• Korean Journal of Plant Resources
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• v.19 no.1
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• pp.83-87
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• 2006

Study on the effective cultivation method for earlier harvest of peony(Paeonia lactiflora Pall.), was carried out in Uiseong Medicinal Plant Experiment Station from 2001 to 2003. Sprouting time and flowering time in house cultivation were earlier than in field cultivation. Planting large crowns of $100{\sim}130g$ increased yield by 34%. The method that is 'Large crown($100{\sim}130g$) + dense planting + vinyl mulching for 2 years' resulted good growth and 54% yield increase. This method made it possible to harvest peony on the second year and reduce productive cost. The yield was decreased more or less in this method but yearly income was increased by 28%.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.469-479
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• 2016

Kimchi cabbage is one of the most important vegetables in Korea and a target crop for market stabilization as well. In particular Kimchi cabbages in a highland area are very sensitive to the fluctuations in supply and demand. Yield variability due to growth conditions dictates the market fluctuations of Kimchi cabbage price. This study was carried out to understand the distribution of the highland Kimchi cabbage growth status in Anbandeok. Anbandeok area in Gangneung, Gangwon-do, Korea is one of the main producing districts of highland Kimchi cabbage. The highland Kimchi cabbage status map of each growth factor was obtained from unmanned aerial vehicle (UAV) imagery and field survey data. Six status maps include UAVRGB image map, normalized difference vegetation index (NDVI) distribution/anomaly map, Crop distribution map, Planting/Harvest distribution map, Growth parameter map and Growth disorder map. As a result, the highland Kimchi cabbage status maps from May 31 to Sep. 6 in 2016 were presented to show spatial variability in the field. The benefits of the highland Kimchi cabbage status map can be summarized as follows: crop growth monitoring, reference for field observations and survey, the relative comparison of the growth condition in field scale, evaluation of growth in comparison of average year, change detection of annual crops or planting areas, abandoned fields monitoring, prediction of harvest season etc.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.14-25
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• 2006

Response of grain yield and milled-rice protein content to nitrogen (N) rates at various growth stages is critical for quantifying real-time and real-amount of applied N requirement for target grain yield and protein content. An experiment including 10 N rate treatments at transplanting, tillering and panicle initiation stages with four rice cultivars in 2003, 6 N treatments with two rice cultivars in 2004 and 2005 was conducted. Increase of N rates at PIS significantly increased both grain yield and milled-rice protein content but increase of N rates at tillering stage significantly increased grain yield but not milledrice protein content. Therefore, high grain yield and low milled-rice protein content would be difficult to obtain only by adjusting N rates at PIS. Internal N use efficiency (INUE) was 60.5 kg grain/kg N accumulation on an average over N treatments, cultivars, and experimental years, showing considerable reduction especially at high shoot N accumulation in the experimental year of low sunshine duration. Milled-rice protein content tended to increase almost linearly with increasing shoot N accumulation, but it revealed big variation even at the same shoot N accumulation at harvest. Milled-rice protein content decreased with increasing INUE. N accumulation in the milled rice increased at an almost constant proportion of 45.5 percent of the shoot N accumulated at harvest, showing slight decresing proportion with the increasing shoot N accumulation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.1
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• pp.23-26
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• 1980

This study was attempted to establish the basic data for evaluating the processing suitability of the mussel, Mytilus edulis, cultured by hanging method in Yeosu Bay, Korea. Seasonal variations in condition index and chemical .composition of the mussel were carried out from March 1978 to February 1979. The results are as follows: 1. The condition index was highest from December to April next year. 2. The glycogen content of mussel was 2.7 to $3.9\%$ from December to May next year and revealed the maximum value, $3.9\%$ in December and March. F and G-values as the condition indices of the mussel showed also the highest value from December to March. 3. The protein content of mussel was highest from July to August. 4. By the results of condition index and chemical composition of the mussel, the suitable harvest season as raw materials for processing is determined to be from December to April next year and from July to August.

