• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.1217-1224
• /
• 2010

These days, the maintenance of closed waste landfill come to the fore social problem such as legal maintenance period, after closed maintenance deposits, stability evaluation guides and environmental survey for closed landfill management. Therefore the many non-sanitary closed waste landfill has been removed by selection and transfer to sanitary landfill and incineration. When the remove the non-sanitary landfill, the pollution level of bottom soil was investigated by related government law. In this case study, the soil contamination survey was performed to evaluate the pollution level of non-sanitary closed landfill bottom soil. Based on this study, the pollution level of studied non-sanitary landfill bottom soil was content with related government law for third area(factory, parking lot, gas station, road, railroad use etc.).

• Korean Journal of Environmental Agriculture
• /
• v.28 no.4
• /
• pp.333-339
• /
• 2009

Various cultural practices have been promoted as management options for enhancing soil quality and health. The use of soil management methods can cause changes in fertility by affecting soil chemical properties. This study aimed to evaluate interactions between soil chemical properties and soil management methods in protected cultivation, and to classify soil management methods that similarly affect soil chemical properties. Water-logging and irrigation reduced soil pH and available $P_2O_5$ content. Application of animal manures has a positive effect on levels of organic matter, Av.$P_2O_5$, K, Zn, and Cu. The electrical conductivites tened to be low in the application of organic amendments, including rice and wood residues. Deeper plowing caused a reduction in Ca content. Practicing soil nutrient-considering fertilization and fertigation did not exert an influence on nutrient element contents. In a cluster analysis of the soil management methods according to major nutrients, low similarities were found with deeper plowing and crop rotation with rice in comparison with other practices. In a cluster analysis by minor nutrient characteristics, crop rotation and application of animal manures and rice residues were linked at a high Ward's distance, while other practices were found to be relatively low distinct. Each soil management method has a similar or different effect on soil chemical properties. These results suggest the necessity of establishing limits and standards according to the effects of soil management methods on soil chemical properties for economic soil practices.

• Korean Journal of Soil Science and Fertilizer
• /
• v.46 no.5
• /
• pp.365-372
• /
• 2013

Crop development and nutrient availability are strongly influenced by soil salinity levels. This study was conducted to investigate the effect of rice straw and nitrogen (N) fertilizer for silage barley under various soil salinity levels at Saemangeum reclaimed tidal land. Three levels of rice straw (0, 2.5, 5.0 ton rice straw $ha^{-1}$) and N (0, 150, 225 kg N $ha^{-1}$) were applied at 0.04, 0.23, 0.35% soil salinity levels. Biomass yield of silage barley was influenced by the interactions between rice straw application and N fertilization. Although there was no single effect of rice straw application on biomass yield, it was significantly increased with N application and a rice straw application of 5.0 ton $ha^{-1}$. Sodium content in silage barley was significantly lower at 0.04% salinity level, and but it was statistically increased with increasing soil salinity levels. Forage qualities such as total digestible nutrients and relative feed value of silage barley were significantly higher with N application at 0.04% salinity level, but there was no effect of rice straw application. Soil organic matter content was increased with N and rice straw application regardless of soil salinity level. The results of this study showed that the effect of rice straw and N fertilization on silage barley was influenced by soil salinity levels, which indicates that the management practice of silage barley at Saemangeum reclaimed tidal land should consider soil salinity levels.

• Korean Journal of Soil Science and Fertilizer
• /
• v.47 no.6
• /
• pp.398-405
• /
• 2014

Salt accumulation at soil surface is one of the most detrimental factors for crop production in reclaimed tidal land. This study was conducted to investigate the effect of capillary barriers beneath the soil surface on dynamics of soil salts at coarse-textured reclaimed tidal land. A field experiment was conducted at Saemangeum reclaimed tidal land for two years (2012-2013). Capillary barriers ($3.5{\times}12m$) were treated with crushed-stone, oyster shell waste, coal briquette ash, coal bottom ash, rice hull and woodchip at 40-60 cm depth from soil surface. Silage corn (Zea mays) was cultivated during the experimental period and soil salinity was monitored periodically. Soil salinity was significantly reduced with capillary barrier compared to that of control. Oyster shell waste was one of the most effective capillary barrier materials to control soil salinity at Saemangeum reclaimed tidal land. At the first growing season capillary barrier did not influence on corn growth regardless of types of the material, but plant biomass and withering rate of corn were significantly improved with capillary barrier at the second growing season. The results of this study showed that capillary barrier was effective on the control of soil salinity and improvement of corn growth, which indicated that capillary barrier treatment can be considered one of the best management practices for stable crop production at Saemangeum reclaimed tidal land.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.5
• /
• pp.944-958
• /
• 2011

