• Economic and Environmental Geology
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• v.22 no.1
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• pp.17-20
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• 1989

Two rhyolitic rocks were taken at punggog of the Jangseong sheet in the Taebaegsan mineralized area and isotopically dated by K-Ar whole rock method. One is a rhyolite which gives $62.69{\pm}1.15Ma$ and the other is a rhyolitic tuff which gives $51.67{\pm}6.64Ma$, respectively. Generally K-Ar whole rock ages of the volcanic rocks can be assumed to be the formation age of them, if there is no geological criterion of secondary effects. But the two rhyolitic rocks were slightly hydrothermally altered and the age the rhyolitic tuff is a little younger than that of the rhyolite. However, there is no geological criterion to show any big hiatus between them in field, yet. Therefore, the age data would be interpreted, as that the rhyolitic rock mass has been probably extruded at about 60 Ma, a little older than 60 Ma, in the area. The ages of them probably appear to be secondary ages after the alteration. This fact well coincides with the K-Ar whole rock age of quartz-porphyry ($57.25{\pm}0.89Ma$) distributed near the 1st Yeonhwa Pb-Zn mine (Park et al., personal comm.), because the quartz-porphyry look to be a product of hydrothermal alteration of the volcanic rock.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.2
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• pp.147-151
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• 1983

In order to know the effect of planting date and cutting management on Jerusalem Artichoke (Helianthus truberosus L.) as a new forage or energy crop, JA tubes were planted from April 7 to June 27 with 20 day interval. Growth and yield could stay high as normal planting if tuber planting had been done until late May. The delayed planting after June caused deterioration of seed tuber, produced poor emergence and retarded growth. Previous harvested field did not need additional planting every spring because there were enough leftover tubers usually small size, less than 3gr., to provide a dense seedling establishment. This plot had too dense in population to adjust its spacing by thinning some of seedlings. One or two times cutting for forage or silage production reduced tuber yield very significantly. Therefore, it was not a good management to harvest for both forage and tuber production. Topping at 20cm from growing point in early July prevented from lodging and assured tuber yield.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.532-537
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• 2011

'Seolgaeng' is a new Japonica rice variety developed from an 'Ilpumbyeo' mutant line, N-methyl-N-nitrosourea (MNU) treatment on fertilized egg cell, by a rice breeding team of National Crop Experiment Station, Rural Development Administration in 2001. This variety has about 134 days of growth duration from transplanting to harvesting in central plain area of Korea, a good semi-elect plant type and resistant to lodging with strong culm. The number of panicles/hill of 'Seolgaeng' is more than that of 'Hwaseongbyeo'. The milled rice appearance of this cultivar is an opaque, but it has amylose content (19.3%) similar to 'Hwaseongbyeo'. It is superior to hypae formation of Aspergillus orzyae in the making of fermented rice and amount of pigmentation in fermented rice by Monascus anka that of 'Ilpumbyeo'. This variety showed slow leaf senescence and considerable resistance to viviparous germination. It is moderately resistant to leaf blast and susceptible to bacterial blight, virus disease and insect pests. The yield performance of this rice cultivar is about 5.27 MT/ha in milled rice in local adaptability test for three years from 1999 to 2001). 'Seolgaeng' is adaptable to central and southern plain areas of Korea.

• Korean Journal of Weed Science
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• v.11 no.1
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• pp.3-10
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• 1991

Several rice herbicides were evaluated to determine the herbicidal efficacy on dry seeded paddy rice. The time of herbicide application was within 1 day after seeding(DAS), 18 DAS, and 40 DAS. Under the upland conditions 30 DAS(before permanent flooding) dominant weed species were Echinochloa sp., Digitaria sp., Leptochla sp., weedy rice and other several annual broadleaved weeds belonging to Cruciferae, but after flooding Echinochloa sp., Aeschynomene sp., Eleocharis kuroguwai, Cyperus sorotinus, Ludwigia prostrata, Aneilema japonica were dominat. Early application (1 DAS) of thiobencarb, pyrazolate/butachlor, or chlomethoxyfen/butachlor resulted in very good herbicidal efficacy only during the first 30 days, but not thereafter. Application of propanil+butachlor on 18 DAS did not control the late occurring weeds effectively. Application of bentazone/quinchlorac on 40 DAS successfully suppressed weed growth throughout the remaining rice growing season and showed similar grain yield as hand weeded plot. Weed growth reduced the plant height, panicle number, 1000-grain weight, percent ripened grains, and grain yield of rice by 7, 82, 19, 55 and 87% respectively. There was a positive linear relationship between weed weight and lodging index of rice.

• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.123-127
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• 2009

This study was carried out to gain the informations about seedling transplanting cultivation of Daehakchal Gold 1 which was developed at the Corn Breed. and Genetics Lab., Coll. of Life and Sci., Chungnam Nat'l Univ. in 2009. This hybrid and Check were sowed over four times at intervals of 10 days from 15th April(1st) to 30th May(last) and transplanted at CNU Corn Breed. Farm the 20th seedling cultivated after sowing, respectively. Results obtained from this experiment were as follows; stem height of this hybrid were variable regardless of sowing and transplanting times, while ear height was gradually increased according to delay of sowing times. Ear size and sharp of fresh corn as one of important traits was good at 2nd harvest times, while tip filling of ear harvested at 1st time was not good and also it's size decreased according to delay of transplanting stage. Stability of this hybrid expressed as ratio of stem height to ear height was very good as 50% below. Accordingly, the proper sowing and transplanting times of Daehackchal Gold 1 considered the late in April to early in May as harvesting proper period.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.529-539
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• 2010

In order to evaluate the effect of soil salinity and culturing conditions including compost application and vinyl mulching on the maintenance of ridge and the growth of upland crops, three crops such as corn, soybean and sweet potato were experimented by using three or four cultivars of crops in the Saemangeum reclaimed tidal land. Average soil salinity before seeding was 2 dS $m^{-1}$, which was low enough for general upland crops to grow. However, high soil EC more than 16 dS $m^{-1}$ was observed in some parts of the experimented field. In the experiment, it was concluded that growth retardation and yield reduction of summer upland crops might be from severe erosion of ridge, soil compaction, flooding or wet soil condition and high salinity of some parts, and then these deteriorations were possibly improved for good crop growth and yield increase by compost application and vinyl mulching cultivation in the Saemangeum reclaimed tidal land.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.124-129
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• 2017

The Experiments were conducted by moderate season culture of each of early, medium and late maturing varieties which were considered to be of strong salt tolerance in low and high salty reclaimed areas (0.2% at the May). This study was carried out to investigate the proper nitrogen fertilizer level and seeding rates at reclaimed saline land in Korea. The proper seeding rates were $40kg\;ha^{-1}$ in 0.2% saline land. The dry matter production of barnyard millet was possibly estimated by exponential functions of $Y=0.0098X^2+0.7030X+2.6267$. Effects of nitrogen rate on agronomic characteristics, forage yield, and chemical composition of barnyard millet to reclaimed tidal land are summarized as follows: The proper nitrogen fertilizer level was $200kg\;ha^{-1}$ in 0.2% saline land. N was absorbed actively before the emergence of the barnyard millet but showed relative decrease thereafter. The early growth of the barnyard millet was inhibited, resulting in the favorable late growth, increased panicle weight and ratio of matured grain. These results suggest that barnyard millet is the most forage crops for cultivation on reclaimed tideland in view of the good emergence and forage production.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.4
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• pp.1-15
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• 2023

This research intended to reveal the special characteristics of the vegetation structure and the tendency of change of -landfill slope districts, which are reclaimed land, through an investigationsinto the presently existent vegetation and plant community structure of the World Cup Park landfill slope district. For the analysis of changes in vegetation, this study compared the results of field surveys in 1999, 2003, 2005, 2007, 2008, 2012, 2016, and 2021. For the investigation into the plant community structure, a field investigation was carried out in 2021 with six fixed investigation districts designated in 1999 as subjects. To analyze the change in the plant community structure, the past data on the population, the number of the species, and the species diversity by the layer in 2021 were compared and analyzed in the landfill slope district, which is reclaimed land. The changes of the vegetation distribution and the power had been affected by typhoons (Kompasu). Above the plantation foundation, which had been dry and poor, Salix koreensis, marsh woody plants that had formed the community, decreased greatly. The Robinia pseudoacacia community, after the typhoon in 2010, decreased in the number of species and population. Afterward, it showed a tendency to rebound. Regarding the Ailanthus altissima-Robinia pseudoacacia-Paulownia tomentosa community, the number of the species and the population had shown a change similar to the Robinia pseudoacacia community. The Paulownia tomentosa and the Ailanthus altissima have been culled. The slope was predicted as a Future Robinia pseudoacacia forest. The Salix pseudolasiogyne community has been transitioning to a Robinia pseudoacacia forest. Only some enumeration districts, the Robinia pseudoacacia forests and the Salix pseudolasiogyne, had been growing. However, most had been in been declining. It was predicted that this community will be maintained as a Robinia pseudoacacia forest in the future. As these vegetation communities are the representative vegetation of the landfill slope districts, which is reclaimed land, there is a need to understand the ecosystem changes of the community through continuous monitoring. The results of this research can be utilized as a basic material for the vegetation restoration of reclaimed land.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.619-624
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• 1996

