• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.58-63
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• 2006

In order to elucidate the adsorption and leaching characteristics of the insecticide imidacloprid in two types of paddy soils near Suwon, this experiment was carried out with $[^{14}C]$imidacloprid as a radiotracer. In an adsorption study conducted using $[^{14}C]$imidacloprid in 2 test soils, the adsorption coefficient was higher in soil A $(K_f\;2.6)$ than that in soil B $(K_f\;1.7)$. As calculated from Freundlich constant, distribution coefficients and half lives in soils, GUS indices showed low leachabilities of imidacloprid treated on the paddy soils into the groundwater. The amount of imidacloprid leached from the soil columns during the 4 weeks of leaching was less than 2% of the originally treated $^{14}C$. In the leaching test the amounts of $^{14}C$ activities distributed in the soil layer of 0-10 cm were more than 80% of the originally tented $^{14}C$ and those in rice plants were less than 3% of the originally treated $^{14}C$, suggesting that imidacloprid has very low teachability and bioavailability.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.5
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• pp.485-500
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• 2020

Due to various advantages such as small facilities, ease of construction and so on, the grouting technology which is widely used in construction field has developed remarkably compared with the past. However, the efforts to improve the homogeneity of quality, long-term durability and environmental problems have been continued. In recent years, new grouting method has been developed in order to solve problems such as low strength, durability and leaching phenomenon of liquid glass (sodium silicate) grouting material in Korea. A newly developed method integrates the injection material with the ground by the self-healing material of crystallization growth type. For this reason, it is known that improvement of the durability and water quality of the ground, prevention of leaching, and environment friendliness can be expected. The present study applied a newly developed method to test sites and verified its effect such as injection range, improvement effect, waterproofing performance and so on. Standard penetration test, field permeability test, borehole shear test, pressuremeter test and pH test were conducted, and the results were compared between before and after developed method application. As results of tests, the field applicability and improvement effect of developed method were proved to be excellent.

• Korean Journal of Medicinal Crop Science
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• v.6 no.3
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• pp.216-220
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• 1998

The objectives of this study were to evaluate the effects of some seed pretreatments on seed germination, emergence, growth and yield of Bupleurum falcatum L. Seed treatments included stratification in open-field during winter, washing with running water, low temperature storage, soaking into $H_2SO_4$ solution, and scarification. Germination increased 15% by stratification and 9% by washing treatment compared to non-treatment, control. It was suggested that washing treatment leached inhibiting substance, while stratification treatment leached inhibiting substance and promoted growth of immatured embryo. In the field mulched with rice straw, stratification and washing treatments were effective to shorten days to emergence by 31 and 21 days and to increase emergence rate by 7 and 5 %, respectively, compared with control. By these two treatments, root growth was improved, the number of harvested plants was increased considerably and dry root yield per ha were increased by 29 and 22 %, respectively, compared with control.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.128-133
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• 1997

This study was conducted to evaluate the adsorption, desorption, leaching and degradation pattern of fungicide fluazinam in the soil environment under the laboratory conditions. The mode of isothermal adsorption of fluazinam in soil was coincident with the Freundlich equation. The adsorption amount of fluazinam was much higher on soils containing organic matter than on soils oxidized with hydrogen peroxide. The presence of organic matter, humic acid or fulvic acid, increased the adsorption amount of fluazinam on soils. The Freundlich constant K was much higher in soil added with humic acid than in soil added with fulvic acid. The desorption ratio of fluazinam adsorbed to soil was increased by removal of organic matter. In leaching experiment using soil column, the fluazinam applied on the soil surface was not moved down to the bottom of soil and was not detected in leachate water. The degradation of fluazinam was faster in Soil I with rich organic matter than Soil II with poor organic matter, in non-sterilized soil than sterilized soil, and in flooded soil than unflooded soil.

• Journal of the Korean GEO-environmental Society
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• v.12 no.4
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• pp.17-24
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• 2011

For the purpose of cut off and ground stabilization, water glass chemical grouting method using sodium silicate has problems of weakening durability and ground water pollution because leaching was conducted when the homogel is exposed to the ground water as time elapses. The purpose of this study is to identify the effect of alkali silica sol ground injection materials, it was compared with the sodium silicate ground injection materials using water glasses. For sodium silicate and alkali silica sol by mixing each case is divided into four different specimens were made and tested. The characteristic of alkali silica sol ground injection material was analyzed by unconfined compression test and environmental impact statement of ordinary portland cement and blast furnace slag cement. Alkali silica sol specimens were made mixing A-solution and B-solution in the proportion of one on one. Through this study, alkali silica sol ground injection mixing blast furnace slag cement has excellent strength and environment-friendly.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.1
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• pp.35-40
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• 1991

