• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.100-104
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• 1989

This study was carried out in order to develop a compound fertilizer for raising rice seedling in trays. A compound fertilizer, a trail product, was manufactured using the major fertilizer sources of ammonium sulfate, diammonium phosphate and potassium chloride in combination with zeolite and glutamic acid fermentation waste. Besides, polyacrylamide for slow release control of the fertilzer and Tachigaren and sulfuric acid for reducing the occurrence of seedling rot were used. The component ratios of N, $P_2O_5$ and $K_2O$ of trial product were 4.19, 5.41 and 4.05 percent respectively. The dissolution rate of nitrogen component in water for the trial product with polyacrylamide was lower about fifteen percents than the product without polyacylamide in six hours. Hymexazole, main component of Thachigaren, from the product was released about 86.2 percents in forty eight hours. When the product with polyacylamide applied on red earth soil and paddy soil, the pH of soil ranged from 4.6 to 5.4 for 25 days experiment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.8-14
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• 2013

The newly developed fertilizer is the slow-releasing fertilizer which can be used as a basal fertilizer without no additional fertilization at tillering stage. It has 30-4-6% of $N-P_2O_5-K_2O$ and was coated with mixture of LDPE (Low density polyethylene), EVA (Ethylene vinyl acetate), BDP (Bio degraded polymer), TALC and nonionic surfactant for the controlled release up to 50 days after application. Coating materials were designed to be decomposed naturally. This fertilizer can be applied directly to the seedling tray mechanically just before transplanting, resulting in significant labor saving effect. The developed slow-release fertilizer, which can replace both basal fertilization and top dressing at tillering stage by single application directly to seedling tray, showed the highest release at 14~21 days after transplanting. Considering the plant growth at different growth stages and yield, the optimal application rate of developed slow-release fertilizer was 300 g per rice nursery tray and the yield of rice at this application rate was 5.25 MT/ha. Rice quality in terms of head rice grain ratio, amylose content, whiteness, and taste value decreased as fertilization rate increased from 200 g to 500 g per nursery tray. Fertilization rate based on quantity of fertilizer ingredients (N, P, K) was reduced by 49.3% compared to the standard application rate and there was 49.2% reduction in labor input for fertilization.

• Analytical Science and Technology
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• v.21 no.6
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• pp.543-552
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• 2008

This paper described the relatively sensitive and simultaneous analytical method for 3-monochloropropane-1,2-diol (3-MCDP, $C_3H_7ClO_2$, MW. 110) as well as 1,3-dichloropropan-2-ol (1,3-DCP, $C_3H_6Cl_2O$, MW. 128) in various foods. Food samples were homogenized in 5M NaCl solution, mixed with aluminum oxide and eluted with dichloromethane. The extracted chloropropanols were concentrated by rotary evaporator and $N_2$ blow serially were derivatized with HFBA (Heptafluorobutyric anhydride, $C_8F_{14}O_3$, MW. 410) and were determined by GC/MS using isotope dilution method. The characteristic molecular ions at m/z 253, 275, 289, 291, and 453 for HFBA derivatives of 3-MCPD (MW. 502) and 110, 275, and 277 for HFBA derivatives of 1,3-DCP (MW. 325) were chosen in selected ion mode. The method validation data showed sufficiently good properties of LOD (0.003 mg/kg), LOQ (0.010 mg/kg), linearity ($R^2{\geq}0.999$ at 0.010~1.000 mg/kg), and recovery rate (${\approx}97%$). The levels of chloropropanols in soy sauce, sauces, processed meat products, fishery products, and seasonings (n=56/157) determined by the presented method were 0.0~0.3 mg/kg.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.318-324
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• 2000

Field experiment was conducted on a sandy clay loam paddy field in the Experimental Farm of the Kangwon National University for four years from 1995 to 1998 to evaluate the effect of different nitrogen fertilizers on soil property and rice yield. The size of each experimental plot was 75 m2. Basal application of fertilizer to the paddy field was on late April, and rice (cv. Odae) was sown with drill seeding on early May. Irrigation was done at 3 leaf stages after rice seeding. Electrical conductivity in soils treated with phosphate- and resin coated slow release fertilizers were relatively greater than those of the other fertilizer application. Available $P_2O_5$ concentration in soils after rice harvest increased significantly compared that in soil before field trial. Rice yield in transplanting culture were $6.516kg\;ha^{-1}$. The rice yield in the direct seeded paddy was 81.9 percents of the yield in the transplanted paddy. The rice yield in phosphate coated slow release fertilizer was the highest among various fertilizer trials in directly seeded dry paddy, while rice yield was the lowest in the organic fertilizer plus urea application. Rice yield between organic fertilizer plus urea and organic fertilizer application were not significantly different. The green manuring effect of rye in the direct seeded rice paddy in Chuncheon was low due to low temperature and short growth period.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.3
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• pp.119-126
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• 2003

