• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.403-411
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• 2013

This study was performed to examine whether it is possible to promote rice growth by midsummer drainage without damage of golden apple snails in environment-friendly rice farming. The effect of drainage on the life of snails was examined in a greenhouse before the filed experiment. Spats (young shells) of snails survived 100% at 12 days after drainage, and 93.3% at 15 days after drainage. The midsized shells survived 100% at 9 days, 93.3% at 12 days, and 86.6% at 15 days after drainage. In the field experiment, 10-days drainage did not affect the snail population and there was no significant difference of weeding activity of snails between the midsummer drainage treatment and the continuous submerged treatment. The plant height and the effective tiller number in the midsummer drainage treatment were higher than those of the continuous submerged treatment. The rice yield of midsummer drainage plot was 511kg/10a, which was 66kg/10a higher than 445kg/10a of continuous submerged plot. In conclusion, midsummer drainage could increase rice growth and yield without damage of golden apple snails in the environment-friendly rice farming.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.687-692
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• 1997

The barley grown in pot-soil was treated with the NaCl solution of -20 bar in osmotic potential for 10 days, varying the time of treatment: from 20th day before heading; from 10th day before heading and the time of heading. The greatest injury was observed in the case of salt stress at heading or at 10th day before heading: Culm length decreased by 87% : the number of spikes per plant by 82% ; the number of grain per spike by 92% : 1, 000-grain weight by 94% ; yield per pot by 75%. The results also greatly varied depending upon the cultivars and the time of salt stress. Salt stress at the time of heading or at 10th day before heading remarkably decreased yield and yield components. And in terms of grain yield the salt resistance was high in the order of Baegdong, Albori, Hyangmaeg, Olbori and Durubori.

• Journal of Applied Biological Chemistry
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• v.65 no.1
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• pp.1-6
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• 2022

Urea is one of the most common nitrogen fertilizer, but nitrogen use efficiency by crop is low because of rapid hydrolysis of urea and loss of nitrogen in environments. Therefore, it is important to control the nitrogen release from nitrogen fertilizers. In this study, pyroligneous acid (PA) was used as a mean to inhibit urease in soil and prevent excessive nitrogen release from urea. Active ingredient in PA (AI) inhibited ammonification of urea in soil by reducing extracted ammonium nitrogen at 79.7% compared to the soil without PA. In order to evaluate the effect of PA on fertilization efficiency of urea, Chinese cabbage (Brassica campestris var. Pekinensis) was cultivated in soil treated with urea and PA both in pot and field. For PA treatment, half amount of urea was used compared to the amount of urea conventionally applied to Chinese cabbage. The PA treatment with half amount of urea resulted in similar Chinese cabbage biomass to the conventional urea application. Nitrogen concentration in Chinese cabbage was less in PA treatment indicating that Chinse cabbage effectively used nitrogen. Consequently, fertilization of urea with PA will reduce amount of fertilizer and frequency of application.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.37-37
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• 2020

홍띠(Imperata cylindrica 'Rubra') 식물자원의 생장점 부위를 기내 배양하여 기내 식물체 재분화와 재분화식물체의 유전적 안정성을 검토하였다. 기내배양은 26±2 ℃, 25 μmol/m²/s, 14h/10h (day/night) 광조건 하의 배양실에서, MS (Murashige and Skoog, 1962) 기본배지에 생장조절물질을 첨가하여 조직절편체로부터 식물체를 유도하였다. 캘러스는 MS기본배지에 0.1 mg/L의 2,4-D와 2 mg/L의 BA를 혼용처리하여 생장점 부위로부터 유도하였다. 캘러스 증식은 MS기본배지에 0.1 mg/L의 2,4-D를 첨가한 배지에서, 이들 캘러스로부터 신초 재분화는 0.01 mg/L의 NAA 및 2 mg/L의 BA를 첨가한 배지에서 유도하였다. 다경줄기 형성(multiple shooting) 후 MS배지에서 4주 동안 배양한 재분화식물체는 멸균한 상토(버미큘라이트)를 포함한 배양병에서 7주간 배양한 다음 점차적으로 배양병 뚜껑을 개방(1/10 정도 1차 개방 1주일, 3/10 정도 2차 개방 2주일)하여 직경 6 cm의 컵포트에 이식하여 활착시켰다. 재분화식물체는 붉은색이 사라지고 녹색을 나타내었으며, 일부개체에서만 잎의 일부분만 붉은색을 나타냈다. 이는 생장점 주변조직에서 유래한 재분화체가 우세함으로써 생장점보다는 생장점 주변의 조직을 구성하는 녹색층에서 주로 식물체가 재생되는 것으로 판단된다. 이에 따라 홍띠 대조구식물체 8개체, 활착한 녹색 재분화 식물체 20개체(실내 재배중인 순화체 10개체, 2020년 6개월간 포장에서 재배중인 순화체 10개체)를 대상으로 ISSR분석을 실시하여 재분화식물체의 유전적 안정성을 검토하였다. 향후 조직학적 측면에서 신초재분화의 기원에 대한 검토가 필요하다고 사료된다.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.8-15
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• 1992

