• Korean Journal of Weed Science
• /
• v.17 no.2
• /
• pp.139-146
• /
• 1997

The experiment was conducted at Gyeongbuk Provincial Rural Development Administration in 1996 to obtain basic information on weed ecology and effective weed control in direct-seeded rice fields under different seeding types and seeding times. A large number of upland weeds such as Echinochloa crus-galli, Digitaria sanguinalis, Capsella bursa-pastoris and Stetaria viridis etc occurred at early growth stage, while Eleocharis kuroguwai, Aneilema keisak and Cyperus serotinus dominated at late stage in dry seeded rice field. In wet seeded rice field, the dominance of E. crus-galli was lower and the occurrence of M. vaginalis and A. keisak were higher than in dry seeded field. Amount of weed occurrence in dry seeded field was 1.8 to 2.4 times greater than in wet seeded field and it increased with delaying seeding time. Increasing rate of weed occurrence through whole life cycle was the highest at 20 days after seeding (DAS) to 40 DAS, regardless of seeding types and seeding times. Simpson index in wet seeded field was higher than in dry seeded field and it gradually increased as growing of dominant species. For F-value test, it was recognized as statistical significant in seeding types, seeding times and interaction of two factors.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.41 no.2
• /
• pp.157-167
• /
• 1996

The method of direct seeding on flooded paddy surface in rice is known to be the most labor saving cultural practice in rice. However, this method has a problem in practical use such as severe lodging occurring at the reproductive growth stage. The objectives of this study were observated degree of field lodging and variation of lodging-related characteristics with different seeding dates. The number of seedlings per m$^2$ were from 91 to 144 plants, and seedling ratios were from ranged from 61.7% to 91.8%. Days from seeding to flowering were shortened from 5 to 15 days by the later seeding dates. Heading dates of Ilpumbyeo, Seoanbyeo, Daecheongbyeo and Donjinbyeo on June 9 showed slightly elapsed on the critical stable heading time from, August 28 to 29. The culm length was effective in longer clum varieties than semidwarf varieties. The degree field lodging (degree of lodging: 0~9< 9 : complete lodging) in Obongbyeo and S101 with semidwarf varieties were 0.17, whereas 1.25 in Dongjinbyeo with long culm. The lodging resistant varieties and later seeding dates shortened the length of fibrous in the clum, and thickened fibrous in the clum, respectively. Obongbyeo and Sl0l showed stronger resistance to field lodging. The lodging resistant varieties, Obongbyeo and Sl0l, showed lower values of lodging index from 1.03 to 1.15 than those of lodging susceptible varieties, Daecheongbyeo and Palgongbyeo ranged from 1.42 to 1.70. Bending moment with leaf sheath were greater in lodging resistant varieties (Obongbyeo and Sl0l),1510.0~1930.4g.cm, than those in the lodging susceptible varieties (Daecheongbyeo and Palgongbyeo), 1127.2~1287.6g.cm.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.29 no.1
• /
• pp.25-30
• /
• 2009

This experiment was conducted to evaluate the effect of direct seeding time on the yield and quality of whole crop rice at experimental field of Grassland and Forages Research Center, National Institute of Animal Science, RDA from 2005 to 2006. Whole crop rice variety, "Namil", was direct seeded at five different calender date (25 April, 10 May, 25 May, 4 June and transplanted at 25 May). The heading date was delayed at late seeding date. Crude protein (CP) was increased with delayed direct seeding date. The content of ADF (acid detergent fiber) and NDF(neutral detergent fiber) increased with delayed seeding date. The average TDN (total digestible nutrient) content was 61.5% and it also decreased with delayed direct seeding date. The highest DM (dry matter) yield was seeded at 25 April and transplanted at 25 May, 15,185 and 15,815 kg/ha, respectively. Although delayed direct seeding date decrease the DM yield, mid-May will be recommendable as proper direct seeding date.

