• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.3
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• pp.226-234
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• 1984

In order ti find out the optimum seeding time(OST) and optimum seed rate(OSR) of Italian ryegrass on seed production, this studies with tetraploid cv. Tetrone were carried out on the experimental field of Livestock Experiment Station. Treatments included seed rates of 1, 2, 3 and 4 kg per 10a and combined with seeding time on 20, 30 Aug, 9, 19 and 29, September 1983. Seeds were sown in rows 50 cm apart and were spaced in a continuous line with width of 15 cm within the rows. The results are summarized as follows: 1. Autumn tillers could be classified into three groups from winter-killing point of view, namely winter-killing completely, damaged growing point only and living tillers. 2. The young inflorescence-bearing stem in Italian ryegrass which were sown earlier than 9. September were more susceptible to winter killing. Tiller buds in those stems which originated from an axillary buds at the stem base within senescent leaf-sheaths emerged lately in spring, and consequently heading was delayed, culm length shortened and seed yield reduced. 3. Tiller buds which originated from damaged growing point only and living tillers in moderate shoots emerged early in spring and those tillers became mainly spike-bearing culm. 4. The emergence-time of tillers influenced on culm-, spike- length and ripenness more than seeding time and seed rate. 5. Seed yield was mostly affected by the number of spikes per unit area. 6. For the safety of over-wintering and enough spikes on seed production, OST and OSR at Suweon were the last part of September and 2-3 kg per 10a, respectively. Especially OSR was 2 kg per 10a for early and 3 kg per 10a for late OST.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.1
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• pp.35-43
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• 2023

Sensory evaluation of shucking pressure, pressure holding time, seeding method, difference in full shucking rate in the aquaculture area and shucking oyster was performed using an ultra-high pressure oyster shucking machine. The reaching time for each target pressure is 2.2-2.4 MPa/sec in the range of 180 MPa to 240 MPa. had a rate of pressure rise. There was a difference of 0.5-1.7℃ in the range of 24-27℃ in the seawater temperature before and after the pressure treatment inside the pressure vessel, but there was no specific increase or decrease in seawater temperature. When only the shucking pressure is increased without the pressure holding time, the critical shucking pressure at which the oyster shell is opened and the flesh is peeled in the range of 200 to 220 MPa. When the critical shucking pressure is reached, the oyster sample in the closed vessel is expected to be shucked by about 40%. If there is no pressure holding time when judged only by full shucking, an increase in pressure of about 1.5 MPa is required to further shuck 3% of the oyster population. The oyster samples cultivated in the south coast of Korea were subject to full shucking under the conditions of 220 MPa shucking pressure and two minutes (120 seconds) of pressure holding time, and the difference in the pressure of the oysters according to the oyster seeding method and the farming area was minute. Finally, the condition of 220 MPa of shucking pressure and three minutes of pressure holding time was the best at 1.52 when the result of the sensory evaluation performed manually was set to 1.0. Next was 1.4 under the conditions of 220 MPa of shucking pressure and one minute of pressure holding time (60 seconds), and 1.3 under the condition of 220 MPa and two minutes of pressure holding time (120 seconds). Therefore, it is considered that the most desirable shucking conditions, considering the efficiency and sensory evaluation results, are the conditions of 220 MPa shucking pressure and two to three minutes of pressure holding time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.181-187
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• 1987

The objectives of the study were to reduce lodging during the stormy rain period of soybean growing season in Korea, and to find out the most efficient foliar spraying of pp 333 solution in order to increase tolerance to lodging of soybean plants. The concentration of the pp 333 solution were three, five and eight percent and the time of spraying were 35th day after seeding and at flowering time. The most efficient foliar spraying practice was to spray five percent solution of pp 333 on the 35th day after seeding, resulting in reduced stem length damage of soybeans alone with shortened plant height and stabilized yield of soybean grains.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.2
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• pp.108-114
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• 1983

This study was conducted to investigate the effects of existing vegetation on seedling establishment and herbage production of oversown grasses in the Pinus rigida forest. The dominant existing vegetations were Miscanthus sinensis, Festuca ovina, and Lycopodium serratum. In establishment year, seedling stands and herbage production were not affected in Miscanthus sinensis and Festuca ovina, while in Lycopodium serratum it was affected relatively seriously. The pattern of sown species response to the existing vegetations was trend to toward simplified two or three species as Dactylis glomerata, Lolium perenne, and Trifolium repens to advancing the time. Among sown species, Dactylis glomerata was a major dominant species in all existing vegetation area. The content of sown pasture grasses in the sward increased markedly, while the existing vegetations before seeding seriously decreased to advancing the cutting time. The above results shown that the improvement of forest pasture with a surface seeding was better in Miscanthus sinensis and Festuca ovina, but in Lycopodium serratum was found very difficult to improvement of pasture without surface treatment, also establishment method must favor the low herbage production potential.

• 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.

