Increasing rainfall intensity had more impact on sediment content in brown soil than Huang-mian soil. It also had more impact on nitrate nitrogen (NO3--N) content in brown soil than ammonia nitrogen (NH4+-N) loss content in Huang-mian soil. Finally, suggestions were provided to reduce the harm of N and P loss in Huang-mian soil and brown soil regions.

APA, Harvard, Vancouver, ISO, and other styles

5

Lv, Qing Feng, Jing Wen Zhao, Sheng Xin Wang, and Yan Xu Zhao. "Study on Unsaturated Mechanism of Loess Compaction." Advanced Materials Research 368-373 (October 2011): 2960–65. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2960.

Full text

Abstract:

The soil-water characteristic curve is an important constitutive feature of unsaturated soils, defining the relationship between the soil suction and moisture content. Mineral component and pore space topology are the most important physical factors affecting the soil-water characteristic, and that dry density synthetically reflects the mineral component and pore space topology. Compaction is a classical application involving unsaturated soil, and dry density represents the pore structure at special moisture content. Soil water characteristic curve for compacted loess is studied by test, and the effect of dry density on soil water characteristic curve is discussed. Based the soil-water characteristic curve and compaction curve, mechanism of compaction is explained. Research results show that the soil-water characteristic curves for all dry density soil intersect at the point, which is optimize moisture content, and suction is the most important factor affecting the compaction.

APA, Harvard, Vancouver, ISO, and other styles

6

Bogucki, Andriy, and Petro Voloshyn. "Engineering-geological characteristic of the rocks of the loess-soil series from the key section Sharovechka (Podolian upland)." Visnyk of the Lviv University. Series Geography, no. 49 (December 30, 2015): 14–24. http://dx.doi.org/10.30970/vgg.2015.49.8510.

Full text

Abstract:

Description and detailed engineering-geological characteristic of rocks of the loess-soil series of one of the most complete loess section of Podolian Upland were given. Sharovechka key section represents the main loess and palaeosol horizons of Lower, Middle and Upper Pleistocene. There is total thickness of loess-soil series approximately is 25 meters in this section. Horokhiv and Korshiv fossil soil complexes, Lutsk and Sokal fossil soils, and lower horizon of Lower Pleistocene loesses can be key horizons for all territory of Volhyn-Podillia. The monoliths were taken from all stratigraphic horizons of this section with the purpose of investigation of engineering-geological features including subsidence. The analysis of the distribution of composition and features indexes in loess and palaeosol succession demonstrates a significant difference between their certain horizons caused by peculiarities of paleogeographic conditions of their formation and diagenetic transformation. It was also deduced that the degree of contrast of parameters of composition and features of loess and palaeosol horizons in comparison with key loess sections of Volhynian Upland was much lower. Probably this was caused by the higher total content of clay in soils of certain stratigraphic horizons and by the direct overlay of different types of fossil soils at each other. Key words: loess, loess-soil series, key section, fossil soil, engineering-geological features.

APA, Harvard, Vancouver, ISO, and other styles

7

Hanegbi, Nadav, and Itzhak Katra. "A Clay-Based Geopolymer in Loess Soil Stabilization." Applied Sciences 10, no. 7 (April 10, 2020): 2608. http://dx.doi.org/10.3390/app10072608.

Full text

Abstract:

Soil erosion has environmental and socioeconomic significances. Loess soils cover about 10% of the global land area. Most of these soils are subjected to increased land uses such as unpaved roads, which increase soil destruction and dust emission to the atmosphere. There is a significant interest in applications for dust control and soil stabilization. Application of geopolymers may significantly reduce environmental impacts. This study examines the use of a metakaolin-based geopolymer for dust control and soil stabilization in a semi-arid loess soil. The application of the geopolymer for dust control in comparison with common products (brine, bitumen, polyvinyl acetate-PVA) resulted in no dust emission. As a soil stabilizer, the geopolymer tested in this study provides remarkably good results in the tensile test. The most successful composition of the geopolymer, which is activation solution of sodium silicate and sodium hydroxide (NaOH) together with an addition of 30% metakaolin, obtained soil strength of 23,900 N after 28 days. The attempt to replace NaOH with lime (CaO) in the activation solution was far inferior to the original composition. There is a strong potential to develop natural soil stabilizers from a mineral base that even surpass their capabilities over existing synthetic stabilizers.

APA, Harvard, Vancouver, ISO, and other styles

8

Mermut, A. R., S. H. Luk, M. J. M. Römkens, and J. W. A. Poesen. "Soil loss by splash and wash during rainfall from two loess soils." Geoderma 75, no. 3-4 (February 1997): 203–14. http://dx.doi.org/10.1016/s0016-7061(96)00091-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Rejman, Jerzy, and Bogus?aw Usowicz. "Evaluation of soil-loss contribution areas on loess soils in SouthEast Poland." Earth Surface Processes and Landforms 27, no. 13 (2002): 1415–23. http://dx.doi.org/10.1002/esp.438.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Song, Jian, Jiaxin Ma, Fengyan Li, Lina Chai, Wenfu Chen, Shi Dong, and Xiaojun Li. "Study on Fractal Characteristics of Mineral Particles in Undisturbed Loess and Lime-Treated Loess." Materials 14, no. 21 (November 1, 2021): 6549. http://dx.doi.org/10.3390/ma14216549.

Full text

Abstract:

In order to explore the fractal characteristics of particle size distribution (PSD) of various minerals in loess and lime-treated loess, the Q4 undisturbed loess and lime-treated loess were studied. From the perspective of multi-scaled microstructure, the internal characteristics of loess were observed and the regularity statistics were carried out from a macroscopic view. Fractal theory was used to quantitatively study the distribution of mineral particles in undisturbed loess and lime-treated loess. It was found that the skeleton particles of undisturbed loess were obvious and the structure of soil was loose. While that of lime-treated loess decreased, the fine particles were connected with each other, and the structure of soil changed from loose to dense. The three mineral particles in the undisturbed loess and lime-treated loess did not accord with the single fractal distribution characteristics, but the total particles had fractal characteristics. The percentage content of the mineral particles in the soil varied greatly with the particle size. In addition, the non-uniform degrees of mineral particles in the two soils from large to small were carbonate minerals of lime-treated loess, carbonate minerals of undisturbed loess, quartz minerals of lime-treated loess, feldspar mineral of lime-treated loess, feldspar mineral of the undisturbed loess, and the quartz mineral of the undisturbed loess. This paper provided a basis for the future study of the different soil mechanical properties of undisturbed loess and lime-treated loess.

APA, Harvard, Vancouver, ISO, and other styles

11

Wang, Yi, Na Mao, Jiao Wang, Laiming Huang, Xiaoxu Jia, and Ming’an Shao. "Spatial variability of soil carbon and water storage across loess deposit catenas in China’s Loess Plateau region." Canadian Journal of Soil Science 100, no. 3 (September 1, 2020): 263–77. http://dx.doi.org/10.1139/cjss-2019-0144.

