• Korean Journal of Weed Science
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• v.16 no.2
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• pp.88-99
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• 1996

In recent years dry direct-seeding of rice has been encouraged by the government and increasingly practiced by farmers in Korea. This has been bringing up an increased occurrence of weedy rites. Some farmers in the southern region dare to sow the rice before winter after harvest, while most farmers wish to sow as early as possible in the spring to secure the growing period, and to disperse the intensive labor in early May. The purpose of this study was to determine the feasibility of moving the sowing of rice to an earlier date under dry direct-seeding, and to elucidate the nature of emergence of an old strain of rice, weedy rites, and barnyardgrasses tinder this farming practice and their adaptive competence over present cultivate. The presently recommended rice cultivar, Dongjinbyo and an old rice strain, Dadajo which prevailed in early 1900s, almost could not emerge from soil deeper than 6cm and could emerge to only 5.3% at best from 1cm deep loamy soil field when the seeds were sown on Nov. 28. However, two strains of weedy rites being weedy for over 200 years emerged by 17.0 to 63.0% from the loamy and sandy clay loam field 1 to 6cm deep. Emergence of the weedy rites was greater in the loamy soil and at a shallow depth, and negligible from the soil depth of 9cm. Barnyardgrasses sown on Nov. 28 emerged by 13.4 to 51 % from the 1 to 3cm deep loamy soil, and 8.6 to 46.7% from the 1cm deep sandy clay loam. Echinochloa crus-galli var. crus-galli emerged more than var. praticola, and var. oryzicola least. Most of the non-emerged barnyardgrasses seem to have entered secondary dormancy. Seeding rice a month earlier than the season lowered the emergence of Dongjinbyo by ca. 10, 18, and 26%, respectively at 1, 3, and 6cm soil depths, indicating that moving the seeding date a month earlier is impractical. The old strain, Dadajo sown in the soil at a depth of 6cm responded similarly. However, the strain has shown a significantly higher ability in emergence from 9cm deep soil. Weedy rices sown a month earlier A month earlier sown weedy rices have shown very similar emergence rates at various soil depths to those sown on May 1. Barnyardgrasses have also shown similar emergence rates when sown between April 3 and May 1. Like barnyardgrasses, the old strain and weedy rices apparantly posessed a greater adaptability to emerge under lower temperatures, and from deeper soil ; Dongjinbyo${\leq}$ Echinochloa species in that order. However, emergence- speed under lower temperature(sown on April 3) was faster in the order of weedy rice

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.4
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• pp.1-10
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• 2011

This study was conducted to compare the growth of Zoysia japonica depending on different soil treatments in Saemangeum sea dike, which is filled with dredged soil. Zoysia japonica was planted using sod-pitching method on the control plot. On plots which were treated with forest soil and soil improvement, Zoysia japonica seeds were sprayed mechanically. Sixteen months after planting, coverage rate, leaf length, leaf width, and root length were measured and analyzed. Also, three Zoysia japonica samples per plot were collected to analyze nutrient contents. Coverage rate was 100% in B treatment plot(dredged soil+$40kg/m^3$ soil improvement+forest soil), in C treatment plots (dredged soil+$60kg/m^3$ soil improvement+forest soil), and D treatment plots (dredged soil+$60kg/m^3$ soil improvement), while only 43% of the soil surface was covered with Zoysia japonica on control plots. The width of the leaf on C treatment plots (3.79mm) was the highest followed by D treatment (3.49mm), B treatment (2.40mm) and control plots (1.97mm). Leaf and root length of D treatment was 30.18cm and 13.18cm, which were highest among different treatments. The leaf length of D treatment was highest followed by C, B, and A treatments. The root length of D treatment was highest followed by C, A, and B treatments. The nitrogen and phosphate contents of the above ground part of Zoysia japonica were highest in C treatment, followed by D, B, and A treatments. The nitrogen and phosphate contents of the underground part of Zoysia japonica were highest in D treatment, followed by C, A, and B treatments. C and D treatments showed the best results in every aspect of grass growth. The results of this study could be used to identify the cost effective way to improve soil quality for soil surface fixation on reclaimed areas using grass species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.50-56
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• 2016