• Korean Journal of Weed Science
• /
• v.8 no.1
• /
• pp.23-27
• /
• 1988

This experiment was conducted to determine germination ability, life cycle, regrowth ability of Portulaca oleracea L. The newly harvested seeds from P. oleracea flowered before July 15 were able to germinate, but percent germination decreased markedly as the flowering time was later than July 15, showing no germination of seed collected at Sept. 12 which were flowered at August 30, 76.5% of seeds can be germinated in the light as seed stored in room condition for 90 days, but in dark condition, it needed 2 years of seed storage for germination. Low temperature treatment at $2^{\circ}C$ for 5 days enhanced seed germination of P. oleracea in both light and dark conditions. The maximum vagetative growth was observed at 30 to 75 days after seeding. The late seeding time such as July 1 shortened the period of vegetative growth. However, regardless of the seeding times, the first flowering was observed at about 40 days after seeding. Leaf numbers, shoot lengths, fresh and dry weights were greatly affected by the seeding dates, showing that the earlier seedings produced significantly higher shoot length, fresh and dry weight, leaf numbers and branch numbers than those of the late seedings. When all branches were removed on 68 days after seeding, their regrowth ability was 50.3% and cuttaged branches showed 78.1% regrowth as compared to intact plant.

• Korean Journal of Medicinal Crop Science
• /
• v.4 no.2
• /
• pp.163-171
• /
• 1996

The influences of temperature, harvest time, sowing time, seeding media, moisture content of media and light on the seed germination of Lycoris are as follows, Both L. koreana and L. aurea had over 90% seed setting, and seed maturity came in September or early October. It took six months to have over 60% seed germination. The optimum germination temperature was $25^{\circ}C$, and the alternating treatment was effective at $20{\rightleftarrows}25^{\circ}C$. The optimum harvest-time was around Sep. 20, and the optimum seed-time was immediately after havest. The optimum seeding media was sand loam, and the optimum moisture content was PF 1. 9/400ml seeding media. The dark condition was more effective for the seed germination than the light condition.

• Journal of Biosystems Engineering
• /
• v.41 no.3
• /
• pp.263-272
• /
• 2016

Purpose: Pulse crop damage due to wild birds is a serious problem, to the extent that the rate of damage during the period of time between seeding and the stage of cotyledon reaches 45.4% on average. This study investigated a method of fundamentally blocking birds from eating crops by conducting vinyl mulching after seeding and identifying the growing locations for beans to perform punching. Methods: Infrared (IR) sensors that could measure the temperature without contact were used to recognize the locations of soybean cotyledons below vinyl mulch. To expand the measurable range, 10 IR sensors were arranged in a linear array. A sliding mechanical device was used to reconstruct the two-dimensional spatial variance information of targets. Spatial interpolation was applied to the two-dimensional temperature distribution information measured in real time to improve the resolution of the bean coleoptile locations. The temperature distributions above the vinyl mulch for five species of soybeans over a period of six days from the appearance of the cotyledon stage were analyzed. Results: During the experimental period, cases where bean cotyledons did and did not come into contact with the bottom of the vinyl mulch were both observed, and depended on the degree of growth of the bean cotyledons. Although the locations of bean cotyledons could be estimated through temperature distribution analyses in cases where they came into contact with the bottom of the vinyl mulch, this estimation showed somewhat large errors according to the time that had passed after the cotyledon stage. The detection results were similar for similar types of crops. Thus, this method could be applied to crops with similar growth patterns. According to the results of 360 experiments that were conducted (five species of bean ${\times}$ six days ${\times}$ four speed levels ${\times}$ three repetitions), the location detection performance had an accuracy of 36.9%, and the range of location errors was 0-4.9 cm (RMSE = 3.1 cm). During a period of 3-5 days after the cotyledon stage, the location detection performance had an accuracy of 59% (RMSE = 3.9 cm). Conclusions: In the present study, to fundamentally solve the problem of damage to beans from birds in the early stage after seeding, a working method was proposed in which punching is carried out after seeding, thereby breaking away from the existing method in which seeding is carried out after punching. Methods for the accurate detection of soybean growing locations were studied to allow punching to promote the continuous growth of soybeans that had reached the cotyledon stage. Through experiments using multiple IR sensors and a sliding mechanical device, it was found that the locations of the crop could be partially identified 3-5 days after reaching the cotyledon stage regardless of the kind of pulse crop. It can be concluded that additional studies of robust detection methods considering environmental factors and factors for crop growth are necessary.

