• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.347-352
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• 2011

Environment-friendly agriculture (EFA) are aimed to reduce use of chemical inputs as possible the recycling of resources and the environment while preserving the local resources in the long term to ensure a constant productivity and profitability for producing safe food. This study was conducted to investigate characteristics on soil environment at paddy field of environment-friendly agriculture regions (EFARs) in Honam area. Survey point of EFARs Chungnam, Jeonbuk and Jeonnam, rice bran farming method in two districts, rice bran + snail farming method in eight districts, snail farming method in five districts and ducks farming method in three districts a total of 18 districts were selected. Annual of farming method, friendly-environment certification, amount of applied fertilizer, and history of cultivation to the farm household were surveyed. The content of available phosphate and silicate among the soil chemical properties in EFA paddy field were a little lower than optimum level, and those of agricultural methods fertilized with rice bran were a little lower than those of others. Hardness among the soil physical properties in EFA paddy field were a little lower than conventional practices, and that of agricultural methods fertilized with rice bran were a little lower than those of others. We showed fertilizer recommendation dose about soil nutritional shortages according to fertilization prescriptions index by crops.

• Korean Journal of Organic Agriculture
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• v.22 no.1
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• pp.97-113
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• 2014

An actual proof experiment was carried out to establish the production of high quality organic rice at farm household in Gwangjin, Junnam, Korea 2011. Experimental plot was designed with conventional organic cultivation and manual organic cultivation in both Hopeongbyeo and Onnuri varities. Experimental field was consisted with suitable drainage loam soil, anryong series, and normal paddy field. Chemical characteristics of the soil were investigated from initial soil and soil after harvest in experimental sites. Seed disinfection was treated with hot water dipping method at $60^{\circ}C$ for 10 min. Rice transplanting was carried out at 17 June with 25 days seedling using machine transplanting. Golden apple snail was used to prevent weed growth as middle size (1.5~1.7 kg/10a) at one week after rice transplanting. Amount of applied fertilizer in experimental plot was supplied with organic fertilizer for the shortage after harvest of hairy vetch (1,100 kg/10a). Bordeaux mixture was used to control of sheath blight and neck blast disease in all experimental plot at 19 Aug. Application of chitin culture solution was treated in manual organic cultivation at 2 and 15 Aug. At late growth stage, incidence rate of neck blast was the highest level at Hopyeongbyeo in conventional organic cultivation. Incidence rate of sheath blight in both Hopyeongbyeo and Onnuri was higher in conventional organic cultivation than in manual organic cultivation. Incidence of rice leaf folder was the highest level at Onnuri in conventional organic cultivation. Yield index in manual organic cultivation was increased by 13% and 38% at Onnuri and Hopyeongbyeo, respectively, compared with conventional organic cultivation. Head rice percentage in both Hopyeongbyeo and Onnuri was slightly increased in manual organic cultivation. These results indicate that high quality production of rice organic cultivation could be depending on management of safe fertilization with nutrient content in soil.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.35-42
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• 2020

17β-estradiol (E₂) is a natural hormone secreted by ovary, and continuously discharged from household and livestock wastewater into aquatic environment. Due to its strong estrogenic activity, it has adverse effects on development and reproduction in crustacean as an endocrine disrupting chemical. Although ecdysteroid signaling pathway play a key role in development in crustacean, little information on transcriptional modulation of ecdysteroid-related genes in response to E₂ is available in small crustacean. Here, we investigated the acute toxicity of E₂ to obtain 24-h LC_x values in the brackish water flea Diaphanosoma celebensis. Time-dependent expression patterns of seven ecdysteroid pathway - related genes (CYP314a1, EcRA, EcRB, USP, ERR, Vtg, VtgR) were further examined using quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR). As results, 24-h LC₅₀ and LC₁₀ values were 9.581 mg/l and 4.842 mg/l, respectively. The mRNA expression of CYP314a1, EcRA, USP, VtgR was significantly up-regulated at 12 or 24 h after exposure to E₂. These findings indicate that E₂ can affect their molting and reproduction by modulating the expression of ecdysteroid pathway - related in D. celebensis. This study will be useful for better understanding of molecular mode of action of endocrine disrupting chemicals on molting process in small crustacean.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.3
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• pp.13-22
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• 2022

In order to improve water quality of the water system contaminated with dyes, biochars prepared using discarded waste resources were applied in this study. Biochars with a large specific surface area were manufactured using street tree pruning products or waste wood, and were applied to remove an organic dye in synthetic water. Biochars were made by pyrolysis of typical street tree porch products (Platanas, Ginkgo, Aak) and waste wood under air-controlled conditions. Methylene blue (MB), which is widely used in phosphofibers, paper, leather, and cotton media, was selected in this study. The adsorption capacity of Platanas for MB was the highest and the q_max value obtained using the Langmuir model equation was 78.47 mg/g. In addition, the adsorption energy (E) (kJ/mol) of MB using the Dubinin-Radushkevich (D-R) model equation was 4.891 kJ/mol which was less than 8 kJ/mol (a criteria distinguishing physical adsorption from chemical adsorption). This result suggests a physical adsorption with weak interactions such as van der Waals force between the biochar and MB. In addition, the physical adsorption may resulted from that Platanas-based biohar has the largest specific surface area and pore volume. The ∆G value obtained through the adsorption experiment according to temperature variation was -3.67 to -7.68, which also suggests a physical adsorption. Considering these adsorption results, the adsorption of MB onto Platanas-based biochar seems to occur through physical adsorption. Overall, it was possible to suggest that adsorption capacity of the biochr prepared from this study was equal to or greater than that of commercial activated carbon reported in other studies.