• Korean Journal Plant Pathology
• /
• v.14 no.3
• /
• pp.253-259
• /
• 1998

Effects of soil disinfection, fungicide application, and narrow ridge cultivation on ginger rhizome rot development were examined in two naturally-infested fields at Seosan, Choongnam province. Soil disinfection treatments were assigned to main plots, and fungicide and ridge treatments to sub-plots in a split plot design with three replications. The rhizome rot started in late July, and progressed rapidly until late September with the peak incidence in mid-august to early September. Soil disinfection by dazomet application showed the most prominent inhibition effects in both fields, where the disease was reduced by the treatment from 17.5% to 4.8% in one field, and from 51.0% to 2.2% in the other field. Three to five applications of fungicide metalaxyl-copper during the growing season inhibited the disease by 89.7% in one field, but less effectively in the other field. Narrow ridge cultivation reduced the disease effectively by 78.1% and 63.9%, compared to the unridged control plots in each field, respectively. Germination rate of seed-rhizomes and growth of ginger plants were similar between treatments, except when the plots received improper aeration after applying dazomet, and then the germination rate was significantly reduced. The greatest yields were obtained in the disinfected plots, regardless of rhizome rot incidence, except one control plot with very little disease. Ginger yield was negatively correlated with disease severity. However, the yield of ridge plots averaged 58∼59% compared to those of the unridged plots, due mainly to the half planting rate of the ridge plots. In spatial progress, the disease in the disinfected plots started from a single focus of the inoculum, and spread into the adjacent areas only, whereas in the untreated plots, the disease started from many foci that were distributed over the plot, and rapidly progressed to make an epidemic during the season. The soil density of P. myriotylum in the disinfected plots was not changed or, if not, increased slightly during the season. However, in the untreated plots it increased rapidly to reach the density 3 to 5 times greater by the end of the season.

• Journal of the Korean Professional Engineers Association
• /
• v.2 no.6_7
• /
• pp.12-23
• /
• 1969

The purpose of this study is to find out the reasonable amount of evapo-transpiration required for the paddy rice plant during the whole growing season. So, on the basis of the 3year experimental data concerning the evapo-transpiration from 1966 to 1968, the author obtained the following results. 1) The leaf area index in the densely planted plot is generally higher than that in the conventionally planted one during the first half of growing season. So, the coefficient of transpiration in the former plot is some what higher than in the latter, and the coefficient of water surface evaporation under the plant cover has the inverse relation between both plots. 2) It is unreasonable that coefficient of evapo-transpiration is applied to the calculation of the evapo-transpiration requirments of each growing stage, because a certain degree of variation in meteorological factors and in the thickness of the plant growth is involved in it. 3) It is most reasonable that the rate of transpiration and of the water surface evaporation is applied to the calculation of the transpirated amount and evaporated one in each growing stage because it shows almost constant value in spite of any meteorological conditions in so far as the variety of rice, planted density and control of applying fertilizer are same and the disease and blight are negligible. 4) The ratio of the amount of transpiration to the weight of the whole air dried yields has the tendency of decreasing as that of the yields increase, having almost constant value despite the amount of pan evaporation; and the value is about 210 when the weight of root parts is included to that of the yields. 5) Although the required amount of transpiration during the whole growing season can be calculated with the above ratio, fig. 7 showing the relation between the amount of transpiration and the weight of the yields is more reasonable and will be convinient to find it. And the requirements of water surface evaporation during the same season can also be directly found with the weight of air dried straw refering to fig.8.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.29 no.1
• /
• pp.152-160
• /
• 2001

