• Ocean and Polar Research
• /
• v.42 no.3
• /
• pp.233-247
• /
• 2020

This study was carried out at 5 sites 11 times over two years to identify the variation of benthic environments and benthic polychaetous community and analyze the benthic healthiness in Dangdong Bay, a small semi-enclosed inner bay of Jinhae Bay. The temperature of bottom water showed the typical temporal fluctuation of a temperate zone and was in the range of 5.94 ~ 23.94℃. The salinity did not change significantly during the study period and was in the range of 32.93 ~ 35.72 psu. The concentration of dissolved oxygen of bottom water fluctuated a great deal and was in the range of 0.31 ~ 10.20 mg/L. The lowest DO value was recorded in July 2015, as 0.31±0.04 mg/L corresponding to the hypoxic water mass. The hypoxic water mass was formed continuously at some sites also in July and August 2016. The mean grain size was in the range of 7.57 ~ 9.81Ø and the average was 8.89±0.20Ø. The surface sediments were mainly composed of fine sediment (mud) above 85%. The mean of TOC was 3.09±0.22% and LOI was 13.30±0.47%, showing very high levels in Korean coastal waters. The concentration of AVS was in the range of 0.33 ~ 1.28 mgS/g-dry. The high values of organic contents and AVS indicated that there had been the serious organic enrichment in Dangdong Bay. The number of species and the density of the benthic polychaetous community in Dangdong Bay were in the range of 2 ~ 38 species and 2 ~ 2,185 ind./㎡ during the study period. The number of species and density were highly sustained in winter and spring, and then decreased gradually with the formation of a hypoxic water mass in summer, and the lowest number of species and density were recorded in autumn. In September and November 2015, the dead zone expanded to almost the whole study area. Dominant polychaetous species were Capitella capitata, Lumbrineris longifolia, Paraprionospio patiens and Sigambra tentaculata, each known as opportunistic species and potential organic pollutant indicator species. In particular, Paraprionospio patiens showed a very high population density of 2,019 ind./㎡ in December 2016. Polychaetous communities at each sampling time were classified into 4 temporal groups according to dominant species in each period by cluster analysis and nMDS. 'Period Group AI' was formed in winter and spring of 2015, dominated by Capitella capitata, 'Period AII' in summer dominated by Lumbrineris longifolia, 'Period B' in autumn with no fauna in the dead zone, and particularly 'Period C' in winter of 2016 dominated by Paraprionospio patiens. As a result of analysis of benthic healthiness, the study area was estimated to be in a Fair~Very Poor condition by AMBI and in a Poor~Very Poor condition by BPI during the study period. Both AMBI and BPI showed that the study area was in a Very Poor condition in September and November 2015, and when the dead zone occurred. In Dongdong Bay, the fact that the formation of a hypoxic water mass occurred in summer and a dead zone in autumn were confirmed. In addition, the dominance of opportunistic and organic pollutant indicator species was also observed clearly. The benthic healthiness indexes such as AMBI and BPI showed that organic enrichment was serious in Dangdong Bay.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.59 no.4
• /
• pp.526-531
• /
• 2014

This study was carried out to compare the growth characteristics and feed values of the whole crop silage rice from paddy field and reclaimed paddy field. The heading dates of tested varieties was August 8 to August 30 in the paddy field, 1~2 days later than the reclaimed paddy field's August 6 to August 29. Plant height was in the range of 105~135 cm in paddy field, and 97~126 cm in reclaimed paddy field, respectively. The plant height of Mokyang was tallest in the paddy field, but Suwon 544 was tallest in the reclaimed paddy field. The number of tiller per plant of Nokyang was largest in the paddy field. Dry matter (DM) yield of whole crop rice ranged from 15.26 to $23.24MT\;ha^{-1}$ in the paddy field and 11.94 to $18.89MT\;ha^{-1}$ in the reclaimed paddy field. The highest DM yield in both fields was attained by Mokwoo. Comparing with the paddy field, the reclaimed paddy field achieved 78~84% in the DM yield. The crude protein content of varieties was 8.5 to 11.6% in the reclaimed tidal land and 6.7~8.7% in the paddy field. Neutral detergent fiber (NDF) of varieties in both fields ranged from 31.2 to 55.5%. Suwon 544 recorded the highest NDF contents in both fields. All varieties did not show any significant difference in acidic detergent fiber (ADF) which had values ranging from 22.3 to 33.2%. Total digestion nutrient (TDN) was more than 60% overall in both fields. Regarding TDN yield, Mokwoo recorded $16.54MT\;ha^{-1}$ in reclaimed tidal land and $12.69MT\;ha^{-1}$ in the paddy field, which showed the highest figure among the varieties. These results suggest the feasibility for cultivation of the whole crop silage rice in reclaimed paddy field, which showed 80% of the yield compared to paddy field, and implied that Mokwoo would show the most excellent yield and feed value.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.19 no.1
• /
• pp.75-80
• /
• 1999

