• Journal of Environmental Science International
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• v.19 no.5
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• pp.533-541
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• 2010

The purpose of this study is to grasp what characterizes the vegetation base of the natural forest as a latent vegetation in the middle region of Korea and thus to offer basic data when improving the vegetation base in the middle region being built or to be built in the future. The findings of this soil section survey show the following: The soil is brown to red color soil group on the whole. In addition, the soil's physical features like soil hardness are rated as high level, which results from the fact that the forest soil exits in its natural form under less influence of stamping. The pH of soil shows a weak acidity, like Korean normal soil. Specific electrical conductance is also rated as middle to high level in accordance with the standards of landscape architecture. The Salix koreensis community and the Pinus rigida community are different from other communities in terms of total nitrogen, available phosphate and exchangeable $K^+$ content. Specifically, the two communities are opposed to each other in terms of total nitrogen and available phosphate, while being similar to each other in terms of available phosphate and exchangeable $K^+$ content. This seems to result from the fact that they are located near each other. In addition, the two communities are characterized by the fact that they are distributed at the altitude mean relatively lowest and in the valley. To sum up, the forest soil around Goesan Gun is of middle level on the whole according to the landscape standards, when judging it in terms of vegetation base. Accordingly, it seems that the construction of the vegetation base around Goesan Gun will not require large investment expenses for soil improvement. Also, it seems that the spatial scope of research is needed to expand the basic data on the construction of the vegetation base for the whole middle region of Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.689-696
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• 2015

The green manure crops are returned to soil when the plants are still green. The green manure crops play a role in reducing chemical fertilizers, improvement of soil fertility, reduction of soil erosion, weed control, and landscapes effect. Typical green manure crops are barley green manure, hairy vetch, chines milk vetch and clovers. We sowed 49 species of green manure crops in upland soil to increase the usage of green manure crops. We searched the effectiveness of green manure yield, C/N ratio, soil mulching, and landscape effect. The green manure crops that have $5tonha^{-1}$ or more of green manure yield (fresh weight) were 6 gramineous crops, 4 leguminous crops, and 3 others. Green manures yield in a short growth period was higher in gramineous crops than leguminous crops. Among the green manure crops, 3 gramineous crops, 12 leguminous crops, and 3 others were under 25 in C/N ratio. Seven gramineous crops, 8 leguminous crops, and 5 others were over 50% of soil covering rate. Green manure crops that have beautiful flowers were in total 16 kinds, such as 4 gramineous crops, 6 leguminous crops, and 6 others. In result, based on green manure yield and C/N ratio, excellent species in the green manure crops were 4 species (triticale, 2 kinds of hairy vetch, and lupin). Green manure crops that were effective at soil mulching were 20 species, like hairy vetch, oats, sorghum, phacelia, buckwheat, etc. Buckwheat, crotalaria, mustard plant, phacelia, and etc. could be available for landscape crops.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.163-173
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• 2018

Background: Deforestation and degradation are currently affecting the ecosystem services of forests. Among the ecosystem services affected by deforestation and degradation are the amount of soil organic carbon (SOC) and total nitrogen (TN) stored in forest soils which have greater impacts in global climate change. This study aimed at examining the amount of SOC and TN in the forest fragments which were separated from the continuous tracts of forests of Jibat and Chillimo through fragmentation processes over four decades. Methods: We have sampled soils from 15 forest fragments of Chillimo and Jibat in the central highlands of Ethiopia. The soil samples obtained in two separate soil depths (0-30 and 30-60 cm) were bulked, dried, and sieved for analysis. Results: Our results have shown that the two sites (Jibat and Chillimo forest fragments) differed in their SOC and TN contents. While the values for Jibat were found to be 29.89 Mg/ha of SOC and 2.84 Mg/ha for TN, it was 14. 06 Mg/ha of SOC and 1.40 Mg/ha for TN for Chillimo. When all forest fragment soil samples were bulked together, Jibat site had twice the value of SOC and TN than Chillimo. When disaggregated on the basis of each fragments, there existed differences in SOC (1.86 Mg/ha and 42.15 Mg/ha) and TN (0.24 Mg/ha and 4.23 Mg/ha) values. Among the forest fragments, fragment four ($F_4$) had the highest Relative Soil Improvement Index (RSII) value of 3826.82% and fragment fifteen ($F_{15}$) had the lowest RSII value (726.87%) which indicated that the former had a better quality of soil properties than the latter. Conclusion: SOC and TN differed across sampled fragments and sites. Variations in soil properties are the reflections of inherent soil parent material, aboveground vegetation, human interferences, and other physical factors. Such differences could be very important for identifying intervention measures for restoration and enhancing ecosystem services of those fragments.

