• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.6
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• pp.492-496
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• 1990

To utilize narrow space of vinyl house for rice seedling raising in three dimensions and raise infant seedling in large quantilies at once, shelves were constructed with few stories in inside of vinyl house and seedlings were raised by use of the shelve. Seedling characters, rice growth status on paddy field and rice grain yield were tested and the following results were obtained. Rice seedling raising was practicable to 10 days after sowing in the interval of 20cm height and 12 days, 30cm height on the shelve for seedling raising. Seedling characters, rice growth status on paddy field and rice grain yield were not varied according to the seedling raising height of the shelve. Seedling characters were not different according to irrigation intervals in raising box of rice seedling.

• Agribusiness and Information Management
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• v.6 no.1
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• pp.37-44
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• 2014

This study was conducted to evaluate light intensity and uniformity of two SMD (surface-mount device) type LEDs for protected crop production. A low-power (0.1 W) and a high-power (1 W) LEDs were selected and the intensity and uniformity was evaluated at different vertical (height) and horizontal (distance) intervals. When the horizontal interval of the LED bar was fixed, the light intensity increased and the uniformity decreased as the height decreased. At the 30~40 cm heights, 20~30% of the area showed $200{\pm}20{\mu}molm^{-2}s^{-1}$. As the horizontal distance of the LED bars increased, while the uniformity increased as well, the light intensity decreased. At the distances of 6~10 cm, 17~23% of the area showed $200{\pm}20{\mu}molm^{-2}s^{-1}$. When the LED bars were added to the sides, the light intensity and uniformity were generally improved. Results showed that the light intensity and uniformity depended on the height and interval of the LED bulbs; therefore, optimum arrangement for the crops interested should be determined through experiments.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.260-260
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• 2017

High temperature is one of major environmental stress. Heat in flowering season of wheat is able to effect negatively to fertilization and also heat effect to maturity. Therefore, Heat stress effects severely to qualities of wheat and yield productivity. In this study, we evaluated to agronomic characteristics and qualities by high temperature in 13 Korean wheat varieties. Weight of 1,000 grains decreased when wheat got the heat stress. In particular, heat stress during the heading dates were more damaged than after the end of heading dates except two varieties Keumkang and Jokyoung. Plant height of each cultivar under high temperature and normal field averaged 80.5 cm and 83.0cm, respectively. The length of spike and awn in each cultivar were similar to both condition. Flour yield and gluten contents of most heat damaged wheat decreased. Under the temperature, protein contents of six varieties like as Keumkang, Baekjoong, Hojoong, Yeonbaek, Joah and Shinmichal 1 decreased but the others increased. The sedimentation values (SDSF) of four varieties decreased under the high temperature. But SDSF of 7 varieties like as Baekjung, Suan, Hojoong, Jojoong, Uri, Shinmichal and Shinmichal 1 was increased. The lightness (L) of wheat flour derived from high temperature treated wheat was darker than non-treated wheat. As a result of this research, we confirmed that agricultural traits and qualities decreased in heat damaged wheat.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.145-151
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• 2009

This study was conducted to develop rational soil management and enhance the productivity of lands converted from paddy soils. Specifically, the changes in the soil physical properties brought about by the change in land usage from paddy soil were evaluated. This was carried out from 1999 to 2001 at 50 site in large-scale converted paddy fields of Kimcheon, Youngcheon, Gyeongsan and Milyang in the Youngnam region, categorized according to soil texture and drainage class. The ridge height of converted paddy soils was higher in coarse-textured and poorly-drained soils than in fine-textured and well-drained soils. The gray color of the surface soil was of lesser degree in converted soils than paddy soils and more notable in welldrained soils. The porosity ratio and the formation of aggregate structure were higher, and the appearance of soil mottling was deeper in converted paddy fields than in paddy soils. The glaying layer "g" of surface soil degraded with time. The porosity and amount of water stable aggregate was found to increase with time after conversion. The penetration resistance of the converted paddy soil was lower and deeper with time after conversion. The soil aeration of the converted paddy soil was lower in sandy loam than in loamy soil. Furthermore, soil aeration was influenced by ridge height and drainage class in poorly-drained soils.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.2
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• pp.112-119
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• 2021

In order to develop a safe seeding technology for low-density transplantation, we analyzed the changes in seeding growth according to different seeding rates and seeding days. We detected changes in leaf number and shoot diameter on the 10th seeding day, and in plant height on the 20th seeding day according to seeding rate. The increase in shoot and leaf number, and shoot diameter per seeding day decreased with anincrease in seeding rate. On seeding day 20, the reductions in shoot and root dry weights according to seeding rate was lower compared with those recorded at seeding day 10. Shoot dry weight was significantly related to root dry weight, plant height, and shoot diameter. With an increase in seeding rate, seeding health decreased and there was an increase in the rate of seeding health per seeding day decreased. For low-density transplantation, the optimal number of seeds required for transplanting 3-5 plants per hill is 11,000, which is estimated to be approximately 280-300 g of seeds for 22 g brown rice. Furthermore, the appropriate number of seeding days is estimated to be 13 to 16 days, which corresponds to a small reduction in seeding health.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.78-78
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• 2022

