• Korean Journal of Plant Resources
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• v.10 no.4
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• pp.401-410
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• 1997

This experiment was conducted to investigate the opimum media, media amount and planting density of nutri-culture for the high quality and yield of wild vegetable, Liguliaria fischeri Turez. The fried rice hull was recognized best media among perlite, sand and fried rice hull for nutri-culture of Ligularia fischeri Turcz. The yield on fried rice hull media at early growing stage was lower, but higher than in other media at late growing stage. Therefore, total yield in fried rice hull media was 15-29% higher than that of the existing perlite media. Growth and yield of Ligularia fischeri Turcz. were not significantly different between medium amounts, therefore considering economical efficiency and stability, the optimum medium amount was 105 $\iota/m^3$, Yield by planting density increased in the high density and 50 plants/$m^2$ was considered as proper planting density in nutri-culture of Liguliaria fishcheri Turcz.

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.279-286
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• 2013

BACKGROUND: Soil incorporation of green manure crop(GMC) is one of the methods for reducing continuous cropping injury and increasing yield of carrot. The purpose of this study was to evaluate the effects of green manure crops on growth and yield of carrot for reduction of continuous cropping injury of carrot through crop rotation. METHODS AND RESULTS: To reduce the injury by continuous cropping system(CCS) of carrot cultivation, GMCs such as crotalaria and sudangrass were applied, which GMC was sowed in latter-June and returned to soil in latter-October. Nutrient contributions of N, $P_2O_5$, $K_2O$, CaO, and MgO in crotalaria were 8.3, 7.5, 4.4, 7.8, and 2.1 kg/10a, respectively. Nutrient contributions of N, $P_2O_5$, $K_2O$, CaO, and MgO in sudangrass were 8.4, 8.6, 26.8, 0.3, and 2.7 kg/10a, respectively. After incorporation of GMCs into soil, bulk density in soil with GMCs was lower than that in soil without GMCs(control). In soil after incorporation of GMCs, pH was not different in all treatment conditions, and ranged from 6.37~6.64. EC in soil after incorporation of GMCs was lower than that in soil without GMCs. The OM, T-N, and avail. $P_2O_5$ contents in soil with GMCs were higher than those in soil without GMCs. The growth and yields were increased as 39.2%(6,226 kg/10a) in the rotational cropping system(RCS) as compared to continuous cropping system(control and without NPK) of 4,473 kg/10a. Crotalaria cultivation were the most effective crop for reducing the injury of continuous cropping of carrot. CONCLUSION(S): This study suggest that the RCS using GMCs showed lower disease outbreak density in soil for carrot cultivation as compared to CCS without GMCs. Especially, the GMCs good effect for reduction of continuous cropping injury of carrot.

• Journal of Sericultural and Entomological Science
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• v.16 no.1
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• pp.1-20
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• 1974

These studies are conducted to find out inducing factors for the non-sprouting bud which appears in the utility reclaimed hill mulberry held and to establish control method for it since 1971. The results are as follows： 1. In spring, winter bud does not germinate at all on the top of branches or does wither suddenly after or during its germination. Necrosis and browning are appeared in cortex and phloem of non-sprouting bud branch. In autumn, the deterioration of leaves, the abnormal leaves on the top of branch, and browning of veins or petioles are also observed. 2. The soil of non-sprouting bud mulberry Held were found to be sand loom derived from granite rocks. The sub soil of it was very poor in development of root system because it had hard soil and lower pore space ratio. Especially, the sub soil to bring about severe non-sprouting bud had been easily appeared with deficiency of moisture content because of high density solid. 3. Content of soil moisture was significantly lower in the severe non-sprouting bud soil than in the healthy field. The sub soil o( the healthy field contained proper moisture content. On the other hand, the sub soil of the severe non-sprouting bud held contained almost critical moisture content for wilting. 4. The depth of available soil was shallow in the non-sprouting bud than in the healthy fold. The more rate of the non-sprouting bud was severe, the more available soil depth was sallow. 5. Available boron content in soil was affected by moisture content in soil. There was. lower moisture content in the non-sprouting bud field than that in healthy fold during 5, June to 5, September. 6. There was no significant correlation between soil pH and available boron content. On the other hand, the correlation of the content of organic matter and available boron content appeared to be highly positive significance. 7. The quantity of boron was significantly contained more in healthy mulberry field (0.34∼0.43ppm) than in non-sprouting bud field (0.10∼0.28ppm). 8. Boron content in leaves and barks was significantly lower in the non-sprouting bud trees than in healthy trees. 9. The symptom of non-sprouting bud induced from boron free sand culture was similar with that arised in the non-sprouting bud field. 10. The rate of non-sprouting bud was high by the increased application of lime. Considering the facts mentioned the above, author may conclude that the non-sprouting bud of mulberry tree is caused by boron deficiency, but also it is affected by the parent rocks, organic matter, soil moisture content and lime application. 11. The non$.$sprouting bud may be completely controlled by the application of 6∼9kg borax per 10a mulberry field twice a year in spring and summer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.1
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• pp.64-71
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• 2018

