The densification and grain growth mechanisms of in and in have been investigated. Uranium dioxide powder compacts were sintered at 1 in or at 110 in for various times from 0.5 h to 16 h. The grain size and density of the specimens were measured. From the measured data, the mechanisms of the densification and grain growth were determined by use of available kinetic equations which express the relations between densification and grain growth. In both atmospheres, it has been found that the densification was controlled by the lattice diffusion and the grain growth by the surface diffusion of atoms around pores. It appears that the surface diffusivity as well as the lattice diffusivity increase considerably with the increase in O/U ratio in the specimen.

This experiment was carried out to investigate the effects of limited nutrient supply during 21 days before and after pollination stage on the growth, fruit quality and nutrient uptake of muskmelon in rockwool culture. Muskmelon, cv. Earl's Favorite seeds sowed on rockwool cube and transplanted on rockwool slab(90×15×7.5cm) when 2 to 3 true leaf appeared on Sep. 6, 1991. Three kinds of nutrient composition recommended by Shizuoka university, combinated with the composition of Otsuka house A and composition Shizuoka III. One half of calcium nitrate(Ca(NO3)2.4H2O) for limiting nitrogen supply during 21 days was treated and then fertigated the nutrient composition recommended by Shizuoka university up to harvest time. Trickling nozzles(Netafim Co. Israel) were used for fertigation of nutrient solution and noncirculating system was employed. Temperature was maintained 18℃ in night but 23 to 25℃ for 10 days after pollination for softening the fruit. The drainage ratio of nutrient solution was adjusted 20 to 30 percent. Fertigated and drained amount, and the pH and EC of nutrient solution were recorded. The concentrations of mineral elements including N, P, K, Ca, and Mg were analyzed and compared among treatments. In both autumn and winter cultivation, the limitation of nutrient supply by adjustment of nutrient composition(NO3-N : 8meㆍl-1) caused the nutrient deficiency in muskmelon plant due to the limited nutrient supply. After pollination nutrient limitation by the lowering the nitrate retarded the over thickening of upper leaves of muskmelon but plant height and fresh weight of fruit were

본 연구는 1991년부터 1993년까지 사료작물과 목초류 7종(호맥, 대맥, 연맥, Italian ryegrass, alfalfa, orchardgrass 및 혼과목초)을 공시재료로 하여 곤포사일리지(BS=baled silage making)조제이용을 위한 수확시기와 이때의 BS 생산성 및 품질을 평가하였다. 시험방법에 있어서 작물재배는 농촌진흥청의 사료작물 및 목초 표준경종방법에 준하여 실시하였다. 사일리지 조제작업중 BS는 자체적으로 제작한 각형 베

연맥의 수확시 생육시기가 건물수량 및 사료적인 가치에 미치는 영향을 알기 위하여 1993년 3월 13일에 계명전문대학 부속목장에서 파종하여 지엽출현전, 지엽출현기, 출수기, 유숙기 및 호숙기에 수확하였다. 1. 사초의 건물함량은 지엽출현전, 지엽출현기, 출수기, 유숙기 및 호숙기에 각각 11.8, 12.3, 14.9, 25.6 및 28.8%로 지엽출현전부터 cnftnrlRK지는 낮았으나 출수기부터 호숙기까지는 급격히 증가되었다. 2. 잎의 비율은 지엽출

To determine the effects of potassium() fertilization level(0, 100, 200 and 300 kg/ha/year) on the growth, dry matter(DM) yield, nutritive value and nitrate nitrogen(-N) concentration of grasses grown under shading condition, this experiment was carried o

This experiment was carried out to determine the effects of nitrogen(N) fertilization levels(0. 120, 240 and 360 kg/ha/y) on seasonal nitrate nitrogen(NO3-N) concentration and water soluble carbohydrate (WSC) content of grasses grown under shading cond

This experiment was carried out to determine the effects of nitrogen(N) fertilizer levels (0, 120, 240 and 360kg ha-1Y-1 Y-') on seasonal grass growth, dry matter (DM) yield and botanical composition in pasture under shade condition. Investigation

This experiment was to study the relationship between shoot and root system in perennial ryegrass at different stages of growth. The results are summarized as follows; 1. The dry weight of shoot was significantly correlated with the dry weight of root at

본(本) 시험(試驗)은 보리를 생육(生育) 단계별(段階別)로 예취(刈取)하여 formic acid를 0.2%~0.6% 까지 3개 수준(水準)으로 첨가(添加)하고 또 예건(豫乾)하였을 때 silage의 품질(品質)에 미치는 영향을 구명(究明)하고져 원료(原料)의 일반성분(一般成分), 식물세포구성물(植物細胞構成物)을 분석(分析)하였다. 또한 silage의 품질(品質)을 평가(評價)하기 위하여 제조(製造)하여 약(約) 60일후에 pH 및 유기산(

