• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.17-23
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• 2011

This research was conducted to investigate the influence of application rate of liming fertilizers on changes in soil chemical properties and growth of 'Red Madness' petunia in plug production. To achieve this, dolomite (DO) with 0, 1.0, 3.5, 8.0 or 13.0 $g{\cdot}L^{-1}$ and calcium carbonate (CC) with 0, 2.0, 2.5, 3.0, 3.5, or 4.0 $g{\cdot}L^{-1}$ were incorporated into peatmoss + vermiculite (1:1, v/v) during the root substrates formulation. The treatments of 3.5 $g{\cdot}L^{-1}$ of DO and 2.5 or 3.0 $gL^{-1}$ of CC had acceptable ranges of pH and EC in soil solution such as 5.6~6.2 and 0.7~1.0 $dS{\cdot}m^{-1}$, respectively. The faster rising of pH was observed in root media containing CC rather than those of DO. This indicates that the solubility of CC is higher than DO. The soil Ca concentrations in all treatments of CC were 1.8 times as high as those of DO. The treatments of 3.5 or 8.0 $g{\cdot}L^{-1}$ of DO had the highest soil Mg concentrations, but all treatments of CC had lower soil Mg concentrations than control treatment indicating that additional application of Mg fertilizers are required. The elevated application rate of DO or CC resulted in the increase of fresh and dry weight. But plant heights were not influenced by application of liming fertilizers. The results of tissue analysis showed that application of DO or CC influenced the $PO_4{^-}P$, Ca and Mg contents, but not influenced the contents of other nutrients such as N, P, Fe, Mn, Zn and Cu.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.369-376
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• 2007

This experiment was carried out to investigate optimum conditions of coir-based substrates for the red pepper plug seedlings. Eleven different coir based substrates prepared by mixing of coir, vermiculite, rice hull, perlite, zeolite, mixed at different ratios were tested. The physical and chemical properties of the substrates were analyzed by the CEN (European committee for standardization) method. Fresh and dry weights of shoot and root, leaf area, root length, and T/R ratio (dry shoot weight/dry root weight) were determined at 55 days after sowing. The results showed that the growing media CRZ 8(coir:rice hull: vermiculite=8:1.9:0.1) and CVSZ 6(coir:silver vermiculite: zeolite=6:3.9:0.1) can successfully be used for pepper plug seedlings judging from dry weight and T/R ratio of the plug seedlings. The optimal range of total pore space, water volume, air volume, easily available water content and water buffering capacity of the coir-based growing substrates for pepper plug seedlings were in the range of 92~94%, 52~60%, 32~43%, 18~21%, and 0.9~8%, respectively.

• Journal of Soil and Groundwater Environment
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• v.20 no.6
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• pp.85-94
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• 2015

RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) is the most important explosive contaminant, both in concentration and in frequency, at military shooting ranges in which green technologies such as phytoremediation or constructed wetlands are the best option for mitigation of explosive compounds discharge to the environment. A study was conducted with two identical lab-scale plug flow constructed wetlands planted with Amur silver grass to treat water artificially contaminated with 40 mg/L of toxic explosive compound, RDX. The reactor was inoculated with or without RDX degrading mixed culture to evaluate plant-microorganism interactions in RDX removal, transformation products distribution, and kinetic constants. RDX and its metabolites in water, plant, and sediment were analyzed by HPLC to determine mass balance and kinetic constants. After 30 days of operation, the reactor reached steady-state at which more than 99% of RDX was removed with or without the mixed culture inoculation. The major transformation product was TNX (Trinitroso-RDX) that comprised approximately 50% in the mass balance of both reactors. It was also the major compound in the plant root and shoot system. Acute toxicity analysis of the water samples showed more than 30% of toxicity reduction in the effluent than that of influent containing 40 mg/L of RDX. In the Amur silver grass mesocosm seeded with the mixed culture, the specific RDX removal rate, that is 1st order removal rate normalized to plant fresh weight, was estimated to be 0.84 kg⁻¹ day⁻¹ which is 16.7% higher than that in the planted only mesocosm. Therefore, the results of this study proved that Amur silver grass is an effective plant for RDX removal in constructed wetlands and the efficiency can be increased even more when applied with RDX degrading microbial consortia.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.235-241
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• 2000

The existing methods for installation of long steel pipe pile have some uneconomical problems such as increase of installation cost and period due to the welding of two piles and removal of soil plug, and decrease of driving efficiency due to the increase of driving resistance resulting from time effect during the welding of piles and removal of soil plug, etc. Thus, in this study, new installation method for long steel pipe pile is suggested to solve the existing problems, and calibration chamber tests were performed to investigate both driving and economical efficiency for the suggested method. The test results showed that the new method increased bearing capacity, and decreased the installation cost and period for long steel pipe piles compared with existing methods.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.269-272
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• 2004

The use of colloidal gas aphron (CGA), as an external oxygen carrier, provides a promising alternative to promote aerobic bioremediation of BTEX in the subsurface environment. CGA is a stable bubble supported by three surfactant layers and can supply oxygen below the soil surface uniformly due to its plug-flow characteristic. Since CGA has a hydrophobic layer that can act as a partitioning medium for hydrophobic contaminants it is known to facilitate desorption of soil-sorbed contaminants. In addition, bioaugmentation and biostimulation are possibly achieved by using CGA when generated from a solution containing BTEX-degrading microorganisms and appropriate nutrients. In this study, we presented the physico-chemical characteristics of CGA generated from a solution composed of microorganisms and nutrients. The applicability of CGA as an in situ aerobic bioremediation technology of BTEX will be further evaluated.