To improve the soil of reclaimed land, we added organic materials at a level of 3,000 kg/10 a. As a result, the electrical conductivity (EC) value of reclaimed soil decreased by 58%, the organic material content increased from 6.7 to 16.0 g/kg, the porosity increased from 1.57 to 1.31%, the soil hardness decreased from 20.2 to 17.9 mm and the plow layer was deepened from 19.8 to 26.8 cm. After these physiochemical improvements to the reclaimed soil, the growth phase of crops was improved compared to that of non-treatment crops. The height of kenaf (Hibiscus cannabinus L.) cultivated in the reclaimed land containing organic materials was increased by 18.8%. Especially, the improvement effects of pellet type manure compost and rice straw on kenaf were more preferable than those of other organic materials. When the kenaf was cultivated in the reclaimed land containing organic materials, the yield increased. The average yield of the treatment crops was 9,218 kg/10 a, 2.1 times higher than that of non-treatment crops. The most effective treatments to increase the yields were pellet type manure compost (10,848 kg/10 a, 148% increase), rice straw (120% increase) and chopped kenaf (95% increase). To increase the physicochemical enhancements to the reclaimed land soil and most improve yields, the most effective type of organic materials was the pellet. The organic material types that maintained a better growth phase and most increased the yield were the liquid and pellet types. When we used pellet type organic material, the plant height of kenaf was increased by 41% in comparison with that of the non-treatment crops and yield was increased by more than 122%. Additionally liquid type organic material improved the yield (by 127%).

• Journal of Wetlands Research
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• v.9 no.1
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• pp.1-11
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• 2007

The objectives of this study are: (1) to compare the rates and pathways of organic matter minerlaization at stagnant freshwater wetland in Shiwha to highly irrigated coastal wetland in Ganghwa; and (2) to discuss the significance of irrigation into the sediment in controlling the organic carbon oxidation in Shiwha wetland. Concentrations of $CO_2$, $NH_4{^+}$ and $H_2S$ in the pore water of the Shiwha wetland were 3 times, 30 times, and 3 times higher than that in the pore water of the Ganghwa wetland, respectively. The ratio of Fe(III) to total reduced sulfur at the Ganghwa wetland was 12 times higher than at the Shiwha wetland. The results indicated that the Ganghwa wetland with frequent tidal inundation were relatively oxidized than highly stagnant Shiwha wetland. Rates of organic matter oxidation at the Ganghwa wetland ($0.039mM\;C\;h{-1}$) was 390 times higher than that at the Shiwha wetland ($0.0001mM\;C\;h{-1}$). Rates of sulfate reduction at the Shiwha wetland ($314{\sim}580nmol\;cm^{-3}\;d{-1}$) were comparable to the sulfate reduction at Ganghwa wetland ($2{\sim}769nmol\;cm^{-3}\; d{-1}$), whereas Fe(III) reduction rates were 1.7 times higher at the Ganghwa wetland ($0.1368{\mu}mol\;cm^{-3}\;d{-1}$) than at the Shiwha wetland ($0.087{\mu}mol\;cm^{-3}\;d{-1}$). The results implied that the water flow system of the Shiwha wetland was too stagnant to flush out the reduced pore water from the sediment, and thus anaerobic microbial respiration was limited by the availability of electron acceptors.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.216-224
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• 1998

