• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.62-69
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• 2014

In the results of monitoring nitrate concentration in more than 8,000 groundwater wells around agro-livestock, the average and maximum nitrate concentration was 9.4 mg/L and 101.2 mg/L, respectively. Since about 31% of the monitoring wells was exceed the quality standard for drinking water, nitrate control such as remediation or source regulation is required to conserve safe-groundwater in South Korea. Typical nitrate-treatment technologies include ion exchange, reverse osmosis, and biological denitrification. Among the treatment methods, biological denitrification by indigenous microorganism has environmental and economic advantages for the complete elimination of nitrate because of lower operating costs compared to other methods. Major mechanism of the process is microbial reduction of nitrate to nitrite and nitrogen gas. Three functional genes (nosZ, nirK, nirS) that encode for the enzyme involved in the pathway. In this work, we tried to develop simple process to determine possibility of natural denitrification reaction by monitoring the functional gene. For the work, the functional genes in nitrate-contaminated groundwater were monitored by using PCR with specific target primers. In the result, functional genes (nosZ and nirK) encoding denitrification enzymes were detected in the groundwater samples. This method can help to determine the possibility of natural-nitrate degradation in target groundwater wells without multiplex experimental process. In addition, for field-remediation application we selected nitrate-contaminated site where 200~600 mg/L of nitrate is continuously detected. To determine the possibility of nitrate-degradation by stimulated-natural attenuation, groundwater was sampled in two different wells of the site and nitrate concentration of the samples was 300 mg/L and 616 mg/L, respectively. Fumarate for different C/N ratio was added into microcosm bottles containing the groundwater to examine denitrification rate depending on carbon concentration. In the result, once 1.5 times more than amount of fumarate stoichiometry required was added, the 616 mg/L of nitrate and 300 mg/L of nitrate were completely degraded in 8 days and 30 days. The nitrite, byproduct of denitrification process, was also completely degraded during the experimental period.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.413-418
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• 1985

Tobacco plant(8-leaf seedlings) were grown on water culture fertilized with different N sources ($NO_3-N$, $NH_4-N$, $NO_3+NH_4-N$) during 15 days. Daily uptake of nutrients and inorganic constituents in plants were investigated in relation to growth responses of them. 1. Nitrate-fed plant showed higher daily uptake of inorganic cations than those in other treatments, and reached about two times higher uptake of nitrogen and three times more uptake of cations (K, Ca, Mg). Potassium was preferentially uptaken at a very fast rate from the beginning after treatment. Also $NO_3-N$ tended to be taken up selectively by the plant from the mixture of nitrate and $NH_4-N$. 2. The initial pH (pH 6.0) of culture medium drastically changed into acid (pH 4.0) in the $NH_4-N$ medium, but into slightly higher (pH 6.4) in the nitrate when measured after exposure of 24 hours. The mixture also tended to show an acidity but much weaker than $NH_4-N$ solution. 3. Nitrate-fed plant had a normal growth pattern but $NH_4-N$ fed plant almost stopped growing. Those plants containing both nitrate and ammonium N were also showed very poor growth.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.1
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• pp.27-32
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• 1971

In 1969, a pot experiment with four replications of 10 treatments including control(without potash) was carried out in order to study the effect of potash top-dressings in the condition of heavy nitrogen application on rice. The results obtained may be summarized as follows. 1. When potash was applied 70% as basic dressing and 30% as top-dressing at ear-formation stage, a considerable increase of the yield of paddy was obtained as compared to the treatment of the whole amount of potash as basic dressing. 2. The antagonism phenomenon of $K_2O$ contents with N contents in the plants appeared to be severe at the maximum reduction division stage and ear-formation stage is next. 3. $K_2O/N$ ratio gave a positive correlation with the yield components before heading and specially, $K_2O/N$ ratio at heading stage was considerably correlated with ripening percentage.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.77-84
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• 1998

In order to investigate microbiological control of malodors, particularly including ammonia, the effect of three thermophilic ammonium tolerant bacteria strains. TAT112. TAT117 and TAT119, were tested during composting of pig manure in the laboratory scale composters. The total weight, volatile solids and BOD of the pig manure compost were decreased during composting process in all treatments. The temperature in all treatments rose in first 3 days dramatically, but that in control without inoculation reached its maximum most lately among the treatments. The nitrogen content of drain water accumulated inside and outside composter, and trapped in 6N $H_2SO_4$ was lower in TAT112 inoculated composter than in control. However, it was not lower in the treatment of TAT117 and TAT119 inoculated. Ammonia concentration in the exhaust gas monitored everyday during composting also demonstrated that it was lowest at TAT112 inoculated among all treatments. It was appeared to have an effect on reducing ammonia emission at the treatment of TAT112 inoculated than the control.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.762-766
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• 2011

Cropping system is very important for environment conservation and improvement of nutrient recovery rates in agricultural land. This case study was conducted to identify the nutrient balance of major upland cropping types with different districts. Typical cropping systems at MuAn and HaeNam located in the south coast district were cultivated with soybean-chinese cabbage or garlic and garlic-soybean-chinese cabbage-hot pepper. Alpine district, PyeongChang was cultivated with double cropping of chinese cabbage and potato-radish or chinese cabbage for one year. Typical cropping type of AnDong, YeongYang where are well known for hot pepper cultivation was hot pepper's mono cropping and hot pepper-soybean or hot pepper-sesame for one year. But SeoSan and HongSeong, where are located in mid-west coast had variety cropping system compareed to other districts. Double cropping of chinese cabbage, a heavy fertilizing crop, caused higher nutrient balance in the field when it was cultivated consistently. Experiment showed that heavy fertilizing crops, such as chinese cabbage, garlic and onion, need to be rotated with soybean and sesame cultivation which need smaller fertilizer level. Alpine arable land has shown higher nutrient balance than other areas, and the introduction of rotation crops are needed to reduce nutrient balance and environmental protection.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1103-1106
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• 2011