영양생장기(營養生長期)의 형태적(形態的)과 건물수량(乾物收量)과의 관계(關係)를 조사(調査)하여 수량(收量)에 관여(關與)되는 형태적(形態的) 형질(形質)과 품종(品種)의 특성(特性)을 비교(比較), 검토(檢討)하였다. 1. 개체중(건물중(乾物重))은 초장(草長), 엽면적(葉面積) 및 경면적(莖面積)과 유의(有意)한 정상관(正相關)을 나타내어, 개체중의 증가(增加)는 초장(草長), 엽면적(葉面積), 경면적(莖面積)의 상호작용(相互作用)이라고 할 수 있다

This study aimed to find a suitable size and a seedling raising stage for growing cuttings of Euonymus fortunei ‘Emerald and Gold’ using plug trays. The experimental method, involved cutting two nodes from a solitary branch of E. fortunei ‘Emerald and Gold’, and the use of 32 (143 mL/cell), 50 (70 mL/cell), 105 (18 mL/cell), 200 (13 mL/cell) plug trays. The cuttings were transplanted to trays after they were filled with a universal horticultural medium. To compare the growths, plant heights, the numbers of leaves, longest root lengths, thickness/radius ratios, dry weights, and fresh weights were measured from July to October, and statistical analyses were performed using both the two-way repeated-measures analysis of variance (ANOVA) and Tukey’s post-test. The results confirmed that the size of the plug tray and the seedling raising stage had a significant effect on the growth of E. fortunei ‘Emerald and Gold.’ In addition, the overall growth was high and the change in growth was relatively rapid in districts 50 and 105. Therefore, it can be considered appropriate to use 50 and 105 trays when growing cuttings of E. fortunei ‘Emerald and Gold’ on plug trays.

This study was conducted to determine the effect of low temperature and low radiation conditions on the yield and quality of hot pepper at an early growth stage in Korea. In plastic greenhouses, low temperature, low temperature with covered shading treatments were set 17 to 42 days after transplanting. The pepper growing degree days decreased by 5.5% due to the low temperature during the treatment period. Radiation decreased by 74.7% due to the covered shading. After commencing treatments, pepper plant growth decreased with low temperature and low radiation. Analysis of the yield showed that the first harvest was delayed by low radiation. The cumulative yields of 119 days after transplanting were 1,956, 2,171, and 2,018 g/m2 for control, low temperature, and low temperature with low radiation respectively. Capsaicin and dihydrocapsaicin concentrations in pepper fruit decreased with low temperature and low radiation. To investigate the photosynthetic characteristics according to the treatment, the carbon dioxide reaction curve was analyzed using the biochemical model of photosynthesis. Results showed that the maximum photosynthetic rate, Vcmax (maximum carboxylation rate), J (electric transportation rate), and TPU (triose phosphate utilization) decreased at low temperatures; the maximum photosynthetic rate, J, and gm (dark respiration rate) were reduced by shading. These results indicate that low temperature and low radiation can retard early growth, yield, and quality, but these can also be recovered 119 days after planting. Based on the results, the yield and quality of pepper can recover from abiotic stresses with proper cultivation.

The aim of this study was to analyze the light traits in a solar light-collector device and its effects on lettuce growth at an early growth stage. The three hyper parameters used were the reflector diameter (2 cm and 4 cm), coating inside the reflector (chrome-coated, non-coated) and distance from the light fiber (15 cm and 20 cm). The results showed that light efficiency, which is the ratio of light intensity inside the fiber to the solar intensity, improved by 41.1 % when using a 2 cm diameter chrome-coated reflector at a distance of 15 cm from the light fiber; whereas it only improved by 20.6% when a non-coated reflector was used. As the reflector size was increased to 4 cm, the light efficiency for the coated and non-coated reflectors increased by 28.5 % and 26.4 %, respectively, hence, no significant difference was observed. When the light fiber was placed at a distance of 20 cm, the increase in light efficiency with coating treatment was 8 % higher than without coating treatment. We also compared the efficiency of light-fiber treatment with that of LED treatment in our lettuce nursery, and observed that the plants exhibited better growth with light-fiber treatment. We observed an average increase of 1.7 cm in leaf height, 7 cm2/plant increase in leaf area, and 32 mm increase in root length upon light-fiber treatment as opposed to those observed with LED treatment. These findings indicate that the collector light-fiber is economically feasible and it improves lettuce growth compared with the LED treatment.

