• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.84-89
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• 1991

This experiment was carried out to determine the effects of oversowing and other seeding methods (oversowing+ raking, oversowing+ raking+compaction, tillage+ broadcasting+ compaction and tillage + drilling+ compaction) on growth, dry matter and crude protein yield of alfalfa (Medicago satiua L.). The results obtained are summarized as follows:1. Soil pH and soil properties were improved by tillage.2. Establishment of alfalfa was increased with raking and compaction, and more by tillage than by oversowing(P

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.223-229
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• 1996

To investigate the effect of seeding date, seeding rate, and sprouted seeds on seedling establishment, yield and its components of rice in barley /rice reley cropping as a minimum tillage, Gancheokbyeo rice seeds sowed by hand broadcast in various overlapped days befer barley harvest. The highest rice seedling stand was at sowed on the day just before barley harvest and l00kg per hectare of seeding rate with sprouted seeds. Also number of tiller and panicle showed the similar tendency. Delayed rice heading dates were found 2 days at l0-day overlap, 2 days at 5-day overlap, and 4 days at 0-day overlap before barley harvest compared with machine transplanting rice at just after barley harvest using l0-days old seedling. The culm length of broadcast rice shortened 2∼4cm compared with the transplanting rice. The rice plants lodged slightly at seeding rate l00kg per hectare and at sowed on the day of barley harvest. The rice panicle number increased with later date sowing and higher seeding rate. Number of spikelets per panicle and ripened grains decreased at higher seeding rates. Sprouted seeds and higher seeding rates showed higher rice yield at later sowing dates.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.106-115
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• 1998

This study was conducted to investigate the effect of oxadiazon, molinate, thiobencarb before seeding on control of red rice and barnyardgrass in water-seeded rice. High application rate plot among oxadiazon treatment plots could observe phytotoxicity symptoms depending on field conditions, but these injury recovered gradually with time. Molinate and thiobencarb application plots at the concentration of 225~400, 210~420g ai/l0a respectively were not observed phytotoxicity. Control of red rice was different according to kinds of herbicides and application rates. Oxadiazon showed higher control performance at the concentration of more than 60g ai/10a. Control effect of molinate and thiobencarb against red rice was enhanced with the increase of application rate, and both herbicides showed satisfactory effect at more than 300g ai/10a. Control of barnyardgrass showed up to 90~100% in all tested herbicides. There was no significant yield reduction by oxadiazon, molinate, and thiobencarb application before seeding in all tested field. In the pot experiment, crop injury, seedling stand, and early growth were more advantageous at time of drainge after one day after seeding than flooding until rooting.

• Weed & Turfgrass Science
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• v.3 no.3
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• pp.225-231
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• 2014

Benzobicyclon induces phytotoxicity to Tongil type rice, although it is an efficient herbicide in paddy. This study was performed to figure out the benzobicyclon-induced phytotoxicity responses of whole crop forage rice genotypes that have the genetic background similar to Tongil type rice, under wet-seeded and transplanted conditions. Mogwoo demonstrated whitening symptom at all the temperatures in both wet-seeding and transplanting by the application of standard and double rates of benzobicyclon. Nokyang, Mogyang and Suweon560 exhibited no or negligible whitening and their plant heights were not reduced at standard rate of benzobicyclon. But in double rate application in wet-seeding, the three genotypes showed 0-8% of white plants at all temperature treatments and reduction in plant height was comparatively larger at $27^{\circ}C$. In transplanting, the double rate application of benzobicyclon at 24 and $27^{\circ}C$ induced 0-32% of whitening plants depending on genotypes while no whitening plants were observed at 18 and $21^{\circ}C$ in all genotypes. Reduction in biomass by double rate of benzobicyclon at 24 and $27^{\circ}C$ was greater than at 18 and $21^{\circ}C$. It is concluded that Mogwoo is extremely sensitive to benzobicyclon and Nokyang, Mogyang and Suweon560 are tolerant to the standard rate of benzobicyclon.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.428-436
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• 1995

The studies were conducted to escape for laber concentration during rice harvest and barley sowing through the scattering sowing before rice harvest(SS) compared to the drilling on high ridge(DS) of barley from 1990 to 1994. There were longer in plant height and more in tiller number under the SS than those under the DS of barley while cold-injured leaves of barley were inversely affected by two different sowing methods. The barley growth was more vigorous in the DS. There was similar at heading and maturing date. The grain yield of barley was lower in the SS by 20.6% which was resulted from the reduction of spike number per m$^2$ and number of grain per spike. There was not significant at growth and yield for sowing date before rice harvest. The variation of successive years on growth, yield and its components were higher in the SS than those in the DS.