A field experiment was carried out to determine the optimum application level of dicamba herbicide for efficient control of Abutilon avicennae in silage corn field. Five treatments of application levels (0 ; control, $0.75{\ell},\;1.0{\ell},\;1.25{\ell}\;and\;1.5{\ell}$) were arranged at National Livestock Research Institute, RDA, Suwon in 1995 and 1996. The hybrid silage corn was P 3352 and dicamba herbicide was applied at 5~6 leaf stage of corn. The growth of corn was poor in control plot, and the days for tasseling and silking were delayed 2~3 days when compared with the plots of herbicide application. The control efficiency of Abutilon avicennae was excellent as 94.7~98.1% in the plots of dicamba application. A slight injury of herbicide was observed at early stage of corn when applied at $1.0{\ell},\;1.25{\ell}\;and\;1.5{\ell}$ of dicamba per ha. Forage dry matter(DM) yield, length and weight of ear in the plots of dicamba treatments were significantly higher than those of control. The DM yield of control(12,070kg/ha) was only 64.2~66.9% of dicamba treatment plot(18,050~18,795kg/ha). However, there was no yield difference among dicamba application level. The percentage of ear to total DM yield was ranged from 53.4 to 56.8%. The nutritive value(crude protein, ADF, NDF, digestibility and TDN) was very similar among all treatments. From the above results, it is recommended that optimum application level of dicamba herbicide was $0.75{\sim}1.0{\ell}/ha$ for efficient control of Abutilon avicennae and for silage corn production without herbicide injury.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.19 no.1
• /
• pp.57-62
• /
• 1999

A field experiment was carried out to compare the growth characteristics, forage yield and nutritive value of four $sorghum{\times}sudangrass$ hybrids (Sorghum bicolor (L.) Moench) grown under application of animal manure in 1995. The application amount of animal manure were 40MT in cattle manure, 30MT/ha in swine and poultry manure. The four NLCF's recommended hybrids used in this study were Pioneer 988, TE-Haygrazer and NC+ 855 (heading type), and Jumbo(headless type). The plant height was ranged between average 219 and 234cm, regardless of animal manure type and cultivar. NC+ 855 was classified as early maturing cultivar(first heading date was 1st July), and then TE-Haygrazer(4th July), and 988 was latest maturing type(12th July) among the cultivars used. Jumbo was going on vegetative stage in this experiment. The dry matter(DM) yield of four $sorghum{\times}sudangrass$ hybrids were ranged between 11.27 and 13.92MT in cattle manure, 11.46 and 12.77MT in swine manure, and 9.70 and 13.52MT/ha in poultry manure. No significant differences in forage yield were found among the cultivars used, but the DM yield of NC+ 855(13.40 MT/ha) was slightly higher than those of 988(11.31MT), Jumbo(11.26MT) and TE-Haygrazer(11.77MT). The nutritive value of $sorghum{\times}sudangrass$ hybrids was very similar among the cultivars. The crude protein yields were 1,526kg in 988, 1,429kg in Jumbo, 1,502kg in TE-Haygrazer, and 1,659kg in NC+ 855. However, there were no significant differences in protein yield. In conclusion, there were no differences of forage yield and nutritive value among four recommended $sorghum{\times}sudangrass$ hybrids, although maturity was different among heading-type hybrids.

