• Journal of Korean Society on Water Environment
• /
• v.25 no.5
• /
• pp.713-719
• /
• 2009

A natural wetland in the Nakdong River basin which effectively removes non-point source pollutants was investigated for 2 years to understand wetland topography, vegetation types, and water quality characteristics. The water depth of the natural wetland was in the range of 0.5~1.9 m which is suitable for the growth of non-emergent hydrophytes. The wetland has a high length to width ratio (3.3:1) and a relatively large wetland to watershed area ratio (0.057). A broad-crested weir at the outlet increases the retention time of the wetland whose hydrology is mainly dependent on storm events. The concentrations of dissolved oxygen in the growing season and the winter season showed anoxic and oxic conditions, respectively. Diurnal variations of DO and pH in the growing season were also observed due to weather change and submerged plants. COD and TP concentrations were low in the winter season due to low inflow rate and increased retention time. Increased TP concentrations in the spring season were caused by degradation of dead wetland plants. Nitrogen in the wetland was mostly in organic nitrogen form (>75%). During the growing season, ammonium concentration was high but nitrate nitrogen concentration was low, possibly due to anoxic and low pH conditions which are adverse conditions for ammonificaiton and nitrification. The results of this study can be used as preliminary data for design, operation, monitoring and management of a constructed wetland which is designed to treat diffuse pollutants in the Nakdong river watershed.

• Fisheries and Aquatic Sciences
• /
• v.13 no.4
• /
• pp.332-339
• /
• 2010

Maturity and spawning of the snailfish, Liparis ochotensis was investigated based on samples collected by gill net in the East Sea of Korea from December 2008 to December 2009. The average total length of L. ochotensis was 63.4 cm and 64.1 cm for females and males, respectively. Gonadosomatic index (GSI) began to increase in July, reaching a maximum in November, then began to decrease in December. Monthly changes in the GSI values of L. ochotensis were similar for females and males. Annual reproductive cycle of this species can be divided into five successive stages in females: early growing stage (May), late growing stage (June to July), mature stage (August to September), ripe and spent stage (September to December), and recovery and resting stage (January to April). Males show four successive stages; growing stage (May to July), mature stage (August to September), ripe and spent stage (September to December), and recovery and resting stage (January to April). Relationship between total length (TL) and fecundity (F) was F=$0.00003TL^{4.002}$ ($R^2$ = 0.703), and F increased with TL. Total length at 50% group maturity was estimated to be 55.8 cm. Our findings suggest that the spawning period takes place from September to December, with the main spawning period occurring from October to December.

• Korean Journal of Environmental Agriculture
• /
• v.35 no.4
• /
• pp.302-305
• /
• 2016

BACKGROUND: The northeast district of China, especially Liaoning province, Jilin province, and Heilongjiang province, is one of the largest agricultural production regions in China. These regions play a significant role in ensuring food security. Accumulated temperature such as growing degree days (GDD) is an important environmental factor for plant growth and yield. Therefore, in this study, temporal and spatial distribution of GDD for maize was examined as a basis to estimate the growth and yield of maize in these regions. METHODS AND RESULTS: Meteorological date produced by NASA (MERRA-2) was used to estimate GDD of maize at this study sites. The GDD was calculated from sowing (May 1) to harvesting (Sep. 30). The average GDD of this region between 2010 and 2015 was $1323.0^{\circ}C$ day (595.3-1838.9). The spatial distribution of GDD showed a similar pattern during the different years surveyed. Double cropping for maize could be in only Liaoning province, northwestern Jilin province, and western and eastern Heilongjiang province where the GDD was over $1600^{\circ}C$day. However, The GDD in eastern Heilongjiang province was varied by year. CONCLUSION: The GDD of maize in northeast district of China was varied spatially, but similar among recent six years at the same region. This result can be used to predict growth stage and yield of maize at these regions.