Direct seeding of sorghum (Sorghum bicolor L. Moench) has a problem of low yield including poor establishment. This poor establishment results from poor quality seed, poor seedbed preparation, seedling pests, poor sowing technique and high soil temperature. This study sought to establish the age at which sorghum seedlings can be transplanted with minimal effects on grain yield. Transplants were raised in 128 nursery tray pot. Five seedling ages were established by transplanting at 10 (T10), 15 (T15), 20 (T20), 25 (T25) and 30 (T30) days after planting (DAP). The treatment combinations were arranged in a randomized complete block design and replicated three times with an individual plot size of $6{\times}5m^2$. Each plot had five ridges with a planting space of $0.60{\times}0.20m^2$ at one plants per stand. Results showed that seedling age on transplanting significantly affected growths and yields to sorghum after transplanting. Plant heights and diameters of transplants at T15 were longer than the other transplants. Conclusively, The advantages of this practice were better control of crop density and greater yields; either to fill gaps after emerging and thinning of crops or to compensate for a growth period that was too short for a complete crop cycle.

• Korean Journal of Agricultural Science
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• v.13 no.2
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• pp.219-226
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• 1986

A study was conducted to provide direct comparisons of the effect of variations in herbage use, grazing and social behaviour upon the flat, slope and forest grassland with a total 30 Korean Native Cattle and 5 Korean Native Goats under 4-year old grassland established by intensive sowing method in Daecheon. The results obtained are summarized as follows; 1. Relative intake index, dry matter intake per animal and dry matter digestibility by Korean Native Goats in flat, slope and forest grassland were 35.2%-462g-63.7%, 35.0%-459g-63.0% and 29.8%-391g-62.1%, respectively. 2. Grazing time by Korean Native Cattle was not different among the grassland types, but ruminating time was increased in slope grassland, whereas in forest grassland was decreased. Resting time was increased in forest grassland, whereas in slope grassland was decreased. Walking time was increased in flat grassland, but loafing time was increased in forest grassland. The number of rumination, chews per bolus and defecation number were decreased in forest grassland. The number of drinks, total drinking water and walking distance were increased in slope grassland. 3. Animal distance, occupied area per animal and sub group formation by Korean Native Cattle in flat, slope and forest grassland were $3.4m-11.9m^2-3.6head$, $3.56m-11.0m^2-3.7head$ and $3.70m-14.6m^2-3.4head$, respectively. The order of grazing movement was similar to the pear-shaped grazing formation, but the relations of dominance between first grazer and last grazer upon different grassland types was not clear.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.505-513
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• 1996

This study was conducted to investigate the variation of chemical components in stagnant water under different mulching amount of barley straw after combine harvesting and the effect of stagnent water on the germinatidn and seedling elongation at early growth stage in rice. pH was lower in barley straw mulching than non-mulching and decreased with increasing of mulched barley straw but was not different among treatments in stagnant water at 15 days after flooding. Dissolved oxygen decreased with the increasing of mulched barley straw and increased with the passing of time, while saline content increased with the increasing of mulched barley straw, showing significant difference among treatments, was peaked at 15 days after flooding and thereafter, decreased. NH4-N was higher 5 days after flooding with thicker barley straw mulching but was not different at 10 days. N $O_3$-N increased up to 10 to 15 days after flooding and increased with thicker barley straw mulching. Water soluble phosphorus and cation content ( $K^{+}$, $Ca^{2+}$, $Mg^{2+}$)were higher in thicker barley straw mulching and peaked at 10 and 15 days after flooding. Germination rate was decreased by thicker straw mulching and was high in order of medium late, medium and early maturing rice variety. Keumobyeo, Gancheokbyeo, Ilpumbyeo, Dongjinbyeo and Gyehwabyeo showed higher germination rate. Seedling elongation at early growth stage was poorer with increasing of barley. straw mulching. Ilpumbyeo had good seedling elongation in one time amount of barley straw mulching and Shinunbongbyeo, Unjangbyeo, Nonganbyeo and Dongjinbyeo had poorer, in two times.mes.