• Journal of Biosystems Engineering
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• v.26 no.3
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• pp.253-262
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• 2001

This study was conducted to develop the vision system of a robotic transplanter for plug-seedling. A color image processing algorithm was developed to identify and locate empty cells and bad plants in the seedling tray. The image of pepper and tomato seedling tray was segmented into regions of plants, frame and soil using threshold technique which utilized Q of YIQ for finding leaves and H of HSI for finding frame of tray in the color coordinate system. The recognition system was able to successfully identify empty cells and bad seeding and locate their two-dimensional locations. The overall success rate of the recognition system was about 99%.

• Korean Journal of Organic Agriculture
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• v.5 no.2
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• pp.125-140
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• 1997

This experiment was carried out to investigate the effects of compost mixed with microorganism compost fermented for the production of high quality plug seedlings of tomato and red pepper. The results are summarized as follows. As a result of compost analysis, EC value was increased with increment of microorganism compost supplemented but lowered gradually in the late period of seedlings growth, pH value of microorganism compost fermented was 9.3 which is strong alkalinity. In the plot of 30 percent of microorganism compost fermented early growth of tomato seedlings was better in terms of plant height, leaf area and total dry weight. However, early growth of red pepper seedlings was shown in the plot of supplemented with 20 percent of microorganism compost fermented. The higher the mixing rate over 60 percent of micrroganism compost fermented to the soil used retarded the seedlings growth regardless of tomato and red pepper.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.59-69
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• 2019

This study was carried out to investigate effects of soil water content on growth and antioxidative enzymes activity of tomato seedlings during the nursery period. The water stress significantly damages morphological, physiological, and biochemical activities in plants. The seedlings planted with soil on the tray were irrigated and categorized into 3 groups with 30 g, 40 g, and 50 g of plant-soil weight. After then, the changes in weight of the soil and the seedling were measured evey 2 hours for 4 days and the leaf temperature was measured with the thermal-camera at the same time. The antioxidant enzymes were measured to determine the level of stress using all of the seedling samples. The result showed that the decrease of soil weight in the day time was faster than that in the night time, but there was no significant difference in the weight loss of the seedlings and soil among the groups. However, the group with 50 g of wight showed the highest SOD and POD contents. This is considered that the continuously wet soil on the root zone of the seedlings caused more stress for the seedlings. Therefore, it is concluded that the excess moisture content causes stress to stimulate the secretion of antioxidant enzymes, and the effect of stress is required to be analyzed comprehensively using environmental data and also the physiological data that are collected over a longer period.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.147-151
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• 2003

Normal seed tubers and plug seedlings raised from stem cutting and mini-tubers ($10\pm3$ g) were planted or transplanted on August 20,2001 in bare soil or under transparent and black polyethylene film mulches to evaluate the effects of mulch material and seedling type on the growth and tuber yield of fall-grown potato (Solanum tuberosum L. cv. Dejima) in Jeju region. Total tuber number per plant was 4.6 regardless of mulch treatment, and direct planting seed potatoes resulted in the greatest tubers (5.14)/plant and followed by transplanting seedlings raised from cutting and mini-tubers (4.15 and 5.15 tubers/plant). Transparent and black polyethylene film mulches increased total tuber yield by 16 and 8%, respectively, and average tuber weight by 14 and 12%, respectively, compared with no mulch (21.16 t/ha and 72.2 g/tuber). Transplanting plug seedlings raised from cutting resulted in the greatest tuber yield, followed by transplanting plug seedlings raised from mini-tubers and direct planting seed potatoes.

• Geotechnical Engineering
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• v.12 no.2
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• pp.85-94
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• 1996

Model pile tests, using a calibration chamber in which the stress state and the relative density can be controlled, were performed in order to study the effects of pile diameter on the plugging rate and bearing capacity of open-ended pile. The model piles used in the test series were devised so that the bearing capacity of an open-ended pile could be measured out into three components. The test results showed that fully plugging depth of an open -ended pile increased with increase in pile diameter and soil density. Moreover, it was found that unit plug capacity decreased with increase in pile diameter, though the penetration ratio or plugging rate of piles was constant. However, the existing formulae for estimation of plug capacity give plug capacity which is constant or increased with increase in pile diameter, when penetration ratio or plugging rate of piles is equal. Thus, it is proposed that the effect of pile diameter as well as plugging rate on bearing capacity of pile must be considered in plug capacity estimation.