Full text

Abstract:

The impact of hillslope vegetation restoration on the distribution and variability of carbon and water storage was studied across two catenary sequences of soils in the Liudaogou watershed of China’s Loess Plateau. Soil organic carbon storage (SOCS) under different land uses in the two catenas decreased significantly in the upper soil layers (<50 cm) but was relatively stable in the deeper soil layers (>50 cm). However, soil inorganic carbon storage (SICS) in the two catenas fluctuated (two maxima) with increasing soil depth. There was no significant difference of SOCS within the 200 cm soil profile between forestlands (FO) and grasslands (GR) at the catenary scale (p > 0.05). However, SICS in the 0–200 cm soil profile differed markedly between FO and GR (p < 0.05) in both catenas due to different degrees of root-facilitated CaCO3 redistribution. Based on the coefficient of variance (CV), soil water storage (SWS) was divided into three layers: active layer (0–100 cm, CV = 20%–30%), subactive layer (100–200 cm, CV = 10%–20%), and stable layer (200–500 cm, CV < 10%). The SWS in the 0–500 cm soil profile was slightly higher in GR than in FO on the two slopes because of the higher water consumption under tree plantation than native grasses. SOCS, SICS, and SWS can be predicted by multiple regression equations using different soil properties. The study demonstrated that SOCS, SICS, and SWS respond differently to vegetation restoration at the catenary scale, which must be taken into account for improving ecosystem model predictions of soil carbon and water fluxes in sloping lands.

APA, Harvard, Vancouver, ISO, and other styles

12

Mctainsh, GH, and NC Duhaylungsod. "Aspects of soil particle size analysis in Australia." Soil Research 27, no. 4 (1989): 629. http://dx.doi.org/10.1071/sr9890629.

Full text

Abstract:

Analysis of the particle-size characteristics of a soil can provide valuable information on the processes and products of soil formation. Studies of loess soils world-wide have used particle size as a major criterion, however, in Australia the particle-size characteristics of parna (a t y e of loess with a high clay content) have not been measured in detail. A modified method of particle-size analysis is proposed which gives more accurate results and which may contribute to a better understanding of soil formation in general, and loess formation in particular, in Australia.

APA, Harvard, Vancouver, ISO, and other styles

13

Liu, Gang, Wennian Xu, and Chongfa Cai. "Chronofunctions of Heilu soil developed from Loess in Luochuan, on the chinese Loess plateau." Revista Brasileira de Ciência do Solo 35, no. 4 (August 2011): 1093–100. http://dx.doi.org/10.1590/s0100-06832011000400003.

Full text

Abstract:

Soil chronofunctions are an alternative for the quantification of soil-forming processes and underlie the modeling of soil genesis. To establish soil chronofunctions of a Heilu soil profile on Loess in Luochuan, selected soil properties and the 14C ages in the Holocene were studied. Linear, logarithmic, and third-order polynomial functions were selected to fit the relationships between soil properties and ages. The results indicated that third-order polynomial function fit best for the relationships between clay (< 0.002 mm), silt (0.002-0.02 mm), sand (0.02-2 mm) and soil ages, and a trend of an Ah horizon ocurrence in the profile. The logarithmic function indicated mainly variations of soil organic carbon and pH with time (soil age). The variation in CaCO3 content, Mn/Zr, Fe/Zr, K/Zr, Mg/Zr, Ca/Zr, P/Zr, and Na/Zr ratios with soil age were best described by three-order polynomial functions, in which the trend line showed migration of CaCO3 and some elements.

APA, Harvard, Vancouver, ISO, and other styles

14

Yang, Xueqin, Mingxiang Xu, Yunge Zhao, Liqian Gao, and Shanshan Wang. "Moss-dominated biological soil crusts improve stability of soil organic carbon on the Loess Plateau, China." Plant, Soil and Environment 65, No. 2 (February 1, 2019): 104–9. http://dx.doi.org/10.17221/473/2018-pse.

Full text

Abstract:

The succession of biological soil crust (biocrust) may alter soil organic carbon (SOC) stability by affecting SOC fractions in arid and semi-arid regions. In the study, the SOC fractions were measured including soil easily oxidizable carbon (SEOC), soil microbial biomass carbon (SMBC), soil water soluble carbon (SWSC), and soil mineralizable carbon (SMC) at the Loess Plateau of China by using four biocrusts. The results show that SOC fractions in the biocrust layer were consistently higher than that in the subsoil layers. The average SOC content of moss crust was approximately 1.3–2.0 fold that of three other biocrusts. Moss crusts contain the lowest ratio of SEOC to SOC compared with other biocrusts. The ratio of SMC to SOC was the highest in light cyanobacteria biocrust and the lowest in moss crust, but no difference was observed in SMBC to SOC and SWSC to SOC in biocrust layers among four studied biocrusts. The results show that the moss crusts increase the accumulation of organic carbon into soil and reduce the ratio of SEOC to SOC and SMC to SOC. Together, these findings indicate that moss crusts increase the SOC stability and have important implications that SOC fractions and mineralization amount are good indicators for assessing the SOC stability.

APA, Harvard, Vancouver, ISO, and other styles

15

Zia, Nayyar, and Patrick J. Fox. "Engineering Properties of Loess-Fly Ash Mixtures for Roadbase Construction." Transportation Research Record: Journal of the Transportation Research Board 1714, no. 1 (January 2000): 49–56. http://dx.doi.org/10.3141/1714-07.

Full text

Abstract:

Southwest Indiana has large deposits of wind-blown loess. Similar deposits are found in other states, including Illinois, Kentucky, Iowa, Minnesota, Missouri, and Nebraska. These soils consist of uniform silt with a plasticity index ranging from 0 to 10. This material is suitable for road construction if it is compacted dry of optimum. However, the material is difficult to work after it becomes wet, which commonly results in construction delays. Indiana also has large stockpiles of Class C fly ash from coal-burning power plants. The ash has cementitious properties after hydration (because of the high calcium content) and can be mixed with native soil to produce a weakly cemented soil. Significant interest exists at the Indiana Department of Transportation about the possibility of using Class C fly ash to improve the engineering properties of Indiana loess soils. The results of a laboratory testing program on the properties of loess–fly ash mixtures are presented. Various percentages of fly ash were mixed with loess soil and specimens were permitted to cure for 3 h to 28 days. Pure loess also was tested for comparison. Changes in Atterberg limits, moisture-density relationships, swell potential, and unconfined compression strength are presented. Based on this testing program, a simple method was developed to determine the optimum fly ash content for construction of a workable loess roadbed to avoid delays in construction due to wet conditions. The data presented will be useful for evaluating the stabilization of loess soils with Class C fly ash in Indiana and other states with significant loess soil deposits.