Soil hydraulic properties such as hydraulic conductivity or water retention which are costly to measure can be indirectly generated by soil pedotransfer function (PTF) using easily obtainable soil data. The field soil structure description which is routinely recorded could also be used in PTF as an input to reduce the uncertainty. The purposes of this study were to use qualitative morphological soil structure descriptions and soil structural index into PTF and to evaluate their contribution in the prediction of soil hydraulic properties. We transformed categorical morphological descriptions of soil structure into quantitative values using categorical principal component analysis (CATPCA). This approach was tested with a large data set from the US National Pedon Characterization database with the aid of a categorical regression tree analysis. Six different PTFs were used to predict the saturated hydraulic conductivity and those results were averaged to quantify the uncertainty. Quantified morphological description was successively used in multiple linear regression approach to predict the averaged ensemble saturated conductivity. The selected stepwise regression model with only the transformed morphological variables and structural index as predictors predicted the $K_{sat}$ with $r^2$ = 0.48 (p = 0.018), indicating the feasibility of CATPCA approach. In a regression tree analysis, soil structure index and soil texture turned out to be important factors in the prediction of the hydraulic properties. Among structural descriptions size class turned out to be an important grouping parameter in the regression tree. Bulk density, clay content, W33 and structural index explained clusters selected by a two step clustering technique, implying the morphologically described soil structural features are closely related to soil physical as well as hydraulic properties. Although this study provided relatively new method which related soil structure description to soil structure index, the same approach should be tested using a datasets containing the actual measurement of hydraulic properties. More insight on the predictive power of soil structure index to estimate hydraulic properties would be achieved by considering measured the saturated hydraulic conductivity and the soil water retention.

• Journal of Soil and Groundwater Environment
• /
• v.18 no.6
• /
• pp.38-47
• /
• 2013

This study was performed to identify the optimal operating conditions and to evaluate the xylene removal efficiency, applying in-situ soil flushing with the low concentrated solution of 'Tween 80' at the xylene contaminated site. The pilot scale test site ($5m{\times}5m{\times}3m$), was mainly composed of 'sandy loam', with the average hydraulic conductivity of $9.1{\times}10^{-4}cm\;s^{-1}$. The average xylene concentration of the site was 42.1 mg $kg^{-1}$, which was more than 2.5 times higher than Korea soil pollution warning limit (15 mg $kg^{-1}$). For the soil flushing, 7,800 L of 0.1~0.2% surfactant solution was injected into three injection wells at the average injection time of 9 hr $d^{-1}$ for 10 days, followed by the additional only groundwater injection of 6,000 L. The same amount of the effluent solution was extracted from three extraction wells. From the analysis for xylene concentration of all effluent at 3 extraction wells, total 166 g of xylene was removed by in-situ surfactant flushing. Even though the residual xylene concentrations of 7 soil sampling locations in the test site were different due to the soil heterogeneity, from the comparison of xylene concentration at 7 locations before/after the feasibility test, 53.9% of the initial xylene in the site was removed from three extraction wells (mainly Ext-N and Ext-M well). The results showed that the in-situ soil flushing by using low concentrated 'Tween 80' solution had a great potential to remediate the xylene contaminated site.

