• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.2 no.2
• /
• pp.129-138
• /
• 2021

Living modified organisms (LMOs) are managed by seven government agencies according to their use in South Korea. The Ministry of Environment is responsible for LMOs used for environmental remediation. This study aimed to develop guidelines for assessing potential risks posed by transgenic plants used for remediation to insect ecosystems by investigating arthropod communities in sunflower fields. A total of 2,350 insects and spiders belonging to 134 species of 10 orders and 71 families were collected from sunflower fields over four growth stages ranging from anthesis to seed maturity. At the R3 phase of flower-bud formation, Chironomidae sp. of a decomposer insect guild presented the highest density, while Apis mellifera of a pollinator guild was the most abundant in the R5.8 phase of flowering. During the R7 seed-filling phase and the R9 phase of seed maturity, herbivorous Pochazia shantungensis predominated. During the R9 phase, richness and diversity indices of arthropod communities were distinctly lower whereas their dominance indices were significantly higher than those at other phases. In addition, the composition of arthropod communities was strongly correlated not only with the sampling date, but also with the sampling method depending on the growth stage of sunflowers. Our results suggest that appropriate sampling timing and methods should be considered in advance and that long-term field trials that cover a variety of environmental conditions should be carried out to evaluate potential risks to insect ecosystems.

• Journal of Korean Society on Water Environment
• /
• v.37 no.4
• /
• pp.306-314
• /
• 2021

The application of organic fertilizer could be accompanied by potential hazards to soil and humans due to trace metals. Livestock manure compost·liquefied fertilizer is a well-established approach for the stabilization of nutrients and the reduction of pathogens and odors in manures, which can be evaluated as compost·liquefied. In this study, the livestock manure compost·liquefied fertilizers produced at 333 liquid manure public resource centers and liquid fertilizer distribution centers were collected from May to December 2019. The nutrient content (nitrogen, phosphorus, and potassium), physicochemical properties, and heavy metal content were investigated. The livestock manure compost·liquefied fertilizer was measured using a mechanical maturity measurement device. The organic matter, arsenic, cadmium, mercury, lead, chromium, copper, nickel, zinc, E. coli (O157:H7), Salmonella, etc. of the livestock manure compost·liquefied fertilizers were analyzed. The average heavy metal content in the livestock manure compost·liquefied fertilizer was as follows: Cr 2.9 mg/kg (0.2~8.7 mg/kg), Cu 20.4 mg/kg (1.6~74.1 mg/kg), Ni 1.3 mg/kg (0.4~4.2 mg/kg), and Zn 79.8 mg/kg (3.0~340.7 mg/kg). Although large-scale organic fertilizer plants and resources recycling centers produce good organic (liquid) fertilizers with proper components, it is necessary to standardize livestock manure compost·liquefied fertilizer in order to facilitate efforts to turn livestock manure into useful resources.

• Journal of the Korean housing association
• /
• v.18 no.4
• /
• pp.89-96
• /
• 2007

This study was intended to examine the change in the perception of the professionals for the environment-friendly apartments. After result of implementing the question survey against the professionals two times, the degree of importance in the environment-friendly design elements didn't show any significant change. However, it showed the degree of maturity on the concept of environment-friendly development is widely spreaded in terms of social, economic and environmental aspects. Based on the description of such results, the conclusion can be deduced as follow; 1) Presumably it would require 5 years for the diffusion of the concept of environment-friendly apartments and 10 years for the construction of developing its materialization and settlement respectively, 2) The proper density would be designed in $150{\sim}200%$ in view of the environmental and economic aspects. 3) It is necessary to change the existing system into the District Unit oriented planning & design method in order to apply the environmental design elements in smooth manner.

