• Journal of Animal Environmental Science
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• v.19 no.1
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• pp.47-54
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• 2013

Two types of reactors were set to investigate the change of characteristics of pig slurry by aeration during fertilization period. One system was equipped with air diffuser to supply oxygen to pig slurry for liquid fertilization, but there was no air diffuser in the other system. Air supply to the experimental systems was regulated by air flow meter. The reactors were set up in the laboratory to protect the pig slurry from external condition such as temperature and humidity changes. Maintaining optimal pH range in the experimental reactors is an important factor for liquid fertilization of pig slurry. In this study, pH ranges of aerobic reactor and anoxic reactor was 7.04~7.19 and 7.34~7.81, respectively. The temperature of aerobic reactors was $2{\sim}3^{\circ}C$ higher then indoor temperature. The amount of sludge accumulated at the bottom layer of non-aerated reactors was 4~5 times more than that of aerated reactors.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.871-879
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• 2022

An increasing global population requires a greater food supply, and accordingly there is demand for enhanced production of rice, as a major crop plant that covers half of the world's population. Rice production in arid area is extremely difficult due to poor soil fertility, salinity, deficit of irrigation water, and weather conditions. The aim of the present study was to determine whether various fertilization recipes could provide a countermeasure to allow rice production while also providing soil amendment such as soil pH adjustment. The study was conducted at an experimental field of the United Arab-Emirates (UAE) from January to April, 2022. Rice seedlings (cv. Asemi, alkaline-resistant) were transplanted in plastic containers, and different types of water and nutrient managements were employed as follows: water management (flooding and aerobic for NPKs treatment group) and nutrient management (NPKs, slow release fertilizers [SRFs] and SRFs + NPK-1 treatment groups with flooding). Water and nutrient management did not show any effect on soil pH adjustment. Rice growth was significantly enhanced in the flooding compared to the aerobic condition, whereas the effect of nutrient management clearly differed among the treatment groups, with SRFs + NPK-1 showing the best results followed by SRFs and NPKs. Most of the fertilization groups markedly accumulated soluble sugars in the shoots and grains of rice plants, but concomitantly a decrease in the roots. Overall, the level of starch showed a tendency of relatively slight perturbation by fertilization. Taken together, the results indicate that soil physical structure should be preferentially amended to find the key for suitable rice production.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.119-122
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• 2006

In both untreated and conventionally stabilized swine manures antibiotic resistant (AR) microorganisms, Staphylococcus-like and Salmonella-like microorganisms were detected. Also pathogens with MAR phynotype were detected. Presence of such microorganisms suggest high level of pathogen-related health risk to farmers who may be in direct contact with the manure and its conventionally stabilized product In contrast the autothermal thermophilic aerobic digestion (ATAD) treatment have efficiently reduced AR and pathogenicity from the swine manure. When soil was fertilized using swine manure and its stabilized products, despite no detection of MAR-exhibiting pathogen-like microorganisms in fertilized soil, potential pathogen-related health risk could not be ruled out from the fertilized soil since the organic fertilization led to increase in AR and pathogenicity in the soil microbial communities. As conclusion, this microbiological study demonstrated that an ATAD process is applicable in control of pathogen-related health risk in livestock manure.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.5
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• pp.47-52
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• 2010

The purpose of this study is to investigate characteristics of total phosphorus (TP) and phosphate phosphorous ($PO_4$-P) concentrations in ponded water and redox potential (Eh) in paddy soil during the growing season. The TP and $PO_4$-P concentrations showed twice peak values after basal dressing and tillering fertilization. The ratio of $PO_4$-P to TP showed low values (0.07~0.18), indicating that most of phosphorus is particlulate. The $PO_4$-P concentrations significantly decreased with dissolved oxygen (DO) concentrations. The Eh showed high values (179~636 mV) under non-ponded aerobic condition, but low values (74~112 mV) under ponded anaerobic condition The TP and $PO_4$-P concentrations in ponded water increased shortly after tillering fertilization even if phosphorus was not applied. This may be due to the release of dissolved phosphorus from the bottom sediment and its associated algal and water flea blooms under anaerobic condition. Therefore, proper water management should be needed shortly after tillering fertilization.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.118-126
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• 2012