• Journal of Bio-Environment Control
• /
• v.12 no.1
• /
• pp.38-44
• /
• 2003

This work was conducted to estimate amounts of irrigating water during the growing periods of pepper after estimating water consumption in the plastic film house in 1997 and 1998. Evapo-transpiration (ET) under conditions of a black and white PE mulch and sandy or clay loam soil which enhanced the growth and yield of red peppers was greater than that at the bare and sand soil. Average ET of pepper grown in pots accounted for 56.5%∼79.7% of total supplying water in 1997 and 1998. Most of ET was proportioned to the transpiration amount (91∼94%), but there was some difference between amounts of ET and transpiration plus evaporation. Although 57 depended on conditions of the soil texture and plant growth, transpiration for pepper growing periods was amounted to 337.7∼774.3 m in the clay soil,910.6 m in the sandy loam soil, and 253.1 mm in the sandy soil.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.4
• /
• pp.743-748
• /
• 2021

Amid the global population growth and climate change, high-tech smart farm technology that combines agriculture and ICT is actively being researched in Korea to solve sustainable crises such as declining population of agricultural and livestock industries. Existing smart farms are growing mainly on crops with low price competitiveness. Food consumption structures are becoming more sophisticated and diverse, and as agricultural consumption patterns change, the smart farm system also needs to be optimized for growing high-value special crops. To this end, an integrated ICT management system was designed and implemented by establishing a containerized smart farm environment specialized in growing sprout ginseng. Through this, it is possible to implement high-tech agricultural production and lead new future convergence industries through the convergence of ICT, agriculture, and the latest technologies and farming.

• Journal of Korean Society of Forest Science
• /
• v.97 no.6
• /
• pp.680-689
• /
• 2008

This present study was conducted to investigate photosynthetic responses and chlorophyll fluorescence performances of Cornus controversa, Fraxinus rhynchophylla, Betula schmidtii, Prunus leveilleana, and Acer mono seedlings growing under four different light intensity regimes (full sun, and 65~72%, 29~40%, 7~12% of full sun). As result, Cornus controversa, Fraxinus rhynchophylla, and Betula schmidtii showed outstanding photosynthetic capacities in full sun and showed low shade tolerance. Prunus leveilleana showed good photosynthetic capacity in three treatment levels except for 7~12% of full sun and showed common shade tolerance. While, Acer mono showed good photosynthetic capacity and chlorophyll fluorescence in 29~40% of full sun. Acer mono showed the highest shade tolerance compared to the other four species.

• Korean Journal of Environment and Ecology
• /
• v.19 no.2
• /
• pp.188-192
• /
• 2005

To seek for proper regeneration methods with under-planting, Photosynthetic rate and chlorophyll contents of three broad-leaved species seedlings, Kalopanax pictum, Fraxinus rhynchophylla and Cornus controversa, were measured and compared between growing sites, below the canopy of Larix kaemferi and open land in the forest. Nursery stocks was planted in open nurs- ery in the forest in late April, 1997, and under-planting below the canopy of Larix kaemferi was conducted in late April, 1998. This experiment examined the relationships between shade-tolerance and physiological response to different light environment by tree species. To adapt the shade environment, leaves of Kalopanax pictum might be increased the more chlorophyll con- tents and photosynthetic ability than other species. From these results, shade-tolerance of the tree might be ordered Kalopanax pictum, Fraxinus rhynchophylla, and Cornus controversa.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.5
• /
• pp.372-378
• /
• 2015