A laboratory column experiment was conducted to learn the desalinization effect of rice straw, fresh or predecayed in limed marine soil, compared with gypsum. One third of Ca equivalent to indigenous Na plus Mg of the soil was applied to the top 10g out of 80g of total column soil, mixing one half of it to the top soil and the rest spreading on the surface. 1. Pre-decaying of rice straw in limed marine soil promoted the permeability of column soil. but showed a less effectiveness in desalinization of sodium than lime alone or lime plus fresh rice straw treatemenents. 2. Gypsum and calcium carbonate treatments without rice straw fixed Mg in the limed top soil and washed it down disolving more from the layer immediatly be low the treated top soil But the treatment of calcium carbonate and rice straw both together washed out Mg more from lower layers than the upper's, showing only physical desalinization. 3. The desalinization of Na was also severe in the layer immediately below the $CaSO_4$ treated top soil, leauing more Na ilo the top soil, which seemed to be attributed to the peptisation of the top soil and retard peptisation of desalinization when washed the soil applying not enough amount or non of gypsum.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.15-20
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• 2016

The grouting method, which can be used to effectively improve small areas within a short amount of time, may have different injection effects depending on the ground conditions and the levels of a water table. In particular, for ground with a relatively large permeability, the strength of the ground and the water proof ability can decrease over time due to the leaching process. To solve this problem, a "self-healing smart grouting (SSG) method", which was designed to maintain the initial strength of the ground by minimizing the leaching process, was developed recently. In this study, uniaxial compression tests were carried out on SSG samples to understand the strength of SSG over curing time where two different curing temperatures have been applied for comparison. The uniaxial compression strength of SSG was further compared with the samples prepared using conventional methods (LW and SGR). The test results showed that the uniaxial compression strength of SSG was higher at both high and low curing temperatures compared to that of the samples prepared using conventional methods. The initial strength of SSG was also relatively higher.

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.177-182
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• 2007

When a football field is constructed using sand medium, the fertilizer management has to be adjusted because of the low nutrient holding capacity and higher leaching rate. The objective of this study was to test the effects of slow release fertilizers on Kentucky bluegrass (Poa pratensis L.) growth in simulated sport field rootzones with PVC pipe pots. Data of turfgrass color, uniformity, growth rate, biomass above ground, and the nitrate content in the leaching solution was collected at different growing stages and during four simulated rain fall periods. The result showed that the nutrient release rate of urea was the highest and that of controlled release nitrogen fertilizer was the lowest. Effects of the controlled release nitrogen fertilizer lasted 14 days more than other lawn fertilizers and 28 days longer than regular urea with acceptable quality levels of turf. The slow release fertilizer also restrained excessive growth of the grass, reduced the times of mowing. Slow release fertilizer used in this study reduced $NO_3$-N leaching by almost 50% at the beginning of turf establishment.

• Journal of the Korean Geosynthetics Society
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• v.21 no.3
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• pp.29-39
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• 2022

The engineering characteristics of synthetic polymer-silica sol, which has the effect of reducing leakage, was evaluate and compared with typical grouting material, the water glass-based SGR injection material in this study. The result of the laboratory tests on strength and durability about the synthetic polymer-silica sol showed more than twice as high as LW-based injection materials in uniaxial compressive strength, significantly lower values in shrinkage rate and permeability. The result of pH was less than 8.5 (the drinking water quality standard). As a result of the leaching test, the Na₂O elution amount of the synthetic polymer-silica sol was measured to be 3 to 4 times smaller than that of the water glass grout. These results be assumed that the synthetic polymer-silica sol has better durability and permeability than those of the typical water glass-based grout.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.2
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• pp.168-174
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• 1992

This study was carried out to find out the distribution of soil components and their relationships in layer of soil profiles under upland condition. Concentrations of nitrate, chloride, and that sort of thing in soil profiles were tested in a field covering $235m^2$ by core sampling down to 150cm depth. Total nitrogen contents in soil profiles progressively decreased in lower depths down to 150cm. Nitrate concentrations in deeper layers than 110cm, which revealed a similar distribution pattern with total nitrogen down to 110cm, increased with the depth lowering to 150cm, indicationg that nitrate has leached to deep layer. Natural abundance of $^{15}N$ in total nitrogen and nitrate in all the soil profiles showed higher values compared with the other general cultivated soils and trended to get higher in deeper layers. The horizontal variation of $^{15}N$ distribution in the field surveyed was not significant. Chloride concentrations and EC values in soil profiles increased with depth where nitrate was accmulated, and showed a highly positive correlation between them.