The objective of this study was to investigate the effect of sesame monoculture and sesame in rotation (SR) with maize. soybean. barley or rye on reduction of injury by continous cropping in sesame. Field studies were conducted for 3-years (1995~1997) at the experimental field of the Crop Experiment Station. Compared to CS (continuous sesame). SR treatments turned out to keep more organic matter and higher exchangeable cation concentrations in soils. BS (barley and sesame in a 1-year rotation) and RS (rye and sesame in a 1-yea r rotation) treatments had significantly greater available $P_2O_5$ contents in soils than CS, MS (maize and sesame in a 3-year rotation) and SbS (soybean a nd sesame in a 3-year rotation). The pH of the soils under different treatments were not significantly different. SR treatments exhibited significantly lower bulk density and higher pore space than CS. Soil microbial biomass C (SMBC) and N (SMBN) were determined by the chloroform fumigation-extraction method. SMBC and SMBN were significantly higher in soils under BS and RS than those under CS, but only during the 1 year of monitoring. MS and SbS treatments resulted in higher SMBC and SMBN than CS. The occurrence of injury by disease of sesame is the important primary factor of injury by continous cropping, but the disease occurrence with rotation did not decrease in th is experiment. Under CS treatment, the growth and grain of sesame was significantly lower than those under other treatments. Compared to CS, the increments of grain yield of sesame were 68, 63, 57 and 51% for MS, RS, SbS and BS, respectively in the first harvest. In the second harvest, they were 24% for MS, 28% for RS, 20% for SbS and 19% for BS. The average increase ratios during the two years were 41, 41, 34, and 33% for MS, RS, SbS and BS, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.167-173
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• 2002

This experiment was conducted to figure out the change of soil physical properties, rice growth and yield with the years of continuous cultivation in direct dry-seeding and no-tillage machine transplanting. Experiments were conducted at NHAES(National Honam Agricultural Experiment Station, RDA, Iksan, Cheon Buk Province, South Korea) with a rice variety "Dongjinbyeo" from 1995 to 2000. In no-tillage machine transplanting cultivation, organic matter in soil was higher than that on direct dry-seeding and was significantly high in topsoil. Problematic weed species were E. crus-galli B., A. keisak H., and L. japonica M. Plant height and tiller number m-2 were higher in common-tillage during the total growth duration. The highest weedy rice occurrence of 27.5% was observed in live years' continuous direct dry-seeding and followed by 6.2%, in four years', and 3.7%, in three years'. The highest yield reduction of 38% was observed in five years' continuous direct dry-seeding. The reduction may resulted from the competition between weedy rice and cultivated rice.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.1
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• pp.13-26
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• 2001

Six ferromanganese crusts from the Lomilik and Litatfooki seamounts in the Marshall Islands were analyzed for texture, geochemistry and stratigraphy to delineate the paleoceanographic conditions. The crusts can be divided into three layers; 1) outermost massive layer (Layer 1), 2) middle porous Fe-oxides rich layer infllled with biointemal clasts (Layer 2), and 3) innermost massive layer cemented and/or replaced by carbonate fluoapatite (CFA) (Layer 3). The Layer 1 contains higher Mn, Co, Ni, and Mg than other two layers, and the Layer 2 was relatively more enriched in Fe, Al, Ti, Ba, Cu, and Zn. However, the Layer 3 shows higher Ca and P and lower Mn, Fe, Co, and Ni contents than overlying two layers. Based on the Co-chronometry, the crusts are postulated to have begun to grow from 56-31 Ma (early Eocene to Oligocene). The boundaries between layers 1 and 2, and layers 2 and 3 are dated to be 7-3 Ma and 26-14 Ma, respectively. High contents of Ca and P in Layer 3 clearly indicate that the layer had been phosphatized prior to the formation of Layer 2. Considering the well-preserved mjcrostructures in Layer 3, it is unlike that the crusts themselves were recrystallized in suboxic condition. Also, the lower Co concentrations in Layer 3 may imply that the Co supply was not constant during the formation of Layer 3. Layer 2, characterized by the porous texture, grew over Layer 3 during 26-9 Ma. Internal biogenic sediments including foraminifera within the original cavities and the enrichment of organophillic elements such as Ba, Cu, and Zn, suggest that Layer 2 have below high production regions. Also, high content of allumino silicate components may indicate increased terrigeneous input during the formation of Layer 2. The Layer 2. The Layer 1 has been subjected to little diagenetic influence since the Pliocene.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.200-206
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• 2006

