• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.3
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• pp.75-81
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• 2008

This study was conducted to analyze the influence of simulated acid rain on leaves of Liliodendron tulipifera seedlings. The seedlings were treated with four levels of simulated acid rain with pH of 5.6, 4.9, 3.9 and 2.9, and then chlorophyll contents and the degree of foliar damage were investigated. Differences were statistically significant among treatments in chlorophyll contents in all of the tested soils. The total contents of chlorophyll tended to decrease as the simulated acid rain treatment was maintained. Chlorophyll contents, however, did not decrease according to the decrement of pH levels. Foliar damage increased as the simulated acid rain was maintained in all tested soils. Especially, the damage dramatically increased between May and July as the acidity increased. As the treatment of simulated acid rain continued, deformed new leaves appeared. In all treatments except the control, the leaves turned brown and the damage increased with time. Necrotic spots appeared during the first month of treatment at the pH level of 2.9 in all soil types. The damage by acid rain should be considered when we plant Liliodendron tulipifera.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.219-224
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• 2016

This study was conducted to investigate the ecology of weed occurrence and to establish an economical paddy field weed control system for direct-seeded rice on water. The main problem weed among annual and perennial weeds was Eleocharis kuroguwai. The control effect of E. kuroguwai was low by the application of azimsulfuron + carfentrazone-ethyl + pyriminobac-methyl at the early stages of rice in directly seeded paddy fields, but most annual weeds including Echinochloa crus-galli were controlled. Also, the additional application of pyrazosulfuron-ethyl + thiobencarb GR at 20 days after first treatment or of bentazone SL at 43 days after the first treatment effectively controlled E. kuroguwai. Tuber formation of E. kuroguwai was inhibited by the additional application of pyrazosulfuron-ethyl + thiobencarb by 84%, but the dormancy rate of old tubers of E. kuroguwai under the soil was higher than that of E. kuroguwai tubers following single application of azimsulfuron + carfentrazone-ethyl + pyriminobac-methyl at the early stages of rice. Tuber formation was inhibited by the additional application of bentazone by approximately 87%, and the old tuber dormancy rate was low in the bentazone treatment. High amounts of old dormant tubers of E. kuroguwai were found in the weedy plots.

• Journal of Animal Environmental Science
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• v.12 no.3
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• pp.161-168
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• 2006

This paper describes the changes of characteristics of pig slurry according to storing depth. Most of the substances containing pollutants, such as were Management of manure and wastewater from animal confinement facilities is a critical factor for pollution control. With proper treatment processing method in both solid and liquid forms, it can be used as a fertilizer and soil conditioner. In Korea, liquid-manure handling system is very popular because its treatment and application is easy and labor saving. In the storage tank treatment, the period of fermentation process and solids-liquid separation averages six months and the supernatant liquid is being used as a fertilizer. In this study, the changes in chemical characteristics of pig slurry at varying depths of the storage tank were investigated. Results showed that the pH value of the fermented pig slurry was > 7, while the major pollutants such as BOD, SS, N and P were highest in the bottom of the tank. Therefore, the above findings proved that varying depths in the storage tank can influence the concentration of pollutants of the fermented pig slurry.

• Current Research on Agriculture and Life Sciences
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• v.2
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• pp.1-8
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• 1984

This study was conducted to evaluate the effect of various fertilizers and their application methods on pH in seedbed soil and seedling vigor of rice cultivars, "Nagdong" and" Samgang", for machine transplanting. The application of amnonium sulfate as nitrogen sources showed higher plant height and dry weight of seedlings than those of the urea treated plot. Seedling rot was highly occured in the basal application of urea than that of split treatment of urea, while the lower seedling rot was observed in ammonium sulfate treated plot than that of treatment. Regardless of the application methods, the higher rooting ability was observed in anmonium sulfate treatment than that of urea. Ammonium sulfate and superphosphate as nitrogen and phosphate sources, respectively, showed lower pH level than that of urea and fused phosphate treated plots. The use of ammonium sulfate and super phosphate as nitrogen and phosphate sources, respectively, seems to be effective to maintain the optimum pH level and to rear the healthy seedling, than that of urea or fused phosphate application.

