• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.43-53
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• 1987

In order to improve effectiveness of rhizobia- legume symbiotic nitrogen fixation, ecological and physiological characteristics of indigenous rhizobia distributed in Korea, that is, symbiotic effectiveness of indigenous soybean rhizobia, nitrate reductase activities of the soybean bacteroid from five different soils, and differences of host-infection abilities among the soybean cultivars under population densities of the same indigenous soybean rhizobia, were investigated. The results were summarized as follows: 1. The number of indigenous soybean rhizobia was ranged from $9.2{\times}10^2$ cells per gram of soil in calcareous soil II to $42.4{\times}10^3$ cells per gram of soil in calcareous soil I in Danyang. 2. The symbiotic effectiveness of indigenous soybean rhizobia from five different soils was high in the case of soybean continuously cultivated, and calcareous soil I that population densities of indigenous soybean rhizobia were observed highly. 3. Inverse relationship was observed between total nitrogenase activity (TNA) and nitrate reductase activity (NRA) from the soybean bacteroids ($r=-0.502^*$), but the correlation between nitrate reductase and specific nitrogenase activities (SNA) could be devided into two groups. It was classified into group I which is high in SNA and low in NRA, and group II which is low in SNA and high in NRA. 4. The infection ability of the indigenous soybean rhizobia in the same soil conditions showed the reciprocal difference among each soybean cultivars. In Kwangkyo and Jangyeup, the symbiotic effectiveness appeared by infection of indigenous soybean rhizobia was higher than it of the other soybean cultivars.

• Geomechanics and Engineering
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• v.19 no.5
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• pp.393-405
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• 2019

This paper evaluates the geotechnical and geo-engineering properties of the South Pars Zone (SPZ) marls in Assalouyeh, Iran. These marly beds mostly belong to the Aghajari and Mishan formations which entail the gray, cream, black, green, dark red and pink types. Marls can be observed as rock (soft rock) or soil. Marlstone outcrops show a relatively rapid change to soils in the presence of weathering. To geotechnically characterise the marls, field and laboratory experiments such as particle-size distribution, hydrometer, Atterberg limits, uniaxial compression, laboratory direct-shear, durability and carbonate content tests have been performed on soil and rock samples to investigate the physico-mechanical properties and behaviour of the SPZ marls in order to establish empirical relations between the geo-engineering features of the marls. Based on the experiments conducted on marly soils, the USCS classes of the marls is CL to CH which has a LL ranging from 32 to 57% and PL ranging from 18 to 27%. Mineralogical analyses of the samples revealed that the major clay minerals of the marls belong to the smectite or illite groups with low to moderate swelling activities. The geomechanical investigations revealed that the SPZ marls are classified as argillaceous lime, calcareous marl and marlstone (based on the carbonate content) which show variations in the geomechanical properties (i.e., with a cohesion ranging from 97 to 320 kPa and a friction angle ranging from 16 to 35 degrees). The results of the durability tests revealed that the degradation potential showed a wide variation from none to fully disintegrated. According to the results of the experiments, the studied marls have been classified as calcareous marl, marlstone and argillaceous lime due to the variations in the carbonate and clay contents. The results have shown that an increase in the carbonate content leads to a decrease in the degradation potential and an increase in the density and strength parameters such as durability and compressive strength. A comparison of the empirical relationships obtained from the regression analyses with similar studies revealed that the results obtained herein are reasonably reliable.

• Korean Journal of Environmental Agriculture
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• v.25 no.2
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• pp.157-163
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• 2006

Investigation of Cd and Zn availability in four different soils as affected by the interactions of these two heavy metals was conducted using the metal desorption quantity-intensity (Q/I) isotherms. The soils were artificially contaminated with proper concentrations of Cd and Zn as $CdSO_4\;and\;ZnSO_4$ solutions. DTPA (diethylene triamine pentaacetic acid) - extractable and water-extiactable Cd or Zn from the soils were used as $Q_{Cd}\;or\;Q_{Zn}\;and\;I_{Cd}\;or\;I_{Zn}$ factors, respectively. The coefficient of determination for Cd and Zn desorption Q/I linear regression in the soils ranged from 0.947 to 0.999, which indicated that Q and I factors were closely correlated. The buffering capacity of Cd, $BC_{Cd}$, in the soils decreased with increasing Zn treatments, and the $BC_{Cd}$ values were ranged between 205.8 and 2255.6. The decreases of $BC_{Cd}$ values were mainly dependent upon the increases of $I_{Cd}$ factors. However, Zn buffering capacity. $BC_{Zn}$ decreased with increasing Cd treatments in acidic soils, and increased in neutral and calcareous alkaline soils. The $BC_{Cd}$ values were ranged from 143.2 to 6158.0. The values of $BC_{Zn}$ as influenced by the treatments of Cd were also controlled by the solubility of water-extractable Zn, $I_{Zn}$ factor. The solubility of water-extractable Cd and Zn was significantly dependent upon the changes of soil pH that were impacted by the treatment of Zn and Cd, respectively. Also, the availability of Cd was higher than Zn availability in the acidic and neutral soils, but Zn was higher than Cd in the calcareous alkaline soil.