APA, Harvard, Vancouver, ISO, and other styles

16

Chen, Xi, and Bin Bin Chen. "Intact Loess Structural Loss Parameter in Humidification Process." Advanced Materials Research 655-657 (January 2013): 1868–73. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.1868.

Full text

Abstract:

Based on soil structural view, the mechanism of loess structure is analyzed in humidification process. The concept of the loess structure loss is proposed.And quantitatively parameter described the loess structure loss is set up, that is structure loss parameter. And then the influence laws of humidification and loading on loess structure loss are discussed. The results show that structure loss parameters is increasing with the increase of the humidification water content. The moistening collapsibility has a good linear relationship with loess structure loss parameters.

APA, Harvard, Vancouver, ISO, and other styles

17

Huang, Xiaohui, Lili Wang, and Qian Lu. "Vulnerability Assessment of Soil and Water Loss in Loess Plateau and Its Impact on Farmers’ Soil and Water Conservation Adaptive Behavior." Sustainability 10, no. 12 (December 14, 2018): 4773. http://dx.doi.org/10.3390/su10124773.

Full text

Abstract:

Analyzing vulnerability and adaptation to soil and water loss is an important part of the study on the human–environment relationship in the Loess Plateau. It has also provided a new perspective for studying the farmers’ adoption behavior of soil and water conservation technology in the soil erosion area of the Loess Plateau. Based on the Turner vulnerability framework, this paper constructs a household-scale index system of soil and water loss vulnerability in the Loess Plateau and evaluates the soil and water loss vulnerability in the Loess Plateau using the field survey data of the Loess Plateau applied entropy method. Finally, we use the binary logistic model to estimate the impact mechanism of farmers’ soil erosion vulnerability on farmers’ adoption behavior of soil and water conservation technology. The main conclusions are as follows: (1) In the total sample, susceptibility > exposure > adaptability, whereas in the Shaanxi and Gansu subsample, susceptibility > adaptability > exposure. The Ningxia subsample was similar to the total sample. For each index, Ningxia > Gansu > Shaanxi; (2) The exposure and susceptibility of soil and water loss have a positive impact on farmers’ adoption behavior of soil and water conservation technology, and natural capital has a positive impact on farmers’ adoption behavior of soil and water conservation technology. Physical capital has a positive impact on farmers’ adoption behavior of biological measures. Financial capital has a negative impact on farmers’ adoption behavior of biological measures and farming measures. Social capital has a positive impact on farmers’ adoption behavior of engineering measures and biological measures; (3) Overall, the marginal effect of the adoption behavior of farmers’ soil and water conservation techniques, adaptability > susceptibility > exposure. Therefore, it is necessary to strengthen the monitoring of soil and water loss, encourage the government and farmers to respond in time, and reduce the losses caused by soil erosion. Enriching the capital endowment of farmers, breaking through the endowment restriction of farmers’ adoption of soil and water conservation technology.

APA, Harvard, Vancouver, ISO, and other styles

18

Brzezińska, Małgorzata, Magdalena Nosalewicz, Marek Pasztelan, and Teresa Włodarczyk. "Methane Production and Consumption in Loess Soil at Different Slope Position." Scientific World Journal 2012 (2012): 1–8. http://dx.doi.org/10.1100/2012/620270.

Full text

Abstract:

Methane (CH4) production and consumption and soil respiration in loess soils collected from summit (Top), back slope (Middle), and slope bottom (Bottom) positions were assessed in laboratory incubations. The CH4production potential was determined under conditions which can occur in the field (relatively short-term flooding periods with initially ambient O2concentrations), and the CH4oxidation potential was estimated in wet soils enriched with CH4. None of the soils tested in this study emitted a significant amount of CH4. In fact, the Middle and Bottom soils, especially at the depth of 20–40 cm, were a consistent sink of methane. Soils collected at different slope positions significantly differed in their methanogenic, methanotrophic, and respiration activities. In comparison with the Top position (as reference soil), methane production and both CO2production and O2consumption under flooding were significantly stimulated in the soil from the Middle slope position (P<0.001), while they were reduced in the Bottom soil (not significantly, by 6 to 57%). All upper soils (0–20 cm) completely oxidized the added methane (5 kPa) during 9–11 days of incubation. Soils collected from the 20–40 cm at the Middle and Bottom slope positions, however, consumed significantly more CH4than the Top soil (P<0.001).

APA, Harvard, Vancouver, ISO, and other styles

19

Vasiliev Oleg Alexandrovich, Semenov Vladimir Grigoryevich, Tuleubayev Zhaxybay, Vasiliev Alexander Olegovich, Sarsembayeva Aiman, Yesembekova Zinagul Tursynkaliyevna, and Ziyaeva Gulnar. "LOESS LIKE LOAMS AS A SOIL FORMATION FACTOR FOR LIGHT-GRAY FOREST SOILS IN THE CHEBOKSARY REGION OF THE CHUVASH REPUBLIC." BULLETIN 6, no. 388 (December 15, 2020): 38–45. http://dx.doi.org/10.32014/2020.2518-1467.180.

Full text

Abstract:

Covering loess-like loams are widespread in the Chuvash Republic and serve as parent rocks. They are heterogeneous both in the course and in the depth of occurrence. A distinctive feature of loess like loams from other overlying quaternary deposits is a sharp predominance in the granulometric composition of coarse dust fractions ranging in size from 0.05 to 0.01 mm, the content of which is 40% or more. Their granulometric composition varies from light loamy to clayey. Loess like loams, due to the peculiarities of their granulometric composition, have relatively good water permeability and moisture capacity and are superior to original loamy and clay parent rocks of the Permian and Jurassic systems in terms of these parameters. The content of moving forms of phosphorus and potassium (according to Kirsanov) in loess like loams is from 15 to 75 mg/kg, of exchange potassium - from 20 to 105 mg/kg. The soils formed based on them have a well-defined profile, the genetic horizons of which are easily diagnosed in the soil section. Because soils formed on loess like loams have well-developed genetic horizons, clearly manifested features of soil formation peculiar to each soil type, they occupy a central subtype and are diagnosed as typical. However, soils formed on loess-like loams and clays have low erosion resistance and marked as erosion threatening on soil maps.

APA, Harvard, Vancouver, ISO, and other styles

20

Yang, Dejun, Yajun Zhang, and Xiuqin Chen. "EFFECT OF COAL MINING ON SOIL NITROGEN DISTRIBUTION IN SEMI-ARID MINING AREA OF WESTERN CHINA." Journal of Environmental Engineering and Landscape Management 27, no. 3 (September 3, 2019): 163–73. http://dx.doi.org/10.3846/jeelm.2019.10795.