In this study, two types of ozone generating experimental instrument were installed in commercial livestock manure fertilization facility, which can treat hundred tons of pig manure in a day. Gas samples to be treated were collected from the upper part of the liquid fertilization system and composting system of the commercial livestock manure fertilization facility. The gas sample was flowed to oxidation reactor through pipe line by suction blower, therefore, contacted with ozone. Ammonia and sulfur compounds of gas samples collected from the inlet and outlet point of the experimental instrument were analyzed. The oxidation effect by the contact with ozone was higher in sulfur compounds than ammonia. Ammonia content was reduced about 10% by ozone contact. Sulfur compounds, on the other hand, reduced significantly while treated with ozone. In case of gas sample collected from liquid fertilization system, the concentrations of hydrogen sulfide ($H_2S$), methyl mercaptan (MM), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS) of inlet gas were 50.091, 4.9089, 27.8109 and 0.4683 ppvs, respectively. After oxidized by ozone, the concentrations of sulfur compounds were 1.2317, 0.3839, 14.7279 and 0.3145 ppvs, respectively. Another sample collected from aerobic composting system was oxidized in the same conditions. The concentrations of $H_2S$, MM, DMS and DMDS of the sample collected from inlet point of the reactor were 40.6682, 1.3675, 24.2458 and 0.8289 ppvs, respectively. After oxidized, the concentrations of $H_2S$, MM, DMS, and DMDS were reduced to 3.013, ND, 8.8998 and 0.3651 ppvs, respectively. By application of another type of ozone, the concentrations of $H_2S$, MM, DMS and DMDS of inlet gas were reduced from 43.397, 1.4559, 3.6021 and 0.4061 to ND, ND, ND, and 0.21ppvs, respectively.

• Applied Biological Chemistry
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• v.49 no.3
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• pp.175-179
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• 2006

This study was carried out to investigate the change of rhizosphere microflora in paddy soils of long-term application of same fertilizer by single cropping. Treatments consisted of no fertilizer, NPK, PK, NK, NP and NPK + compost and the same fertilizer has been applied to the soil of each treatment for thirty five years. Any remarkable difference of the microbial population structure was not detected from the rhizosphere of Hwayeongbyeo and that of Hwasambyeo. However, slight difference of dominant microbial species in the rhizosphere was recognized between different fertilization practice. The bacterial population in the rhizosphere was steadily reduced over time after rice plant setting out, while actinomycetal population was increased over time. The increase of actinomycetal population was the highest in the NPK + compost treatment, suggesting the effect of organic matters in the change of actinomycetal population. As for the aerobic culturable bacterial diversity, Bacillus megaterium, B. mycoides, B. licheniformis and B. subtilis were dominants in genus Bacillus, and Streptomyces spororaveus, S. canus, S. tauricus and S. galbus in genus Streptomyces and genus Micromonospora was another dominant in actinomycetes.

• Journal of Microbiology
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• v.33 no.4
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• pp.273-277
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• 1995

Although trout farming is well established in Korea, very little information is available on the composition of intestinal microflora in rainbow trout (Salmo gairdnerii). In 1994, from October through November, we investigated the composition and succession of intestinal bacteria. As fish grew, total viable counts increased dramatically until 45 days after fertilization when anaerobes started to appear on the media. After this time, they increased steadily. Ten aerobic generic were identified and Gram negative bacteria constituted 85% of total isolates. Among these, Pseudomonas, Eikenella, and Alcaligenes were the three major genera. Six anaerobic genera were isolated and identified. The ratio of anaerobes to aerobes was about 1 : 1 in adult trout and the composition of genera was changed under different conditions.