• Geomechanics and Engineering
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• v.28 no.5
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• pp.531-546
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• 2022

Ground displacements caused by the construction of overlapping twin shield tunnels with small turning radius are complex, especially under special geological conditions of construction. To investigate the ground displacements caused due to shield machines in the unique calcareous sand layers in Israel for the first time and determine the main factors affecting the ground displacements, field monitoring, laboratory geological analysis, theoretical calculations, and parameter studies were adopted. By using rod extensometers, inclinometers, total stations, and automatic segment-displacement monitors, subsurface tunneling-induced displacement, surface settlement, and displacement of the down-track tunnel segments caused by the construction of an up-track tunnel were analyzed. The up-track tunnel and the down-track tunnel pass through different stratum, resulting in different construction parameters and ground displacements. The laws of variation of thrust and torque, soil pressure in the chamber, excavated soil quantity, synchronous grouting pressure, and grout volume of the two tunnels from parallel to fully overlapping orientations were compared. The thrust and torque of the shield in the fine sand are larger than those in the Kurkar layer, and the grouting amount in fine sand is unstable. According to fuzzy statistics and Gaussian curve fitting of the shield tunneling speed, the tunneling speed in the Kurkar stratum is twice that in the fine-sand stratum.

• The Korean Journal of Ecology
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• v.14 no.2
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• pp.159-169
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• 1991

Floristic cmposition and soil properties were analyzed in chines cork oak(quercus variabilis)cmmunities in the limestone area, tanyang, ch'ungbuk province in korea. The tree layer was composed of quercus dentata, platycarya strobilacea, fraxinus rhynchophylla and others as wel as quercus variabilis. the shrub layer was dominated by ulmus davidiana for. suberosa,shrubby q. variabilis. euonymus alatus and rhus chinensis. among these, u. davidiana for. suberosa was known to have a restricted distribution to calcareous area, and 9 species in the shrub layer including e. alatus, indigofera kirilowii and rhamnus davurica belonged to the calcicole. The herb layer was dominated by carex lanceolata and spodiopogen cotulifer. ten specirs including g. lanceolata, clematis mandshurica, isachne globosa, lithospermum arvense and scabiosa mansenensis belonged to the calcicode. soil texture was classified to clay loam in both top and subsoil. Water cotent and organic matter were consistentl higher in top soil than in subsoil. soil ph rangd 7.8~8.4. Total n concentration in top soil ranged from 0.2 to 0.4mg/g, which was higher than that in subsoil. Available p and exchangeable k concentretion were also significantly higher in op soil than in subsoil. However, exchangeable ca concentration was similar betweenthe top and the subsoil. Unlike the other nutrients, exchangeable mg concentration in top soil was lower than that in subsoil. orangic matter, n, p and k content in this chinese cork oak stand showed as much as the other noncalcareous sites. Soil properties in this study area seemed to have been influenced by casts forming activities of earthworms.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.59-65
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• 2004

Interactions of phosphorus and zinc in soils are important to determine the availability of the elements because those elements are closely related in the agricultural environment. The objective of this study was to investigate the interactions of P and Zn using desorption quantity (Q)-intensily(I) isotherms. Physically and chemically different soils, acidic Egan, acidic sandy Egeland, calcareous Glenham, and neutral Maddock, were used. The soils were enriched with different concentrations of P and Zn as $KH_2PO_4$ and $ZnSO_4$ solutions, respectively. Zinc enrichments affected availability of P in the Egan soil, which contained higher amounts of clay, organic matter, and exchangeable Fe than the other soils tested. After Zn enrichments, the pH drastically decreased in Egeland sandy soil, not changed in the calcarious Glenham soil, and slightly decreased in Egan and Maddock soil systems. The values of $Q_{max}$ and $I_0$ of phosphorus decreased with increasing Zn concentrations enriched in all soils, the changes of those values did not influence the P buffering power, |$BP_o$| values, in most soils. The influences of P treatment on Zn availability were varied. The values of Zn buffering capacity, $BC_{Zn}$, were lowest in the Egeland soil that had the lowest soil pH, amounts of clay minerals, organic matter, CEC, and exchangeable Fe, and were highest in the calcareous Glenham soil. The $BC_{Zn}$ values ranged from 202 to 4480. With P application, the changes of $BC_{Zn}$ values were more affected by the changes of soil solution Zn contents (I) than the changes of DTPA extractable Zn contents(Q). The change of Q and I values was found to be dependent upon soil properties, especially, soil pH.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.223-235
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• 2006