Full text

Abstract:

Soil nitrogen is a key indicator of soil quality and plays a significant role for plant growth. Therefore, it is very important to study soil nitrogen distribution, especially in semi-arid area of western China. Fewer scholars paid attention to the effect on soil nitrogen due to coal mining in semi-arid mining areas of western China. In this paper, soil samples of different locations were tested in both the loess region and the aeolian sand region in the Daliuta mining area in Shaanxi Province. The impacts of mining subsidence on soil nitrogen were investigated. The soil nitrogen distributions between the loess region and the aeolian sand region were compared, and used the principal component analysis method to evaluate soil quality in semi-arid mining area. The results showed that the comprehensive score of soil quality in the loess region was as follows: the internal pulling stress zone (NLS) > the external pulling stress zone (WLS) > the compressive stress zone (YS) > the neutral zone (ZX). The content of soil total nitrogen in YS-zone was the lowest in the loess region. The loss of nitrogen increased with time in the mining area, in which the total nitrogen loss at the depth of 0−15 cm was 0.27 g/kg, and the alkaline nitrogen loss at the depth of 0−15 cm was 1.08 mg/kg. In the aeolian sand region, the comprehensive score of soil quality was as follows: WLS > FC (the non-mining zone) > ZX > NLS > YS. The amount of soil nitrogen content in the loess region was larger than that in the aeolian sand region. It was found that for the loess region, the relationship between total nitrogen and nitrate nitrogen showed a significant positive correlation. It was also a significant positive correlation between ammonium nitrogen and alkaline nitrogen. In the aeolian sand region, there was a significant positive correlation between total nitrogen and alkaline nitrogen. There was no significant correlation among other nitrogen forms.

APA, Harvard, Vancouver, ISO, and other styles

21

Finke, Peter A., and John L. Hutson. "Modelling soil genesis in calcareous loess." Geoderma 145, no. 3-4 (June 2008): 462–79. http://dx.doi.org/10.1016/j.geoderma.2008.01.017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Gerei, L�szl�, and Magda Rem�nyi. "Utilisation of loess for soil amelioration." GeoJournal 36, no. 2-3 (1995): 281–83. http://dx.doi.org/10.1007/bf00813186.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Sun, Xiaohao, Linchang Miao, Runfa Chen, Hengxing Wang, Linyu Wu, and Jinxin Xia. "Liquefaction Resistance of Biocemented Loess Soil." Journal of Geotechnical and Geoenvironmental Engineering 147, no. 11 (November 2021): 04021117. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0002638.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Shi, Hui, and Mingan Shao. "Soil and water loss from the Loess Plateau in China." Journal of Arid Environments 45, no. 1 (May 2000): 9–20. http://dx.doi.org/10.1006/jare.1999.0618.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Bogucki, A., and P. Voloshyn. "Engineering-geological characteristics of the loess-soil series deposie Novo-myliatyn key profile (Pasmove Pobuzhia)." Visnyk of the Lviv University. Series Geography, no. 36 (May 15, 2009): 51–57. http://dx.doi.org/10.30970/vgg.2009.36.2959.

Full text

Abstract:

The Pasmove Pobuzhia is the only geomorphic region with loess cover on all six loess ridges within the Male Polissia province. This is mainly Upper Pleistocene loess of up to 10 m deepness. The paper deals with the description of the Novo-Myliatyn key profile, as well as with the detailed engineeringgeological study of the separate loess and palaeo-soil horisons. Key words: Pasmove Pobuzhia, loess, fossil soils, engineering-geological properties.

APA, Harvard, Vancouver, ISO, and other styles

26

Wang, Li, Quanjiu Wang, Sanping Wei, Ming’an Shao, and Yi Li. "Soil desiccation for Loess soils on natural and regrown areas." Forest Ecology and Management 255, no. 7 (April 2008): 2467–77. http://dx.doi.org/10.1016/j.foreco.2008.01.006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Guo, Qinghua, Fuchu Dai, and Zhiqiang Zhao. "Analysis of the Hydraulic Properties of Undisturbed Layered Loess in Northwest China." Water 11, no. 7 (July 4, 2019): 1379. http://dx.doi.org/10.3390/w11071379.

Full text

Abstract:

Extensive agricultural irrigation in the loess region of Northwest China has seriously damaged the local hydrogeological environment. To properly understand the hydrological processes and the hydraulic properties of the layered soil, the field soil column irrigation test, laboratory soil column infiltration test, and undisturbed soil sample hydraulic experiments were carried out. The results showed that the proposed infiltration model can continuously simulate the infiltration process of the loess–palaeosol sequence well. The layered structure may form a temporary groundwater table at the interface of the two different soils under irrigation conditions. This provides a scientific basis for proposing reasonable irrigation measures.

APA, Harvard, Vancouver, ISO, and other styles

28

Liu, Feifei, Xuesong Mao, Cheng Xu, Yingying Li, Qian Wu, and Jianxun Zhang. "“Covering Effects” under Diurnal Temperature Variations in Arid and Semiarid Areas." Advances in Civil Engineering 2020 (February 21, 2020): 1–12. http://dx.doi.org/10.1155/2020/7496182.

Full text

Abstract:

“Covering effects” dominated by water vapor migration in arid and semiarid areas threaten the stability of engineering entities. To explore the “covering effects” dominated by water vapor migration under the influence of diurnal temperature variations, a series of one-side evaporation experiments were conducted. Characteristics of water vapor migration between the unsaturated loess soil column with and without a lid were compared in detail to illustrate the “covering effects” on water vapor migration, as were the effects of test time. Further, the characteristics of “covering effects” in loess and sand soil columns were compared. The results show that the “covering effects” formed in the loess soil column with a lid by cycling day and night temperature differences led water vapor to accumulate and condense beneath the lid. However, unlike the “covering effects” during freezing conditions that lead to a significant increase in the moisture content in the top layer, in this study, the moisture content in the top layer (0–8 cm) decreased. Although “soil lid” and the “soil covering effects” exist in both loess soil columns with and without lids, the “soil covering effects” for the former are much more obvious, and the moisture content in the upper part of the loess soil column (8–45 cm) shows a significant increase. By cycling day and night temperature differences, the “covering effects” or “soil covering effects” grew as the test time increased. Compared to the loess soil column, the “covering effects” in the sand soil column were extremely weak, and the moisture migration in the sand soil column was dominated by the downward movement liquid water. This paper illustrates the “covering effects” under the influence of diurnal temperature variations and reveals the mechanism of water vapor migration in subgrade soils in arid and semiarid areas.