• Korean Journal of Plant Resources
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• v.28 no.2
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• pp.243-252
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• 2015

This study was performed to establish a production system for in situ and ex situ conservation of Elsholtzia minima Nakai, an endemic plant grown in Jeju Island. Moreover, this study aimed to identify root-growth characteristics according to the use of pre-treatment agents and seedling growth effect according to fertilizer application. The mean temperature was similar in greenhouse and vinyl-moist chamber, but air humidity was higher in vinyl-moist chamber than in greenhouse. After stem planting of Elsholtzia minima Nakai, initial root growth was observed after 10 days in greenhouse and after 7 days in vinyl-moist chamber. Root growth rate was more rapid in vinyl-moist chamber. Moreover, survival rate, root growth rate and root number was slightly higher in vinyl-moist chamber than in greenhouse, indicating that vinyl-moist chamber is more effective in plant growth. When pre-treatment agents were used to remove root growth-inhibiting substances, a higher root growth rate of more than 95% was found in pre-treatment groups, excluding the group treated with AgNO₃ at 77.5%. Thus, Elsholtzia minima Nakai is thought to have less root growth inhibitors. In the analysis of nitrogen application rate and Osmocote application by seedling container, a difference was found in survival rate and growth according to application rate and container conditions. When Osmocote, a slow release fertilizer, was applied to the soil surface around each culture container, survival rate and the growth of aerial and root parts were most favorable. Thus, Osmocote fertilizer is thought to be desirable for seedling propagation of Elsholtzia minima Nakai.

• Journal of Appropriate Technology
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• v.6 no.1
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• pp.37-44
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• 2020

Medical waste is any kind of waste that contains infectious material and recommended not to be transferred for infection control. As a means of disposal, incineration has better points than dumping or landfill in the quantity reduction, odorless and nonhazardous. However, open burning and incineration of health care wastes under bad circumstances, can result in the emission of environmental pollutants to air. A burial of biological waste brings pollution of soil and water. Most of sub divisional hospitals in Fiji transfer their medical wastes to divisional hospitals for incineration. In 2011, 62,518 kg of medical waste was incinerated in the three divisional hospitals. However, some medical wastes are considered as general waste and burnt or sent to landfill site, some are buried on site in some sub-divisional hospitals. In this regards, urgent education is necessary for awareness promotion to relevant personnel in medical waste treatment. On site incineration using small scale incinerator is more recommended than transportation of medical wastes treatment in Fiji. Moreover, remotely controllable and fixable small scale of incinerator is more desirable in sub-divisional hospitals. It is recommended that Fiji government to set up a legal framework for medical waste management (MWM), to develop specific guidelines for MWM, to set up a training system for MWM to ensure that all relevant personnel are trained, to develop a monitoring and supervision system for MWM, to clarify the future financing of MWM activities, and to improve the MWM infrastructure.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.239-246
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• 2022

Lactuca scariola L. is one of ecosystem-disturbance plants that grow everywhere such as roadsides, grasslands, railroads, banks, and fields. L. scariola usually occurs in autumn. It overwinters in rosette form. It flowers and produces seeds in early summer of the next year. Seeds of L. scariola can germinate immediately without dormancy when the temperature is over 20℃. Due to endogenous bacteria in seeds of L. scariola, it has a strong drought tolerance. Thus, it can grow well on roadsides. L. scariola should be controlled as it can result in 60-80% of soybean yield loss at densities above 50 plants m^-2. It is advisable to remove L. scariola as it competes with native plants by acting as a pioneer to other ecosystem-disturbance plants. Among various control methods, chemical control is the most effective method that is widely used. Soil treatment with herbicides such as oxyfluorfen EC and pendimethalin EC can inhibit the development of L. scariola. Foliar treatment herbicides glyphosate and glufosinateammonium are widely used. L. scariola is resistant to 2,4-D, dicamba, and MCPA among foliar treatment herbicides. Thus, it is recommended to apply herbicides with different modes of action.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.2
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• pp.105-114
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• 2018

