• Korean Journal of Environmental Agriculture
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• v.18 no.4
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• pp.344-348
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• 1999

To investigate hormetic effect of low dose ${\gamma}$-ray on the uptake of mineral nutrients in Chinese cabbage (Brassica campestris var. Hekjinju var. Surim and) and radish (Raphanus sativas var. Chung-un), seeds of these plants were irradiated with the dose of 1 to 10 Gy. Germination rate and dry weight were examined at pot experiment in greenhouse. Samples for analysis of mineral nutrient were harvested at 17 days and at 59 days after seedling and were analyzed by ICP. Brassica campestris varieties showed higher germination rate and dry weight production with increasing ${\gamma}$ ray dose. Dry weight of Hekjinju Surim and were 143% and 138% at 10Gy dose. respectively. There was no tendency in germination rate and dry weight production for Raphanus sativas var. Chung-un with ${\gamma}$-ray irradiation. The pattern of mineral nutrient content of these plants showed ${\gamma}$ or ${\delta}$ type of dose-reaction curve with no siginificant. This investigation suggests that the more results can be required to understand the hormetic effect of low dose ${\gamma}$ ray on the uptake of mineral nutrient for these plants.

• Journal of fish pathology
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• v.14 no.1
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• pp.11-15
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• 2001

For the production of healthy shrimp(Penaeus chinensis, Penaeus japonicus) seedlings free from the white spot baculovirus(WSBV), we tried to disinfect shrimp eggs with iodine. A relative hatching rate of over 50% has resulted from the treatments of fertilized eggs of fresh shrimps(P. chinensis) with an effective povidon-iodine concentration of 20-200 ppm for 30 seconds and 60 seconds, respectively. The 60 sec treatment group with a 20 ppm effective povidon-iodine concentration showed nearly a 50% relative hatching rate. The over 50 ppm treatment group, however, did not result in hatching show a relative hatching rate. These hatching rates were similar to those in the fertilized eggs of kuruma prawns treated with povidon-iodine solutions. In case of washing fertilized eggs with UV-irradiated seawater 33.3% relative hatching rate in fresh shrimps was much lower than 55.2% in kuruma shrimps. Treatment fertilized eggs of 2 species of shrimp with 200 ppm iodine for 30 sec did not affect the survival rate of the larvae until the early stage of the post larvae even though the hatching rates were low. In order to produce healthy shrimp seedlings non-infected by WSBV, the shrimp eggs should be washed with UV-irradated seawater and sterilized with a low povidon-iodine concentration for a short time.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.45-50
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• 2005

Virus-free stocks was produced by the combination of the heat treatment of virus infected plant and shoot-tip grafting (STS). To produce virus-free stocks, the plants infected with citrus viruses were used for virus-free stock production using the modified method of STG in thermotherapy at $40^{\circ}C$ for 16 hours in the light, and at $30^{\circ}C$ for 8 hours of darkness for 4 weeks. Trifoliate orange (P. trifoliata) were used as rootstock seedling for STG. Percentages of virus-free stocks against citrus tristeza virus (CTV), satsuma dwarf virus (SDV) and citrus tatter leaf virus (CTLV) were $75.7\%,\;100.0,\%\;82.6\%$ respectively. Shoot tip size for successful STG were as small as possible. Less than $0.3\;\cal{mm}$ of shoot tips gave the hight efficiency of virus free plants but survival rates were low. And, survival rate after shoot-tip culture was analyzed and the rates were dependant on the cultivars; Yuzu cultivar showed the hight survival rate ($74.6\%$) and early satsuma mandarin (Iwasagi) was $13.3\%$ as the lowest cultivar. But citrus trees were not succeed to grown, turned brown, and died.

• Korean Journal of Environmental Agriculture
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• v.19 no.5
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• pp.401-418
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• 2000