APA, Harvard, Vancouver, ISO, and other styles

29

Bibus, Erhard, Manfred Frechen, Michael Kösel, and Wolfgang Rähle. "Das jungpleistozäne Lössprofil von Nussloch (SW-Wand) im Aufschluss der Heidelberger Zement AG." E&G Quaternary Science Journal 56, no. 4 (December 1, 2007): 227–55. http://dx.doi.org/10.3285/eg.56.4.01.

Full text

Abstract:

Abstract. At the Nussloch section located south of Heidelberg, a more recently exposed new loess wall was pedologically investigated. The profiles were investigated multidisciplinarily including grain-size spectra, organic and carbonate content, magnetic susceptibility, as well as biomorphology and malacology and infrared optically stimulated luminescence (IRSL). The lower part of the Late Pleistocene includes the subdivided Eemian paleosol and the Wuermian loess about 18 m thick. A Bt horizon, a humic-rich horizon (“Humuszone”) and several tundra gleysols (“Nassböden”) of different intensity, with and without Bw horizons could be detected. Five brown soils (WB2 – WB6) are intercalated in the loess. The brown soils WB2, WB4 and WB5 correlate to interstadial periods, as evidenced by the mollusc spectra. Furthermore, WB1 correlates to one of the three Early Wuermian interstadials (“Mosbacher Humuszone”). Soil WB1 with an age estimate of about 75 ka BP represents the reduced Early Wuermian sequence. The most intensive brown soil (WB4) has the typical soil criteria of an arctic brown soil, which most likely correlates to the about 30 ka old Lohne Soil (“Lohner Boden”). The Late Wuermian loess covering the Lohne Soil is about 12 m thick and intercalated by at least ten tundra gleysols. The equivalent of the E2-Nassboden forms a tundra gley complex including also the weak brown soils WB5 and WB6. The youngest Upper Wuermian loess about 4.50 m thick covers the Eltville tephra and is designated to correlate to the E4/E5 complex. The paleopedological results are in excellent agreement with the results and interpretation by means of malacology and magnetic susceptibility enabling detailed stratigraphic and paleoclimatic reconstruction.

APA, Harvard, Vancouver, ISO, and other styles

30

Bogucki, Andriy, and Petro Voloshyn. "Engineering-geological characteristic of the rocks of the loess-soil series from the key section at Korshiv (Volhynian Upland)." Visnyk of the Lviv University. Series Geography, no. 42 (October 15, 2013): 11–21. http://dx.doi.org/10.30970/vgg.2013.42.1757.

Full text

Abstract:

Korshiv key section is one of the best studied and most complete sections of periglacial loess-soil series of Volhyn-Podillia. There is total thickness of loess-soil series approximately is 30 meters in this section. This key section is stratotype of Korshiv fossil soil complex and Lutsk fossil soil. Pseudomorphs after the structures of cellular ice of several stages of Middle Pleistocene palaeocryogenesis were allocated here for the first time for Volhyn-Podillia. Detailed description of the section and the results of engineering-geological studies of rocks of all selected loess and palaeosoil horizons were done. Individual properties of selected stratigraphic horizons and their dependence on the paleogeographic conditions of sedimentation were displayed. Key words: loesses, fossil soils, palaeogeographical conditions, engineering-geological features, subsidence, Volhynian Upland.

APA, Harvard, Vancouver, ISO, and other styles

31

Yang, Min, Youning Xu, Jianghua Zhang, Huaqing Chen, San Liu, Weiliang Li, and Ying Hao. "Near-Infrared Spectroscopic Study of Heavy-Metal-Contaminated Loess Soils in Tongguan Gold Area, Central China." Minerals 10, no. 2 (January 21, 2020): 89. http://dx.doi.org/10.3390/min10020089.

Full text

Abstract:

Loess soil is a kind of widespread soil type in northwest China. Human engineering activities such as mining have caused numerous problems related to heavy metal pollution in soils, which threaten people’s health. The band formation mechanism of the near-infrared (NIR) spectral features in loess soils forms the theoretical basis for the study of the soil environment by hyperspectral remote sensing. Some NIR features of loess soils will shift because of the variations of the soil composition and microstructure after they adsorb heavy metal cations. In this study, we focused on the heavy metal adsorption of the illite, smectite, and illite–smectite (I/S) mixed layer in loess soils; evaluated the pollution by Nemerow indexing; applied X-ray diffraction (XRD), mid-infrared (MIR) spectral analysis, and inductively coupled plasma mass spectrometry (ICP-MS); and carefully observed the shift behavior of the MIR and NIR features. Then, the NIR bands were assigned to MIR bands according to the vibration behavior. Furthermore, the relationships between the NIR band positions and the six heavy metal cations as well as the Nemerow index were investigated via multiregression and simple linear correlation methods. Finally, the relationship obtained from the experiments was analyzed using the physical and chemical mechanisms of the heavy metal cations in the clay minerals. These findings may benefit the application of NIR and remote sensing techniques for detecting heavy-metal-polluted soils.

APA, Harvard, Vancouver, ISO, and other styles

32

Lipiec, Jerzy, Ewa A. Czyż, Anthony R. Dexter, and Anna Siczek. "Effects of soil deformation on clay dispersion in loess soil." Soil and Tillage Research 184 (December 2018): 203–6. http://dx.doi.org/10.1016/j.still.2018.08.005.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Rubinstein, Aviv, Meni Ben-Hur, and Itzhak Katra. "Dust Emission Thresholds in Loess Soil Under Different Saltation Fluxes." Applied Sciences 10, no. 17 (August 27, 2020): 5949. http://dx.doi.org/10.3390/app10175949.

Full text

Abstract:

Soil-derived dust particles produced by aeolian (wind) processes have significant impacts on humans and the Earth’s systems. The soil particle size distribution is a major soil characteristic in dust emission models. Yet empirical information on the dependence of dust emission thresholds on soil particle size distribution is still lacking. The main goal of this study was to explore the dust emission threshold from semi-arid loess soil samples by a targeted wind-tunnel experiment. The results clearly show that the dust emission threshold is associated with the saltation threshold with no distinct direct aerodynamic lifting of the loose dust particle. The dust flux depends on the amount of the clay-silt fraction in the soil, the shear velocity, and the saltation flux under certain shear velocity. The study aimed to advance our understating of the dust emission processes, and to provide empirical information for parametrization in dust emission models and for management strategy of soils in preventing dust emission.

APA, Harvard, Vancouver, ISO, and other styles

34

Li, Heng, Zhao Duan, Chenxi Dong, Fasuo Zhao, and Qiyao Wang. "Impact-Induced Liquefaction Mechanism of Sandy Silt at Different Saturations." Advances in Civil Engineering 2021 (March 29, 2021): 1–14. http://dx.doi.org/10.1155/2021/6686339.