Soil testing laboratories unfamiliar with turfgrasses will often overestimate the plant's need for phosphorus and underestimate the need for potassium. This is partly due to differences in rooting between grasses and many garden plants and crops. The grasses are generally more efficient in extracting phosphorus from the soil, reducing their need for phosphorus fertilizer. The fact that crop yield is often the primary objective in field crop production, and is usually of little interest in turfgrass management, may affect soil test interpretation for potassium. Potassium levels above those required for maximum tissue yield of grasses may improve stress tolerance and turfgrasses will usually benefit from higher applications of this element. There are also diffrrences in soil testing philosophies. Some laboratories use the sufficiency level of available nutrients(SLAN) approach, whereas others prefer the basic cation saturation ratio(BCSR) approach. Some will use a combination of the two methods. The use of the BCSR theory easily lends itself to abuse and questionable fertilizer applications and products are sometimes recommended citing imbalances in cation ratios. The usefulness of the BCSR ratio theory of soil testing varies with soil texture and interpretations on tests performed on sand-based media are particularly a problem. Other soil testing problems occur when sand-based media used on sports fields and golf greens contain free calcium carbonate. The ammonium acetate extractant at pH 7.0 dissolves excessive amounts of calcium that can bias cation exchange capacity measurements and measurements of cation ratios. Adjusting the pH of the extractant to 8.1 can improve the accuracy of the testing procedure for calcareous media.

• Economic and Environmental Geology
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• v.30 no.2
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• pp.89-103
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• 1997

The purpose of this research is to investigate the enrichment and distribution patterns of naturally occurring potentially toxic elements in soils derived from black shales and slates. Soil samples were collected from the Chubu area covered with uranium-enriched black shales and slates of the Changri Formation of the Okchon Super Group, and analysed for multiple-elements using INAA, ICP-AES and AAS. Soil pH and loss-an-ignition were also measured. Trace element contents in black shale and slate of the Chubu area are relatively lower than those in black shales, and higher than those in black slates reported elsewhere (Chon, Jung, 1991; Chon et al., 1996). Soil pH values range from 3.5 to 6.5, and loss-an-ignition values are in the range from 3 to 10%. Potentially toxic elements including As, Ba, Cr, Cu, Mo and U are highly enriched in residual soils with maximum content of $540{\mu}g/g$, $35,000{\mu}g/g$, $280{\mu}g/g$, $300{\mu}g/g$, $240{\mu}g/g$ and $860{\mu}g/g$, respectively. Significant concentrations of those elements were found in soils taken from the Tojangkol, the Chubu tunnel and the Meokti areas. Soils derived from black shales and slates, calcareous and phyllitic rocks, and intrusions were discriminated in terms of As, Ba, Co, Cr, Cu, Mo, Sc and U contents. Enrichment index was calculated using the concentrations of As, Ba, Cr and Mo, and enrichment index map shows very similar trend with U distribution in soils.

• Structural Engineering and Mechanics
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• v.40 no.1
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• pp.29-48
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• 2011

Under large storm loads sections of a long pipeline on the seabed can be uplifted. Numerically this loss of contact is extremely difficult to simulate, but accounting for uplift and any subsequent recontact behaviour is a critical component in pipeline on-bottom stability analysis. A simple method numerically accounting for this uplift and reattachment, while utilising efficient force-resultant models, is provided in this paper. While force-resultant models use a plasticity framework to directly relate the resultant forces on a segment of pipe to the corresponding displacement, their historical development has concentrated on precisely modelling increasing capacity with penetration. In this paper, the emphasis is placed on the description of loss of penetration during uplifting, modelled by 'strain-softening' of the force-resultant yield surface. The proposed method employs uplift and reattachment criteria to determine the pipe uplift and recontact. The pipe node is allowed to become free, and therefore, the resistance to the applied hydrodynamic loads to be redistributed along the pipeline. Without these criteria, a localised failure will be produced and the numerical program will terminate due to singular stiffness matrix. The proposed approach is verified with geotechnical centrifuge results. To further demonstrate the practicability of the proposed method, a computational example of a 1245 m long pipeline subjected to a large storm in conditions typical of offshore North-West Australia is discussed.

• The Journal of Engineering Geology
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• v.23 no.1
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• pp.47-55
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• 2013

To analyze lateral displacement of excavation walls exposed during the construction of Subway Line 1 in the Daegu region, inclinometer measurement data for sites D4, D5, and Y6 are investigated from the perspective of engineering geology. The study area, in the Banyawol Formation, Hayang Group, Gyeongsang Supergroup, is in the lower part of bedrock of andesitic volcanics, calcareous shale, sandstone, hornfels, and felsite dykes that are unconformably overlain by soil. The rock mass around the D4 site is classified as RMR-V grade and the maximum lateral displacement of 101.39 mm, toward N34W, was measured at a bedding-parallel fault, at a depth of 12 m. The rock mass around the D5 site is classified as RMR-IV grade and the maximum lateral displacement of 55.17 mm, toward the south, was measured at a lithologic contact between shale and felsite, at a depth of 14 m. The rock mass around the Y6 site is classified as RMR-III grade and the maximum lateral displacement of 12.65 mm, toward S52W, was measured at an unconformity between the soil and underlying bedrocks, at a depth of 7 m. The directions of lateral displacement in the excavation walls are vector sums of the directions perpendicular to the excavation wall and horizontally parallel to the excavation wall. Lateral displacement graphs according to depth in the soil profile show curvilinear trajectories, whereas those in bedrock show straight and rapid-displacement trajectories.