• 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 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.3
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• pp.296-302
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• 2007

This study was conducted to evaluate the effect of slow release fertilizers (SRF), crotonylidene diurea (CDU) and latex coated urea (LCU), on nitrogen (N) use efficiency (NUE) and nitrate-N leaching in a silty clay loam soil under polyethylene film mulching (PFM) for sesame cultivation. In PFM plot, concentrations of $NO_3-N$ and $NH_4-N$ in SRF applied soils were less than that in the urea plot during the whole growing period. However, $NO_3-N$ and $NH_4-N$ in all the non-mulched plots (NM) were not significantly different. Urea-N in soil treated with SRF was higher than urea plot until 50 days after application and was comparable in all the treatments after 50 days. $NO_3-N$ concentrations in leached solution in 21 days after urea fertilization in PFM and NM were 26 mg $L^{-1}$ and 83 mg $L^{-1}$, respectively. However, $NO_3-N$ in leached solution at applied CDU and LCU was less than that of urea similar to nitrate concentration in soil. $NO_3-N$ in leached solution in applied CDU and LCU in 44 days after application was about 25% lower than that urea plot and PFM, while the $NO_3-N$ concentration of CDU and LCU treatment in NM did not changed. Application of SRF increased the yield of sesame and N recovery compared to urea and there was a little difference between SRF and N levels. In conclusion, application of 80% N level with SRF increased N recovery and reduced nitrate leaching without reduction of yields compared with urea application.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.114-121
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• 2020

BACKGROUND: Biochar-based fertilizers delay the nutrient release and feature a slow release effect for agricultural and environmental advantages. This experiment was conducted to evaluate agro-environmental effects of different application ratios of modified biochar pellets supplemented. METHODS AND RESULTS: The treatments consisted of the control, 40% N, 60% N and 60% N (0.07M MgO) of modified supplemented biochar pellets (MSBP), which were based on recommended ratio of nitrogen for rice cultivation. For the paddy water, the NH₄-N and NO₃-N concentrations in whole treatments rapidly increased at 84 days and 40 days after transplanting, respectively. The PO4-P concentrations in the MSBP were generally lower than those of the control. For the paddy soil, NH₄-N concentrations in the MSBP were higher than those of the control at 5 days after transplanting, while NO₃-N concentrations were not significantly different in the treatments through rice cultivation. P₂O₅ concentrations in the control were higher than those of the MSBP until 40 days after transplanting while K₂O concentrations were not significantly different among the treatment. The highest carbon sequestration was 970 kg ha^-1 in the 60% N (0.07M MgO), and the potential carbon storage in the 60% N (0.07M MgO) was higher at 222 kg ha^-1 than the control during rice cultivation. It shown that the rice yield in the control was not significantly different from the 40% N and 60% N (0.07M MgO) application plots. CONCLUSION: Application of MSBP for rice cultivation was effective for carbon sequestration and agro-environmental effects even though nitrogen application ratio was reduced at 40% based on recommended application ratio of fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.3
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• pp.135-152
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• 1975

The following informations are known from physical and chemical characteristics of orchard soils and nutritional diagnosis of orange leaves in Jeju. 1. Most orange orchards are located on terrace and cindercone thus soil moisture and microclimate of an orchard will greatly be affected by its topography. 2. Excessive well drainage, shallow soil depth, high content of gravels, low solid phase ratio and strong wind will give severe problem of soil moisture and wind errosion, thus the exte- nsion of soil depth is necessary for maintain nutrients, water and sufficient root volume. 3. Available soil water was significantly and positively correlated with organic matter content and clay content also contributes to available soil water. Vinyl mulching was greatly helpful for soil water conservation, wind errosion prevention, soil temperature increases during winter. 4. Abundant amphoteric amorphous allophane take a key role to fix phosphorus and also rations and thus it is the major factor to determine fertilizer efficiency. Lime and phosphorus must be applied in deeper soil layer. Release of filed phosphorus must be reevluated for availability. 5. Organic matter such as see weeds will greatly increase fertilizer efficiency and low fertilizer efficiency during spring may be related to available soil water. 6. Nitrogen was in superoptimum and Mg was enough but P and Ca were somewhat deficient according to leaf analysies while K was deficient according to fruit analysis. Phosphorus application increased sugar/acid ratio and potassium decreases rind percentage. 7. Manganese deficiency and toxicity appeared in a few places. Iron and boron were enough. Most places showed tendency of copper excess but some places showed copper deficiency. 8. Soiling after elimination of rock base, application of slow release fertilizer and abundant organic matter, vinyl mulching and drip irrigation will increase fertilizer efficiency greatly and fruit yield drastically.

• Journal of Microbiology
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• v.43 no.4
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• pp.319-324
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• 2005

Estuarine sediments are frequently polluted with hydrocarbons from fuel spills and industrial wastes. Polycyclic aromatic hydrocarbons (PAHs) are components of these contaminants that tend to accumulate in the sediment due to their low aqueous solubility, low volatility, and high affinity for particulate matter. The toxic, recalcitrant, mutagenic, and carcinogenic nature of these compounds may require aggressive treatment to remediate polluted sites effectively. In petroleum-contaminated sediments near a petrochemical industry in Gwangyang Bay, Korea, in situ PAH concentrations ranged from 10 to 2,900 ${\mu}g/kg$ dry sediment. To enhance the biodegradation rate of PAHs under anaerobic conditions, sediment samples were amended with biostimulating agents alone or in combination: nitrogen and phosphorus in the form of slow-release fertilizer (SRF), lactate, yeast extract (YE), and Tween 80. When added to the sediment individually, all tested agents enhanced the degradation of PAHs, including naphthalene, acenaphthene, anthracene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, and benzo [a] pyrene. Moreover, the combination of SRF, Tween 80, and lactate increased the PAH degradation rate 1.2-8.2 times above that of untreated sediment (0.01-10 ${\mu}g$ PAH/ kg dry sediment/day). Our results indicated that in situ contaminant PAHs in anoxic sediment, including high molecular weight PAHs, were degraded biologically and that the addition of stimulators increased the biodegradation potential of the intrinsic microbial populations. Our results will contribute to the development of new strategies for in situ treatment of PAH-contaminated anoxic sediments.

• 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.