• Environmental Engineering Research
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• v.12 no.4
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• pp.129-135
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• 2007

This study evaluated microbial risk that could develop within soil microbial communities after amended with organic fertilizers from stabilized swine manure waste. For this purpose, we assessed the occurrences and competitiveness of antibiotic resistance and pathogenicity in soil microbial communities that were amended with swine manure wastes stabilized by a traditional lagoon fermentation process and an autothermal thermophilic aerobic digestion process, respectively. According to laboratory cultivation detection analysis, soil applications of the stabilized organic fertilizers resulted in increases in absolute abundances of antibiotic resistant bacteria and of two tested pathogenic bacteria indicators. The increase in occurrences might be due to the overall growth of microbial communities by the supplement of nutrients from the fertilizers. Meanwhile, the soil applications were found to reduce competitiveness for various types of antibiotic resistant bacteria in the soil microbial communities, as indicated by the decrease in relative abundances (of total viable heterotrophic bacteria). However, competitiveness of pathogens in response to the fertilization was pathogens-specific, since the relative abundance of Staphylococcus was decreased by the soil applications, while the relative abundance of Salmonella was increased. Further testes revealed that no MAR (multiple antibiotic resistance) occurrence was detected among cultivated pathogen colonies. These findings suggest that microbial risk in the soil amended with the fertilizers may not be critical to public health. However, because of the increased occurrences of antibiotic resistance and pathogenicity resulted from the overall microbial growth by the nutrient supply from the fertilizers, potential microbial risk could not be completely ruled out in the organic-fertilized soil samples.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.8-14
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• 2015

Livestock waste compost tea is a liquid extract of compost obtained by mixing livestock compost. In this study, some chemical and microbiological characteristics of compost tea depending on the kind of raw materials used were examined, and several experiments to investigate the practical effects on Chinese cabbage cultivation were conducted. This experiment showed that livestock composts needed to be added into aerated water at the ratio between 1:100 and 1:10 (1 part compost to 10~100 parts water) to produce the high quality compost tea. Compost teas must be aerated more than 24 to 48 hours to be able to support aerobic organisms. In cultivation test with compost teas, swine manure compost teas were made by the extracting ratio of 50x, in the aerated condition for 24 hours in water and oil cake in the extracting ratio of 100x were added as supplements. Following the input of oil cake, the concentration of nitrogen and aerobic bacteria increased. Another experiment was conducted to determine the effect of different swine manure compost teas on plant growth and yield of Chinese cabbage. The fresh yield of Chinese cabbage was higher in the fertigated plots by compost tea with oil cake compared to those of N, $P_2O_5$, $K_2O$ fertilization plot with chemical fertilizer by soil test recommendation (Fert. NPK). The effect of compost tea on growth of Chinese cabbage was largely attributable to the increased number of microorganisms as well as nutrients.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.751-760
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• 2015

Management of renewable organic resources is important in attaining the sustainability of agricultural production. However, nutrient management with organic resources is more complex than fertilization with chemical fertilizer because the composition of the organic input or the environmental condition will influence organic matter decomposition and nutrient release. One of the most effective methods for estimating nutrient release from organic amendment is the use of N mineralization models. The present study aimed at parameterizing N mineralization models for a number of organic amendments being used as a nutrient source for crop production. Laboratory incubation experiment was conducted in aerobic condition. N mineralization was investigated for nineteen organic amendments in sandy soil and clay soil at $20^{\circ}C$, $25^{\circ}C$, and $30^{\circ}C$. N mineralization was facilitated at higher temperature condition. Negative correlation was observed between mineralized N and C:N ratio of organic amendments. N mineralization process was slower in clay soil than in sandy soil and this was mainly due to the delayed nitrification. The single and the double exponential models were used to estimate N mineralization of the organic amendments. N mineralization potential $N_p$ and mineralization rate k were estimated in different temperature and soil conditions. Estimated $N_p$ ranged from 28.8 to 228.1 and k from 0.0066 to 0.6932. The double exponential model showed better prediction of N mineralization compared with the single exponential model, particularly for organic amendments with high C:N ratio. It is expected that the model parameters estimated based on the incubation experiment could be used to design nutrient management planning in environment-friendly agriculture.