• Korean Journal of Agricultural Science
• /
• v.49 no.2
• /
• pp.379-387
• /
• 2022

A large amount of the mineral nitrogen is necessary for crop growth. With the use of nitrogen fertilizers, agricultural yield has increased during the last few decades. However, at the same time, nitrate from the cultivated land can be a source of environmental pollution, especially in water systems. For nitrogen management, it is necessary to analyze the pattern of nitrogen movement in soil. In this study, nitrogen leaching in upland soils was evaluated using undisturbed lysimeters with different soil textures during sesame cultivation. The soil texture of the lysimeters was clay loam (Songjung series) and sandy loam (Sangju series) soils. Sesame was cultivated from May 25 to August 24 in 2020. The standard amount of NPK fertilizer (N-P₂O₅-K₂O = 2.9-3.1-3.2 kg·10 a^-1) was applied before sowing. The amount of nitrogen leaching was calculated by multiplying the nitrogen (NO₃-N + NH₄-N) concentration and the amount of water drained below 1.5 m soil depth. The water was drained through percolation into macropores in the clay loam lysimeter. In contrast, in the sandy loam lysimeter, water drained more slowly than in the clay loam lysimeter. There was a slight difference in the total amount of leachate during the cultivation period, but the amount of nitrogen leaching was high in sandy loam soil. During the sesame cultivation period, the amount of nitrogen leaching from clay soil was 5.64 kg·10 a^-1, and 10.70 kg·10 a^-1 for sandy soil. We found that there was a difference in leaching depending on the soil physical characteristics. Therefore, it is necessary to consider the characteristics of soil to evaluate the leaching of nitrogen.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.3
• /
• pp.229-233
• /
• 2011

BACKGROUND: Soil acidification, which is known to be one of the reasons of forest decline, is associated with decreases in exchangeable Ca and increases in Al concentration, leading to low Ca/Al ratio in soil solution. As tree rings are datable archives of environmental changes, Ca/Al ratios of annual growth ring may show decreasing pattern in accordance with the progress of soil acidification. This study was conducted to investigate Ca/Al pattern of Pinus densiflora tree ring in an attempt to test its usefulness as an indicator of historical soil acidification. METHODS AND RESULTS: Three P. densiflora tree disks were collected from P. densiflora forests in Jeonnam province, and soil samples (0-10, 10-20, and 20-30 cm in depth) were also collected from the tree locations. Soils were analyzed for pH and exchangeable Ca and Al concentrations, and Ca/Al was calculated. Annual growth rings formed between 1969 and 2007 were separated and analyzed for Ca/Al. Soil Ca/Al was positively (P<0.01) correlated with soil pH, suggesting that soil acidification decreased Ca while increasing Al availability, lowering Ca/Al in soil solution. The Ca/Al of tree rings also showed a decreasing pattern from 18.2 to 5.5 during the period, and this seemed to reflect historical acidification of the soils. CONCLUSION(s): The relationship between soil pH and Ca/Al and the decreasing pattern of Ca/Al of tree ring suggest that Ca/Al of tree ring needs to be considered as a proxy of the progress of soil acidification in P. densiflora forest in southern Korea.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.299-307
• /
• 2009

New lake dike in Saemanguem area is 125km length and require a great amount of fill materials, but it's difficult to get the amount of materials and develop a quarry because of environment conservation. Therefore, the solution is to use the dredged soil in project area as the fill materials not to develop quarry. However, characteristic of dredged soil as a silty fined sand is very weak at seepage, sliding, erosion of dike due to infiltration of rainfall, wind etc. So, lake dike using dredged soil must be constructed safely against the unstable problem of dredged sand. The objective of research is to make safe lake dike using dereged soil on construction of Saemangeum new lake dike. So, we analyzed the characteristic of dredged soil and suggested a standard section of lake dike.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.1073-1085
• /
• 2012

Soil microbial communities are immensely diverse and complex with respect to species richness and community size. These communities play essential roles in agricultural soil because they are responsible for most of the nutrient cycles in the soil and influence the plant diversity and productivity. However, the majority of these microbes remain uncharacterized because of poor culturability. Next-generation sequencing techniques have revolutionized many areas of biology by providing cheaper and faster alternatives to Sanger sequencing. Among them, amplicon pyrosequencing is a powerful tool developed by 454 Life Sciences for assessing the diversity of complex microbial communities by sequencing PCR products or amplicons. This review summarizes the current opinions in amplicon sequencing of soil microbial communities, and provides practical guidance and advice on sequence quality control, aligning, clustering, OTU- and taxon-based analysis. The last section of this article includes a few representative studies conducted using amplicon pyrosequencing.