• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.35 no.6
• /
• pp.539-542
• /
• 1990

This experiment was conducted to obtain some informations on the effects of number of leaf harvest and time to agronomic characters and grain yield in perilla. For the experiments perilla seedlings of 40days old were transplanted on June 20, July 20 and August 20 in 1988, and leaf harvested at 30. 40. 50 and 60 days after transplanting, respectively. The following results were obtained from the experiments. In the case of the fully developed leaves were harvested, culm length were decreased by more harvests and by the later harvests. However culm diameter, number of nodes and branches were little influenced by the leaf harvests. Number of clusters, weight of 1,000 grain and grain yield were significantly influenced by the number of leaf harvest and time. As the above results, considering the grain yield, leaf harvest would be available in the case of once or twice at the early growing stage.

• Journal of the Korean Society for Heat Treatment
• /
• v.24 no.6
• /
• pp.327-337
• /
• 2011

Effects of microstructural change, tensile properties and impact property according to the change of austenitizing temperature and tempering temperature of AISI 51B20 steel were examined. Regardless of austenite grain size, lath martensite with needle and packet shapes was found at tempering temperature of $300^{\circ}C{\sim}400^{\circ}C$. The needles of lath martensite changed to parallel packet at tempering temperature of $450^{\circ}C{\sim}600^{\circ}C$. As tempering temperature increased, tensile strength, yield strength and hardness decreased, while elongation, ratio of reduction area and Charpy impact energy increased. Grain size increased when quenching temperature was $930^{\circ}C$. Grain size had prominent effect on the mechanical properties of AISI 51B20 steel. Ratio of tensile strength/yield strength and yield strength autenitized at $880^{\circ}C$ followed by tempering at $350^{\circ}C{\sim}450^{\circ}C$ showed higher values than that of autenization at $930^{\circ}C$ due to fine grain size.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.8 no.3
• /
• pp.183-189
• /
• 2006

Six japonica and three Tongil type cultivars that were released in different years and planted to a large area during different periods were grown at the experimental farm of Seoul National University in 2001 and compared for traits related to dry matter production and grain yield. The varieties chosen were Jodongji released in 1896, Paldal in 1944, Jinheung in 1962, Nagdong and Tongil (Tonsil type) in 1971, Milyang#23 (Tongil type) in 1976, Hwasung in 1986, Ilpum in 1991, and Dasan (Tonsil type) in 1996. The more recent cultivars tended to have lower canopy light extinction coefficients (K). The K value was 0.601 in the oldest cultivar, Jodongji, and decreased below 0.5 in the cultivars released since 1971. Radiation use efficiency (RUE) was significantly different among cultivars before heading stage, showing no consistent tendency with the year of release and not significantly different after heading. Leaf area duration (LAD) was significantly different among varieties, and LAD values tended to be higher in the more recent cultivars. In particular, this tendency was more obscure in Tongil type cultivars. LAD of whole growth period had a significantly positive correlation with dry matter yield at harvest $(r=0.776^*)$. Dry matters measured at heading and harvest tended to be higher in recently released cultivars, but not significantly. The grain yield of Jodongji was the lowest but there was no significant difference among the other varieties in japonica, while higher yield occurred in the more recent Tongil type. Grain yield was correlated with grain number per square meter, and the more recent Tongil type cultivars had the greater grain number per square meter, In conclusion, not only the dry matter and grain yield but also related traits except K value showed no clear changes when compared with the year of their release in japonica cultivars. However, the increased grain yield in the more recent Tonsil type cultivars might have resulted from the enhanced LAD that lead to the higher dry matter production and in turn to the enlarged sink size.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.11
• /
• pp.99-103
• /
• 1972