Nitrate-N concentrations and the corresponding ${\delta}^{15}N$ values were determined with water samples collected periodically from artesian wells (3 and 6 m deep), underdrainage and gushout waters in a Welsh onion cultivated area in the Kushibiki Fan, Saitama Prefecture, Japan. Average $NO_3-N$ concentrations in waters from 3 and 6 m wells were 25.7 and $2.8mg\;L^{-1}$, whereas ${\delta}^{15}N$ values were 3.6 and 4.7‰, respectively. The $NO_3-N$ concentration and ${\delta}^{15}N$ value of the underdrainge water were $35.5mg\;L^{-1}$ and 6.6‰, reflecting rapid input of chemical fertilizers and farmyard manure. The mean values of $NO_3-N$ concentration and ${\delta}^{15}N$ in the gushout water flown out of the edge of Kushibiki Fan were $19.4mg\;L^{-1}$ and 7.9‰, respectively. As a results the ${\delta}^{15}N$ values of the gushout water were higher than those of the artesian wells and underdrinage water. The ${\delta}^{15}N$ values of total-N and $NO_3-N$ of the soils were 6.1 and 5.10‰, respectively, while those for nitrification-inhibitor containing fertilizer and slow-release fertilizers were -6.1 and -2.2‰, respectively.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.1-10
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• 2016

In this paper, an analysis of the inflowing pollution load of the rivers in Hampyeong bay showed the average organic matter pollution loads of BOD, COD, and TOC to be 79.7 kg-BOD/day, 144.06 kg-COD/day, and 93.0 kg-TOC/day, respectively. The inflowing organic matter pollution load was the heaviest in Sonbul dike, followed by Jupo bridge and Yangman complex. With regard to season, the load characteristics were outstanding in July, the rainy period in the summer. The average inflowing pollution loads of nutrients were 20.9 kg-DIN/day, 17.1 kg-DIP/day, 148 kg-TN/day, and 37.4 kg-TP/day A comparison of the inflowing nutrients loads for each river showed the load to be the heaviest in Yangman complex, followed by Baegok bridge and Jupo bridge. In the experiment on the material budgets of Hampyeong bridge conducted using a box model, the detention time of fresh water was found to be 52.4 days, with the bay displaying the characteristics of a so dissolved inorganic nitrogen (DIN) in the nutrients material budgets, ${\Delta}DIN$ values were found to be negative, indicating the tendency of consumption and open sea leak by photosynthesis to be higher than the nitrogen that flowed in. As for dissolved inorganic phosphorus (DIP), ${\Delta}DIP$ showed positive values, indicating a tendency for accumulation as the supply through organic matter decomposition, elution load of sediments, and inflowing load of the river turned out to be higher than the consumption by phytoplankton and outflow to open sea.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.295-303
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• 2000

The water clarification efficiency was examined in a shallow wetland where dense vegetation was formed naturally in an abandoned paddy field. And, also two enclosure experiments were carried out to measure the effects of materials exchange between sediment and the overlying water with the existence of vegetation and accumulated litter. The hydraulic retention time of wetland was regulated in 1.2 day. The removal rates of SS (56%) and $NO_3-N$ (61%) were high, considering its short retention time. However, removal efficiencies of VSS (28%), COD (14%), DOC (1%),and TP (0.2%) were relatively lower. This low removal efficiencies were thought to be due to the release of dissolved form of organic matter and phosphorus from the sediment. Most of constituents except nitrate were higher in the enclosure at the beginning of enclosure installation than that of the outflowing water from wetland. And then, it has fluctuated and decreased with time. The wetland was in equilibrium state of settling, accumulation of organic debris, and regeneration of dissolved material from sediment. So ultimately high primary production by dense vegetation in the wetland may be the reason of unfavorable or low treatment efficiency of wetland after many years of operation for wastewater treatment. However, the water quality of effluent from the wetland showed smaller variation and better condition than that of inflow, especially during storm events. It can be concluded that this wetland is suitable for the improvement of water quality from nonpoint sources.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.326-330
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• 2007