• Journal of Crop Science and Biotechnology
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• v.11 no.1
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• pp.23-30
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• 2008

The relationship between three phenological parameters and somatic embryogenesis was investigated during a two-year period. Staminodes and petals from six hybrids and two clones as controls were sowed on three distinct primary callus growth media. Flowering level, fructification level, and leaf thrusts rhythm as phenological parameters were measured simultaneously during the weekly harvest of flower buds. Mean and coefficient of variation of the measured parameters highlighted stable phenological phases. The relationship between phenological parameters and somatic embryogenesis was investigated first by comparing the variation of somatic embryogenesis and that of the phenological parameters, and second by using Pearson's linear correlation. Except for the fructification level in both control clones the first year, the other parameters recorded stable phenological phases, regardless of the genotype and year. Favorable and unfavorable phases for the somatic embryogenesis were identified. In hybrids, favorable phases included February, August, September, and October. In both control clones, time interval propitious to embryogenesis stretched from February to December. The significance of the coefficient of correlation seemed to establish a relationship between somatic embryogenesis and phenology. However, a causal link could not be established. Leaf thrusts rhythm was revealed to be the phenological parameter most linked to somatic embryogenesis. Attempts to optimize embryogenesis during unfavorable phases, showed that a correction of 2.4 D/TDZ concentration is not the solution.

• Korean Journal of Medicinal Crop Science
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• v.21 no.6
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• pp.461-465
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• 2013

This study was investigated to evaluate germination rate of Astragalus membranaceus B. in Korea as affected by storage temperature, germination temperature and storage period of seed. The highest germination rate was obtained from condition of $25^{\circ}C$ in germination temperature. Seeds were stored at $-20^{\circ}C$ and $5^{\circ}C$ for 8 weeks has showed higher germination rate than one at room temperatures. The germination rates showed significantly difference by harvested year of 2010, 2011 and 2012. The seed of A. membranaceus in harvested year of 2011 and 2012 had germinated well. On the other hand, seeds in harvested year of 2010 were not nearly germinated. Consequently, the longer storage period after seed harvest lower germination rate and seed vigor as well.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.145-145
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• 2022

South Korea greenhouse gas emissions have increased year by year, resulting in a total emission of 727.6 million tons of CO₂ eq in 2018, a 2.5% increase compared to 2017. Among them, the agricultural sector emitted 21.2 million tons of CO₂ eq., accounting for 2.9% of the total. Among the greenhouse gases emitted from the agricultural sector, a particularly problematic is methane gas emitted from rice paddies. Methane is one of the important greenhouse gases with a global warming potential (GWP) that is about 21 times higher than that of carbon dioxide due to its high infrared absorption capacity despite its relatively short remaining atmospheric period. Since the pattern of methane generation varies depending on the rice variety and ecological type, research related to this is necessary for accurate emission calculation and development of reduction technology. Accordingly, a study was conducted to find out the changes in greenhouse gas emission according to rice varieties and ecology types. As for the rice eco-type cultivar, early maturing cultivar (Haedamssal) and medium-late rice cultivar (Saeilmi) were used. Haedamssal was transplanted on May 25 and June 25, and Saeilmi was transplanted on June 10 and June 25. The amount of methane generated according to the growing day showed a tendency to increase as the planting period was earlier. The difference between varieties was that Haedamssal showed higher methane production than Saeilmi. The total CH₄ flux in the saeilmi was 18.7 kg·h^-1(Jun 10 transplanting), 12.4 kg·h^-1(Jun 25 transplanting) during rice cultivation. Lower methane emission was observed in Saeilmi than in Haedam rice. In addition, the earlier the planting period, the higher the methane emission. This study is the result of the first year of research, and it is planned to investigate the amount of greenhouse gas emission between double cropping and single cropping using wheat cultivation after harvest for each ecological type.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.266-271
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• 2001