1. Production of the artificial zeolite from coal ash Coal fly ash is mainly composed of several oxides including $SiO_2$ and $Al_2O_3$ derived from inorganic compounds remained after burning. As minor components, $Fe_2O_3$ and oxides of Mg, Ca, P, Ti (trace) are also contained in the ash. These components are presented as glass form resulting from fusion in the process of the combustion of coal. In other word, coal ash may refer to a kind of aluminosilicate glass that is known to easily change to zeolite-like materials by hydrothermal reaction. Lots of hot seawater is disposing near thermal power plants after cooling turbine generator periodically. Using seawater in the hydrothermal reaction caused to produce low price artificial zeolite by reduction of sodium hydroxide consumption, heating energy and water cost. As coal ash were reacted hydrothermally, peaks of quartz and mullite in the ash were weakened and disappeared, and new Na-Pl peaks were appeared strengthily. Si-O-Si bonding of the bituminous coal ash was changed to Si-O-Al (and $Fe^{3+}$) bonding by the reaction. Therefore the produced Na-Pl type zeolite had high CEC of 276.7 $cmol^+{\cdot}kg^{-1}$ and well developed molecular sieve structure with low concentration of heavy metals. 2. Utilization of the artificial zeolite in agro-environment The artificial zeolite(1g) could remove 123.5 mg of zinc, 164.7 mg copper, 184.4 mg cadmium and 350.6 mg lead in the synthetic wastewater. The removability is higher 2.8 times in zinc, 3.3 times in copper, 4.7 times in cadmium and 4.8 times in lead than natural zeolite and charcoal powder. When the heavy metals were treated at the ratio of 150 $kg{\cdot}ha^{-1}$ to the rice plant, various growth inhibition were observed; brownish discoloration and death of leaf sheath, growth inhibition in culm length, number of panicles and grains, grain ripening and rice yield. But these growth inhibition was greatly alleviated by the application of artificial zeolite, therefore, rice yield increased $1.1{\sim}3.2$ times according to the metal kind. In addition, the concentration of heavy metals in the brown rice also lowered by $27{\sim}75%$. Artificial Granular Zeolites (AGZ) was developed for the purification of wastewater. Canon exchange capacity was 126.8 $cmol^+{\cdot}kg^{-1}$. AGZ had Na-Pl peaks mainly with some minor $C_3S$ peaks in X-ray diffractogram. In addition, AGZs had various pore structure that may be adhere the suspended solid and offer microbiological niche to decompose organic pollutants. AGZ could remove ammonium, orthophosphate and heavy metals simultaneously. Mixing ratio of artificial zeolite in AGZs was related positively with removal efficiency of $NH_4\;^+$ and negatively with that of $PO_4\;^{3-}$. Root growth of rice seedling was inhibited severely in the mine wastewater because of strong acidity and high concentration of heavy metals. As AGZ(1 kg) stayed in the wastewater(100L) for 4days, water quality turned into safely for agricultural usage and rice seedlings grew normally.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.617-624
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• 2002

Annual legume is being used as an important source of protein for farm animals and an ingredient for nitrogen fertilizers. There are, however, difficulties in selecting appropriate cultivar and forage management technique. The objective of this study is to select the best performing cultivars and evaluate a forage value on annual legume at two locations (Suwon and Sunghwan) for 1 year (1999${\sim}$2000). All cultivars shown a seedling vigor and lodging resistance of 8 rating or higher. Crimson and rose clover showed that they are appropriate for overwintering, but ;Laser; (35.9%) and 'Nitro'(9.1%) of persian clover variety did not overwinter well from 1999 to 2000. Flower stage was observed 4th of May for 'Tibbee', 6th of May for 'Contea' crimson clover, and 29th of April for 'Bolta balansa' rose clover. DM yield of a crimson clover 'Contea' (4,218kg/ha) was the highest among the legume forage. A crimson clover 'Tibbee' and rose clover 'Bolta balansa' also had a high production yield (3,874 and 3,828kg/ha). Calculations of relative feed value (RFV) based on the acid and neutral detergent fiber (ADF and NDF) of annual legume were over 125, which means that quality was high. According to the results of this study, crimson and rose clovers are recommended due to their high winter survival rate and high DM yield. Persian clover is not recommended because of a low overwintering rate at the Central region in Korea.

• Journal of Forest and Environmental Science
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• v.32 no.4
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• pp.329-343
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• 2016

The present study was conducted on ridge tops of moist temperate Oak forests in Garhwal Himalaya to assess the plant diversity, regeneration, biomass production and carbon assimilation in different Oak forests. For this purpose, three Oak forest types viz., (a) Quercus leucotrichophora or Banj Oak (FT1; between 1,428-2,578 m asl), (b) Quercus floribunda or Moru Oak (FT2; between 2,430-2,697 m asl) and (c) Quercus semecarpifolia or Kharsu Oak (FT3; between 2,418-3,540 m asl) were selected on different ridge tops in Bhagirathi catchment area of Garhwal Himalaya. A total of 91 plant species including 23 trees (8 gymnosperms and 15 angiosperms), 21 shrubs and 47 herbs species belonging to 46 families were recorded from all the ridge top Oak forests. The highest mean tree density ($607{\pm}33.60trees\;ha^{-1}$) was observed in Q. floribunda forest with lower mean total basal cover (TBC) value ($48.02{\pm}3.67m^2ha^{-1}$), whereas highest TBC value ($80.16{\pm}3.30m^2ha^{-1}$) was recorded for Q. semecarpifolia forest, with lowest mean stem density ($594{\pm}23.43stems\;ha^{-1}$). The total biomass density (TBD) across three Oak forests ranged between $497.32{\pm}83.70$ (FT1) and $663.16{\pm}93.85t\;ha^{-1}$ (FT3), while the total carbon density (TCD) values ranged between $228.75{\pm}22.27$ (FT1) and $304.31{\pm}18.12t\;ha^{-1}$ (FT3). Most of the tree species were found with good regeneration (GR) status (average 45%) in all the forest types whereas, few species were found not regenerating (NR) (average 17%) however, few new recruitments were also recorded. ANOVA (Post-Hoc Tukey's test at 5% significance level) indicated significant forest-wise differences in TBC, TBD and TCD (in tree layer); family and evenness (in shrub layer only) values, while insignificant differences were noticed in density values of tree, seedling and herb layer.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.325-325
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• 2017