This study is conducted to evaluate the effects of containerized landscape tree production methods on post-transplant stress. Two types of container such as plastic pot(pot), fabric growing bag(bag) were adopted to restrict tree roots. Each types of containers was divided into seven sub-types. One traditional production method was included as comparison. Two landscape woody plants species (Magnolia denudata, Albizzia julibrissin) were implanted in the 7 sub-types of container. After one or two growing season in the container, each types of container trees was transplanted. Half of the trees were transplanted in the mild spring season, and another half of trees were transplanted in the improper summer season. The data were collected on the crown wilting ratio and trunk die-back ratio. The result of the analysis based on these data were as follows; 1) The container production methods were lower than the traditional production methods by 3 times in the average wilting ratio of summer season's transplanting point. 2) Post-transplant stress was more successfully mitigated, in case the "pot" type as was the "bag" types of container. 3) The effective and economic way of mitigating post-transplant stress by container production methods was selecting container plants of vigorous and deep root systems. 4) The "pot" type of container was to restrict tree roots more successfully, But, winter chilling and low temperature attacked the "pot" type tree's twigs and suckers. These results indicated that "pot" grown container plants should managed carefully during the winter after transplanting. Based upon the results of this study, a subsequent research on the development of container material, growth type of the container trees, and other maintaining method will be required.es, and other maintaining method will be required.

• Journal of Korean Society of Water and Wastewater
• /
• v.27 no.5
• /
• pp.591-601
• /
• 2013

In modern society, we are living indoor at 80 - 90 % or more of the day, therefore most people are exposed to unconscious indoor air pollutants by various causes. When mother and infant, whose level of immunity are weak, are exposed to polluted indoor air, respiratory diseases and atopy can occur by the growth of bacteria. Therefore, appropriate indoor air quality management is important especially at nursery, elementary school and postpartum clinic etc. In this study, we compared the characteristics of the indoor air qualities of primary school facilities and infant facilities. In this study, seasonal effects were investigated. Also the effects of individual activity area were studied for indoor air quality. During summer season(May-August), the air qualities of each 16 elementary school and nursery school were investigated. During winter season(October-december), the air qualities of each 10 elementary school and nursery school were investigated. As a result, during winter season in 10 of 16 nursery school, $CO_2$ concentration exceeded regulation level of 1000 ppm. This resulted from the operation of heating system and poor ventilation. Also the air quality of all parameters during winter season were worse than during summer, maybe due to poor ventilation. Except HCHO, the concentrations of other parameters were higher in nursery school. This seems to result from relatively low individual activity area of nursery school than elementary school. From this research, more strong regulation for ventilation and installation of air purifier should be implemented.

• Journal of Bio-Environment Control
• /
• v.12 no.4
• /
• pp.207-216
• /
• 2003

Most severe problem in production of potted kalanchoe during summer season is retardation of growth caused by high temperature. The aim of this experiment was aimed to investigate the effects of natural products such as algin-oligosacchride and glucosamine oligosaccharide, plant growth promoting rhizovacteria such as Pseudomonas sp. B and Pseudomonas sp. D2, and AG-solution on the growth of potted kalanchoe under the different root zone temperature in the greenhouse. Growth characteristics in terms of plant height, leaf length, leaf width, leaf area, leaf weight, fresh weight of shoot and root and root length were recorded under three root zone temperatures (25$^{\circ}C$, 30$^{\circ}C$, 35$^{\circ}C$). In 25$^{\circ}C$, the mixed treatment of Pseudomonas sp. B and glucosamine oligosaccharide resulted in the best growth in terms of plant height, leaf area and root weight. In 3-$^{\circ}C$, glucosamine oligosaccharide treatment gave fair result in plant height and leaf weight, but the mixed treatemtn of Pseudomonas sp. D2 and algin-oligosaccharide showed better growth on leaf area and root weight. In 35$^{\circ}C$, the mixed treatment of Pseudomonas sp. B and glucosamine oligosaccharide could greatly improve the plant height, leaf area, leaf weight and root weight. These results demonstrated that the mixed treatment of natural products and microorganisms could overcome the detrimental effects caused by high temeprature in the production of kalanchoe.