In a biological aerated filter (BAF) packed with ceramic media (void fraction of BAF=0.32), nitrite accumulation was studied with the variation of hydraulic retention time (HRT) and superficial air velocity. Synthetic ammonium wastewater and petrochemical wastewater were fed at a constant load of $1.6kgNH_4^+-N/m^3{\cdot}d$. Ammonium removal rate was mainly affected by the superficial air velocity in BAF, but nitrite ratio($NO_2-N/NO_x-N$) in the effluent was dependent on both HRT and superficial air velocity. For a fixed HRT of 0.23 hr (corresponding to the empty bed contact time of 0.7 hr) ammonium removal rate was 73/90/92％ and nitrite ratio was 0.92/0.82/0.48 at the superficial air velocity of 0.23/0.45/0.56 cm/s, respectively. When HRT is increased to 0.9 hr with superficial air velocity ranging from 0.34 to 0.45 cm/s, the ammonium removal rate was 89％ on average. However nitrite ratio decreased significantly down to 0.13. When HRT was further increased to 1.4 hr, ammonium removal rate decreased, thereby resulting in the free ammonia ($NH_3-N$, FA) build-up and nitrite ratio gradually increased (>0.95). Although aeration rate and FA concentration at HRT of 0.23 hr were unfavorable for nitrite accumulation compared with those at HRT of 0.9 hr, nitrite ratio at HRT of 0.23 hr was higher. Taken together, HRT and nitrogen load were found to be critical, in addition to FA concentration and aeration condition, for nitrite accumulation in the BAF tested in the present study.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.371-378
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• 2009

This study was carried out to investigate the improvement effect of soil fertility by incorporation of GMC(green manure crops) at rice cropping after cultivation GMC such as the barley for alternative rye in paddy field over the past two years(2006~2007). Plots, which consisted of incorporation time of GMC as rye; heading stage, barley; heading stage, heading stage of rye and 10days after heading stage were divided by amount of applied rates; standard fertilizer fertilization, diagnosis fertilization and non-fertilization. we investigated change of soil physico-chemical properties, degree of decomposition on GMC in soil, growth and yield potential. The obtained results were summarized as follows. The fresh weight of GMC at incorporation time on heading stage of rye, heading stage and 10days after heading stage of barley were $2,715,\;2,352,\;2,867kg\;10a^{-1}$ respectively. Content of total nitrogen at three incorporation times was 1.31, 1.46, 1.38% and the C/N ratio were 33.4, 28.7, and 34.6, respectively. Some soil physical properties, such as soil hardness and bulk density tended to decrease with incorporation of GMC, while surface soil depth and porosity were increased. Some soil chemical properties, such as content of exchangeable cations and cation exchangeable capasity(CEC) were increased with incorporation of GMC compared with before experiment. Rice yields was increased 3~9% in diagnosis application plots on application of barley compared with control($559kg\;10a^{-1}$) and incorporation of barley caused to improve perfect kernel ratio 73.6~78.7% in appearance characteristics of brown rice compared with cotrol(73.0%). It was found that incorporation with 10days after heading stage of barley was more effective to reduce chemical nitrogen fertilizer and to improve soil fertility.