Optimum application level of liquid pig manure for increasing Astragalus sinicus L. (ASASI) and Lolium multiflorum Lam. (LOLMU) yield was investigated. The green manure crop yield were generally high in the order of ALPM 100 ${\geqq}$ APLM 75 ${\geqq}$ APLM 50 ${\geqq}$ APLM 0 in site 1 (ASASI), and LPLM 100 ${\geqq}$ LPLM 75 > LPLM 50 ${\geqq}$ LPLM 0 in site 2 (LOLMU). The optimum application level of liquid pig manure was 100% of nitrogen fertilization level.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.403-412
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• 2021

This study aimed to identify plant growth-promoting activity, phytopathogenic fungi growth inhibitory activity, mineral solubilization ability, and extracellular enzyme activity of the genus Bacillus in soil and the rhizosphere. With regards to antifungal activity against phytopathogenic fungi, DDP257 showed antifungal activity against all 10 pathogenic fungi tested. ANG20 showed the highest ability to produce indole-3-acetic acid, a plant growth-promoting factor (70.97 ㎍/ml). In addition, 10 species were identified to have 1-aminocyclopropane-1-carboxylate deaminase production ability, and most isolates showed nitrogen fixation and siderophore production abilities. Thereafter, the isolated strains' ability to solubilize minerals such as phosphate, calcite, and zinc was identified. With extracellular enzyme activity, the activity appeared in most enzymes. In particular, all the strains showed similar abilities for alkaline phosphatase, esterase (C4), acid phosphatase, and naphtol-AS-BI-phosphohydrolase production. This result was observed because the genus Bacillus secreted various organic substances, antibiotics, and extracellular enzymes. Therefore, through the results of this study, we suggest the possibility of using strains contributing to the improvement of the soil environment as microbial agents.

• Korean Journal of Organic Agriculture
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• v.29 no.1
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• pp.111-123
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• 2021

This study was conducted to investigate the growth characteristics of strawberries and N₂O emission by treating the compost for each type of livestock manure, which was an organic farming material, as a basal fertilization in plastic film house. Livestock manure compost, which made from cattle manure, swine manure, and poultry manure as raw materials, were applied to this experiment, treated by mixing or single on the basis of nitrogen content with the standard amount of fertilizer for strawberries. Total emission of N₂O were 10.7% higher than those in poultry manure compost treatment compared to the inorganic fertilizer treatment, but 16.5~41.9% lower than those in other livestock manure compost treatment. The period of N₂O emission mainly was up to the 17th day after fertilizer application, accounting for 70~87% of the total amount of discharge, and 13~30% of the total amount was emitted for 158 days later. N₂O emission was decreased significantly NH₄⁺-N content in the soil, and increased NO₃^--N. As compared with control, the number of leaves, leaf width and crown diameter of livestock manure compost treatments were not significantly different, leaf length of cattle+poultry, cattle+ swine, swine+poultry treatment higher, and SPAD (soil plant analysis development) values of cattle+poultry treatment highest. There was no significant difference in weight and sugar content of strawberry fruits among treatments.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.356-361
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• 2022

Bacillus sp. is a useful strain for agriculture because it promotes plant growth and controls plant pathogens through a variety of mechanisms. In this study, we obtained a microbial preparation with a high number of viable cells by culturing newly isolated soil bacteria on an optimized medium. Subsequently, we applied this preparation to lettuce to enhance its growth and yield. First, B. amyloliquefaciens ISP-5 was isolated from soil. Next, optimization of culture medium was carried out using 5 L scale fermenters. When culturing B. amyloliquefaciens ISP-5 on this optimized medium, the number of viable cells was approximately 1000 times higher than that obtained from culturing on the commercial medium. Afterwards, the plant growth promotion properties of the ISP-5 strain were evaluated using lettuce as a test plant. Foliar spray treatment of lettuce was carried out by inoculating half the standard concentration suspension (0.5 × 10⁷ cfu/ml). As a result, leaf width increased by 8.6% and leaf length increased by 12.9% compared to the control group. Live weight also increased by 24.2% and dry weight by 23.9%. Considering the results from field test, B. amyloliquefaciens ISP-5 showed potential as a plant growth-promoting bacteria.

• Journal of agriculture & life science
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• v.50 no.4
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• pp.27-34
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• 2016

Sclerotium rolfsii is a well known broad host range soil borne plant pathogenic fungus and caused serious damage to various vegetable crops. To develop an effective biological control agent for S. rolfsii, an isolate which showed strong inhibitory effect on the mycelial growth of S. rolfsii was selected among the antagonistic bacterial isolates collected from vinyl-house soil. The bacterial isolate was identified as Bacillus amyloliquefaciens KBC1009 based on the morphological, physiological characteristics and by 16S rRNA sequence analysis. The growth conditions for B. amyloliquefaciens KBC1009 were optimized in LB media(pH7) by culturing at 30℃ for 72 hrs. Glucose and yeast extract were confirmed as the best carbon and nitrogen sources, respectively. In order to test the inhibitory effect of B. amyloliquefaciens KBC1009 to stem rot of pepper, green house experiment was conducted. Drench of 1/500 diluted bacterial suspension of B. amyloliquefaciens KBC1009(5×108 cfu/ml) to each pepper plant 3 times with 10 days interval showed 66.7% control effectiveness. These results suggest that B. amyloliquefaciens KBC1009 is one of promising biocontrol agent to control stem rot caused by Sclerotium rolfsii.