• 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.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.437-443
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• 2003

Bioremediation technologies were applied to experimental microcosms, simulating an oil spill in a lower intertidal area. Three treatments (oil only, oil plus nutrients, and oil plus nutrients and microbial inocula) were applied, and each microcosm was repeatedly filled and eluted with seawater every 12 h to simulate tidal cycles. To minimize washing-out of the inoculum by the tidal cycles, microbial cells were primarily immobilized on diatomaceous earth before they were applied to the oiled sand. Oil degradation was monitored by gravimetric measurements, thin layer chromatography/flame ionization detector (TLC/FID) analysis, and gas chromatography (GC) analysis, and the loss of oil content was normalized to sand mass or nor-hopane. When the data were normalized to sand mass, no consistent differences were detected between nutrient-amended and nutrient/inoculum-amended microcosms, although both differed from the oil-only microcosm in respect of oil removal rate by a factor of 4 to 14. However, the data relative to nor-hopane showed a significant treatment difference between the nutrient-amended and nutrient/inoculum-treated microcosms, especially in the early phase of the treatment. The accelerating effect of inoculum treatment has hardly been reported in studies of oil bioremediation in the Tower intertidal area. The inoculum immobilized on diatomaceous earth seemed to be a very effective formulation for retaining microbial cells in association with the sand. Results of this study also suggest that interpretation of the effectiveness of bioremediation could be dependent on the selection of monitoring methods, and consequently the application of various analytical methods in combination could be a solution to overcome the limitations of oil bioremediation monitoring.

• 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.11 no.2
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• pp.75-80
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• 1979

Ammonium desorption from 16 soils treated with $(NH_4)_2HPO_4$ solution (2000 ppm $NH_4$) was investigated by seven extractions with 0.01M $CaCl_2$. 1. There were 2 to 4 steps alternately appeared with fast and slow mode. 2. Desorption equation, log y=b-ax where y is desorption amount, b a constant indicating adsorption maximum, a retention constant, and x extraction number, was held for each step. 3. Desorption rate (100${\times}$desorption / adsorption) was 65% for the average of 15 soils, maximum 87% in Gimcheon series, minimum 32% in Samgag series. Yongho series (a peat soil) showed 156% indicating the release of large quantity of indigenous soil ammonium. 4. Desorption rate was negatively correlated with initial adsorption and in this relation the tested soils were classified into 3 groups. 5. The cumulative desorption curve was approaching almost to maximum in all tested soils with seven extractions. The final retention amount, ranged from 25% of CEC (Gimhae series) to 502% (Samgag Series). 6. Amount and rate of desorption did not have any significant relation with Langmuir adsorption maxima of ammonium, CEC and contents of clay, available phosphorus and organic matter. 7. The above results may indicate that adsorption and desorption of ammonium is closely related with iron, aluminum silicate and adsorption and desorption characteristics of accompanied anions.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.3
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• pp.63-70
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• 2018

This experiment was conducted to investigate nutrient leaching and mobility through soil column for application of biochar pellet during rice cultivation. For nutrient leaching through soil column experiment, it was also consisted with four treatments as control, 100% of pig manure compost pellet (PMCP), biochar pellet (pig manure compost:biochar, 6:4)(BP), and slow release fertilizer (SRF). For experimental results, it was observed that $NH_4-N$ concentration in the leachate was gradually decreased at pick of 35 days and $NO_3-N$ concentration was highest from 60 to 98 days after transplanting. $PO_4-P$ concentration in the leachate was shown to be lowest in the PMCP and BP. K concentration in the leachate was highest in the control, but lowest in SRF. For mobility of nutrient in soil depths, it shown that $NH_4-N$ concentrations were highest from 40 to 60cm and did not significantly different among treatments except the control. It was observed that the deeper depth, the higher concentration for $NH_4-N$ concentrations, but for $PO_4-P$ concentrations the deeper depth, the lower concentration. And also $PO_4-P$ concentration was highest in the control. For K mobility in soil, its pattern was appeared to be approximately same between the control and PMCP, and between BP and SRF. Therefore, it might be potential to be applied biochar pellet to reduce mobility of plant nutrients for rice cultivation.