Full text

Abstract:

Landslide-induced liquefaction has received extensive attention from scholars in recent years. In the study of loess landslides in the southern Loess Plateau of Jingyang, some scholars have noted the liquefaction of the near-saturated sandy silt layer that is caused by the impact of loess landslides on the erodible terrace. The impact-induced liquefaction triggered by landslides is probably the reason for the long-runout landslides on the near-horizontal terrace. In order to reveal the mechanism of impact-induced liquefaction, this paper investigates the development of pore pressure and the impact-induced liquefaction of sandy silt under the influence of saturation through laboratory experiments, moisture content tests, and vane shear tests. It has been found that both the total pressure and pore water pressure undergo a transient increase and decrease at the moment of impact on the soil, which takes 40–60 ms to complete and only about 20 ms to arrive at the peak. Moreover, silty sand with a saturation of more than 80° was liquefied under the impact, and the liquefaction occurred in the shallow layer of the soil body. The shear strength of the liquefied part of the soil is reduced to 1.7∼2.8 kPa. Soils with lower saturation did not liquefy. The mechanism of the impact-induced liquefaction can be described as follows: under impact, the water in the soil gradually fills the pores of the soil body as the pore size decreases, and when the contact between the soil particles is completely replaced by pore water, the soil body loses its shear strength and reaches a liquefied state. Soils in the liquefied state have a very high permeability coefficient, and the water inside the soil body migrates upward as the particles settle, resulting in high-moisture content in the upper soil.

APA, Harvard, Vancouver, ISO, and other styles

35

Guo, Xingjian, and Quanqin Shao. "Spatial Pattern of Soil Erosion Drivers and the Contribution Rate of Human Activities on the Loess Plateau from 2000 to 2015: A Boundary Line from Northeast to Southwest." Remote Sensing 11, no. 20 (October 19, 2019): 2429. http://dx.doi.org/10.3390/rs11202429.

Full text

Abstract:

The Loess Plateau is one of the most fragile areas in the world, where the problem of soil erosion is particularly prominent. The spatial and temporal variation characteristics and mechanisms of soil erosion in this region have always been hot topics for researchers. In this study, Revised Universal Soil Loss Equation (RUSLE) is used to estimate the soil erosion modulus of the Loess Plateau from 2000 to 2015, the dynamic characteristics of its temporal and spatial variations and driving mechanisms are determined, and meteorological data are combined with remote sensing data to quantitatively calculate the contribution rate of human activities. The results show that from 2000 to 2015, the soil erosion modulus of the Loess Plateau had a downward trend as a whole, with a rate of −0.6408 t/ha/a, but the downward trend gradually slowed down. Precipitation mainly resulted in changes in the soil erosion modulus in the northwestern part of the Loess Plateau, where a significant positive correlation was seen. Meanwhile, the Vegetation Fractional Coverage (VFC) mainly affected the southeastern part, where a significant negative correlation was measured. The human-activity contribution rate was −1.0774 on the Loess Plateau, which means human activities effectively reduced the soil erosion modulus while climate change promoted soil erosion combined with the result of the analysis of variance (ANOVA). “Hilly and gully regions” and “Gully region of Loess Plateau” as the main implementation areas of ecological projects, human activities had contribution rate of 0.5513 and 0.7805 toward the declining of soil erosion, respectively. Interestingly, the spatial differentiation characteristic of the soil erosion driving mechanisms and human contribution rates on the Loess Plateau showed the same boundary line from northeast to southwest, which was well explained by the 400-mm isohyetal line and Hu’s Line. This boundary can guide the geographical layout of the ecological management projects and urban development spaces on the Loess Plateau.

APA, Harvard, Vancouver, ISO, and other styles

36

Ai, Hui. "Research on the Management Pattern of Small Watershed Treatment in Loess Plateau Region." Advanced Materials Research 664 (February 2013): 117–22. http://dx.doi.org/10.4028/www.scientific.net/amr.664.117.

Full text

Abstract:

Loess Plateau region has the severest problem of The Water Loss and Soil Erosion, not only in China, but around the world as well. Due to severe situation of soil erosion, the natural environment was badly damaged in this region and the economy was also deeply influenced. This paper analyses the present situation of soil erosion and controlling measure for erosion in Loess Plateau region, and concludes some valuable experience in managing small watershed of Loess Plateau region. Concluding、analyzing、advancing and extending these successful experiences will exert an important and directive significance for the ecological construction and sustainable development in China.

APA, Harvard, Vancouver, ISO, and other styles

37

Bogucki, A., and P. Voloshyn. "Engineering-geological description of the loess-soil series rocks at Zdolbuniv key profile (Volyn’ upland)." Visnyk of the Lviv University. Series Geography, no. 38 (December 15, 2010): 21–27. http://dx.doi.org/10.30970/vgg.2010.38.2210.

Full text

Abstract:

A detailed description and engineering-geological characterization are made for the loess-soil series rocks of Zdolbuniv key profile, which represents the main loess, palaeo-soil, and palaeo-cryogenic horizons of the Middle and Upper Pleistocene within the Volyn’ Upland – a classical region of the European loess development. The analysis of the differentiation in the composition and properties of the loess, palaeo-soil, and palaeo-cryogenic horizons imply on their significant difference caused by palaeogeographical conditions of their development and of the dia-genetic metamorphism. Key words: loess, loess-soil series, key profile, fossil soil, palaeo-cryogenesis, engineering-geological properties.

APA, Harvard, Vancouver, ISO, and other styles

38

Bogucki, A., R. Dmytruk, M. Lanchont, and A. Jacyshyn. "Torhanovychi – a new pleistocene key profile in the Fore-Carpathians." Visnyk of the Lviv University. Series Geography, no. 38 (December 15, 2010): 28–36. http://dx.doi.org/10.30970/vgg.2010.38.2211.

Full text

Abstract:

A detailed description and engineering-geological characterization are made for the loess-soil series rocks of Zdolbuniv key profile, which represents the main loess, palaeo-soil, and palaeo-cryogenic horizons of the Middle and Upper Pleistocene within the Volyn’ Upland – a classical region of the European loess development. The analysis of the differentiation in the composition and properties of the loess, palaeo-soil, and palaeo-cryogenic horizons imply on their significant difference caused by palaeogeographical conditions of their development and of the dia-genetic metamorphism. Key words: loess, loess-soil series, key profile, fossil soil, palaeo-cryogenesis, engineering-geological properties.

APA, Harvard, Vancouver, ISO, and other styles

39

Rousseau, Denis-Didier, Natalia Gerasimenko, Zhanna Matviischina, and George Kukla. "Late Pleistocene Environments of the Central Ukraine." Quaternary Research 56, no. 3 (November 2001): 349–56. http://dx.doi.org/10.1006/qres.2001.2270.

