• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.158-162
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• 2006

Achyranthes bidentata was recorded to new medicinal crop in a revised 8th edition of the Korean pharmacopoeia. Therefore, A. bidentata began to use for same purpose with Achyranthes japonica which was cultivated since old times in Korea. This study was conducted to investigate the adaptability of A. bidentata in Korea. The germination rate and speed of A. bidentata seeds were higher than those of A. japonica in $15^{\circ}C\;and\;25^{\circ}C$. The growth of A. bidentata was greater than that of A. japonica until the 60 days after transplanting, but growth after that was the opposite. There were remarkable differences between two species in growth characteristics such as flowering date, leaf fall date, plant height, stem color and no. of branches. The flowering and leaf fall date of A. bidentata were earlier than A. japonica by July 7 and September 26. The plant height and number of branches of A.japonica were longer and more than A. bidentata, but the cluster length and no. of flowers per cluster of that were shorter and fewer than this. Number of supporting roots of A. bidentata and A. japonica was 10.7 and 14.6 per plant, respectively. The average yield was not different between two species. The yield of A. bidentata was 166 kg/l0 a in Suwon and 309 kg/10 a in Naju of Korea. The suitable cultivation region of A. bidentata was judged to southern area of Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.323-332
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• 1997

Drainage is needed to run off excessive water stress during the rainy season for soybean cultivation in the converted upland from paddy field. This study was conducted to evaluate the effect of planting dates and drainage methods on growth and yield of sprout soybeans in the converted upland from paddy field. The stem and root growth at flowering stage showed no difference by drainage method but plant height, number of nodes and branches, and fresh weight of stem and root were much greater as planting date delayed. Seed yield was correlated positively with fresh weight of stem and root, and T/R ratio at the flowering stage, respectively. Lodging degree was not different by drainage method but was higher in planting at June 16 than May 15. Number of pods and 100 seed weight were not different by drainage method and 100 seed weight was heavy in Eunhakong, light in Kwangankong as planting date delayed. Higher seed yield was observed in surface drainage than open ditched drainage. Yield performance of Eunhakong was good in late planting, while that of Kwangankong was in early planting.

• The Journal of Natural Sciences
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• v.4
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• pp.161-177
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• 1991

This experiment was carrid out to investigate the effect of organic fertilizer and plant growth regulators application on the growth and quality of tomato. The results are summarized as follows. 1. Plant height of tomato was recorded highest when chemical fertilizer plus organic fertilizer was applied, and did not have significant effects in number of leaf. But stem diameter was positively effected by chemical plus organic fertilizer application than chemical fertilizer alone. 2. Flower formation, flower weight, anther weight and ovary weight were generally increased by organic fertilizer application. 3. Fruit-set and number of flower were significantly increased by organic fertilizer application. 4. Deformity fruit was the lowest rate at chemical plus organic fertilizer application when it was 14.7 percent, and it was increased by chemical fertilizer application. 5. Days of ripening was slightly delayed by organic fertilizer application and also flowering date shortened by chemical fertilizer application. 6. Plant growth regulators had positive effects on number of flower, flower weight, anther weight, and ovary weight, and variations of their effect by cluster were apparent. 7. Fruit-set was increased by 2,4-D 10ppm and BA 20ppm treatments but was decreased by treatments of Ethephon 10ppm and control. 8. By the BA 20ppm and 2,4-D 10ppm treatments, the rate of deformity fruit was decreased and fruit ripening date was also shortened.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.195-201
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• 2001

Sowing date experiments were carried out by employing a rice variety "Kwanganbyeo" in both field and phytotron with natural daylength. In phytotron, temperatures were controlled at daily mean of 21$^{\circ}C$ and 24$^{\circ}C$. The responses of final leaf number and beading date were analyzed in relation to daylength during photo-sensitive period (PSP). Based on the component models predicting the final leaf number and leaf appearance rate, a rice phenology model was established and verified. Days from sowing to flowering (DSF) were shortened and final number of leaves (FNL) increased as sowing dates were delayed from 25 April to 5 June in field and phytotron. The increased leaf appearance rate (LAR) and the reduced FNL, respectively, due to the higher temperature and the shorter daylength in delayed sowings in the field brought about greater shortening of DSF than in the phytotron where only FNL was reduced by shorter daylength in delayed sewings. FNL showed very close relationship with the average daylength during PSP of six-leaf stage to panicle initiation, being well fitted to the following rational function ($R^2$=0.98):(equation omitted) where D is daylength and a, b, and c are the constants that were estimated as 14.694, -0.992, and -0.068 in Kwanganbyeo, respectively. The rice phonology model, which was composed of two component models for LAR and FNL, predicted DSF very accurately. The differences between the observed and predicted DSF was less than two days in the sewing date field experiments in 1999 and 2000 of which data were not used for the model construction.struction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.96-102
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• 1981