• Structural Monitoring and Maintenance
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• v.11 no.3
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• pp.187-202
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• 2024

For the problems of high compressibility and low strength of peat soil formed by lake-phase deposition in Dianchi Lake, microbial-induced calcium carbonate deposition (MICP), phyto-urease-induced calcium carbonate deposition (EICP) and phyto-urease-induced calcium carbonate deposition combined with lignin (EICP combined with lignin) were used to reinforce the peat soil, the changes in mechanical properties of the soil before and after the reinforcement of the peat soil were experimentally investigated, and the effect and mechanism of peat soil reinforcing by the three reinforcing techniques were tested and analyzed using X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that: compared to the unreinforced remolded peat soil specimens, the unconfined compressive strength (UCS), cohesion and internal friction angle of the specimens reinforced by MICP, EICP and EICP combined with lignin techniques have been greatly improved, and the permeability resistance has been improved by two, two and three orders of magnitude, respectively; the different methods of reinforcing generate different calcium carbonate crystalline phases, with the EICP combined with lignin technique generating the most stable calcite, and the MICP and EICP techniques generating a mixed phase of calcite and spherulitic chalcocite. Analyses showed that for peat soil reinforcement, the acidic environment of peat soil inhibited the growth and reproduction of bacteria, EICP technology was superior to MICP technology, and the addition of lignin solved the defect of the EICP technology that did not have a "nucleation site", so EICP combined with lignin reinforcement was preferred for the improvement of peat soil.

• Korean Journal of Organic Agriculture
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• v.31 no.3
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• pp.167-189
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• 2023

Korea has become the highest nitrogen balance (228 kg/ha) among 34 OECD member countries, and has the stigma of being a 'Nutrient overload country' as of 2019. Accordingly, research on the derivation and utilization of nutrient balance indicators and the 'regional nutrient management system' are being promoted to improve Korea's nutrient balance. It is necessary to support these policies and studies, form a public consensus on improving the nutrient balance, and evaluate the function of the public benefit. This paper aims to estimate the public benefit value of improving the nutrient balance based on an analysis of consumers' willingness to pay and recognition of Korea's nutrient excess for 600 consumers nationwide. As results, 21.2% of the respondents said they were aware of excessive nutrients in Korea, and 76.7% of the respondents said they were aware of the need for nutrient management. The average amount of intention to pay for the improvement of three pollution (soil, water quality, and air) that can occur due to a nutrient overload was ￦2,321.1 for soil pollution improvement, ￦2,391.2 for water pollution improvement, and ￦2,377.9 for air pollution improvement. The average willingness to pay for the three pollution reduction was ￦6,002.3. These results are expected to be used to form a public consensus on the balance of payments and to establish measures to enhance public interest values in the future.

• Korean Journal of Remote Sensing
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• v.35 no.6_4
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• pp.1351-1361
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• 2019

In this study, the annual surface soil erosion amount of before (2007 year) and after (2015 year) the river improvement projects were calculated using RUSLE (Revised Universal Soil Loss Equation) in the Geumgang basin (Daecheong-Dam to Geumgang Estuary-Bank). After the results were classified into five classes, the results were compared and analyzed with the results of the change in the land cover. In order to generate each factor of RUSLE, various spatial information data, such as land cover maps for 2007 and 2015 years, national basic spatial information, soil map, and average annual precipitation data were utilized. The results of the analysis are as follows: 1) annual surface soil erosion in the study area increased the area of class 1 in 2015 years compared to 2007, 2) the area of class 2, 3 and 5 decreased, 3) the area of class 4 increased. It is believed that the average annual amount of surface soil erosion decreased in most areas due to the reduction of annual average precipitation, the formation of ecological parks, the expansion of artificial facilities, and the reduction of illegal farmland.