In the 20th century, the average temperature of Korea has risen by $1.5^{\circ}C$, whereas it has risen by $0.6^{\circ}C$ globally. Few studies have investigated the effect of seeding date in hilly pastures on their growth characteristics and productivity. The purpose of this study was to elucidate the effect of seeding dates at a hilly pasture establishment on its growth characteristics and productivity caused by increasing temperatures in Korea. The experiments were conducted from 2014 to 2016 at Pyeongchang, South Korea, at an altitude 600-700 m above sea level. The composition of grass mixture was tall fescue, orchard grass, perennial ryegrass, Kentucky bluegrass, timothy, and white clover. Treatments comprised four seeding dates (August 13 and 27, and September 10 and 24). The establishment rate was lowest on September 24, resulting in only 20% establishment over the winter, and the proportion of weeds was highest on September 24 (58%). Early seedling growth before overwintering is a critical approach to ensure successful establishment of grassland. The main components were orchard grass and tall fescue on the early seeding date (August 13), and Kentucky bluegrass on the late seeding date (September 24). Late seeding increased the proportion of bare lands invaded by weed species, especially during second and third cutting periods. Early seeding date resulted in a progressive increase in biomass. Total annual production was significantly affected by the seeding date; lowest dry matter production was on September 24 ($2,441kg\;ha^{-1}$), whereas maximum dry matter yield was on August 27 ($6,608kg\;ha^{-1}$). The results of the study indicate that growth condition and productivity could be increased by early seeding, and seeding of grass in the Pyeongchang area should be completed before August 27. However, further studies are needed to determine the ideal seeding date at the hilly pasture establishment in Pyeongchang.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.195-200
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• 1982

Fused phosphate and slag have used as a sources of phosphate and silicate fertilizers. In order to find out effects of these fertilizers on the growth of young rice plants in nursery, relationships between dry matter production and nutrient uptake at different fertilizer application rates were investigated for two rice varieties, Milyang 23 (a Indica-Japonica hybrid) and Akibare (a Japonica). The results were summarized as followers; 1. The maximum dry matter production was obtained at 75-150 kg/10a of fused phospate and 100-200 kg/10a of slag, respectively, however, a some variations between varieties were recognized. 2. The top/root ratio of varieties around 1.0 was proper for healty see dings and this ratio was reached at application of 75 kg/10a of fused phosphate and 200 kg/10a of slag. 3. The efficiency of applied silicate of rice seedlings was higher in fused phosphate than in slag. 4. The growth of seedling was severely retarded when soil pH was increased above 7 by the application of more than 225 kg/10a of fused phospahte and 400 kg/10a of slag.

• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.219-230
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• 2020

This study was conducted to determine the optimum medium and humidification period for the strawberry (Fragaria × ananassa Duch. cv. Maehyang) cutting seedling production. The cuttings were planted in coir (CO), rockwool (RW), phenolic foam (PF), and organic foam medium (OFM) with fogging treatment in 0, 3, 6, 9, or 12 days on February, 2019. And, as the field verification examination research, cuttings were planted in CO, RW, PF, and OFM, with misting treatment in 0, 6, 9, 12, or 15 days on June, 2019. In fogging treatments, rooting and survival rates of seedlings tended to increase with longer fogging periods, and rooting and survival rates were showed significantly higher in CO medium with more than 9 days of fogging periods. In misting treatments, rooting rate was significantly higher in CO and RW medium with more than 9 days of misting periods, and survival rate was significantly higher with more than 12 days of misting periods. There was no significantly difference by growth medium and humidification period in shoot and root growth. Therefore, when considering the rooting and survival rate the CO medium with 9 days of humidification period could be beneficial for the production of the 'Maehyang' strawberry cutting seedlings.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.139-146
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• 2004

Kenaf (Hibiscus cannabinus L.), an annual plant of the family Malvaceae, is considered to be the most promising for alternative plants with potential use as a non-wood fiber source. The objectives of this study were to select the optimum seeding date and adaptable cultivar among newly introduced kenaf cultivars (Everglades-41, Tainung-2 and Chingpi-3) in Jeju island, and to clarify the photosynthetic characteristics of those cultivars. Among the three cultivars, the fresh shoot weight per unit area of Chingpi-3 at harvest season showed highest through all seeding dates, that of while Everglades-41 was the lowest. The difference of shoot yield at harvest mainly due to seedling stand rate and plant number per unit area among the cultivars. The Chingpi-3 showed the highest shoot fresh weight in the seeding date of May 11 and decreased trend in the late seeding dates. Net photosynthesis rate was higher on Everglades-41 with entire type leaf than other two cultivars with palmate type leaf. The activity of ribulose-1,5-bisphosphate carboxylase/foxygenase (rubisco) estimated from the A-Ci curve showed highest in Chingpi-3 among three cultivars. These results suggest that Chingpi-3 might be adaptable cultivar with seeding date of around May 10 for kenaf production in Jeiu island.