Effect of shifting planting-time and different nitrogen on the yield and characteristics of plant growth in safflower, Chrthamus Tinctorius L. This study was carried out to investigate the optimum sowing-date and the ecological variations due to differerent amount of nitrogen for safflower on the Experiment Farm of Sang Ji college from March 17 to may 16, 1980, sowing seeds with an interval of 10 days and the amount of nitrogen were applied in 5 levels (Non, half-standard, standard, one and half-ordinary amount-No and twice amount). The triple super phosphate and pottassium chloride were applied only in standard amount. The results obtained are summarized as follows; 1. As sowing-date was delayed, the germination-ratio decreased, germinating speed increased, and the time required to attain the most vigorous germinating stage and days required for germination shortened. 2. Plant height, number of branch and stem diameter showed a decrease as sowing-date was delayed. And at the same time, plant height and number of branch showed a tendency to increase as amount of nitrogen was increased. 3. As sowing-date was delayed, the number of pods and the weight of 1000-grains were decreased. Moreover, the earlier sowing-date was, the more it increased. And as amount of nitrogen was increased, number of pods and yield also were strikingly increased. 4. The fresh-weight of flower with orange and orange-red colour, as influenced by the different sowing-date, was found out to be largest at the begining of April. But increasing amount of nitrogen did not show influence upon the promotion of flowering. 5. Judging from the results reported above, the optimum sowing-date of safflower seemed to be the begining of April; also the culture of safflower seemed to be the effects of much amount of nitrogen.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.134-134
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• 2022

Mungbean is used for not only seed but sprout, so, consumption of mungbean has been on the rise in Korea. Life cycle of mungbean tends to be short among Legume. For that reason, Mungbean can be harvested for various cropping system and season per regions and farmers regardless of sowing date and harvesting date. So, Prior research is needed about growth characters and life cycle of mungbean per sowing period. Mungebean cultivar 'Dahyun' and 'Sanpo' supplied by Korea Agriculture Technology Promotion Agency(KOAT) is cultivated in wagner pot. Sowing period is proper time of seeding in Jeollanam-do and Gyeongsangnam-do that is major cultivation region of mungbean in korea from early May to mid July every 2 weeks. Length at maturity stage tends to increase from early May(sowing date: 4^th May) to early July(sowing date: 5^th July), but after that, It tends to decrease from mid July(sowing date: 19^th July). Number of branches and nods shows a similar trend. Length of pod has no tendency and no difference per sowing date. Number of pod per plants has also no tendency per sowing date. Test plots sowing in late May has the most number of pods.(Sanpo 22.9pods, Dahyun 16.8) Number of seeds per pod tends to increase to late May and Test plots sowing in mid July has the most number of seed per pod. In case of sowing at early May, Days of emergence is 7d. its summation of temperature is 132.2℃. After that, it tends to decrease to mid June. After mid June, Days of emergence is fixed to 3d. Average temperature growing up in this season, Summation of temperature from sowing to emergence takes the lowest point in test plots sowing in mid June.(Sanpo 88.6℃, Dahyun 88.6) Days of flowering tends to fasten from early May to mid July. Two cultivar shows same level. Days of maturity tends to fasten to mid June, after that tends to slow. In case that many research results about growth characters and life cycle mungbean per sowing period are drawn, it is expected that it result in increase of cultivation area and income of farmer.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.1
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• pp.42-54
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• 2016

It is highly anticipated that warming temperature resulting from global climate change will affect the phenological pattern of kiwifruit, which has been commercially grown in Korea since the early 1980s. Here, we present the potential impacts of climate change on the variations of flowering day of a gold kiwifruit cultivar, Haegeum, in the Jeonnam Province, Korea. By running six global climate models (GCM), the results from this study emphasize the uncertainty in climate change scenarios. To predict the flowering day of kiwifruit, we obtained three parameters of the 'Chill-day' model for the simulation of Haegeum: $6.3^{\circ}C$ for the base temperature (Tb), 102.5 for chill requirement (Rc), and 575 for heat requirement (Rh). Two separate validations of the resulting 'Chill-day' model were conducted. First, direct comparisons were made between the observed flowering days collected from 25 kiwifruit orchards for two years (2014-15) and the simulated flowering days from the 'Chill-day' model using weather data from four weather stations near the 25 orchards. The estimation error between the observed and simulated flowering days was 5.2 days. Second, the model was simulated using temperature data extracted, for the 25 orchards, from a high-resolution digital temperature map, resulting in the error of 3.4 days. Using the RCP 4.5 and 8.5 climate change scenarios from six GCMs for the period of 2021-40, the future flowering days were simulated with the 'Chill-day' model. The predicted flowering days of Haegeum in Jeonnam were advanced more than 10 days compared to the present ones from multi-model ensemble, while some individual models resulted in quite different magnitudes of impacts, indicating the multi-model ensemble accounts for uncertainty better than individual climate models. In addition, the current flowering period of Haegeum in Jeonnam Province was predicted to expand northward, reaching over Jeonbuk and Chungnam Provinces. This preliminary result will provide a basis for the local impact assessment of climate change as more phenology models are developed for other fruit trees.