Food productivity in North Korea is about 50% lower than in South Korea. In order to increase the productivity of major crops, it is necessary to develop early maturing, disease resistance, and high-yielding varieties and apply them early. Since the late 1990s, North Korea has been actively developing potatoes, rice and com as major food crops, and soybeans are considered important as a protein-supplying crop. Domestic cultivated varieties, which are expected to be most adaptable eco-climatologically, are mainly selected from soil with high nutrient soil. It is necessary to test separately for adaptability in low organic soil. So it is very necessary to apply technology to improve soil improvement through rotational crop selection in the middle and long-term. Therefore, this study was conducted to test the adaptability to low organic soils of domestic cultivars and to select varieties. In 2021 there are twenty two (22) varieties of soybeans were grown in low organic soil at the field of Chungbuk National University. This year twenty two (22) varieties of soybeans were also grown in low organic soil at the field of Chungbuk National University. Sowing was done on June 10, the planting distance was 70cm × 15cm, after opening the cotyledons fully, the soybeans were thinned and leaving two plants per hole. In addition, various types of growth characteristics and quantitative components were investigated to evaluate the adaptability to low organic soil of domestic varieties. This study was conducted to investigate the growth characteristics and quantitative components of soybean varieties grown in low organic soil. The flowering period of 22 varieties of soybeans was about 14 days from July 22 to August 4. The flowers of the beans were white, purple, light purple and the pubescence color was gray and brown where most of them were gray. The highest plant height was up to 130.4 cm and lowest was 20.3 cm, highest stem length was up to 119.5 cm and lowest was 15.3 cm. Highest first pod height (FPH) was up to 34.0 cm and lowest was 3.0 cm. Highest stem diameter was up to 15.76mm and lowest was 1.76 mm. Number of main stem nodes was up to 19 and at least 1. Number of branch was up to 10 and at least 0. The number of pod per plant was up to 121. Bacterial pustule has been spread in soybean field.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.159-170
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• 1998

This study was initiated to investigate the applicability of the dredged soil from agricultural reservoirs on the crop cultivation. Four reservoirs were selected for this experiment, and properties of the dredged soils were analyzed physically and chemically. Soil textures were sandy loam(SL), silty loam(SiL), gravelly loam(GL), graveHy silty loam(GSiL), respectively. General chemical components, organic matter contents, main cations, heavy metals, etc. showed no adverse effects on crop growth. Tomato, cucumber, radish, Chinese cabbage were cultivated during 8 months period, in the soil treated with fertilizer and compost(Tmt.1), fertilizer(Tmt.2), compost(Tmt.3) and none (Tmt.4). Data for plant height, root zone depth and crop yield were collected and analyzed, and the yield for most crops showed increase as Tmt.1 >Tmt.2>Tmt.3>Tmt.4 by fertilizing methods, and as GL>GSiL>SL>SiL by soil textures. From the results, the crop cultivation using dredged soil was considered to be effective, due to its soil texture, organic matter content and fertilization.

• Korean Journal of Medicinal Crop Science
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• v.11 no.4
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• pp.259-263
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• 2003

This study was carried out to get basic information about the morphological and production characteristics of fennel populations different origin under different ecological conditions in Hungary. The Korean population can be registered as a medium high genotype and showed a more accelerated growth characters than Hungarian taxon and the two populations have a medium homogeneity $(CV\;=\;4{\sim}22%)$. In the second year plant height in Hungarian taxon was significantly higher than that of the Korean population. The shooting dynamic of individual plants might be heterogeneous in both taxa and the Korean population was not only shorter in the height but had also less shoots by 16% than the Hungarian one. The Hungarian taxon exceeded the umbel size and numbers to the Korean one (by 3.62 cm in the average) and the variability in the populations was high $(CV\;=\;29{\sim}49%)$. Seed size was proved to be also a discriminative feature between the examined taxa. With small deviations (CV < 2) the Hungarian population produced seeds longer by 38%. Homogeneity in the populations was dependent more on the vegetation years and on the characteristics measured but less on the origins, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.360-365
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• 1993

The infant seedling of rice(8-to 10-day-old) has often suffered from submergence just after transplanting due to the too short seedling height, 5 to 8cm, This experiment was conducted to elucidate the effect of gibberellic acid($GA_3 : 25% soluble liquid) with the application methods of foliar spray and seed-soaking on the elongation of seedling height of infant rice seedling in machine transplanting, We used a japonica rice variety, Hwaseongbyeo, and the seeding rate was 200g per seed tray(30$\times60$\times3cm). Generally,$GA_3 and Metalaxyl increased the elongation of seedling height of infant seedling while Tetracycle decreased the seedling height, To increase the seedling height of infant seedling, the foliar spary application of $GA_3 was better than seed-soaking treatment. The optimum concentration of $GA_3 for the foliar spray was about l0ppm and the optimum application time of $GA_3 was 3 to 4 days after sowing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.133-137
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• 1969

This experiment was conducted to determine the optimum row width and plant spacing within row under the tropical environment for a leading soybean variety Palmetto and it was carried out at Eakmat Experiment Station in Vietnam. The experiments were arranged in a split plot design with four replications and the test was repeated twice in two years. Variations for seed yield due to the distance between rows were significant at 1 per cent level in 1967 test(dry season growing) and at 5 per cent level in 1968 test. Significant differences for plant height, lodging, maturity, number of branches per plant, and number of pods per plant due to the row width were not found in both tests, while significant differences in difference spacing within row was found in all traits studied. Interaction between width of row and spacing within row for seed yield and plant height were found at five percent level in 1967 test. These results indicate that close planting may increase in seed yield and plant height in both seasons, and decrease in loadging. From these studies, one could be understood that the plant population, particularly in dry season, plays decisive roles on seed yield in soybean culture, and the maximum plant height and minimum value of lodging index were also observed in closest spacing plots. The highest soybean yield in late planting would be expected by a combinations of 30 cm(between rows)${\times}$5cm(between hills) plot, while 40cm ${\times}$ 5cm planting method would be suggested for rainy season growing. Highest seed yield was obtained at closet spacing in both dry and rainy season, and these results led to drilling method in seeding where about 20 seeds per meter of row could be recommended. Besides the seed yield, the close planting may produce some advantages, such as increase plant height and decrease lodging, weeds and erosion of surface soil.