Full text

Abstract:

AbstractThe Vyazivok loess sequence from the Dnieper Plain, Ukraine, documents regional environmental changes during the late Pleistocene and Holocene. Pedological and palynological analyses and low-field magnetic susceptibility document changes from dense temperate forest during the last interglacial maximum to open, harsh, loess–steppe during the latest Pleistocene. The Vyazivok section overlies hillwash derived from a lower Pleistocene terrace and consists of two stratified soil complexes (Kaydaky and Pryluky; marine isotope stage [MIS] 5 equivalent) separated by a layer of eolian dust (Tyasmyn silt). The lower soils in both complexes formed within forest. These soils are overlain by the Uday (MIS4) and Bug (MIS2) loess units, which are separated by boreal soils of the Vytachiv (MIS3) complex. The coldest conditions within the record occurred in the youngest loess. Holocene soils cap the Bug loess. The Vyazivok section shows remarkable similarities with other classical loess sequences in western Europe, the Czech Republic, and Austria. The Kaydaky, Pryluky, and Vytachiv deposits, correlate with the PKIII, PKII, and PKI soil complexes, respectively, of the Czech Republic. The Tyasmyn and Prylyky silt layers correspond to marker horizons from central Europe.

APA, Harvard, Vancouver, ISO, and other styles

40

Johnson, William C., Karen L. Willey, Joseph A. Mason, and David W. May. "Stratigraphy and environmental reconstruction at the middle Wisconsinan Gilman Canyon formation type locality, Buzzard's Roost, southwestern Nebraska, USA." Quaternary Research 67, no. 3 (May 2007): 474–86. http://dx.doi.org/10.1016/j.yqres.2007.01.011.

Full text

Abstract:

AbstractThe middle Wisconsinan Gilman Canyon Formation at the Buzzard's Roost type locality in southwestern Nebraska was investigated to document the stratigraphy and to reconstruct the environmental and climate record. The Gilman Canyon Formation was subdivided into three loess units and three soils, with radiocarbon ages constraining it between about 40 ka and 25 ka. Stable carbon isotope ratios, magnetic susceptibility, and carbon content were used to define and characterize soils within both the Gilman Canyon Formation and underlying Illinoian Loveland Loess. At the height of soil development within the Gilman Canyon Formation, climate was supporting C4-dominated grassland, with July temperatures equal to or exceeding those of today. Soil-forming intervals within the Loveland Loess, including the Sangamon Soil, also exhibited relative increases in C4 biomass. Climate, as recorded in the Gilman Canyon Formation, is corroborated by regional proxy data. The formation accumulated during MIS 3, and concurrent soil formation coincided with a summer insolation maximum.

APA, Harvard, Vancouver, ISO, and other styles

41

Zhi, Bin, Liang Yang, and En Long Liu. "Study on the Mechanical Properties of Lime-Cement-Treated Loess Soils." Applied Mechanics and Materials 638-640 (September 2014): 1408–13. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.1408.

Full text

Abstract:

The cement-lime treated loess soils and cement-treated loess soils are widely used all over the world, but their strength features and physical mechanism are investigated few at the moment. The cement-lime treated loess soil samples and cement-treated loess soil samples were prepared according to their weight ratio and tested to study their physical indices and strength varying with age. The tested results demonstrate that: (i) The content of cement has great influence on the liquid limit and plastic limit of the samples. With the increase of adding content of lime, the average plasticity indices also increase gradually, and the values of plastic limits of the samples will also increase; (ii) The stregnth of the samples increases with the increase of curing age, which is affected by many factors including treated materials, compatcion work, water content, and age.

APA, Harvard, Vancouver, ISO, and other styles

42

FEHRENBACHER, J. B., K. R. OLSON, and I. J. JANSEN. "LOESS THICKNESS IN ILLINOIS1." Soil Science 141, no. 6 (June 1986): 423–31. http://dx.doi.org/10.1097/00010694-198606000-00004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Gao, Haidong, Zhanbin Li, Lianlian Jia, Peng Li, Guoce Xu, Zongping Ren, Guowei Pang, and Binhua Zhao. "Capacity of soil loss control in the Loess Plateau based on soil erosion control degree." Journal of Geographical Sciences 26, no. 4 (February 4, 2016): 457–72. http://dx.doi.org/10.1007/s11442-016-1279-y.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Zhang, Yao, Shaoqiang Guo, Ning Li, Zaiqiang Hu, Zhixiang Zhao, Yu Xi, and Shuai Shao. "Field study on soil collapsibility sensitivity." E3S Web of Conferences 276 (2021): 01032. http://dx.doi.org/10.1051/e3sconf/202127601032.

Full text

Abstract:

The sensitivity of loess collapsibility is generally considered as the difficulty, speed and size of loess collapsibility after water immersion. It is different from collapsibility of loess, but they are related to each other. In this paper, the time to complete 90% collapsibility and the coefficient of collapsibility are used to evaluate the collapsibility sensitivity of loess and its site. The method is verified by taking the site with excessive collapsibility as an example. The results show that the method can accurately reflect the collapsibility sensitivity of collapsible site, and has certain guiding significance for engineering construction on collapsible site. In addition, the method is simple, scientific, and can be combined with the current specifications, so it is easy to be accepted and promoted by the industry, and is a useful supplement to the existing few researches on loess collapsibility sensitivity.

APA, Harvard, Vancouver, ISO, and other styles

45

Xue, Chen, Xingang Wang, and Kai Liu. "Effect of Soaking Time and Salt Concentration on Mechanical Characteristics of Slip Zone Soil of Loess Landslides." Water 12, no. 12 (December 9, 2020): 3465. http://dx.doi.org/10.3390/w12123465.

Full text

Abstract:

Loess landslides are closely related to the variation in mechanical properties of soils due to the leaching of irrigation water in the irrigation area which causes the loss of soluble salt in the loess stratum. To investigate the effect of leaching on the mechanical characteristics of loess, ring shear tests were conducted on the slip zone soil samples obtained from a typical loess landslide under different soaking time and salt concentration. Furthermore, the microstructural observations were made on shear planes by using SEM (scanning electron microscopy) tests. The experiment revealed that: firstly, the shear strength of loess decreases with the increase of soaking time before reaching the minimum value at the soaking time of 1 d, and then increases with the soaking time until reaching a relatively stable value. Secondly, the shear strength of loess has an increasing tendency with the salt concentration before reaching a maximum value at the salt concentration of 8%, and then shear strength decreases. In addition, a “stress-softening” was found for the loess samples with the soaking time of 1 d and salt concentration of 8%. It is found that the total number of micropores and small-pores in loess samples decreases with increasing salt concentration up to 8%, but increases rapidly between salt contents of 8% and 20%. The SEM tests showed that the increase in salt concentration (0% to 8%) facilities the formation of small aggregates within loess soils, which in turn promotes the increasing of shear strength. However, further increase in salt concentration (8% to 20%) helps the development of relatively large aggregates in loess samples, resulting in the reduction in shear strength.