An experiment was conducted to find out effect of soil water condition on shoot and root growth and P, K uptake by soybean plants. Soybean plants were grown under different soil water table levels, 20cm, 40cm and 60cm below the soil surface using minirhizotron with 20cm in diameter, and well irrigated and water stressed conditions using 1/2000a Waganer pots. Three soybean plants, Paldal culfivar, were grown and sampled at the early growing period, 37 days after planting, and at the harvesing period, 115 days after planting. Shoot and root growth were restricted by water stresed condition and by excessive soil water condition with the 20cm water table. Little difference in shoot and root growth were found between well irrigated condition and 40cm or 60cm water table conditions. The P and K contents in shoot under water stressed condition were higher than well irrigated condition at the early growing period but reversed at later harvesting period. The dry weight and length of roots were more severely restricted by water stress than those of shoots. Root morphological difference was found by anatomical observation. Normal cortex was developed under the well irrigated condition, while abnormal cortex with aerenchyma formed by lysis under excessive water conditions of 20 or 40cm water talbes. Aerenchyma was formed at outer skirt of pericycle. Role of formation of aerenchyma of soybean roots might be an adaptation to excessive soil water condition and possibly related to survival of soybean roots growing under near flooding condition on dikes of paddy lands.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.246-261
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• 2023

We investigated critical temperature for early marginal transplanting (CT-EMT) of the contemporary japonica rice varieties in Korea through the field, pot seedling tray, and the phytotron experiments during 2020 to 2023. The lowest mean temperature for 10 days from transplanting (MT-10DFT) that resulted in earlier heading date was 12.4℃ and the highest MT-10DFT that did not show the earlier heading date was 12.0℃ in the field study when the MT-10DFT varied by changing transplanting date. The lowest MT-10DFT that induced the increased biomass but not the earlier heading date was 11.6℃ and the highest MT-10DFT that showed neither the increased biomass nor the earlier heading date was 11.4℃. Compared to the 10-day later transplanting, the dates of the first root development, initiation of the chlorophyll recovery, and the first tiller development were earlier when the MT-10DFT was 9.1℃ or higher, 10.5℃ or higher, and 11.6℃ or higher, respectively, in the pot seedling tray and field experiments. The earliness of the first tiller development was a practical index for the estimation of CT-EMT during the early growth stage of rice. The response of transplanted rice to temperature treatments with the diurnal change of 10℃ in the phytotron study was similar to that shown in the field study. The data shown for constant temperature without a diurnal change revealed that the extent of positive effects of high temperature at day-time was greater than the extent of negative effects of low temperature at night-time on the early growth of transplanted rice. It was concluded that the critical MT-10DFT for early marginal transplanting of japonica rice in the temperate environments was between 11.4 to 11.6℃ based on the plant growth and between 12.0 to 12.4℃ based on the plant development.

• Korean Journal of Plant Resources
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• v.16 no.2
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• pp.130-133
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• 2003

This study was conducted to investigate the effect of activated charcoal on growth and yield of taro in different degree of activated charcoal concentration. The results obtained are summarized as follows. Stem length was shown the longest in activated charcoal of 10-20％, but shorter in control. Also stem diameter was shown the thickest in activated charcoal of 10-20%, but thinner in control. Length of main root and thickness of main root were good in activated charcoal of 10-20%. Quality and yield of Bupleurum fatcatum was the highest in activated charcoal of 10-20%. Therefore, optimum consistency of activated charcoal was 10-20%.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.112-121
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• 2004