• 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.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.314-321
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• 2007

This study was conducted to select leaf vegetables suitable for cultivation in apartment verandas and simple and easy fertigation method for home gardening. In order to develop the convenient fertigation method, hydroponics, wick irrigation, and overhead irrigation methods were compared. For the wick irrigation, two types of nutrient sources were used; one was slow release fertilizers mixed with medium and the other one was nutrient solution filled in container located under pots. The growth of leafy lettuce, leaf mustard, and leaf beet was better in both of the wick irrigation methods rather than in overhead irrigation and hydroponics. The wick irrigation method is very easy, so that it is expected to bring a good result from the cultivating and managing point of view, if it brings with commercialized system along with slow release fertilizer. As a result of investigation of environment such as temperature, relative humidity, and irradiance level in apartment verandas in autumn the highest irradiance level during a day was just 48% and 35% in verandas facing south and feeing southeast, respectively, comparing to that in greenhouse. The light environment was investigated as a limiting factor for vegetable growing in verandas. Therefore, to select the vegetables showing good growth under low irradiance environment, nine leaf vegetables such as romaine lettuce, lent lettuce, head lettuce, endive, pak-choi, leaf mustard, garland chrysanthemum, leaf beet, and Chinese chive were grown under 0%, 50%, 70%, 90% shading. Among them, Chinese chive showed the best growth under low irradiance levels. Endive showed line growth reduction according to shading degree, however, even under 90% shading condition, it showed good growth. And then leafy lettuce, garland chrysanthemum, and pak-choi followed. Therefore, these results will be of help in selecting vegetables for veranda gardening with different light levels.

• 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.

• Horticultural Science & Technology
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• v.35 no.3
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• pp.289-299
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• 2017

The objective of this study was to determine the effect of replacing perlite (PL) with pellets processed with poultry feather fiber as an inert material to prepare growing medium. The growth and flowering of Salvia splendens 'Vista Red' grown in individual growing medium $Biosangto^{(R)}$, peat moss (PM), PL, and two pellets (P45-1 and P45-2) were evaluated. Peat moss was mixed with PL, P45-1, or P45-2 at various ratios (1:0 to 1:3 or 3:1 by volume) to investigate the feasibility of replacing PL with pellets. Nutrient composition of the growing medium and leaf tissues was analyzed. The number of florets, inflorescence length, plant height, and fresh weight of plants grown in media containing P45-1 or P45-2 were reduced compared to those grown in individual growing medium PM or PL. As the mixing ratio of P45-1 or P45-2 to PM was higher, the growth of salvia, such as inflorescence length, plant height, number of leaves, and fresh weight was inhibited. Our results indicate that mixing three parts PM with one part of P45-1 (PM/P45-1/3:1) or P45-2 (PM/P45-2/3:1) accelerated flowering and increased the number of florets and leaves compared to other mixing ratios of PM and pellets media. The concentrations of phosphorus (P), calcium (Ca), boron (B), iron (Fe), and copper (Cu) in individual growing medium PL, P45-1, and P45-2 were significantly lower than those in PM. The concentration of N was the highest in leaves of plants grown in P45-1 or P45-2 amended media, and the concentrations of P, Ca, and zinc (Zn) in leaves were lower in individual growing medium P45-1 or P45-2 than in PM and PL. The pH of PM/P45-1/3:1 or PM/P45-2/3:1 media was maintained at optimal level (5.8-5.9) and the concentrations of macro- and micro-elements in the media and leaves were considered to be optimal levels. Therefore, mixing three parts PM with one part P45-1(PM:P45-1/3:1) or P45-2 (PM:P45-2/3:1) is recommended for improved growth and flowering in salvia. This suggests that P45-1 or P45-2 can replace PL as an inert material to prepare growing medium.