APA, Harvard, Vancouver, ISO, and other styles

46

Chen, Liding, Wei Wei, Bojie Fu, and Yihe Lü. "Soil and water conservation on the Loess Plateau in China: review and perspective." Progress in Physical Geography: Earth and Environment 31, no. 4 (August 2007): 389–403. http://dx.doi.org/10.1177/0309133307081290.

Full text

Abstract:

The Loess Plateau, China, has long been suffering from serious soil erosion. About 2000 years ago, larger areas were used for grain production and soil erosion was thus becoming severe with increase in human activity. Severe soil and water loss led to widespread land degradation. During the past decades, great efforts were made in vegetation restoration to reduce soil erosion. However, the efficiency of vegetation restoration was not as satisfactory as expected due to water shortage. China initiated another state-funded scheme, the `Grain-for-Green' project in 1999, on the Loess Plateau to reduce soil erosion and improve land quality. However, the control of soil erosion effectively by land-use modification raised problems. In this paper, the lessons and experiences regarding soil and water conservation in the Loess Plateau in the past decades are analysed first. Urgent problems are then elaborated, such as the contradiction between land resource and human population, shortage of water both in amount and tempospatial distribution for vegetation growth, weak awareness of the problems of soil conservation by local officials, and poor public participation in soil and water conservation. Finally, suggestions regarding soil and water conservation in the Loess Plateau are given. In order to control soil erosion and improve vegetation, a scientific and detailed land-use plan for the Loess Plateau has to be made, in the first instance, and then planning for wise use of water resources should be undertaken to control mass movement effectively and to improve land productivity. Methods of improving public awareness of environmental conservation and public involvement in vegetation rehabilitation are also important.

APA, Harvard, Vancouver, ISO, and other styles

47

Dong, Yuequn, Tingwu Lei, Shuqin Li, Cuiping Yuan, Shumei Zhou, and Xiusheng Yang. "Effects of rye grass coverage on soil loss from loess slopes." International Soil and Water Conservation Research 3, no. 3 (September 2015): 170–82. http://dx.doi.org/10.1016/j.iswcr.2015.05.006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Tomeniuk, O. "Exploration of loesses in Volyn-Podillia region as a cornerstone of Yuriy Polians’kyi’s scientific quests." Visnyk of the Lviv University. Series Geography, no. 39 (December 15, 2011): 342–63. http://dx.doi.org/10.30970/vgg.2011.39.2196.

Full text

Abstract:

On the basis of the detailed analysis of scientific works, written by Yuriy Polians’kyi, the main scientific achievements of the scholar are characterized. These works are concerning researches of loesssoil stratum on the Middle Dniester region. In particular, progressive technique of researches of Quaternary deposits and using of the newest terminology are considered. Yuriy Polianskyi’s major scientific ideas are analyzed: loess and terraces, loess and glaciations, loess and Paleolithic, stratigraphic significance of fossil soils in loess-soil stratum etc. The influence of scientific achievements of Yuriy Polians’kyi at the field of loess problematic on the development of modern palaeogeographic researches of loess of Ukraine is analyzed. Key words: loess, terraces, fossil soils, glaciations, Pleistocene, Paleolithic, Dniester, Volyn-Podillia region.

APA, Harvard, Vancouver, ISO, and other styles

49

Bogucki, Andriy, Andriy Yatsyshyn, Roman Dmytruk, and Olena Tomeniuk. "Solonske section and the perspectives of the cognition of Loyeva level." Visnyk of the Lviv University. Series Geography, no. 50 (December 28, 2016): 54–66. http://dx.doi.org/10.30970/vgg.2016.50.8677.

Full text

Abstract:

New geological and geomorphological investigations carried out in different parts of the Fore-Carpathian region of the Dnister River basin gave an opportunity to distinguish at least four separate different-age levels (terraces) within the Loyeva level (sixth terrace): Torhanovychi, Dubrivka, Susidovychi and Biskovychi. In the Solonske section the alluvial and cover loess-soil sediments from the Lower to Upper Pleistocene of the total thickness of about 30 m are revealed. Loess-soil series of the investigated section represents a number of loess and palaeosol horizons from modern soil (MIS 1), which is developed on the Horokhiv fossil soil complex (MIS 5), to the soil with spot-medallions (MIS 17–19). The last one was formed above the permafrost and obviously can be correlated with one of the soils of fossil soil complex of Zahvizdia type. A very thick (almost 10-meter) stratum of deposits that, apparently, have a limnic origin is underlying this soil. Alluvial deposits, which are directly under the limnic stratum, are composed of the channel and flood-plain facies and represent one of the identified separate levels of the Loyeva level (the sixth over-floodplain terrace of the Dnister River). In Solonske section two levels of the development of palaeocryogenic structures like spot-medallions are revealed (above the Lutsk fossil soil (MIS 9) and over one of the soils of fossil soil complex of Zahvizdia type). Undoubtedly, under the conditions of the proper further investigations of the section, Solonske can become a key point for Pleistocene not only for Fore-Carpathians. It will be important in determining the time of the formation of different-age levels of the Loyeva level. Key words: loess-soil series, alluvium, terrace, palaeocryogenesis, spot-medallions, Pleistocene, Loyeva level, Dnister, Fore-Carpathians.

APA, Harvard, Vancouver, ISO, and other styles

50

Rukh, Shah, Saleem Akhtar, Ayaz Mehmood, Sayed Hassan, Khalid Khan, Syed Naqvi, and Muhammad Imran. "Arsenate and arsenite adsorption in relation with chemical properties of alluvial and loess soils." Journal of the Serbian Chemical Society 82, no. 7-8 (2017): 943–54. http://dx.doi.org/10.2298/jsc170209042r.

Full text

Abstract:

Arsenic is one of the most toxic elements in the soil environment. Understanding of the arsenic adsorption chemistry is essential for evolving the extent of soil and groundwater contaminations. This research was conducted to determine the variation in adsorption behaviour of arsenite and arsenate with depth in different lithology soils. We sampled two parent materials at genetic horizons, and within a parent material, we selected two soils. Besides basic soil characterizations, a laboratory batch experiments were carried out to study the adsorption of arsenate and arsenite. Freundlich adsorption approaches were employed to investigate the adsorption of arsenate and arsenite in the soils. Freundlich isotherms fit arsenate and arsenite sorption data well with r2 values of 0.88?0.98 in most soils. Arsenate and arsenite adsorption varied with the soil properties, especially in clay composition and in the oxides of iron and aluminum. Arsenic adsorption parameters also varied with depth in parent materials, and loess derived soils had greater adsorption capacity as compared to alluvial soils in most of the adsorption parameters. This research concludes that the loess soils had higher arsenic adsorption capacity than the alluvial soils.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Loess soil'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles