• Journal of Aquaculture
• /
• v.18 no.4
• /
• pp.231-235
• /
• 2005

A 6-week feeding trial was conducted to determine optimum feeding frequency for growth of juvenile flounder Paralichthys. olivaceus during the summer season. Triplicate groups of fish (initial mean weight 3.7 g) were fed a extruded pellet with 5 feeding frequencies (one meal every 2 days, one meal a day, two meals a day, three meals a day and four meals a day) at $24.0\pm0.50^{\circ}C$ (mean$\pm$SD). Survival of fish fed one meal every 2 days was significantly (P<0.05) lower than that of the other groups. Weight gain, specific growth rate and daily feed intake increased with increasing feeding frequency (P<0.05). However, no significant differences were observed in weight gain, specific growth rate and daily feed intake of fish fed among two, three and four meals a day. feed efficiency and protein efficiency ratio were not affected by feeding frequency. Whole body contents of moisture, crude protein, crude lipid and ash were not significantly affected by feeding frequency. These results indicate that optimum feeding frequency is two meals a day for the optimum growth of juvenile flounder grown from 3.7 to 19.0 g under the experimental conditions.

• Fisheries and Aquatic Sciences
• /
• v.12 no.2
• /
• pp.104-110
• /
• 2009

Feeding trials were performed at two different water temperatures (summer and winter seasons) to identify suitable protein and lipid (energy) levels to be used in formulating extruded pellets for olive flounder. Experiments were conducted to determine the effects of protein and lipid levels in extruded pellets on the growth and body composition of the flounder in both feeding trials. Six experimental diets were prepared containing three protein levels (46%, 51%, and 56%) and two lipid levels (10% and 17%). In the first experiment, during the summer season ($22{\pm}2.2^{\circ}C$), a triplicate group of fish (initial weight, 114 g) were fed to satiation one of the six diets for 11 weeks. The highest weight gain was observed in fish fed the 56/17 (% protein/% lipid) diet, but this weight gain was not significantly different from that of fish fed the other diets, except for those fed the 46/10 diet. The feed efficiency and protein efficiency ratio of fish fed the 17% lipid diets were higher than those of fish fed the 10% lipid diets at each protein level. In the second experiment, during the winter season ($13{\pm}1.5^{\circ}C$), a triplicate group of fish (initial weight, 107 g) were fed to satiation one of the six diets for 9 weeks. Weight gain was not significantly different among all groups. The feed efficiency and protein efficiency ratio tended to increase with increasing dietary lipid level at each protein level. The whole-body crude lipid content of the of fish fed the 17% lipid diets was significantly higher than that of fish fed the 10% lipid diets at each protein level in both feeding trials. Based on the data obtained in this study, the inclusion of dietary protein at a level of 46% appears to be sufficient to support optimal growth, and increasing the dietary lipid level from 10% to 17% had no beneficial effects on the growth and feed utilization of olive flounder (110-300 g), except for fish fed a 56% protein diet in the summer season.

• Asian Journal of Turfgrass Science
• /
• v.23 no.2
• /
• pp.229-240
• /
• 2009

The high temperature and water content in soil profile probably affect the physiological disorder especially on cool-season turfgrasses in warm and humid weather of Korean summer. The purpose of this research was to analyze the effect of soil temperature and water content on the growth and stress response of creeping bentgrass(Agrostis palustris Huds.) under a humid and warm temperature. USGA(United State of Golf Association) green profile in laboratory test, Daily temperature changes were tested under a dried sand, 70% water content of field capacity, and saturated condition at $34^{\circ}C$ of the USGA green in lab. In this test, the dried sand reached to $80^{\circ}C$, however, the surface temperature decrease of $10^{\circ}C$ on the saturated condition. In the thermal properties test in field, thermal conductivity, thermal diffusivity, and soil temperature were increased followed by irrigation practise. In the water-deficient condition, the highest soil temperature was reached temporally right after irrigation, however, the excessive soil water content higher than field water holding capacity showed the highest soil temperature after a while. This result indicated that a heat damage to root system was caused from the thermal conductivity of a high surface soil temperature. The excessive irrigation when a high turf surface temperature should occur a negative result on tufgrass growth, moreover, it would be fatal to root growth of creeping bentgrass, especially when associated with a poor draining system on USGA sand green. Overall, this study shows that high soil temperature with water-excessive condition negatively affects on cool-season grass during the summer season, suggesting that excessive irrigation, over 70% field capacity of soil condition, does not help to reduce soil temperature for summer season in Korea. In the study that cool-season grass were treated with different water content of soil, The soil had higher temperature and more water holding capacity when treatment rate of soil conditioner was increased. The best growth at the normal water condition and the worst state of growth at thee water-excessive condition were observed.

• Journal of Korean Society of Forest Science
• /
• v.7 no.1
• /
• pp.8-18
• /
• 1968

This experiment is a comparative study of influence on the seedling in individual pH treatment of culture soil I. T-R ratio and growth 1. T-R ratio has almost similar tendency in its range according to tree species, but in individual treatment there were lots of differences. In the strong acidic and the strong alkali conditions T-R ratio was small. This means the seedling body is out of balance. 2. Where the resistance to H-ion was stronger, the growth of root-system, that is, the resistance of fine root was comparatively better. 3. The growth of root system was greatly influenced by pH, and in the condition of pH3, pH8, pH9, the growth was especially worse. 4. Ginkgo biloba, Pinus rigida and Pinus banksiana kept on growing in the strong acidic condition. 5. The growth season has higher pH of culture soil than the dormant season, and tree species which have strong resistance of acidic had better growth and had stronger resistance of draught in the acidic condition of culture soil ; especially, Pinus rigida and Pinus banksiana were worse in the alkali condition. II Seedling pH 1. According to the tree species, there were differences in seedling pH, and tree species, considred to be strong in resistance of draught, had been high in seedling pH. 2. Seedling pH of the growth season was higher than that of the dormant season. 3. Seedling pH was not significant in pH treatment of the culture soil.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2006.05a
• /
• pp.326-327
• /
• 2006

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2000.04a
• /
• pp.204-205
• /
• 2000

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 2007.05a
• /
• pp.168-172
• /
• 2007

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1997.10a
• /
• pp.60-61
• /
• 1997

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1997.10a
• /
• pp.122-123
• /
• 1997

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.180-180
• /
• 2022