• Journal of Animal Environmental Science
• /
• v.19 no.2
• /
• pp.183-190
• /
• 2013

Establishment of a new concept of environmental friendly livestock manure management is required based on the facts. But now liquid fertilizer quality in korea shows a large difference among regions and the regulations are uncertain. Focusing on precedent study on main level-grading factors of liquid fertilizer quality certification, the study collected laws and standards related to liquid fertilizer of livestock manure at home and abroad and produced evaluation standards. Liquid fertilizer was divided into four factors (fertilizing value, harmfulness, stability and uniformity). According to each item, scores were awarded based on 16 details: fertilizing value (Nitrogen concentration, the whole concentration of Nitrogen, Phosphoric acid and Kalium), harmfulness (heavy metals, pathogenic microorganism and antibiotics), stability (maturity degree and odour), uniformity (EC, BOD, SS, moisture content and salt). The grade of liquid fertilizer, A (42~48), B (34~41), C (26~33) were rated using total scores.

• The Korean Journal of Malacology
• /
• v.29 no.4
• /
• pp.313-323
• /
• 2013

Gonad development, the reproductive cycle, first sexual maturty and size at 50% of group sexual maturity (the biological minimum size) of Gomphina (Macridiscus) veneriformis were investigated for clams collected from the coastal waters of Donghae City, the East Sea of Korea by histological, and morphometric analysis. Monthly variations of the gonad index showed a pattern similar to that of the reproductive cycle. The reproductive cycle with the gonad developmental stages in female and male G. (M.) veneriformis can be classified into five successive stages: early active stage (December to March), late active stage (March to June), ripe stage (June to July), partially spawned stage (June to August), and spent / inactive stage (September to December). The spawning period continued from June to August, with a peak between July and August when the seawater temperature exceeds $20^{\circ}C$. The percentages of first sexual maturities of female and male clams ranging from 25.1 to 30.0 mm were 56.3% in females and 61.1% in males, and for clams over 30.1 mm shell length, it was 100%. Shell lengths at 50% of group sexual maturity (biological minimum size, $RM_{50}$) were 27.71 mm in females and 26.31 mm in males. Because harvesting clams < 26.31 mm in shell length could potentially cause a drastic reduction in recruitment, a measure indicating a prohibitory fishing size should be taken for adequate fisheries management.

• The Korean Journal of Malacology
• /
• v.21 no.1
• /
• pp.1-11
• /
• 2005

Reproductive cycle, first sexual maturity, spawning amount related with the size and spawning interval in female Ruditapes philippinarum were investigated by histological observation and the analysis of morphometric data during artificial spawning induction. Ruditapes philippinarum is dioecious and oviparous. The reproductive cycle of this species can be subdivided into five successive stages: early active stage (January to March), late active stage (February to May), ripe stage (April to August), partially spawned stage (May to October), and spent/inactive stage (August to February). The spawning period was once a year between May and early October, and the main spawning occurred between July and August when seawater temperature was approximately $20^{\circ}C$. Percentages of first sexual maturity of female clam of 15.1-20.0 mm in shell length were 56.3%, and 100% for the clams > 25.1 mm. The mean number of the spawned eggs increased with the increase of size classes (shell length). In case of spawning induction by the same size class, the number of spawned eggs were gradually decreased with the increase of spawning frequencies (the first, second, and third spawnings). In the experiments of artificial spawning induction during the spawning season, the interval of each spawning was estimated to be 15-17 days (average 16.5 days).

• The Korean Journal of Malacology
• /
• v.28 no.4
• /
• pp.363-375
• /
• 2012

The gametogenic cycle, the number of spawning seasons per year and first sexual maturiity of the pen shell, Atrina (Servatrina) pectinata, were investigated by quantitative statistical analysis using an Image Analyzer System. Compared two previous results (the spawning periods in the reproductive cycles in 1998 and 2006) by qualitative histological analysis with the present results by quantitative statistical analysis, there are some differences in the spawning periods: the spawning period (June to September) by quantitative statistical analysis was one month longer than those of two previous reports (June to July or June to August) by qualitative histological analysis. However, the number of spawning seasons studied by the qualitative and quatitative analyses occurred once per year. In quantitative statistical analysis using an image analyzer system, the patterns of monthly changes in the percent (%) of the areas occupied by follicles to the ovary area in females (or that of the areas occupied by spermatogenic stages to the testis area in males) showed a maximum in May, and then sharply droped from June to September, 2006. From these data, it is apparent that the spawning season of A. (S.) pectinata occurred once a year from June to September, indicating a unimodal gametogenic cycle during the year. Shell heights of sexually mature pen shells (size at 50% of group sexual maturity, $GM_{50}$) that were fitted to an exponential equation were 15.81 cm in females and 15.72 cm in males (considered to be one year old).