• Journal of Korean Society of Forest Science
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• v.110 no.3
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• pp.322-340
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• 2021

Due to climate change and its consequential spring temperature rise, flowering time of Robinia pseudoacacia has advanced and a simultaneous blooming phenomenon occurred in different regions in South Korea. These changes in flowering time became a major crisis in the domestic beekeeping industry and the demand for accurate prediction of flowering time for R. pseudoacacia is increasing. In this study, we developed and compared performance of four different models predicting flowering time of R. pseudoacacia for the entire country: a Single Model for the country (SM), Modified Single Model (MSM) using correction factors derived from SM, Group Model (GM) estimating parameters for each region, and Local Model (LM) estimating parameters for each site. To achieve this goal, the bloom date data observed at 26 points across the country for the past 12 years (2006-2017) and daily temperature data were used. As a result, bloom dates for the north central region, where spring temperature increase was more than two-fold higher than southern regions, have advanced and the differences compared with the southwest region decreased by 0.7098 days per year (p-value=0.0417). Model comparisons showed MSM and LM performed better than the other models, as shown by 24% and 15% lower RMSE than SM, respectively. Furthermore, validation with 16 additional sites for 4 years revealed co-krigging of LM showed better performance than expansion of MSM for the entire nation (RMSE: p-value=0.0118, Bias: p-value=0.0471). This study improved predictions of bloom dates for R. pseudoacacia and proposed methods for reliable expansion to the entire nation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.268-278
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• 2020

Flowering time has been put forward due to the recent abnormally warm winter, which often caused damages of flower buds by late frosts persistently. In the present study, cumulative chill unit and cumulative heat unit of Niitaka pear, which are required for releasing the endogenous dormancy and for flowering after breaking dormancy, respectively, were compared between flowering time prediction models used in South K orea. Observation weather data were collected at eight locations for the recent three years from 2018-2020. The dates of full bloom were also collected to determine the confidence level of models including DVR, mDVR and CD models. It was found that mDVR model tended to have smaller values (8.4%) of the coefficient of variation (cv) of chill units than any other models. The CD model tended to have a low value of cv (17.5%) for calculation of heat unit required to reach flowering after breaking dormancy. The mDVR model had the most accurate prediction of full bloom during the study period compared with the other models. The DVR model usually had poor skills in prediction of full bloom dates. In particular, the error of the DVR model was large especially in southern coastal areas (e.g., Ulju and Sacheon) where the temperature was warm. Our results indicated that the mDVR model had relatively consistent accuracy in prediction of full bloom dates over region and years of interest. When observation data for full bloom date are compiled for an extended period, the full bloom date can be predicted with greater accuracy improving the mDVR model further.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.1
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• pp.17-22
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• 2005

This experiment was conducted to investigate the effect of seeding dates and rates on the productivity and nutritive value of hairy vetch(Vicia villosa Roth) at experimental field of Grassland and Forage Crops Division, National Livestock Research Institute, RDA, Suwon from 1999 to 2000. The experimental design was consisted of split-plot design with three replications. The main plot was seeding dates(25 Aug., 15 Sep. and 5 Oct.) and the subplot was seeding rates(20, 30 and 40 kg/ha). Late seeding dates increased the plant height and delayed the flowering stage as 1 or 2 days. The dry matter(DM) content was decreased with low seeding rates, and the trend was same in the all plots. Average crude protein(CP) content was $24.1\%$ and increased with delayed seeding date and lower seeding rate. The content of acid detergent fiber(ADF) and neutral detergent fiber(NDF) was increased with higher seeding rate, but seeding date did not affect. In vitro dry matter digestibility(IVDMD) of hairy vetch tended to decrease with high seeding rate, and total digestible nutrient(TND) did not show significant difference among seeding rates. Average relative feed value(RFV) of hairy vetch showed 140 which means very high quality. Dry matter and CP yield was decreased with delayed seeding date. The results of this experiments indicated that seeding in middle-August with 40 kg/ha would be recommended to produce the highest yield and quality f3r the cultivation of hairy vetch in middle part of Korea