• Proceedings of the Korean Society of Crop Science Conference
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• 2020.06a
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• pp.132-132
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• 2020

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.04a
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• pp.18-18
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• 2022

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.292-297
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• 2006

A research was carried out to investigate the release pattern of slow release nitrogen fertilizer compound(SRNC) that is latex coated urea(LCU) and to recommend the application rate of the fertilizer at dry seeding rice culture in Honam plain area. The experiment was conducted at experimental field(Jeonbug series, fine silty, mixed, nonacid, mesic family of Fluvaquentic Endoaquepts) of National Honam Agricultural Research Institute. A medium late maturing rice variety (Dongjinbyeo) was seeded at the rate of $60kg\;ha^{-1}$ by drill seeder on April 1, 1997 and March 30, 1998. Fertilizer application rate was $160-90-110kg\;ha^{-1}$ for $N-P_2O_5-K_2O$. Soil ammonium nitrate($NH_4-N$) contents remained higher in all SRNC plots than conventional ones and higher with the increase of SRNC application rate until panicle formation stage, but the contents was higher in the conventional than NRNC plots at the heading stage. The plant hight was taller in SRNC than conventional plots until maximum tiller stage, but became similar in both conventional and SRNC plots at heading stage. The culm and panicle number was greater in SRNC than conventional plots throughout all growth stage, but the effective tiller rate was higher in conventional ones. Nitrogen efficiency was higher in the SRNC than conventional plots, but the efficiency was decreasing with the higher SRNC level. The spikelet number per unit area was greater in SRNC than conventional plots, and increased with higher SRNC level. The more spikelet number with higher NRNC level resulted in lower 1,000-grain weight. The rice yield in conventional plot was similar with only 60% SRNC level, but lower than 80% and 100% SRNC levels. However, slight lodging was observed in 100% SRNC level. In conclusions, we recommend NRNC application level as 80% of standard nitrogen application for early dry seeding culture of rice Honam plain area.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.7-14
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• 2006

In this study, nitrogen removal characteristics of SBR3 process, which is two-sludge system of sequencing batch reactor(SBR) type, were investigated, with comparison of those of SBR1 process, which is conventional SBR process, and SBR2 process, which was designed to enhance denitrification efficiency through step-feeding of wastewater, using domestic wastewater. SBR3 process of two-sludge type can perform external nitrification, on which nitrification occurs in separated reactor, and enhanced denitrification using biosorbed organics. In the results with domestic wastewater, T-N removal efficiency of SBR3 process was better than those of SBR1 and SBR2 processes. It was observed that bigger difference of T-N removal efficiency between SBR3 process and SBR1 & SBR2 processes was showed at low C/N ratio than that at high C/N ratio resulting from more efficient use of organics by biosorption mechanism in denitrification of SBR3 process than those of SBR1 and SBR2 processes. In addition, T-N removal efficiency of SBR3 process according to influent T-N loading rate was better than those of SBR1 and SBR2, even though influent T-N loading rate of SBR3 process was higher than that of SBR1 and SBR2 process resulting from operation of SBR3 process in short hydraulic retention time(HRT) by external nitrification.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.470-479
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• 2004

The experimental conditions and relationships between parameters such as organic matter, aeration volume, aeration time, and precipitation time for the effective treatment of domestic wastewater were investigated. With the batch systems, the adsorption amount of unit microbe was measured with the change of MLSS concentration, precipitation time, and aeration amount. Theoretical adsorption amount of microbes was then numerically formulated by use of a SPSS multiple analysis as follows: $$Y=-0.0106(X_1)+0.07310(X_2)+42.705(X_3)+62.700$$ In this study, the amount of organisms to be removed in the range of MLSS concentration 2,000~4,500 mg/l were examined. In order to investigate the optimal condition of nitrification, the upper water in the biosorption stage was used as the initial experiment water. The results showed that the C/N ratio was 1.5 and the reaction time for the optimal nitrification was 1.5 hr. When the adsorption efficiency for microbe biosorption was 66%, the optimum denitrification efficiency was 83.3%. When the optimum parameters obtained from the batch experiment were applied to the lab-scale operation, the total retention time from the flow-in to flow-out was 10 hours and the removal efficiency was 93.8% for $COD_{cr}$ and 80.9% for TN. For the full-scale operation, the total retention time was 9.0 hours and the removal efficiency was 94.4% for BOD, 89.6% for $COD_{cr}$, 88.0% for TN, and 86.2% for TP.

• Korean Journal of Organic Agriculture
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• v.20 no.2
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• pp.211-220
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• 2012

This study was conducted to evaluate soil nutrient concentrations and N uptake efficiency of paddy rice as affected by nutrient sources from 2009 to 2011. The treatments included chemical fertilizer, compost, oilcake, oilcake 2X, hairy vetch, vetch+rye, and control. Nutrient applications were made at rates equivalent to approximately 90 kg of actual N per hectare. Oilcake had the lowest C:N ratio from the raw materials, but compost had the highest C:N ratio of 34:1. Soil pH and concentrations of C, N, Ca, and Mg were unaffected by nutrient source treatments. N uptake efficiency was the greatest for oilcake-treated rice compared to those treated by NPK, hairy vetch, and compost in 2009 and 2010. Composttreated rice had the greatest N uptake efficiency in 2011 when the high amount of precipitation occurred.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.151-159
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• 2003

Absorbent Biofilter Systems (ABS), composed of an anaerobic septic tank, a pump chamber and an absorbent biofilter tank, have been found to economically provide rural on-site wastewater treatment. This study was conducted to assess the potential of ABS effluent as an alternative water resource for agricultural and environmental use, with respect to the removal of pathogenic microorganism and their fertilization effect. A pilot scale ABS was used to compare its removal efficiency of pathogens from effluent water. Overall, more than 95 percent of Salmonella and E. coli were removed. This result demonstrates that a significant reduction in the pathogenic microorganism of effluents can occur in ABS, which implies the feasibility for the use of ABS effluent in agriculture and environment, with the provision of a further simple disinfection step, in order to satisfy the WHO guidelines for the microbiological quality in agriculture. In addition, because of the abundant nutritional content of ABS effluent, the substitution effect of fertilizer (N, P and K) in paddy irrigation, i.e. 2/3 for nitrogen, l/3 for phosphorus and 1/5 for potassium would be expected. Based on the experimental data, the ABS effluent could be used as a new alternative water resource for paddy irrigation, as well as for environmental purposes, such as supplying water to ecological parks in rural villages.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.5
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• pp.483-493
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• 1996

Advances in silage technology, including precision chop forage harvesters, improved silos, polyethylene sheeting, shear cutting silo unloaders, and the introduction of total mixed rations, have made silage the principal method of forage preservation. A better understanding of the biochemistry and microbiology of the four phases of the ensiling process has also led to the development of numerous silage additives. Although acids and acid salts still are used to ensile low-DM forages in wet climates, bacterial inoculants have become the most widely used silage additives in the past decade. Commercial inoculants can assure a rapid and efficient fermentation phase; however, in the future, these products also must contribute to other areas of silage management, including the inhibition of enterobacteria, clostridia, and yeasts and molds. Nonprotein nitrogen additives have the problems of handling, application, and reduced preservation efficiency, which have limited their wide spread use. Aerobic deterioration in the feedout phase continues to be a serious problem, especially in high-DM silages. The introduction of competitive strains of propionic acid-producing bacteria, which could assure aerobically stable silages, would improve most commercial additives. New technologies are needed that would allow the farmer to assess the chemical and microbial status of the silage crop on a given day and then use the appropriate additive(s).

• Applied Biological Chemistry
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• v.24 no.4
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• pp.230-237
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• 1981

For the investigation of efficient use of fertilizer nitrogen NPK simple trials were carried out using newly bred Tongil line(japonica indica hybrid selection) and the leading local varieties with sulfur coated area in fields for two years. The yield of Tongil line was higher than that of leading local varieties by 16% in the cool year and 23% is warm year with high solar radiation from NPK simple trials including SCU and 2-split application which were carried in 130 fields at 32 locations. Warm year increased yield by 9% in Tongil but only 3% in the local than the cool year did. Optimum nitrogen level was higher in Tongil by 3.8㎏ in the cool year and 5.5㎏ in warm year than for the local. Yearly variation of optimum nitrogen in the carne variety was greater than varietal variation in the same Year. Two-split application resulted in 1 to 2% of inconsistent yield variation. Sulfur coated urea increased yield by average 2 to 4% even at 20% reduced rate of nitrogen. It was remarkably effective in same $(27{\sim}39%)$, virgin (20%) and unmatured (10%) soils.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.3
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• pp.37-44
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• 2020

The Project supporting organic fertilizer started in 1999 as a national policy. In farmhouse, over application of mixed organic compound fertilizer(OC) caused salt accumulation in plastic film house soil. To replace inorganic fertilizer with OC fertilizer, this study was investigated the effect of OC application on yield and soil chemical properties for lettuce cultivation in plastic film house. The OC fertilizer was applied at 50(OC50+N50), 100(OC100), and 150(OC150) % level of the basal amount of nitrogen fertilizer in soil testing recommendation. And these were compared to NPK(nitrogen, phosphat, and potash fertilizer) and PK treatment. The yield of lettuce in OC100 was similar to that of NPK treatment. In OC 50, 100 and 150 treatments, pH had a tendency to increase than that of NPK treatment. Nitrate nitrogen(NO₃-N) and electrical conductivity(EC) were similar to NPK treatment. These showed that nutrients from OC fertilizer were less likely to accumulate in soil than NPK. Also, use efficiency of nitrogen in OC100 treatment were similar to NPK treatment. These results suggest that OC application as the basal dressing at the 100% level could be best to prevent a nutrient accumulation of soil and to increase the yield and commercial quality for lettuce.