• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.351-358
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• 2006

This study was conducted to evaluate herbicidal properties of picolinafen in terms of crop safety, weed control spectrum, application window, residual efficacy and resistant weed control. Herbicidal phytotoxicity of picolinafen to wheat and barley was greatest when applied at 0 days after sowing (DAS), but decreased significantly as plant growth advanced. Picolinafen showed greater activity against broadleaved weeds than grass weeds. Picolinafen showed highest activity when it was applied at early post emergence timing (5 to 15 DAS), and showed significantly decreased activity at 20 DAS application. The $LT_{50}$ values (the period from application required for residual control by 50%) was 9.3 and 6.5 days against Digitaria ciliaris and Brasica naus at 60 g ai $ha^{-1}$, respectively. Picolinafen showed similar activities against both triazine resistant and sensitive Amaranthus retroflexus. Collectively, picolinafen appeared to have a good fitness to control resistant broad leaved weeds control by early post emergence application.

• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.1-14
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• 1977

These studies were carried out to know the variation of morphological tree forms, needles, cotyledons, seed characters and top height growth of seedlings of Pinus koraiensis S. et Z. by populations in Mt. Jiri. The results are summarized as follows: 1. It was observed that the characteristics of length, needles of serration density of needles, percentage of full seeds length, of seeds, thickness, of seeds length of cotyledons, width of cotyledon, numbers of the stomata line in cotyledons and the top height growth of seedlings were significantly different in individual trees and populations. 2. The characteristics of branch angle specific gravity of wood and resin canal numbers of cotyledons were significantly different in populations. 3. It was that the characteristics of numbers of stomata line, width, of seeds weight, of seeds serration density of cotyledons, numbers of cotyledons were significantly different in individuals. 4. The resin canals of needles showed three principle resin canals in individual trees and population, and the coefficients of variation were not shown in individual trees and populations. Stem forms showed to be a straight form with all populations. 5. The characteristics of cotyledons had generally higher tendency than the characteristics of needles in comparison with coefficience of variation.

• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.393-407
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• 2019

In this study, we prepared lignocellulosic artificial soil that contains Bacillus subtilis (peat moss/perlite/ steam-exploded oak wood/microbial culture = 3:1:3:3, w/w/w/w) for use in the restoration of damaged soil areas. The prepared lignocellulosic artificial soil was mixed with soil at ratios of 0%, 25%, 50%, 75%, and 100%. These mixed soils were then applied to fields, and the resultant physicochemical properties and their effects on the plant growth of Lespedeza cyrtobotrya were observed. The mixture of the prepared artificial soils (mixed at ratios of 25%-100%) with soil had a bulk densities of <$0.04g/cm^3$, porosities of >85%, pH values between 4.3 and 4.7, electrical conductivities of <0.5 dS/m, C/N ratios between 15.0 and 26.5, organic matter content between 23.6% and 43.2%, and bacterial densities between $157{\times}10^6$ and $624{\times}10^6CFU/g$. In addition, the prepared artificial soils mixed with soil at ratios of 25%-50% exhibited higher plant growth rates for L. cyrtobotrya compared with the control. Overall, we identified positive correlations between the plant growth of L. cyrtobotrya and soil bulk density, porosity, water-holding capacity, C/N ratio, organic matter, and bacterial densities.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.78-83
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• 1982

Seedling blight of sesame (Sesamum indicum L.) is one of the most serious diseases in Korea. This study was performed to control seedling blight in the field where sesame has been cultured for 4 years of Industrial Crop Division at the Crop Experiment Station. The pathogenic fungi of seedling blight which is known Fusarium oxysporum f. vasinfectium and Rhizoctonia solani was inoculated to the wheat media and it was spreaded on the experimental field in the concentration of 109 of wheat media mixed with 10g of fine soil. Seed sterilization was the most effective method for seedling blight control for two year experiment. Seed sterilant Benlate-T was highly effective for con trolling seedling blight with infection rate of 4% and yield of 40.7kg per 10a comparing to the control with infection rate of 96% and grain yield of 6.4kg per l0a, the other chemicals, Busan 30, Vitathiram, Captan showed good effect to control seedling blight, but less effect to the Benlate-T. The spraying treatments on leaf surface 25 days after sowing were not effective to seedling blight.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.277-286
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• 1985

From a series of studies conducted on the local maize lines at the Agr. College of the Chungnam National Univ., a few maize lines with many tillers and ears per plant were identified and tentatively named as MET. The purpose of the study was to evaluate the MET lines, which were selfed for five generations, for silage purpose under the different plant densities. A hybrid, Suwon #19 and a synthetic variety, Puyo #3${\times}$#2, were included for comparison. Plant height at harvesting times showed no significant varietal differences. However, the MET lines were very slow in early plant growth compared to the hybrid or synthetic variety, probably due to inbreeding depression of the MET lines. Total fresh weight at the harvesting times was highest in the MET 1 line. The MET 1 line was about 2,000 kgr. per 10a. higher than the hybrid at the harvesting time. The highest fresh weight was obtained when grown under the plant density of 60 ${\times}$ 20cm. Total dry weight per unit area showed the same tendency as the fresh weight. Total dry weight of MET 1 line was about 2.4 tons per 10a., which was about 10% higher than the hybrid, Suwon #19. As the fresh weight, the total dry weight was also highest in the plant density of 60 ${\times}$ 20cm. The grain yield per 10 are of MET 1 was comparable to the grain yield of the hybrid, especially in the low plant density, 60 ${\times}$ 40cm. The average number of effective tillers of MET lines were 4.5, while the mean tiller number of the hybrid or synthetic variety were none. However, the lodging was one of the problem for growing MET lines. The 100 kernel weight of MET lines was about 9 gr., while the 100 kernel weight of the hybrid or synthetic variety was about 30 grm.

• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.51-61
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• 2002

This study was conducted to investigate and compare species composition, stand structure, and growth pattern for two different sites in which silvopastoral system has been taking place. One site was the pasture area where a number of trees were removed and grasses were planted for cattle grazing, and the other site was the deciduous forest that has been established by ecological succession. The results were as follows: 1. Nine tree species were present equally in the pasture area and the deciduous forest. Of these species, seven tree species were growing in common for two sites. However, the species composition, including density and frequency, was varied by sites. 2. The number of stems per hectare in the pasture area was 71, and that in the deciduous forest was 1,433, having shown the big difference. It is estimated that, considering the growth rate, better grown trees were remained at the time of harvesting in 1996. 3. The growth of diameter, height, and basal area in the pasture area was superior to that in the nearby deciduous forest. In spite of higher values of diameter and height, the timber volume of pasture area per unit area was less than 15% of that in the deciduous forest. 4. Providing sufficient growing space, the pasture area supported higher values of diameter and height. The wider growing space also had influence on the expansion of crown of trees by the result of deliquescent growth pattern. From this point of view, more research would be needed to establish appropriate number of trees for silvopastoral system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.190-194
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• 2000

Double cropping is important for increase of farm income and rate of arable land utilization. This study was carried out to obtain information for optimum plant density of the second crop in a double cropping system. A waxy corn hybrid, Chalok #2, was sown on July 10 at the first corn cropping site. Growth characteristics and yield response of fresh waxy corn were examined under different planting densities, which were 55.5, 66.6, 83.3, and 111.1 thousands plants ${ha}^{-1}$. Plant height was higher under high planting density than low planting density and 154cm at the 55.5 thousand plants ${ha}^{-1}$, and 168cm at the 111.1 thousand plant ${ha}^{-1}$. It showed same trends in ear height and gravity center height. But planting density did not affect root lodging and silking date. At the silking stage, stalk and leaf dry matter weight and leaf area index (LAI) were increased significantly with increasing planting density, Filled ear lengtg was shortened significantly under the hi임est planting density (111.1 thousand plants ${ha}^{-1}$), while ear length and ear diameter were no differences among planting densities. The number of marketable ears increased with increasing planting density, but husked fresh ear weight was the highest at 83.3 thousand plants ${ha}^{-1}$ with 11.2MT ${ha}^{-1}$and optimum planting density was estimated as about 80 thousand plants ${ha}^{-1}$.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.146-150
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• 2007

For autumn cutting of Sedum sarmentosum, the influences of bedsoil and cutting date were investigated. Among six kinds of bedsoils mixed upland soil, carbonized rice and sand, the mixture with upland soil and sand (1:1 and 2:1, v/v) showed excellent root and shoot growth. The mixtures with upland soil and carbonized rice were lower rooting than the mixture with upland soil and sand. In field condition, autumn cutting was conducted with $10{\times}5cm$ space using the mixture with upland soil and sand (2:1, v/v) at intervals of 10 days from September 1 to October 10. Both root and shoot growth were significantly decreased by delayed date. In cutting from early to middle September, root and shoot growth, and number of rosette before wintering were desirable for shoot production next spring. The safety date to autumn cutting before wintering was on September 20 in field condition. If autumn cutting is late than September 20, the number of scion has increased 25-30% to secure a full rosette before wintering. The results could provide the beneficial information for cutting propagation of S. sarmentosum under field condition in autumn.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.33-39
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• 2001

An isolate of the indigenous fungus Pythium myriotylum was isolated from Monochoria vaginalis in Yusung, Korea in year 2000 and evaluated potential as a biocontrol agent in laboratory and greenhouse. P. myriotylum MD2 grew in a wide range of temperature regimes and the optimal growth temperature was $35^{\circ}C$. The fungus was highly pathogenic to Monochoria vaginalis at 30 to $35^{\circ}C$. Several weeds such as Rotala, indica, Lindernia procumbens, Ludwigia prostrata, Cyperus difformis, Scirpus juncoides, Aneilema keisak were also susceptible to the fungus, but Echinochloa crus-galli was not. The fungus affected the growth of rice seed germinated, but not to rice seedlings of 1- to 3-leaf stage. A total of 12 rice cultivars (3- to 4-leaf stage) tested showed no disease symptoms when inoculated with the fungus. Eleven crops, including Chinese cabbage, corn, soybean except wheat were immune to the infection of the fungi. These data suggest that P. myriotylum MD2 has a potential as a mycoherbicide to control weeds in paddy fields.

• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.513-523
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• 2013

This ecological study was conducted to analyze seasonal variation characteristics of Zostera marina at HAENAM SAGUMI on the Southern Coast of Korea. Environmental characteristics, plant morphological characteristics, shoot density, biomass, and leaf production were monitored from August 2008 to March 2011. Zostera marina occurred in the subtidal zone from 0 to 2.5 m below the mean low water level. Water temperature showed a clear annual pattern, with increase in spring and summer, and decreases in fall and winter. Irradiance showed seasonal variation, even though daily weather condition has short-term variation in the incident irradiation. Plant morphological characteristics, shoot density, biomass, and leaf production showed clear seasonal variation. Seasonal variation in the above biomass of Zostera marina was mainly caused by changes in shoot length. We found that there are correlations between environmental characteristics (water temperature, irradiation) and the growth of Zostera marina. There is stronger correlation between water temperature and the growth of Zostera marina, compared to the correlation between irradiation and the growth of Zostera marina. In particular, the growth of Zostera marina is inhibited by both higher and lower water temperature.