A study was performed to examine the effects of UV-disinfected reclaimed water on microorganism concentration during rice culture. Four treatments were used and each one was triplicated to evaluate the changes of microorganism concentrations: stream water irrigation (STR), biofilter effluent irrigation (BE), UV-disinfected water irrigation with dose of 6 mW ${\cdot}$ s $cm{-2}$ (UV-6), and UV-disinfected water irrigation with dose of 16 mW ${\cdot}$ s $cm{-2}$ (UV-16). The indicator microorganisms of interest were total coliform (TC), fecal coliform (FC), and E. coli. The biofilter effluent from 16-unit apartment sewage treatment plant was used as reclaimed water and flowthrough type UV-disinfection system was used. Concentrations of indicator microorganisms in the treatment plots ranged from $10^2$ to $10^5$ MPN/100 mL during 24 hours after irrigation in May and June, where initial irrigation water for transplanting reparation was biofilter-effluent without UV-disinfection. It implies that initial irrigation using only non-disinfected reclaimed water for puddling in paddy field can be health-concerned because of more chance of farmer's physical contact with elevated concentration of microorganisms. The concentrations of microorganisms varied widely with rainfall, and treatments using UV-disinfected water irrigation showed significantly lower concentrations than others and their levels were within the range of paddy rice field with normal surface water irrigation. The mean concentrations of STR and BE during growing season were in the range of 4 ${\times}\;10^3$ MPN/100 mL for TC, and 2${\times}\;10^3$ MPN/100 mL for FC and E, Coli, While mean concentrations of UV-S and UV-lS were less than 1${\times}\;10^3$ MPN/100 mL for all the indicator microorganisms. Overall, UV-disinfection was thought to be feasible and practical alternative for agricultural reuse of secondary level effluent in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.232-238
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• 1999

Effects of animal manure application on the yield of crops were studied. Red pepper (1995) and Chinese cabbage (1996) were planted in pot with chicken, cow and pig manure application at $1.6mg\;ha^{-1}$, $3.2mg\;ha^{-1}$. Silage corn was grown in pot at 100%, 75%, 50% and 0%of recommended chemical fertilization rate among previously manure applied soils to predict the reduction of fertilizer. Results were as follows: Chemical properties of manure applied soils for two years were increased as pH 6.1~7.1, OM $17.1{\sim}23.7g\;kg^{-1}$, $P_2O_5$ $370{\sim}1.058mg\;kg^{-1}$, while those of chemical fertilizer applied soils were pH 5.8. OM $16.9g\;kg^{-1}$, $P_2O_5$ $249mg\;kg^{-1}$. Exchangeable cation and $P_2O_5$ content were increased in chicken manure applied soils than those in manure applied soils. Red pepper yield in manure applied pots was 121~192% compared to that in only chemical fertilizer applied pot. Effects of manure application was in the order of pig, chicken and cow manure. Chinese cabbage yield in manure applied pots was 55%~111% compared to that in chemical fertilizer applied pot. Effects of manure application were higher in red pepper than in Chinese cabbage. Fresh corn yield showed no significance between reducing 0% and 25% of recommend fertilization rate in previously manure applied plots, except in previously cow manure applied plots at $1.6mg\;ha^{-1}$. Fresh corn yield showed a positive correlation ($r=0.75^{**}$) with organic matter content and showed a positive correlation ($r=0.85^{**}$) with total nitrogen in untreated plot among previously manure applied soils.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.77-82
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• 1999

Three floating islands have been constructed for water quality improvement for a polluted irrigation reservoir. Each floating island consists of 10 segments. Each segment hay an area of $16m^2$(4×4m) and is made of wood frames and floats(polystyrene foam). We planted three species of aquatic macrophytes(Typha angustifolia, Zizania latifolia, and Phragmites australis) in floating island on June, 1998. They grew very well without death. We would like to evaluate Phragmites australis is the most suitable aquatic macrophyte that could be planted in a floating island because it maintained the best balance of its root and shoot among them. During their grown period, net primary productivity of Typha angustifolia was $962gDM/m^2$, Zizania latifolia was $1,115gDM/m^2$, and Phragmites australis was $523gDM/m^2$. From these data, it would be estimated to 5.0Kg uptake of nitrogen by aquatic macrophytes and phosphorus 0.8Kg in 3 floating islands. The floating islands worked well as a habitat of fish and prawns. Many kinds of insect lived on the floating islands. The floating island has not only the function of water quality treatment but also several advantages: improvement of landscape and species diversity; low cost of maintenance; low technology; unnecessary of energy; less susceptible to variations in pollutant loading. It could be evaluated a good measure of water quality improvement for an irrigation reservoir. However, it should be intensively studied to develop more light, strong, durable and low-priced frames for efficient floating islands.