In order to clarify the relationship between the characters and the influence of each character on the yield of perilla, correlation coefficients and path coefficients were calculated. The results obtained are summarized as follows; 1. A highly significant positive correlation was found between stem length and stem diameter, number of pods per plant, stem weight, respectively. Number of internodes showed also significant positive correlation , with number of pods per plant, stem weight, respectively as well as the relationship between number of valid branches and number of pods per plant. On the other hand, a significant negative correlation was appeared between number of valid branches and l000-grain weight as well as the relationship between number of pods per plant and l000-grain weight. 2. It seemed to be clear that stem weight, number of pods per plant, l000-grain weight, number of valid branches and stem diameter have direct and positive influence on the yield of perilla. 3. Indirect influence was observed between stem length and stem weight, between number of valid branches and number of pods per plant, and between number of pods per plant and stem weight, respectively. 4. It may be concluded that the yield of perilla is positively correlated with stem length, number of valid branches, number of pods per plant, l000-grain weight and stem weight.

• Applied Biological Chemistry
• /
• v.9
• /
• pp.149-152
• /
• 1968

In order to establish a effective application method of compost and phosphorus fertilizer for rice plant, a field experiment has been conducted and the variation of the organic matter content in soils has been observed. The results may be summarized as follows. 1. It was more effective to split the application time into basic and in 2 weeks before the young premodia formation for the yield increase of rice grain than to applicate once basic, and it was apparent that the lesser amount of organic matter during the growing period of rice was consumed, the higher yield of rice grain was resulted. 2. The combined application of compost and phosphorus fertilizer showed a tendency to raise higher the grain yield than the separated application. 3. It was suggested that the split application of compost bring yield increase of rice grain.

• Korean Journal of Environmental Agriculture
• /
• v.28 no.1
• /
• pp.53-58
• /
• 2009

The propose of this study was to find out optimum conditions for no-tillage rice-winter cover crops cropping system. A field research was conducted to evaluate productivity and quality of rice cultivars (Dongjinbyeo and Junambybyeo) in rice-winter cover cropping systems at Doo-ryangmyeon., Sacheon, Gyeongsangnam-do, Korea from January 2005 to October 2006. The experimental soil was Juggog series (fine silty, mesic family of Fluvaquentic Eutrndepts). The rice cultivars were experimented under some different high residue farming systems, i.e. no-tillage no treatment (NTNT), no-tillage amended with rice straw (NTRS), no-tillage amended with rye (NTR), no-tillage amended with Chinese milkvetch (NTCMV), tillage no treatment (TNT), and conventional cropping system (Control). The miss-planted rate was 8.8% in 2005 and range of 10.8% to 13.3% in 2006 at NTR, and the other treatments were carried out at miss-planted rate ranging from 1.2% to 5.0%. Tiller numbers of Junambyeo, and Dongjinbyeo in both of years were the highest in Control, and decreased nearly in NTCMV, NTR, NTRS, NTNT, and TNT in that order. The lowest grain yield was observed in TNT both cultivars due to the lower tiller numbers per area, and spikelet numbers per panicle. Also, no-tillage treatments were lower grain yield than control. On the other hand, 1,000-grain weight was lowest in control due to higher tiller numbers per area, and spikelet numbers per panicle. Ripened grain ratio was a similar aspect in all treatments. The palatability score of milled rice was lowest in control while protein content of milled rice was highest in control. The NTCMV was considered an effective sustainable farming practice for rice yield and quality.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.1
• /
• pp.14-22
• /
• 1989

Rice varieties showing different degree of resistance were compared with their yield losses due to the damage of sheath blight disease in field condition through 1985 to 1986. Gayabyeo showed the lowest value of disease severity among 5 varieties tested in 1985 and 8 in 1986. and Taebaekbyeo, Kwanakbyeo and Labelle showed higher value of disease severity under the condition of artificial or natural disease inoculation. Grain yield of Gayabyeo, a moderate resistant rice variety, was reduced by 0.3 to 5％ in the rate due to sheath blight disease damage and Taebaekbyeo. a susceptible variety. showed the highest in the rate of yield loss, 6.8 to 25.8 ％. The matured grain rate and 1000-grain weight of the matured tiller were decreased when the developing disease lesion reached to the flag leaf, and then panicle weight was decreased more than 25 ％ compared with panicle of healthy culm. In conclusion, Gayabyeo showed the lower rate of yield loss because of slow development of disease to the upper leaves after initial disease occurence on the lower parts of rice plants.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.38 no.2
• /
• pp.183-188
• /
• 1993

This experiment was conducted to investigate the effect of sulfur containing fertilizers on growth, yield and nutritive quality of soybean as affected by lime application at reclaimed soil. Lime application for neutralization requirements showed the effect of increased grain yield about 32% compared to the non application at newly opened land of red and yellow soil. In case of lime application, the sulfur containing fertilizers combined with super phosphate, ammonium sulfate, and gypsum increased the grain yield by 31%, 11%, and 3%, respectively. When lime was not applied, magnesium carbonate application increased the yield by 47%, super phosphate by 22%, and gypsum by 15%. The protein content of grain was higher at lime application than those of non lime application and was increased by the application of sulfur containing fertilizer. But lipid content was not affected by lime or sulfur application. From the above results obtained it was concluded that sulfur fertilizer effect under lime application was significant when combined with super phosphate or ammonium sulfate application. Magnesium carbonate or super phosphate application was the best combination with sulfur-containing fertilizer.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2023.04a
• /
• pp.51-51
• /
• 2023

Global warming has significant effects on the growth and development of wheat and can cause a reduction in grain yield and quality. Grain quality is a major factor determining the end-use quality of flour and a reduction in quality can result economic losses. Therefore, it is necessary to study the physiological characteristic of wheat to understand its response to temperature elevation, which can aid in the development of strategies to mitigate the negative effects of high temperature and sustain wheat production. This study investigated the effects of elevated temperature on grain characteristics and quality during the grain filling period of two Korean bread wheat cultivars Baekkang and Jokyoung. These two bread wheat cultivars were subjected to an increasing temperature conditions regime; T0 (control), T1 (T0+1℃), T2 (T0+2℃) and T3 (T0+3℃). The results showed that high temperature, particularly in T3 condition, caused a significant decrease in the number of grains per spike and grain yield compared to the T0 condition. The physical properties, such as grain weight and hardness, as well as chemical properties, such as starch, protein, gluten content and SDSS, which affect the quality of wheat, were changed by high temperature during the grain filling period. The grain weight and hardness increased, while the grain size not affected by high temperature. On the other hand, amylose content decreased, whereas protein, gluten content and SDSS increased in T3 condition. In this study, high temperature within 3℃ of the optimal growth temperature of wheat, quantity properties decreased while quality-related prosperities increased. To better understand the how this affects the grain's morphology and quality, further molecular and physiological studies are necessary.

• Korean Journal of Soil Science and Fertilizer
• /
• v.33 no.5
• /
• pp.340-346
• /
• 2000

This experiment was conducted to investigate the effect of nitrogen fertilization in job's tears (Coix lachryma-jobi L.) on the growth characteristics, grain yield, nitrogen accumulation, and chemical property of soil after harvest. Heading and budding stages were shorter than control but growth periods was increased because of the increase of ripening periods according to the increase of nitrogen fertilizer applications. Number of main culm node and culm diameter was similar but culm length and tiller number per plant were better according to the increment of nitrogen fertilizer applications than control but the decrease of grain yield was attributed to the fact that damage by corn borer was 30% in $240kg\;ha^{-1}$ of nitrogen treatment. Some of yield components was better according to the increment of nitrogen fertilizer applications but grain number per plant of $160kg\;ha^{-1}$ of nitrogen treatment was greater. So grain yield was the highest ($3,410kg\;ha^{-1}$) at the $160kg\;ha^{-1}$ of nitrogen fertilization. Nitrogen use efficiency decreased according to the increase of nitrogen fertilization. Total nitrogen of soil after experiment in 0, $80kg\;ha^{-1}$ of nitrogen treatments was lower and in 160, $240kg\;ha^{-1}$ of nitrogen treatments was higher than that before the experiment.