도시화 면적이 증가하면 불투수 면적이 증가하고 그에 따라 도시 하천의 평상시 유출이 감소한다. 도시유역의 평상시 수량을 회복시키는 방법으로는 침투 증진시설(투수성 포장, 침투 트렌치, 침투 측구 등)의 설치, 하수의 고도처리 후 방류 저수지에 의한 유황 개선, 지하철 용출수 활용 등이 있다. 우리나라의 경우에 일부 도시하천의 수량 감소가 심각한 상황에 이르고 있으며 이를 해결하고자 하는 노력이 최근에 나타나고 있다. 수량을 회복하려면 유량 평가를 위한 현장조사, 수량회복 계획, 재원의 반영, 수량회복 시설의 설치 및 관리의 순서로 단계별 사업이 수행되어야 한다. 계획 단계의 과업에서 필요한 사항은 여러 가지 수량 회복 방법의 영향을 정량 평가하는 것이다. 이에 핵심이 되는 것은 수량 회복 요소를 포함하거나 추가한 수문순환 평가 도구이다. 침투시설 중 투수성 포장과 침투 트렌치를 모의하도록 기존의 SWMM 모형을 수정하였다. 그 과정에서 증발량 처리와 지하수 출력기능에 대한 오류도 수정되었다. 수정 개발된 SWMM을 침투시설 모형실험 결과와 비교하여 수정된 프로그램의 적합성을 검증하였다. 투수성 포장과 침투 트렌치를 고려하여 수정된 프로그램을 안양천의 지류인 학의천 유역에 적용하여 침투시설의 효과를 분석하였다. 만일 학의천 불투수 면적의 10%를 투수성 포장으로 교체하면 하류 비산교 지점의 저수량$(Q_{275})$이 3 %, 갈수량$(Q_{355})$이 17 % 증가하는 것으로 분석되었다. 침투 트렌치의 경우 학의천 소유역 별로 100m 트렌치를 $5{\sim}10$개 시공할 경우 저수량은 약 1 %, 갈수량은 약9 %가 증가하였다. 수정 개발된 SWMM을 사용하면 침투 트렌치와 투수성 포장 이 도시 유역의 건기 수량회복에 미치는 영향을 분석할 수 있다.해 경보발령 이전에 한계수위를 넘어서는 경우(case_3)로서 분석되었다. 이러한 실패한 경보발령의 경우에 대한 원인분석 결과, 기존의 모형화를 통해 고려되지 못하였던 해안도시 홍수의 특성 중 총강우량에 대한 고려, 선행강우 여부 및 강우 지속시간, 지속시간 내 강우집중도 그리고 선정지점 내 조위의 영향과 유역내 합류식 하수관거 시스템의 영향 등 자연유역과는 다른 다소 복잡한 요소를 고려한 해안도시홍수 경보발령 기준에 대한 개선이 필요함을 확인할 수 있었다.이 좋다고 고찰된다. 6. 우리 나라의 현행 수도작기로 본 기온 및 일조조건은 수도의 분얼전기에 대해서는 호조건하에 놓여 있으나, 분얼후기인 7월 중ㆍ하순 경의 일조부족과 고온다습조건은 병해, 특히 도열병의 유발원인이 되고 있다. 7. 우리 나라의 현행수도작기로 본 전국각지의 수도의 출수기는 모두 일조시간이 적은 부적당한 시기에 처해 있다. 8. 출수후 40일간의 평균기온에 의한 적산온도 88$0^{\circ}C$의 출현기일은 수원에서 8월 23일이었고, 년간편차를 고려한 안전출수기일은 8월 19일로서 적산온도면에서는 관행 출수기일은 약간 늦다고 보았다. 9. 등열기의 평균기온에 의한 적산온도는 현행 수도작기로서는 최종한계시기에 놓여 있으며, 평균기온의 년간편차와 우리 나라의 최저기온이 낮은 점을 고려할 때, 현행출수기는 다소 늦은 것으로 보았다. 10. 생육단계별의 수도체내의 질소함량은 영양생장기의 질소함량이 과다하였으며, 출수 이후에 영양조락을 여하히 방지하느냐가 문제된다고 보았다. 11. 수리불안전답 및 천수답이 차지하는 전답면적의 비율은 차차 감소되고 있는데, 이와 전체 10a당 수량의 증가율과의 상관계수를 산출하였는데, 수리불안전답과의 상관계수 (4)는 +0.525였으며, 천수답과는 r=+0.832, 그리고 수리불안전답과 천수답을 합계한 것과의

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.499-505
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• 1992

This experiment was carried out to find out the optimum application method of slow-release fertilizer under different soil textures, clay loam(Deogpyeong series), sandy loam (Gangseo series) in the southern region(Milyang, Kyeongnam) of Korea. The fertilizers used were Chosun slow-release fertilizer(silicate latex coated fertilizer: N-P$_2$O$_{5}$-K$_2$O=18-12-13) and Meister 15 (thermoplastic resin coated fertilizer : N-P$_2$O$_{5}$-K$_2$O=14-14-14). The two whole basal application methods such as side band placement at transplanting time of rice plant(cv.Donghaebyeo) and incorporation with soil as basal were tested. The released amount of ammonium nitrogen from the soils for 4 days submerged was 95ppm in sandy loam and 60ppm in clay loam. The greenish degree of rice leaf was higher at the whole plow layer placement method than the others. The nitrogen efficiencies of the fertilizers were Meister 15 > convention > Chosun in order and between the application methods were similiar. The growth status was better at the whole plow layer placement application method of Meister 15 regardless of soils and seedling ages. The ripening ratio was increased at slow-release fertilizer application, and between application methods, whole plow layer placement was lower because of lodging damage. The yield in clay loam soil showed a significant difference between the ferilizers, but there were slight differences between the application methods and fertilizers in sandy loam soil. As a result, the slow-release fertilizer, Meister 15, applied at the whole layer showed a good rice growth and seemed a plausible fertilizing method.