The aim of this study was to evaluate the change of phenolic compounds after phosphite treatment on Cheorwon onion. Onion is a perennial plant belonging to the lily family. It is native to Persia of Southwest Asia. It is widely cultivated in the temperate regions of the world. Onion is a good name for the 'Okchong' to drop blood cholesterol and cardiovascular blood flow to increase the prevention of adult diseases. Cheorwon area is inland, but it has high continental climate due to its high altitude. Therefore it is said that the onion cultivated in this region has higher sugar content and higher taste than onion grown in the southern region. Phosphorus components are particularly important ingredients for promoting muscle development. However, if the phosphoric acid content of the soil part is maintained to a large extent until the harvest, the competition of the nutrients tends to cause decay of the root part. Therefore, it is important to improve the quality and shelf life of onion by inducing nutrient balance by applying foliar fertilization method on the reducing phosphorus at harvest time. In this study, acidity was controlled by diluting phosphorous acid(H₃PO₃) and potassium hydroxide(KOH), followed by leaf surface treatment with phosphite on onion. In this study, the concentration of phosphite was diluted to 500, 1,000, 1,500ppm and sprayed three times over the onion leaves in May 2018 using an atomizer and harvested at the end of June, and the phenolic compounds were analyzed by HPLC. As a result, the content of quercetin, one of the important substances in onion, was phosphite 500ppm(179.70㎍/g), 1,000(150.27), 1,500(105.95). The contents of caffeic acid, p-coumaric acid, ferulic acid, rutin, kaempferol, and sugar content were higher in the treatments than in the control. Therefore, the phosphite does not have a great influence on the growth, but it may play a role as a method of achieving balance with nitrogen in the rainy season by supplying the role of the material catalyst and the water soluble phosphoric acid and the potassium in the influence of the material change.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.3
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• pp.197-206
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• 2023

This study was conducted to investigate how maize (Zea maize L.) growth and yield were affected by irrigation and fertigation using a subsurface drip system. The system consisted of a buried (40 cm underground) drip pipe that can be used in a semi-permanent manner without affecting agricultural work on the ground. The amount of water required for the fertigation treatment was determined to be 24.3 tons 10a^-1 for the sandy loam soil used in this experimental field. Fertigation treatments based on the previously calculated 24.3 tons 10a^-1 were carried out as topdressing applications. They were applied through the subsurface drip system with the following fertilizer concentration (nitrogen only, written in kg 10a^-1: N 4, N 6, N 8, N 10 ). The other treatments were irrigation only and control (non-treatment). The results indicated that the N 8 treatment was the most effective, increasing yield by 30% and 14% compared with the control and irrigation treatments, respectively. These results highlight the effectiveness of fertigation (N 8 kg 10a^-1) at V6 and R1 stage as a form of topdressing fertilization using a subsurface drip system for achieving a high yield and stable maize production.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.484-491
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• 2023

Tomatoes in greenhouse are a widely cultivated horticultural crop worldwide, accounting for high production and production value. When greenhouse ventilation is minimized during low temperature periods, CO₂ enrichment is often used to increase tomato photosynthetic rate and yield. Plant-induced electrical signal (PIES) can be used as a technology to monitor changes in the biological response of crops due to environmental changes by using the principle of measuring the resistance value, or impedance, within the crop. This study was conducted to investigate the relationship between tomato growth data, vital response, and PIES resulting from CO₂ enrichment in greenhouse tomatoes. The growth of tomato treated with CO₂ enrichment in the morning was significantly better in all items except stem diameter compared to the control, and PIES values were also higher. The growth of tomato continuously applied with CO₂ was better in the treatment groups than control, and there was no significant difference in chlorophyll fluorescence and photosynthesis. However, PIES and SPAD values were higher in the CO₂ treatment group than control. CO₂ enrichment have a direct relationship with PIES, growth increased, and transpiration increased due to the increased leaf area, resulting in increased water absorption, which appears to be reflected in PIES, which measures vascular impedance. Through this, this study suggests that PIES can be used to monitor crops due to environmental changes, and that PIES is a useful method for non-destructively and continuously monitoring changes of crops.