• 한국농공학회논문집
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• 제47권1호
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• pp.51-59
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• 2005

The settling rate of the dredged soil may vary with mineral composition, grain size distribution, initial con contration and salt concentration of suspension of the site. A series of settling column test was performed to investigate the settling rate characteristics of solid suspension material from dredging and reclamation. The settling rate of soil mixed with various size of particles depended on clay fraction which showed a inherent flux. A model was developed to predict the particle flux of mixed soil from the clay flux and its applicability was verified.

• 한국토양비료학회지
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• 제46권6호
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• pp.474-481
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• 2013

Understanding the microbial community structure of agricultural soils is important for better soil management in order to improve soil quality. Phospholipid fatty acid analysis has been popularly used in determining the microbial community structure in different ecosystems. The microbial community structure of paddy soil under long-term fertilizer treatments was investigated after 45 years using PLFA analysis. Treatments were control (no fertilization, Con), compost (COM), NPK, NPK+compost (NPKC), PK, NK, and NP. Soil chemical properties were mainly affected by the addition of compost and inorganic P fertilizer. Total nitrogen and organic matter contents were significantly higher in treatments with compost while available $P_2O_5$ and exchangeable calcium were significantly higher in treatments with added inorganic P fertilizer. It was found that microbial communities were responsive to the different fertilizer treatments. PLFA results showed that the soils were dominated by gram-negative bacteria, followed by the actinomycetes, then gram-positive bacteria, and fungi. Principal component analysis of the soil chemical properties and PLFA composition proved to be a more reliable tool because it was more responsive to the changes in soil chemical properties.

• 한국농공학회논문집
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• 제52권2호
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• pp.43-50
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• 2010

This study was carried out to evaluate the vertical stress properties in sandy soil according to changes of foundation condition in soil bin compacted three layers. The following conclusions and comparisons have been made based on careful analysis from theoretical and experimental methods. : When sandy soil subjected to circular uniform load, the vertical stress increments ($\Delta\sigma_z$) was increased as load increasing, the maximum values of $\Delta\sigma_z$ was achieved at the point loading axis, and $\Delta\sigma_z$ was not shown over at a distance of three times of loading plate width (B). The vertical stress increments were achieved largely at 80 % relative compaction (Rc) compared to 95 % relative compaction due to stress concentration in sandy soil. When sandy soil subjected to circular uniform load, the $\Delta\sigma_z$ differences between theoretical and experimental values as load increased were more increased and its maximum differences were achieved at stress axis. When gravel surface macadamized over sandy soil subjected to load, the $\Delta\sigma_z$ was concentrated to load axis as load increasing, so that macadamization will be decreased load transmission.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.231-240
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• 2016

The change in chemical compositions of leachate and medium density fiberboard (MDF) from a laboratory-scale simulated landfill which constructed in a plastic container containing alternating layers of soil and MDF was investigated to evaluate decomposing of MDF in soil. Four treatments were conducted: 1) MDF in soil, 2) MDF only, 3) cured UF resin in soil, and 4) soil only. Molecular weight (MW) distribution of compounds in leachate from soil only treatment did not change over time. In UF resin in soil treatment, the MW distribution shifted to a lower MW distribution over time, while the peak shifted to the left indicated changing to higher MW distribution in leachate from treatment 1 and 2 contained MDF. Higher percent nitrogen in leachate was observed in MDF containing treatments due to the UF resin in the MDF. The percent carbon slightly increased in MDF only while that greatly decreased in MDF in soil treatment maybe due to bacterial activity. The percent of extractable materials from the MDF decreased greatly on day 35 compare to day 0, and subsequently did not change much on day 77. In contrast, percent holocellulose and lignin did not change much over time. No structural change of the wood fiber in MDF occurs during the study. Water-soluble materials from MDF in soil contributed the change in chemical composition of leachate.

• The Korean Journal of Ecology
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• 제13권4호
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• pp.285-295
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• 1990

Floristic composition and soil properties were analyzed in red pine($Pinus densiflora$) communities in the limestone areas. Tanyang, Ch ungbuk Province in Korea. The tree layer was composed of $Juniperus rigida, Quercus dentata, Q. mongolica$ and others as well as $P. densiflora$, all of which also appeared in soils of grinite origin The shrub layer was dominated by $Q. dentata, Lespedeza cyrtobotrya, Securinega suffruticosa, Abelia coreana$ and $Uimus davidiana$ for $suberosa$. Among these $A. coreana$ and $U. davidiana$ for $suberosa$ belonged to calcicole plant. The herb layer dominated by $Carex lanceolata$. Soil pH ranged 7.9-8.3. Total nitrogen and available phosphorus content of the soil were lower than those of noncalcareous soils. However, exchangeable calcium and magnesium content were 10 times and 2~3 times greater than those of noncalcreous soils, respectively. The difference of soil texture between top soil(loam soil) and subsoil(sand soil), and higher soil organic matter content than noncalcareous red pine forest soils seemed related to the casts forming activities of earthworms.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.152-157
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• 2003