• Journal of Plant Biology
• /
• v.17 no.1
• /
• pp.15-21
• /
• 1974

The most commonly grown economical and flue-cured tobacco cultivar Yellow Special A was used in pot-culture tests in order to study Ethrel (2-chloroethyl phosponic acid) effects on accelerating maturity of tobacco leaves in relation to the most adequate level of the chemical useful for field growing, nitrogen level in soil for the most pronounced response, and the most suitable spray period during the growth stages of pre-, post- and topping periods. The following conclusions, thus, were obtained from the present studies; 1. 500ppm Ethrel spray was reconfirmed to be adequate in the practical applications, although the extent of yellow-ripening of tobacco leaves was increased as the Ethrel level increased. The highest leevel treated resulted in causing chemically damaged lesions on leaves and early defoliation. 2. Ethrel-treated leaves showed deeper yellowish tinge to them than those without treatment, while different levels of the chemcial had less influence on the tinge. 3. An adequate level of nitrogen supply to plants favored the Ethrel response, whereas either very low or high level of nitrogen in the soil lowered the chemical effect on accelerating the yellow-ripening. When carbohydrates versus total nitrogen ratio became relatively high, the condition brought out some outstanding Ethrel effects. 4. Chlorophyll level of leaves increased as soil applications of nitrogen level increased, and that also increased carotenoid level of the tobacco leaves. Ethrel-treated leaves showed deeper orange tinge than those without treatment, while the highest level of nitrogen application showed the deepest orange tinge to tobacco leaves. 5. Pre-topping treatment (12 days before topping and flowering) resulted in almost no Ethrel response, and that treatment right on the day of topping, showed response of yellow-leaf ripening at nearly bottom-half leaves of a tobacco plant. The post-topping treatment (12 days after topping) made plants showing full response of Ethrel from bottom to the top leaves of tobacco plant in accelerating the leaf maturity. 6. The extent of Ethrel responses on accelerating yellow-ripening of tobacco leaves was discussed for the modifying influences brought about by certain environmental factors. Discussions were also made about the possible practical applications (particularly for pre-rice planting) and quality difference that may be caused by such growth environments.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1993.10a
• /
• pp.526-537
• /
• 1993

The development of composting techniques is essential to the low input sustainable agriculture. This paper resents an evaluation of composting system, compost materials, aeration & temperature effects, compost maturity , and operational concerns for compost utilization. The composting of organic waste is markedly affected by the nature of the feedstock and the operational temperature employed for the process. These two major parameters are critically examined in this paper, with references to the decomposition of the organic waste. Future research should concentrate on the indications of stability and environmental problems.

• Journal of Animal Environmental Science
• /
• v.19 no.2
• /
• pp.163-168
• /
• 2013

Today, a desirable way to manage livestock manure is to activate its utilization as a resource. The production of high quality liquid fertilizer of livestock manure is very important because it increases the use of various liquid fertilizer. However, the result of mature evaluation with a maturity measuring instrument for liquid fertilizer showed that the deviation of concentration between liquid fertilizer did not bring into uniformity. The result is also making sure that quality management for liquid fertilizer is not smoothly made. Quality evaluation for compost and liquid fertilizer includes physical, biological, chemical and microbiological methods, but a chemical method is mainly being implemented due to fairness and field application. Therefore, this study figured out correlation in feces and urine through regression analysis of livestock manure and tried to create a research plan to carry out efficient quality analysis of managing livestock manure.