• Asian Journal of Turfgrass Science
• /
• v.22 no.2
• /
• pp.133-140
• /
• 2008

The growth of root and shoot normally decline dramatically in mid-summer of Korea, moreover the cool-season turfgrassgrass eventually wither to death over $30^{\circ}C$. The increase of air temperature also drives the heat of soil, that makes stress on root system. The heat stress affects physiological mechanisms of hormonal unbalance that stimulates shoot growth, photosynthesis, and transpiration. To solve those problems, many studies have been carried out to control soil moisture and OM content to decrease soil temperature for dissolving the growth retardant by heat stress. This study initiated to analyze the change of soil temperature with soil moisture, and the effect of soil depth and moisture content on heat transmit and thermal changes on turfgrass growth(productivity, green color, and damage by dryness and high temperature). Kentucky bluegrass plots prepared with 25%, 33%, 40% soil moisture treatments. Soil temperature was measured every five min. with four thermo-sensors at 12 and 2 cm soil depth. The most acceptable growth showed at 33% soil moisture, but the worst result showed at 40%. The soil moisture seriously affected on the growth of Kentucky bluegrass, however the quality of turfgrass may acceptable if we can control soil moisture down to 33% when the flooding season of monsoon.

• Korean Journal of Ecology and Environment
• /
• v.36 no.2 s.103
• /
• pp.139-149
• /
• 2003

This study was conducted to determine limiting nutrients and the physiological characteristics of phytoplankton in response of nutrients in Lake Paldang from March 2002 to October 2002. A field research was conducted along with laboratory batch culture experiment to find the limiting nutrients and the growth kinetics. According the results of Chl. a TP relationship, TN/TP ratio, and nutrient addition bioassay, phosphorus appeared to be a major limiting nutrient in Lake Paldang and thus the lake productivity was greatly influenced by it. P limitation for the phytoplankton of Lake Paldang varied with season, and the possibility of limitation by nitrogen and silica also occurred. The degree of P limitation was greatest during spring when the concentration of dissolved phosphorus is relatively much lower than summer and autumn. The maximum growth rate (${\mu}_{max}$) and half saturation concentration ($K_u$) of Lake Paldang phytoplankton ranged from 0.8${\sim}$1.1$day^1$ and from 0.1${\sim}$O.8${\mu}M$, respectively. $K_u$ was highest during May ($0.8{\mu}M$) and the lowest during September ($0.1{\mu}M$). Such result may be induced by the phytoplankton cell quota that showed the lowest concentration ($0.13{\mu}gP/{\mu}gChl.$ a) during May. The growth kinetics showed that phytoplankton growth in Lake Paldang was faster during summer and autumn than spring, suggesting that the Potential of algal bloom is high after the summer monsoon season.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.19 no.1
• /
• pp.53-65
• /
• 2014

In order to estimate the effect of nutrients addition for phytoplankton growth and community compositons in spring and summer season, we investigated the abiotic and biotic factors of surface and bottom waters at 20 stations of inner and offshore areas in Gwangyang Bay, Korea. Nutrient additional experiments were also conducted to identify any additional nutrient effects on phytoplankton assemblage using the surface water for the assay. Bacillariophyceae occupied more than 90% of total phytoplankton assembleges. Of these, diatom Eucampia zodiacus and Skeletonema costatum-like species was mainly dominated in spring and summer, respectively. Here, we can offer the season why the two diatom population densities were maintained at high levels in both seasons. First, light transparency of spring season in the euphotic zone was greatly improved in the bay. This improvement is one of important factor as tigger of increase in E. zodiacus population. Second, low salinity and high nutrient sources supplied by Seomjin River discharge are a main cue for strong bottom-up effects on S. costatum-like species during the summer rainy season. Based on the algal bio-assays, although maximum growth rate of phytoplankton communities at inner bay (St.8) were similar to those of outer bay (St.20), half-saturation constant ($K_s$) for phosphate at outer bay was slightly lower than those of inner bay. This implied that adapted cells in low nutrient condition of outer bay may have enough grown even the low phosphate and they also have a competitive advantage against other algal species under low nutrient condition. In particular, efficiency of N (+) addition in summer season was higher compared to control and P added experiments. In the bay, silicon was not a major limiting factor for phytoplankton growth, whereas nitrogen (N) was considered as a limiting factor during spring and summer. Therefore, a sufficient silicate supply form water mixing Si recycled from diatom decomposition and river water is favorable form maintaining diatom ecosystems in Gwangyang Bay.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.8
• /
• pp.1108-1117
• /
• 2003