Diesel-contaminated soils were ozonated for different times (0 - 900 min) and incubated for 9 wk to monitor petroleum hydrocarbons (PH)-degradative potential of indigenous microorganisms in the soils. Increased ozonation time decreased not only concentration of PH but also number of microorganisms in the soils. Microorganisms in the ozonated soils increased during 9-wk incubation as monitored by culture- and nonculture-based methods. Higher (1-2 orders of magnitude) cell number was observed by quantitative analysis of soil DNA using probes detecting genes encoding 165 rRNA(rrn), naphthalene dioxygenase (nahA), toluene dioxygenase (todC), and alkane hydroxylase (alkB) than microbial abundance estimated by culture-based methods. Such PH-degraders were relatively a few or under detection limit in 900-min ozonated soil. Further PH-removal observed during the incubation period supported the presence of PH-degraders in ozonated soils. Highest reduction (25.4%) of total PH (TPH) was observed in 180-min ozonated soil white negligible reduction was shown in 900-min ozonated soil during the period, resulting in lowest TPH-concentration in 180-min ozonated soil among the ozonated soils. Microbial community composition in 9-wk incubated soils revealed slight difference between 900-min ozonated and unozonated soils as analyzed by whole cell hybridization using group-specific rRNA-targeted oligonucleotides. Results of this study suggest that appropriate ozonation and subsequent biodegradation by indigenous microorganisms may be a cost-effective and successful remediation strategy for PH-contaminated soils.

• 한국환경복원기술학회지
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• 제10권6호
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• pp.99-109
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• 2007

The main objectives of this comparative study were 1) to compare the floristic similarity of species composition between the extant vegetation and seedlings from soil seed bank and 2) to quantify the potential contribution of soil seed bank to revegetation of forest in a constructed area, which is called "ecological impact mitigation" in conjunction with the power plant extension. Forest topsoil of seven plots was collected from the surface soil after measurements were taken on the ground vegetation in each plot. A greenhouse experiment was conducted and monitored to analyze the germination potential of soil seed bank. The forest topsoil was spread on plastic trays ($0.7m^2{\times}7$) filled with a 5cm layer of sterilized potting mix. The results of monitoring for 2 years in a greenhouse were as follows : 1) seedlings of soil seed bank per 4.9$m^2$ were 1,269 with 36 species (1st year) and 2,615 with 25 species (2nd year). 2) 38${\pm}$8% of the flora species were germinated from soil seed bank. It can be concluded that the use of soil seed bank would be effective to promote establishment of diverse species and vegetation. However, it behooves to continue monitoring on succession of vegetation and pursue revegetation with other methods for ecological restoration. Finally, adequate topsoil deposit and gathering methods should be studied properly.

• The Korean Journal of Ecology
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• 제15권1호
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• pp.67-73
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• 1992

This study was carried out to investigate the effects of soil improver on the population density and composition of microarthropods in the upland which cultivated pepper consecutively. We have treated soil improver sucf as zeolite, compost, ca, sio2 , and integrated improvement i. e. treated zeolite, compost, ca, and deep cultivate ; 20 cm. We sampled soil to collect soil microarthropods from a week to 15 months after treament at each site by soil-corer and extracted 48 hours in berlese- tullgren funnel. We have classified 16 families, 35 species diversity index of soil microarthropods are highe in the integrated improver and compost site than those found in any other sites. We suggest that soil improvement effrcts of integrated improved site are influenced by compost.

• 한국환경과학회지
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• 제30권1호
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• pp.87-96
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• 2021

Herb has been categorized as a special plants from the beginning of human history and used in different medical systems in different cultures. This research has classified soil into 6 kinds that have diverse elements to see to which various kinds of savory(satureja hortensis) adapt well, experimenting from sowing to flowering for around 13 weeks, and also divided indoor conditions to get the result below. In conclusion, growth status of savory depending on the kinds of soil suggest that in indoor conditions the savory if planted in ⑤ bed soil compounded with saprolite and poultry manure grew better than any other condition. On the other hand, the growth status was bad in ① masato, ② clay, ④ bed soil mixed with saprolite, and ⑥ bed soil mixed with clay conditions. Though you can see the immediate effect of soil on the growth of savory, I'd like to reveal the details of how elements of savory operate in which kind of soil and outdoor conditions the goal of this research, in the next research.

• The Korean Journal of Ecology
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• 제19권1호
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• pp.47-53
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• 1996

Effects of group breeding of herons on pine community were studied at Pomaeri, in Yangyang, Kangwon Province, Korea. This site has been protected as a Natural Monument (No. 229) since 1970. Herons have used this habitat as a breeding site from] anuary to October every year. In 1995, more than 500 herons were observed in this habitat. Many big pine trees are dying or already dead due to group inhabitation of herons, and no pine saplings were found at forest floor in this habitat. Nutrient contents of soil in this habitat were much higher than those in control plot. This must be due to the addition of feces from herons and of thin twigs and other organic materials from the canopy and bird nests. Species composition of herb layer in this habitat was quite different from that in control plot. Breeding site was dominated by Humulus japonicus. Persiearia perJohata, Persicaria thunbergii. and Commelina communis. which are indicator species of soil eutrophication.