• Korean Journal of Weed Science
• /
• v.1 no.1
• /
• pp.52-56
• /
• 1981

A 2-year field experiment was conducted to determine the influence of early and late soybean (Clycine max Merr) seeding times on competitive relationships between soybeans and annual weeds. Soybeans were planted on May 20 and June 20. Durations of weed competition and weed control were 0, 3, 6, 9, and 12 weeks after planting sad for full growing season. Dominant weeds were Portulaca oleracia, Centipeda minima, Rorippa cantonienais, Chenopodium album, Acalypha australis, Echinochloa crusgalli, and Digitaria sanguinalis. The dry weight of weeds increased with extended competition, especially at early seeding time of soybeans. Soybean yields were decreased as duration of weed competition was extended. More severe yield reduction occurred at late-planted soybeans with early stage weed competition but at early-planted soybeans when weeds competed with soybeans for a 2 weeds and full growing season. The dry weight of weeds emerged after weeding was decreased at early and late seeding times of soybeans as duration of weed control was prolonged. Soybean yields decreased with shortening duration of weed control end this trend of yield reduction was slightly more remarkable at late-planted soybeans than at early-planted soybeans. Late-planted soybeans were required longer than 6 weeks of weed control period to achieve maximum yield as compared to early-planted soybeans.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.15
• /
• pp.77-83
• /
• 1974

This experiment was conducted to study the effexts of seeding time and varieties on yield components, protein and oil content of soybean. Four varieties of soybean(Chung Buk Baek, Iksan, Keum doo, Chang dan Baek mok)wrere applied in this experiment and were seeded at May 15th, June 5th, and June 25th, the results obtained are as follows. 1.When the soybean was seeded at May 15th, stem height, stem diameter and number of nodes on main stem came to an end about 70days after seeding. In case that the seeding time was delayed 20 days and 40 days from May15th, respectively, the time to be almost cimpleted the growth of the characteristics was shortened 10days and 20days during ther debelopment. Among varieties, Chung Buk Beak grew faster than any other varieries. 2.When seeded at May 15th, the plants produced many pods, and had high proportion of branch pods. When seeded late, the proportion of branch pods were low. Branches had large proportion of empty pods and one grain pods, but on main stem, the proportion of two grain pods and three grain pods were more than that of branch. Among varieties, Chung Buk Baek had high proportion of two and three grain pods, Keum doo and Chang dan Baek mok had high proportion of one and two grain pods, and Iksan had high proportion of one and three grain pods. 3.Tields were less by the late seeding.The proportion if decreased yields to the yields when seeded at May 15th, that of Chung Buk Baek was decreased 6% when seeded at June 5th and 14% when seeded at June 25th, that of Ik san was decreased 9% and 17%, that of Keum doo decreased 15% and 26% and that of Chang dan Baek mik decreased 18% and 27%. 4.Protein content was highest in the plots seeded on May 15th, but oil content was highest in the plots seeded in June 25th. Among varietiesm Xhang dan Baek mok had the highest proportion of protein content and Iksan had the highest of oil content.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.6
• /
• pp.353-355
• /
• 2000

The seasonal occurrence of aphids was investigated in the soybean Held to increase the control efficiency of aphid vectors of Soybean Mosaic Virus. The patterns of aphids occurrence were different according to planting time. There were two peaks in late June and mid-August in aphid population in optimum seeding (May 20), whereas the peak was around mid-June in early seeding(Apr, 20). Acyrthosiphon solani was dominant Species in early seeding, while Aphis glycines was dominant in optimum seeding. In early seeding, SMV incidence increased rapidly between 20 June and 30 June, suggesting that virus spread was strongly correlated with increased colonization of aphids. Imidacloprid WP, benfuracarb EC and acephate WP showed a good effect for the control of aphids without phytotoxicity. In the plot with infurrow treatment of imidachloprid G until 52 days after shooting, aphids were controled effectively. Acephate WP was applied as a foliar spray at V4, V6, or V4/V6 stage and all the treatments were effective on reducing: SMV incidence.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.21 no.1
• /
• pp.9-14
• /
• 1976

This experiment was conducted to find out the ., effects of various fertilizer level and Drill-seeding on the growth and yield of the two newly bred naked-barley varieties, Kwangsung and $Bangsa^6$ the former that was bred for the first time in Korea in 1972, is resistant to winter and productive, and the latter that was also bred in Korea by radioisotope treatment in 1974, is of short-stem, early maturing and productive. The grain yield in Drill-seeding was 8 percent higher than that in Conventional seeding. $Bangsa^6$ was more resistant to lodging and more adaptable to the amounts of the increased-fertilizer level than Kwangsung. In Drill-seeding, $Bangsa^6$ is thought to be more suitable naked-barley variety than Kwangsung.