• Korean Journal of Remote Sensing
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• v.14 no.2
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• pp.165-174
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• 1998

The observation of liquid water content(LWC) and the estimation of precipitation enhancement by cloud seeding were made over the Andong in Korea from March 1997 through Feb 1998. A dual-channel microwave radiometer was used to measure the liquid water content and water vapor. It was shown that the 90% of observational period had the amount of less than 0.1 mm in LWC, and that the amount of precipitation was proportionally increased to liquid water content. The amount of LWC has maximum in summer and minimum in winter. The content of liquid cloud water was showed higher value from the time of 12 to the time of 17 except for summer season in which it extremely fluctuated with a large precipitation. The majority of liquid water content over the area occurred with westerly and southwesterly wind which were flowed from the Sobaek mountain. The ratio of horizontal LWC flux and vertical precipitation flux, $P_{en}$ is almost ranked in the interval of 0.0~0.5 with maximum of 0.5 in spring, 0.2 in summer and fall, and 0.1 in winter. Accordingly, it is estimated that the potential enhancement of precipitation over Andong area by cloud seeding has high value in spring with westerly wind.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.383-393
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• 1991

Lodging of rice plant is the most important damage by unfavourable weather conditions in rice cultivation. High levels of nitrogen application and growing of Japonica rice variety is one factor to increase the lodging damage. Lodging of rice plant decreasing grain yield; 34% at milky. 21% at dough. 20% at yellow stage. decreasing grain Quality. increasing green rice. and increasing labor cost to harvest. To decrease lodging damage. the lodging resistant varieties will be selected and cultural practices such as amount and time of nitrogen application. planting density. water management. and disease and pest control methods have to be study for the short and strong culm. and good rooting system. Also. application methods such amount and time of plant growth regulators and new types of chemicals will be develop for the reducing lodging of rice plant. To decrease the lodging damage in direct seeding cultivation. first identifying the differences of lodging mechanisms between hand transplanting and direct seeding, second establish the suitable direct seeding methods such as seedling establishement. fertilization. and water menagement.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.287-292
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• 2016

The objective of this study was to determine the effect of harvesting time of rice on growth characteristics and dry matter yields of Italian ryegrass (Lolium multiflorum Lam., IRG) 'Kowinearly' after seeding them in paddy field. Experiments were performed in National Institute of Animal Science, RDA (Cheonan, Choongcheongnam-do province of Korea) for four years (2011~2014). Italian ryegrass variety 'Kowinearly' was seeded at experimental paddy fields before rice harvest in late September. Rice were harvested at 10, 20, and 30 days after seeding of IRG. As the harvest time of rice became later, the number of tillering before winter was reduced and IRG plant length before winter was shorter. The dry matter yield of IRG was also reduced. When rice were harvested at 20 days and 30 days after sowing of IRG compared to the rice harvested in autumn at 10 days after sowing of IRG, the number of tillering for IRG before winter was decreased by an average of 19% and 40%, respectively. The winter survival ratio of IRG was decreased by an average of 13% and 19%, respectively. Their dry matter yields were also reduced by an average of 8% and 19%, respectively. The heading date was different from each other in three years. The plant length at the time of IRG harvest in the spring was not significantly different among treatment groups. Taken together, our results suggest that when Italian ryegrass is grown in paddy fields by the method of 'seeding of IRG before rice harvest', rice should be harvested as soon as possible after sowing of IRG 'Kowinearly' in the autumn to increase forage productivity.

• Journal of Biosystems Engineering
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• v.27 no.2
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• pp.143-150
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• 2002

Several researches for site-specific weed control have tried to increase accuracy of weed detection with machine vision technique. However, there is a problem which needs substantial time to perform site-specific spraying. Therefore, new technology for real-time precision spraying system is needed. This research was executed to develope the new technology to estimate weed density and size in real time, and to conduct a real-time site-specific spraying. It would effectively reduce herbicide amounts applied for a crop field. The real-time precision spraying system consisted of a Differential Global Positioning System (DGPS) with an error of 2 cm, a machine vision system, a geomagnetic sensor for correction of view point of CCD camera and an automatic sprayer with separately controlled nozzle. The weed density was calculated with comparison between position information and a pre-designed electronic map. The position information was obtained in real time using the DGPS and the machine vision. The electronic map contained a position database of crops automatically constructed when seeding. The developed system was tested on an experimental field of Seoul National University. Success rate of the spraying was about 61%.

• Journal of Animal Science and Technology
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• v.52 no.5
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• pp.441-448
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• 2010

This study was carried out to investigate the effects of the seeding dates and growth periods on the growth characteristics, dry matter yield and feed value of corn for silage in paddy field. The experimental design was arranged in a randomized block design with three replications. Treatments consisted of five seeding dates, 1 May (T1), 8 May (T2), 15 May (T3), 22 May (T4) and 29 May (T5). And harvesting time homologized by August 24. Therefore, growing periods were 115 days (T1), 108 days (T2), 101 days (T3), 94 days (T4) and 87 days (T5), respectively. In maturities at harvest time, T1, T2, T3, T4 and T5 were full dent, early dent, late dough, dough and early dough stage, respectively. Plant height and numbers of root system were highest in T5 (p<0.01), but leaf length was higher in T4 than others (p<0.05). Dead leaf, tip filling degree and ear circle were higher in T1 than others (p<0.05, 0.01). Leaf width, ear height, leaf number, ear length, stem diameter, stem hardness and brix were not significantly different among the treatments. Dry matter yield and TDN yield were higher in the order of T1 > T2 > T3 > T4 > T5 (p<0.01). Crude protein, crude ash, NDF, ADF and crude fiber were significantly higher in T4 (p<0.05, 0.01). But crude fat was the highest in T1, T3 was the lowest as compared to other treatments (p<0.01). Total EAA(essential amino acids) were higher in order of T4 > T3 > T1 > T2 > T5, and total NEAA (nonessential amino acids) were higher in order of T1 > T4 > T2 > T3 > T5, and total amino acids were higher in order of T4 > T1 > T3 > T2 > T5. But no significant differences were found among the treatments. TUFA (total unsaturated fatty acid) and TSFA (total saturated fatty acid) were in order of T1 > T2 > T3 > T5 > T4 (p<0.01). Minerals were the highest in T4 (4,721.25 mg/kg), and T2 (2,970.80 mg/kg) was the lowest as compared to other treatments (p<0.05). Based on the above results, seeding dates could be recommended as early May, and harvest times is yellow ripe stage for qualitative and quantitative production of corn for silage in rice paddy field soil.