An experiment was carried out to find out the effects of water foxtail on weed control and rice yield as well as on the reduction of nitrogen application in no tillage transplanted paddy field. Paddy field was dominated by water foxtail whose soil covering degree was adjusted from 8 to 6 by treatment of paraquat (70 l /10a of solution diluted by 1, 000 times). Thirty five-day old seedling was mechanically transplanted and reduced nitrogen, 80% of conventional application was applied at the paddy field. The higher failure in seedling stand was observed at higher degree of soil covering by water foxtail. The failure of seedling stand with covering degree of 8(no paraquat) was 37.4%, while that of covering degree of 6(paraquat-treated) was 12.3%. However, the seedling stand failure was completely recovered at covering degree of six at two weeks after transplanting. The mechanical transplanting made water foxtail in the paddy field fall on the ground whose panicle part was recovered from falling sometimes after transplanting and whole plant died with slow scenesence untill the late of June. But the water foxtail affected by paraquat produced the new panicle from uppernode of stem with dead leaves at early of June and it become die slowly untill the early of July. Though several rice field weeds were observed in the order of Echinochloa crusgallis, Cyperus serotinus, Lemma paucicostata during the active tillering stage of rice, the value of weed control due to the dominance of water foxtail was 77~78%. The death and subsequent decay of water foxtail during the active tillering stage of rice induced the soil reduction which again defect the growth of rice root. The more vigerous rice growth was observed in the plot dominated with water foxtails, than control plot. The yields of rice in the water foxtail (degree 6) plot was 629kg per l0a as brown rice, the same as that of control plot. In conclusion, the no-tillage transplanting with control of covering degree of water foxtail (to degree 6) was effective in reduction of input cost such as herbicide and nitrogen fertilizer, as well as weed control without reduction of rice yield.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.182-191
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• 1999

A study was conducted for the determination of application rate of pig-dung composted with sawdust (referred as pig manure hereafter) for wetland rice. The study involved the field experiments with the cultivation of rice under different rates of application of pig manure in combination of different rates of chemical fertilizers, in a wetland rice soil. The field experiment involved following treatments : (I) Without fertilizer, (II) Standard rate of chemical fertilizers based on soil testing($98-73-71kg\;ha^{-1}$ as $N-P_2O_5-K_2O$), (III) $2.1Mg\;ha^{-1}$ of pig manure $>+80-37kg\;ha^{-1}$ of $N- K_2O$ as chemical fertilizer(Less $N-P_2O_5-K_2O$ contained in the compost), (IV) $4.2Mg\;ha^{-1}$ of pig manure+ $62-3kg\;ha^{-1}$ of $N-K_2O$as chemical fertilizer(Less $N-P_2O_5-K_2O$ contained in the compost), (V) $10Mg\;ha^{-1}$ of pig manure+ Treatment(II), (VI) $20Mg\;ha^{-1}$ of pig manure +Treatment(II). Number of tillers in treatment (I) were higher than other treatments in tillering and panicle formation stage. After heading stage, treatments (V) and (VI) have higher number of tillers, but treatment (III) and (IV) have fewer number of tillers during all growing stage. Uptake of NPK in rice plants was higher in treatment (VI), but the efficiency of N, P and K was higher in treatment (I), (III) and (IV). The yield of unhulled rice were in order of tretments (VI)>(V)>(IV)>(II)>(III), although the difference was not statistically significant. Inorganic nitrogen, available P and exchangable K contents in soil were highest at tillering stage in all treatments and became low from panicle formation to harvest stage. Available P in soil was increased by the application of pig manure upto 20 cm depth. Exchangeable cation contents in 40 to 60 cm soil depth was much higher in treatment (VI) than in other treatments. Treatment (V) and (VI) showed much higher losses of N. $P_2O_5 $ and $K_2O$ than other treatment. Though treatment (VI) tended yield higher than in other treatments, showed lodging and occurrence of leaf and neck blast in this treatment. Yield of unhulled rice in treatment (IV) was not significant statistically and reduced nutritional losses. It is conclude that treatment (IV) seems to be the most reasonable one for the application of pig manure in combination of chemical fertilizers.