• Korean Journal of Organic Agriculture
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• v.23 no.2
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• pp.291-299
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• 2015

This study aimed to investigate the effect of inoculation time of phosphate- solubilizing Kluyvera sp. CL2 on fruit quality in cultivation of Campbell early' grape. When phosphate-solubilizing strain was treated at the stone-hardening stage, soil phosphorous increased, exchangeable cations such as K, Ca and Mg also increased. Soil pH was not changed severely due to the soil buffer capacity. Water soluble phosphate concentrations did not decrease heavily up to 20 days after inoculation. When this strain was treated at the berry-softening stage, soil phosphate solubilization ratio was high, cluster weight and sugar content also increased. Both anthocyanin contents and Hunter's values were seen to be significant when inoculation times were stone-hardening stage and berry-softening stage, in particular, increase of Hunter's value a resulted in the improvement of coloration. From these results, we could find that the inoculation of phosphate-solubilizing Kluyvera sp. CL2 at berry-softening stage was the most effective in improvement of fruit productivity and quality in cultivation of'Campbell early' grape.

• Research in Plant Disease
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• v.6 no.1
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• pp.39-42
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• 2000

This study was conducted to improvement of control efficiency on clubroot disease. To improve the control efficiency on clubroot disease of chinese cabbage by chemical persistent effect, Flusulfamide DP was examined with soil mixed treatment. When Flusulfamide DP was applied, the more application times, the higher control value. The control value and marketable yield per 10a of the untreated cultivation plot after two application of Flusulfamide DP were 53.9%, 4,822kg, respectively. However, based on marketability and marketable yield, untreated cultivation plot after two application of Flusulfamide DP has been thought as economic application times compared to three times application. On the other hand, the combination of soil mixing and bed soil mixing treatment Flusulfamide DP was more effective than each treatment. The control value and marketable yield of the combination treatment was 73.3∼88.9%, 5,633∼5,770kg, those of soil mixing 66.7∼70.0%, 2,847∼3,167kg, respectively.

• Structural Engineering and Mechanics
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• v.61 no.2
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• pp.245-253
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• 2017

The increasing lack of good quality soils allowing the development of roadway, motorway, or railway networks, as well as large scale industrial facilities, necessitates the use of reinforcement techniques. Their aim is the improvement of the global performance of compressible soils, both in terms of settlement reduction and increase of the load bearing capacity. Among the various available techniques, the improvement of soils by incorporating vertical stiff piles appears to be a particularly appropriate solution, since it is easy to implement and does not require any substitution of significant soft soil volumes. The technique consists in driving a group of regularly spaced piles through a soft soil layer down to an underlying competent substratum. The surface load being thus transferred to this substratum by means of those reinforcing piles, which illustrates the case of a piled embankment. The differential settlements at the base of the embankment between the soft soil and the stiff piles lead to an "arching effect" in the embankment due to shearing mechanisms. This effect, which can be accentuated by the use of large pile caps, allows partial load transfer onto the pile, as well as surface settlement reduction, thus ensuring that the surface structure works properly. A technique for producing rigid piles has been developed to achieve in a single operation a rigid circular pile associated with a cone shaped head reversed on the place of a rigid circular pile. This technique has been used with success in a pile-supported road near Bourgoin-Jallieu (France). In this article, a numerical study based on this real case is proposed to highlight the functioning mode of this new technique in the case of industrial slabs.

• Journal of Environmental Health Sciences
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• v.11 no.2
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• pp.29-39
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• 1985

This experimental study was carried out to evaluate the improvement of rural privys and to develop the system of the three septic tank privy. For this study, 42 samples of excreta, 42 samples of soil and 26 samples of vegetables were drawn out of the conventional privys while 26samples of excreta, 26samples of soil and 26samples of vegetables out of the three septic tank privys from five villages in Chun Song County. Kang Won Province for the period from 22th August to 13th October, 1984. The major findings are as follows : 1. Positive cases of helminthes are found 41 out of 42(97.6%) excreta of the conventional privys whereas those from the three septic tank privys are found 2 out of 26 (7.7%). Average numbers of helminthes from the excreta of the conventional privys are 4.4 whereas those from the three septic tank privys are 1.1. 2. Positive cases of helminthes are found 33 out of 42 (78.6%) soil of the conventional privys whereas those from the three septic tank privys are found 20 out of 26(76.9%). However, this difference does not reveal statistical significance (P>0.01). Average numbers of helminthes from the soil of the conventional privys are 2.3 whereas those from the three septic tank privys are 1.7 and the difference in total number of helminthes reveals statistical significance (P<0.05). 3. Positive cases of helminthes from vegetable samples drawn out of the conventional privys are found 13 out of 26(50.0%) whereas those froin the three septic tank ptivys are found 10 out of 26(38.5%). Average numbers of helminthes from vegetable samples drawn out of the conventional privys are 1.1 whereas those from the three septic tank privys are 0.7. However, these differences in both positive rates and total numbers of helminthes do not reveal statistical significance (P>0.05).