Soybean can produce high-N residue due to N-fixation, so soybean rotation may increase yield of subsequent corn and reduce N fertilizer on the corn fairly. To find out the contribution of nitrogen to subsequent corn following soybean cultivation, soil nitrate, corn yield, and nitrogen uptake were measured for three continuous corn cropping years after soybean rotation. Three N rates of 0, 80, and 160 kg/ha were applied to three continuous corn following soybean cropping. At 6-leaf stage, soil nitrate amount at the soil depth of 0-30cm ranged from 60 to 80 kgN/ha higher in the first corn cropping year than that in the second and third corn cropping years. Judging from corn N status such as SPAD value, N concentration of ear-leaf and stover at silking stage, N contribution of previous soybean to corn in the first corn year was N fertilizer of approximately 80 kg N/ha. Stover N uptake at silking stage increased from 47 to 52 kg N/ha at the 0, and 80 kg N/ha of N rates in the first corn cropping year compared with those in the second and third corn cropping years. Corn grain yield at the 0 kg N/ha of N rate was 6-7 ton/ha higher in the first corn cropping year than that in the second and third corn cropping years, respectively. When compared the first corn year following soybean cropping with the second and third corn cropping years, N uptake of grain and stover at harvest with low N rates such as 0 and 80 kg N/ha increased from 45 to 67kg N/ha, from 35 to 60 kg N/ha, respectively. N uptake of whole plant by soybean rotation increased from 93 to 118 kg N/ha in the first year compared with that in the second and third corn cropping years. However, the N contribution by soybean cropping was small in the second and third continuous corn cropping years. Therefore, it was concluded that the nitrogen fertilizer of 80-100 kg N/ha in the first corn cropping year could be saved by soybean rotation and annual alternative corn-soybean rotation could be the best rotation system.

• The Korean Journal of Malacology
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• v.23 no.1
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• pp.31-38
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• 2007

Population ecological parameters and stock biomass of the purplish washington clam, Saxidomus purpuratus (Sowerby), in the southern coastal areas of Korea were determined based on the fishery data from the Divers Fisheries Cooperative and other available biological data. Instantaneous coefficient of total mortality (Z) of purplish Washington clam was estimated to be 0.7479/year. The estimated instantaneous coefficient of natural mortality (M) was 0.2012/year. From the values of Z and M, the instantaneous coefficient of fishing mortality coefficient (F) for the recent years was calculated to be 0.4578/year. The age of purplish Washington clam at its first capture ($t_c$) was 2.7506 year. Yield-per-recruit and spawning biomass-per-recruit were estimated under harvest strategies that bases on $F_{max}$, $F_{0.1}$, $F_{35%}$ and $F_{40%}$ were shown as 81.60 g, 61.68 g, 115.07 g and 131.51 g, respectively. The acceptable biological catch (ABC) was estimated to be about 1,404 metric tons.

• Journal of Bio-Environment Control
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• v.13 no.2
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• pp.73-80
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• 2004

Two red pepper(Capsicum annuum L.) cultivars, 'Geumtap' and 'Bugang', were cultivated at main producing areas in Korea and harvested four times in 1998 and 1999. Length, weight, dry matter ratio and color of red peppers were measured at each harvest. The relations between external characteristics with regional climatic elements such as total accumulated air temperature, total amount of precipitation and duration of sunshine during the fruit growing periods were compared. Length and fruit weight decreased by delayed harvest. These characteristics were shown significant difference according to cultivars, but not to growing year. Dry matter ratio had a tendency to increase at the 3rd and 4th harvest. The red color as measured a${\times}$L values of pepper powder, increased with being later in harvesting, but the trend was uncertain. In fruit growth, fruit length showed a positive correlation with total accumulated air temperature in later growth period of fruits(from 1st to 20th day before harvesting), and fruit weight had relationships with accumulated air temperature and total amount of precipitation in later growth period of fruit. There was no relation between dry matter ratio and climate elements. The red color was shown high correlations with total amount of precipitation and duration of sunshine. There was highest coefficient of determination($r^2$) in all external characteristics.