• Journal of Animal Environmental Science
• /
• v.11 no.3
• /
• pp.197-206
• /
• 2005

This study was carried out to investigate the concentration and characteristics of dust originating from windowless broiler building in each season. 12.0m width and 46m tenth with side wall height of 3.0m was investigated and capacity was 12,800 birds at a stock density of 23.2 birds per square meter. Dust concentrations in terms of total suspended particles (TSP), and particulate matter of sizes $10{\mu}m(PM10),\;2.5{\mu}m (PM2.5),\;and\;1{\mu}m(PM1)$ were measured at 30-minute intervals. On the basis of broiler age, the average dust concentration in summer in TSP as follows: 1,229 904.5 558.8 and $1,053{\mu}g/m^3$ on the broilers' first to fourth week of age, respectively. But during winter, the average dust concentration showed an increasing pattern, as follows: 465.4, 1,401, 4,497, 5,097 and $6,873{\mu}g/m^3$ on the broilers' first to fifth week of age, respectively. The maximum dust concentration of $11,132{\mu}g/m^3$ was observed on the fifth week. On a daily basis, the maximum dust concentration during summer was detected in early morning, and the minimum in the afternoon. The aerial dust particle size of $0.05\~0.35{\mu}m$ was the highest in number. But on volume basis, particle size of 16~99 un had the largest percentage in the broiler house. Crude protein of the dust $(42.8\~65.2\%)$, on dry matter basis, was higher than that $(20.5\~24.5\%)$ fed to the broilers. Heavy metal concentration of the dust also had high levels compared with that of the feed.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.48 no.6
• /
• pp.484-489
• /
• 2003

It is well known that root distribution of rice is a crucial factor for nutrient absorbtion and affect by soil fertility management. However, the findings on root distribution are limited due to laborious and tedious work. The characteristics of root distribution were investigated in long-term fertilizer experiment plots that were established in paddy soil, a fine silty family of typic Hal-paqueps (Pyeongtaeg series) in 1967. fertilizer experiment plots of no fertilizer, compost, NPK and NPK+compost plot have been maintained consistently for the past thirty six year and Npk+silicate plot for the past twenty two years. In NPK plot, 150kg N (urea), 100kg -$\textrm{P}_2\textrm{O}_5$ (fused phosphate) and 100kg $\textrm{K}_2\textrm{O}$(potassium chloride) per hectare have been applied. For NPK+silicate plot, 500kg $\textrm{Si}\textrm{O}_2$ (silicate) was applied in addition to fertilizer in NPK plot. For the compost plot, 10,000kg rice straw compost per hectare were applied. Root samples were taken from the positions of hill-center (below hill) and mid-point of four adjacent rice hills at heading stage by cylinder monolith (CM) method. The soil cores were sampled 20cm depth from the soil surface and partitioned four into layers at an interval of 5cm. The soil particles surrounding roots were washed out with tap water, Length and weight of the roots in each soil layer were measured and root length density (RLD), root weight density (RWD), specific root length(SRL) and rooting depth index (RDI) were calculated. Total root length was measured by intersection method. Plant height, tiller and shoot dry weight were the highest in NPK+compost plot. But RLD of hill-center soil cores was the highest in no-fertilizer plots. In the soil cores from mid-point position of four adjacent hills, RLD at 15-20cm soil depth was higher in compost plot than NPK plot. RLD in compost plots showed even distribution compared to those in chemical- fertilizer plots. RWD was the highest in the NPK+compost plot. SRL was the lowest in the NPK+silicate plot. RDI was the highest in the compost plot. Also, in this experiment it was found that the distribution of roots was closely related to the physical properties of the soil as affected by fertilization management.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.26 no.4
• /
• pp.257-266
• /
• 2006

Studies were carried out to evaluate the effect of liquid pig manure on the production of Japanese millet, the chemical characteristics of pasture soil and leaching water. The study was undertaken from June to September 2005. Randomized complete block design was used to allot four treatments: T1 (no fertilizer), T2 (N : 200 kg/ha, p : 150 kg/ha, K : 150 kg/ha), T3 (liquid pig manure containing 1.7% DM 200 kg N/ha) and T4 (liquid pig manure containing 7.0% DM 200 kg N/ha). Leaching water was sampled at 21 August (1st time), 9 September (2nd time) and 26 September (3rd time), 2005, respectively. No significant differences in the dry matter yield of Japanese millet was found among the four treatments, whereas the plant lengths of Japanese millet were higher in the T2, T3 and T4 than in T1 (p<0.05). Nitrogen, P and K uptake of J. millet tended to be influenced by application of chemical fertilizer or 7.0% DM liquid pig manure compared with T1 or 1.8% DM liquid pig manure. The organic matter (OM) content of soil was higher in T2, T3 and T4 than in T1. Na content was highest in T3 among the four treatments. $NO_{3^-}N\;or\;NH_{4^-}N$ content in leaching was not different among the four treatments. $SO_4$ content in leaching water sampled in 1st time was high in T4, but in T3 from 3rd time (p<0.05). Cl, Mg and Na contents were high in leaching water sampled in the 1st time from T4, whereas high in those from T3 in 2nd or 3rd time. Results show that the application of a high DM liquid pig manure is not better for producing Japanese millet and improving the properties of pasture soil than a low DM liquid pig manure. However, the contents of $SO_4$, Cl, Mg and Na in leaching water sampled in 1st time were high in a high DM liquid pig manure.