• Korean Journal of Plant Taxonomy
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• v.34 no.2
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• pp.119-152
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• 2004

Allium taxa of Korea were taxonomically reviewed, and classified as three subgenera, ten sections, seventeen species, and three varieties. Among these, Korean endemics were recorded as six taxa; A. koreanum, A. taquetii, A. deltoide-fistulosum, A. linearifolium, A. thunbergii var. deltoides, A. thunbergii var. teretafolium. In addition, A. condensatum, A. splendens and A. maximowiczii proved to distribute only in North Korea. Keys to the subgenera, sections, species and infraspecies with descriptions of each taxon were provided.

• Journal of Korean Port Research
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• v.12 no.1
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• pp.75-86
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• 1998

To design a coastal structure in the nearshore region, engineers must have means to estimate wave climate. Waves, approaching the surf zone from offshore, experience changes caused by combined effects of bathymetric variations, interference of man-made structure, and nonlinear interactions among wave trains. This paper has attempted to find out the effects of two of the more subtle phenomena involving nonlinear shallow water waves, amplitude dispersion and secondary wave generation. Boussinesq-type equations can be used to model the nonlinear transformation of surface waves in shallow water due to effect of shoaling, refraction, diffraction, and reflection. In this paper, generalized Boussinesq equations under the complex bottom condition is derived using the depth averaged velocity with the series expansion of the velocity potential as a product of powers of the depth of flow. A time stepping finite difference method is used to solve the derived equation. Numerical results are compared to hydraulic model results. The result with the non-linear dispersive wave equation can describe an interesting transformation a sinusoidal wave to one with a cnoidal aspect of a rapid degradation into modulated high frequency waves and transient secondary waves in an intermediate region. The amplitude dispersion of the primary wave crest results in a convex wave front after passing through the shoal and the secondary waves generated by the shoal diffracted in a radial manner into surrounding waters.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.130-133
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• 2006

This study was conducted to select Codonopsis lanceolata seed's new pelleting particulate materials and adhesives. Different adhesives (Polyvinyl alcohol (PVA), Carboxymethyl cellulose (CMC), Polyvinyl pyrrolidone (PVP), Xanthan gum (XG), Arabic gum (AG)) and particulate materials (Illite, Diatomite, Pyrophyllite + Illite + Diatomite (PID), Pyrophyllite + Illite + Talc (PIT), Bentonite + Talc (BT)) were tested for seed pelleting. PID for Codonopsis lanceolata seed pelleting appeared to be the best particulate material. Among the pelleting adhesives, PVP was the best adhesive for seed pelleting, and the optimum concentration for germination of pelleting seed was 1 %. Germination rate of the pelleted seeds treated with PID particulate material and PVP adhesive was higher (86.8%) than those of raw seeds (85.5%). $T_{50}$ and MDG of pelleted Codonopsis lanceolata seed required five and eight days at soil moisture content of 50%, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.2
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• pp.160-165
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• 1991

Growth performance of dry seeded paddy rice was studied at four N levels (10, 15, 20, and 25 kg/l0a) in tillage and no-tillage systems. Althougth the number of seedlings and maximum tillers tended to be higher and heading date was delayed by 2 days in tillage compared with those in no-tillage system, grainyield, yield components, lodging related characteristics, and N uptake were similar between two tillage ,systems. As N level increased, grain yield increased due to increased panicle number althougth the number of spikelets per panicle and percent ripended grains were similar and I, 000 grain weight decreased slightly. {Lodging index increased with increased N level due to higher plant height and decreased breaking strength and (culm base weigth, but lodging was not occurred in the field. Cellulose, hemicellulose, and lignin contents of culm base were similar among N levels. Concentration and uptake of N increased as N level increased.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.4
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• pp.189-196
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• 1999

In order to verify a numerical model for the calculation of wave motion around an offshore barrier in shallow water, laboratory physical experiments are necessary. In this study, sample experiments are carried out on the wave and wave induced current fields due to a sloping bottom topography and on that due to an isolated structure from the coastline. The water body is divided into 4 levels, in which the current tracking floaters are deployed to measure the wave induced currents. Data measurement was continued using the limited wave gauges and current tracking floaters including a video camera from the top. The wave heights for the preselected surface and time-averaged velocity distributions at each level were measured in detail. The distribution of wave and current fields was analyzed precisely combining the whole measured laboratory data. Moreover, comprehensive analyses were carried out on non-linearity of wave transformation in terms of skewness and atiltness.