Background : This experiment was conducted to study the characteristics of Korean ginseng (Panax ginseng C. A. Meyer) growth by LED artificial light source in the plastic house using multi-stage cultivation facility and artificial soil. Methods and Results : Seedlings of Korean ginseng cultivar cultivated from 6:00 am to 6:00 pm by adjusting the ratio of 1 : 1, 2 : 1 and 3 : 1 for red light and blue light for the LED light quality test. Controls were tested by treating the white light (fluorescent lamps) for the same time. The average temperature inside the plastic house remained above 25℃, then below 25℃ after mid-August and below 20℃ after mid-September. The temperature near the roots of the artificial soils was higher than 26℃ in late July and early August and lowered to 20℃ or lower in all treatments in September. The pH of the soil was in the standard range, but the EC value was 2.89 in the soil before the test and 5.83 in the white light treatment, higher than the standard range of 1.0. The light intensities were 95.3 μmol and 94.9 μmol in the 3 : 1 and 2 : 1 ratios of red and blue light, respectively. The photosynthetic rate was 1.72 μmole CO2/㎡/s in 3 : 1 treatment and 1.9 times higher than white light treatment. As the red light ratio increased, the light amount and photosynthetic rate increased. Growth characteristics of aerial parts (plant height, leaf length etc.) by LED irradiation were longer than that of white light treatment in the 2 : 1 or 3 : 1 treatment of red light and blue light. The root length was the longest at 13.7 ㎝ in the 3 : 1 treatment of red and blue light, taproot length were 6.9 ㎝ and 6.6 ㎝ in the 2 : 1 treatment and 3 : 1 treatment, respectively, longer than 4.3 ㎝ in white light. Root fresh weight was the heaviest (3.6 g/plant) in 3 : 1 treatment for red and green lights. Conclusion : It was confirmed that the rate of photosynthesis of Korean ginseng was higher than that of white light treatment and the growth characteristics of aerial and root parts were excellent at the ratio of 3 : 1 of LED red light and blue light in plastic house using multi-stage cultivation facility and artificial soil.

The effects of weather variations on winter hulless barley were analyzed using data obtained from winter crop situation test at Iksan from 1985 to 2015. The wintering stage in the 16 years from 2000 to 2015 has become colder and shorter than that in the previous 15 years from 1985 to 1999. This has resulted in an early sequence of regrowth date, heading date, and ripening date. Heading date of hulless barley was mostly influenced by regrowth date and period of stem elongation. Futher, the regrowth date and period of stem elongation were strongly negatively correlated with the average air temperature in February and the maximum air temperature in March, respectively. The number of spikes per m2 and 1000-grain weight of Saechalssal cultivated from 2003 to 2015 showed strong positive correlations with yield. In early heading years, yield increased with extended ripening period and with increased 1000-grain weight. There was a strong negative correlation between 1000-grain weight and the average temperature during the ripening period. In the 15 years from 1985 to 1999, warm winters contributed to yield increase with increase in the number of spikes per m2 and a long ripening period. In contrast, in the recent 16 years from 2000 to 2015, the large variability in air temperature during the wintering stage, the decreasing number of spikes per m2 and the steadily increasing air temperature and decreasing precipitation during the ripening stage have caused high temperature stress and yield loss in late heading years.

Background : The roots of Curcuma longa Radix is used to make herbal medicine, which is registrated in the Korean Pharmacopoeia. This species is a perennial herb, and is distributed throughout tropical and/or sub tropical regions. High temperature and humidity with small difference between daytime and nighttime is the finest environment condition in this species. Recently, demand for C. longa has been expanded to cultivation area as central region from southern region. Therefore, this study aimed to investigate the effect of harvest time on the growth, yield characteristics and main composition contents in C. longa. Methods and Results : Curcuma longa rhizomes were harvested from farmland in Jindo, Jeollanam-do in end October, early November, middle November, end November, early December, middle December and end December 2015. Harvested rhizome were dried in hot air drier, and it was investigated as growth characteristics and yield. Contents of curcumin, demethoxycurcumin, bisdemethoxycurcumin was analyzed from dried powder of rhizome. The analysis column was used to Phenomenex, Kinetex 2.6um F5 100A 100*2.1mm. 10 mg of standard was taken, 80% MeOH was added to dissolve in 10 ㎖ flask. 0.5, 1, 2, 4 ㎖ was taken from dissolved solution and then was added to 10 ㎖ of 80% MeOH. It was filtered through 0.45 ㎛ filter and then 5 μℓ was taken to make standard solution. Analytical calibration curve was measured to diluted solution within sample concentration. 2 g of ground sample was taken, 40㎖ of 80% MeOH was added to extract by ultrasound sonication during 60 minutes and then it was filtered through 0.2 ㎛ filter to analyze component content. Conclusion : The root weight significantly increased from 376.1 g in end October to 695.9 g in end December as 1.8 double. Curcumin contents differed significantly among harvest times in end November and early December. Demethoxycurcumin increased from early November to end November, and Bisdemethoxycurcumin increased to the early November.

In this study, we examined the impact of transplant timing of mother plants for seedling strawberry on growth and development of daughter plants and field stage. The leaf growth of treated mother plants and crown thickness were low when transplant was performed on April 10th. Based on the results collected until July 13th, the numbers of daughter plants with more than two leaves were 20.6 and 19.5 for March 10th and March 25th, and these values decreased by April 10th and April 25th showing values of 15.1 and 11.8, respectively. After seedling growth was complete, leaf area and fresh weight of the saplings were remarkably low beginning from the transplant on April 10th. Crown thickness of saplings was generally lower when transplant timing was late. After 45 days of transplant leaf length and width were noticeably lower than the transplant on April 10th and 25th. First cluster was 100% for both the March 10th and 25th transplant, followed April 10th and 25th with values of 66% and 43%. The results revealed that transplant on March 10th and 25th had a greater positive impact on the growth and development of the strawberry cultivar ‘Seolhyang’. A supplementary study will have to be conducted to determine the relationship between the harvest period of the first cluster and the yield of marketable strawberries depending on the transplanting time of mother plants.