• Journal of Korean Society of Forest Science
• /
• v.80 no.2
• /
• pp.202-209
• /
• 1991

This study was carried out to examine seed germination, seedling growth, and biomass production of Eucommia ulmoides. The results were summarized as follows ; 1. Cold moist stratification at a refrigerator showed 60.3% of seed germination, which is the most effective among pretreatment methods. 2. In case of 1-0 seedlings, sixty seedlings per $1m^2$ was the most appropriate density, and the growth quality of seedlings differed significantly among densities. 3. Height growth showed continuous growth pattern and the maximum growth was shown during the period 21 June to 20 July, which corresponds 32.7% of total annual growth. 4. As tree age and DBH increased, the production of bark and leaf increased, however, its increment rate remarkably dropped down after ten years. 5. When tree age was ten years, the rate of bark volume showed the maximum value, 12.42%. 6. Dry weight of barks and leaves and bark volume were positively related to the growth of DBH and height. 7. As tree age increased, leaf area decreased, but the number of leaves increased.

• Journal of Korean Society of Forest Science
• /
• v.84 no.4
• /
• pp.479-488
• /
• 1995

Relationships between pine-mushroom(Tricholoma matsutake) yield and important climatic factors for the yield(such as monthly precipitation, relative humidity, temperature, and radiation percentage) were examined to find out limiting factors for pine-mushroom production and to develop a method for overcoming the factors by analyzing the yield and climate data for 17 years collected from 18 main regions of pine-mushroom production. Although there were variations among the production regions, climatic condition of September was the most significant factor for pine-mushroom yield in general, and the degrees of importance of each climatic factors were different among the production regions. Mean minimum temperature of September was positively correlated with pine-mushroom yield($$r^2{\geq_-}0.41$$) at the 1% level, of which were 9 regions such as Youngduck, Uljin, Samchuck, Bongwha arid so on. In these regions, vegetation control was expected to be effective for pine-mushroom production by allowing much sunlight penetration to the pine stand, which may increase soil temperature and keeping the temperature around the fungal colony in soil. Precipitation during September was positively correlated with pine-mushroom yield($$r^2{\geq_-}0.41$$) at Namwon, Moonkyung and Sangju. Thus, irrigation around fungal colony in dry soil during September would be effective for enhancing mushroom yield at the regions. Pine-mushroom yield of 1994 was quite low, similar to that of 1993, due to serious drought. In this period, we could manifest the possibility of enhancing pine-mushroom yield by irrigation for overcoming drought at Moonkyung and Keochang regions.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.12
• /
• pp.1966-1971
• /
• 2013

Pholiota adiposa is an edible as well as medicinal mushroom cultured in China and Japan with anti-tumor, anti-microbial, anti-hypertensive, and anti-hyperlipidemic activities. This study was carried out to investigate the quality characteristics of cookies added with Pholiota adiposa powder. Chemical composition of Pholiota adiposa powder was as follows: 3.8% moisture, 6.9% ash, 1% crude lipids, 3% protein, 53.3% carbohydrates, and 31.9% crude dietary fiber. To analyze quality characteristics during the manufacture of cookies, pH, texture, color, antioxidant activity, total polyphenol content, and sensory evaluation were determined. As the content of Pholiota adiposa powder increased, the pH of cookies decreased from 6.7 to 6.02. Hardness of cookies decreased with increasing Pholiota adiposa powder content, and cookies added with 5% powder were softer than the control. Regarding surface color, L-value decreased with increasing powder content compared to that of the control, whereas in surface color among various powder levels was not significantly different. As the content of Pholiota adiposa powder increased, both antioxidant activity and total polyphenol content increased. In the sensory evaluation, cookies added with 3% Pholiota adiposa powder showed remarkably higher values compared to control and other amples in all aspects.