Growing crops under different soil textures may affect crop growth and yield because of soil N availability, soil N leaching, and plant N uptake. The objective of this study was to evaluate effects of three different soils (sandy loam, loam, and clay loam) on cucumber (Cucumis sativus L.) yield, nitrogen (N) use efficiency (NUE), and water use efficiency (WUE) by subsurface drip fertigation in the greenhouse. Three different soil textures are sandy loam, loam, and clay loam with 3 replications. The dimension of each lysimeter was $1.0m(W){\times}1.5m(L){\times}1.0m(H)$. Cucumber was transplanted on April $8^{th}$ and Aug $16^{th}$ in 2011. The subsurface drip line and tensiometer was installed at 30 and 20 cm soil depth, respectively. An irrigation with $100mg\;NL^{-1}$ concentration was automatically applied when the tensiometer reading was 10 kPa. Volumetric soil water content for cucumber cultivation was the highest in 30 cm soil depth regardless of soil texture and was lowered when soil depth was deeper. The volumetric soil water contents at soil depths of 10, 30, 50, and 70 cm were the highest at clay loam, followed by loam, and sandy loam. The growth of cucumber at the $50^{th}$ day after transplanting was the lowest at sandy loam. Cucumber fruit yields were similar for all three soil textures. The highest amount of water use at sandy loam was observed. Nitrogen and water use efficiencies for cucumber were higher for clay loam, followed by loam and sandy loam, while the amount of N leaching was the greatest under sandy loam, followed by loam, and clay loam. Overall, growing cucumber on either loam or clay loam is better than sandy loam if subsurface drip fertigation is used in the greenhouse.

• Journal of the Korean Wood Science and Technology
• /
• v.51 no.6
• /
• pp.542-554
• /
• 2023

This study is a continuation of our previous work, which focused on the resistance of jabon wood to termites after impregnation with wood vinegar (WV) and animal-based adhesive (kak). This paper presents the physicomechanical properties of fast-growing jabon wood impregnated with kak at two concentrations (8% and 10%) in wood vinegar or water as a solvent with and without 4% borax. The physical properties of the impregnation solution, that is, viscosity, density, pH, and solid content, were evaluated according to SNI 06-4567-1998. Some physical parameters, such as weight percent gain (WPG), density, water uptake, anti-swelling efficiency (ASE), crystallinity, and mechanical properties, i.e., modulus of elasticity (MOE), modulus of rupture (MOR), and compression strength parallel to the grain (CS), of the impregnated wood were determined. Based on these results, wood impregnated using a mixture of kak in WV presented better physical (increased WPG, density, dimensional stability, and crystallinity) and mechanical (increased MOE/MOR and compression strength) properties than wood impregnated with a water solvent or untreated wood. The wood impregnated using WV and water solvent improved the physical and mechanical properties. The density of the wood increased by 44%-58% and 32%-47%, ASE radial-tangential increased by 38%-45%; 15%-28% after 24 h of water immersion, crystallinity increased by 59%-74%; 36%, MOE increased by 46%-57%; 28%-31%, MOR increased by 29%-34%; 14%-27%, and compression strength increased by 40%-76%; 38%-72% values to untreated wood.

• Journal of Environmental Science International
• /
• v.33 no.7
• /
• pp.477-487
• /
• 2024

This study aimed to identify the growth environment of Cudrania tricuspidata by analyzing the site environment, soil characteristics, and vegetation structure of the species habitats and to provide basic data for identifying suitable cultivation sites for mass production. The study was conducted on 17 sites in five cities/counties of Gyeongnam and Jeonnam province. It was found that C. tricuspidata habitats were mainly distributed on gentle slopes in the southeast and southwest, with an average altitude of approximately 290 m. The soil of the C. tricuspidata habitats was sandy loam with a high proportion of sand, averaging 73.9%, 4.6%, and 21.5% sand, silt, and clay, respectively. The soil had a pH value of 5.41 (5.20-5.79), organic matter content of 8.2% (3.6-12.6%), total nitrogen content of 0.36% (0.19-0.54%), available phosphorus content of 3.50 ppm (0.95-7.61 ppm), and cation exchange capacity of 15.9 cmol⁺/kg (10.0-20.7 cmol⁺/kg) on average. The vegetation structure analysis showed that C. tricuspidata appeared in the tree layers of regions A (Jinju) and E (Yeosu), but the importance of C. tricuspidata was found to be high in the subtree and shrub layers in all regions. The ecological niche breadth was widest (0.874) in region B (Hadong) and narrowest (0.480) in region E (Yeosu).