In Guadeloupe small ruminants (SR) are reared for meat production under pasture conditions. Intensive rotational grazing systems (irrigated, fertilised and high stocked) allow reasonable levels of production but generate high post-grazing residues. Experiments were designed to control them. A system in which residuals were mown (RM) was tested in comparison to the control system (Residuals Remained, RR). The same design was carried out for two years with Creole goat (G) and Martinik sheep (S). An accelerated reproductive rate (3 parturitions over 2 years) was carried out. Systems were compared at three parturition seasons per year(dry, intermediate and rainy seasons). Each group was composed of 20 goats ($36.0{\pm}2.5kg$) or 20 ewes ($46.8{\pm}2.4kg$). The female body traits did not vary according to pasture management and seasons. The stocking rate averaged 1,400 kg LW/ha. The mean fertility rate for does varied significantly (p<0.05) within the kidding season, from $80.4{\pm}0.5%$ to $93.7{\pm}2.9%$ while the mean litter size was $2.30{\pm}0.07$ total kids born. No effect of pasture system was observed. Corresponding values for ewes were $83.2{\pm}12.8%$ vs. $75.6{\pm}12.5%$ (p<0.05) and $2.43{\pm}0.24$ vs. $2.03{\pm}0.29$ (p<0.01) total lambs born for SRM and SRR ewes, respectively. A seasonal effect was observed upon ewe performances. The preweaning mortality of kids and lambs averaged 16.3% and 14.4%, respectively. It was 7 and 9 percentage points more (p<0.01) for RR than for RM kids and lambs, respectively. For both species, weaning took place at an average age of $81.4{\pm}3.6days$. In Creole kids, live weight at birth and at weaning were $1.9{\pm}0.2kg$ and $8.9{\pm}0.8kg$, respectively. In the Martinik sheep, the traits averaged $2.9{\pm}0.2kg$ and $18.9{\pm}0.9kg$. For both traits in both species, significant (p<0.05) group${\times}$season interactions were recorded. The consequences of elimination of post-grazing residues varied according to the SR species, the environmental conditions and the animal physiological status. The forage characteristics were not limiting factors since forage availability in the RM systems (2,300 and 2,600 kg DM/ha, respectively) and chemical composition were at satisfactory levels (CP content averaged 12 and 10%). It is recommended to develop new grazing system which would allow the use of post-grazing residues instead of mowing the refusals.

• Journal of Korean Society of Forest Science
• /
• v.62 no.1
• /
• pp.1-18
• /
• 1983

Sum of daily mean temperature, sum of daily mean relative humidity and sum of daily mean duration of sunshine during the growing season (March-October), and daily mean temperature, daily mean relative humidity and daily mean minimum temperature during the dormant season (November-February) were obtained respectively from the climactic data recorded at 26 different standard stations for 30 years from 1951 to 1980, to provide a method for proper selection of tree species suitable to a certain site. They were also marked on the map of Korea. The whole country was divided into 6 regions by trend of temperature variation and the regression equations for each region were produced to estimate the sum of daily mean temperature of the growing season and the sum of daily mean minimum temperature of the dormant season in a certain site where tree plantings are planned. The natural range of distribution of each species was expressed by the sum of daily mean temperature and daily mean minimum temperature on the basis of "Horizontal and vertical distribution of the Korean woody plants" reported by Chung and Lee (1965).