• Horticultural Science & Technology
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• v.30 no.1
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• pp.34-41
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• 2012

The study was conducted in a glasshouse to examine the possibility of producing paprika plug seedlings in a newly developed inert phenolic foam growing medium. Plug seedlings of 'Fascinato' paprika were grown in five media, Grodan rockwool (Grodan Co. Ltd., Denmark), UR rockwool (UR Co. Ltd., Korea), phenolic foam LC (Smithers Oasis Korea Co. Ltd., Korea), phenolic foam RC, and phenolic foam 3813-4 all in a pellet type. Seeds were germinated in a growth chamber ($25^{\circ}C$, 90% RH, dark) for 4-5 days and then seedlings were grown in a glasshouse with nutrient solution supplied by an overhead irrigation system. Seedling growths were measured 20 days after sowing. The medium pH was the highest in the Grodan rockwool, and medium EC was the highest in phenolic foam 3813-4, although no nutritional excess disorders were observed. Germination rates of paprika were higher than 90% in all the media. Plant height, stem diameter, T/R ratio, leaf area, and chlorophyll showed a similar to those in the rockwool medium. Number of leaves, length of the longest root and dry weights of shoot were not significantly different among treatments. Overall, phenolic foam LC and RC produced seedlings with a similar growth as the rockwool medium. The results obtained suggest that rockwool can be replaced with a new material such as phenolic foam in the commercial scale production of plug seedlings of 'Fascinato' paprika.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.10
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• pp.1364-1373
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• 2012

Four crossbred (75% Holstein Friesian) lactating dairy cows, with an average live weight of $418{\pm}5$ kg and $36{\pm}10$ d in milk were randomly assigned according to a $2{\times}2$ factorial arrangement in a $4{\times}4$ Latin square design to evaluate the effects of cassava hay (CH) and rice bran oil (RBO) on feed intake, nutrient digestibility, ruminal fermentation, milk yield, and milk composition. Factor A was non-supplementation or supplementation with CH in the concentrate. Factor B was supplementation with RBO at 0% or 4% in the concentrate mixture. The four dietary treatments were (T1) control (Concentrate with non-CH plus 0% RBO; C), (T2) Concentrate with CH plus 0% RBO (CH), (T3) Concentrate with non-CH plus 4% RBO (RBO), and (T4) Concentrate with CH plus 4% RBO (CHRBO). The cows were offered concentrate, at a ratio of concentrate to milk production of 1:2, and urea-lime treated rice straw was fed ad libitum. Urea-lime treated rice straw involved 2.5 g urea and 2.5 g $Ca(OH)_2$ (purchased as hydrated lime) in 100 ml water, the relevant volume of solution was sprayed onto a 100 g air-dry (91% DM) straw, and then covering the stack with a plastic sheet for a minimum of 10 d before feeding directly to animals. The CH based concentrate resulted in significantly higher roughage intake and total DM intake expressed as a percentage of BW (p<0.05). Ruminal pH, $NH_3$-N, BUN and total VFA did not differ among treatments, while RBO supplementation increased propionate, but decreased acetate concentration (p<0.05). Furthermore, the population of total ruminal bacteria was significantly lower on the RBO diet (p<0.05). In contrast, the total ruminal bacteria and cellulolytic bacteria on the CH diet were higher than on the other treatments. Supplementation with CH increased (p<0.05) F. succinogens and R. flavefaciens populations, whereas the populations of B. fibrisolvens and M. elsdenii were increased on the RBO diet. In addition, supplementation with CH and RBO had no effect on milk production and composition in dairy cows, while fatty acid composition of milk was influenced by RBO supplementation, and resulted in significantly lower (p<0.05) concentrations of both short-chain and medium-chain FA, and increased (p<0.05) the proportion of long-chain FA in milk fat, as well as significantly increased cis-9, trans-11 CLA and total CLA. In conclusion, RBO or CH exhibited specific effects on DMI, rumen fermentation, microbial population, milk yield and composition in lactating dairy cows, which were not interactions between CH and RBO in the diets. Feeding lactating dairy cows with RBO could improve fatty acid in milk fat by increasing cis-9, trans-11 CLA.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.510-515
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• 2014

Duckweed (Lemna perpusilla J. Torrey) is a typical floating aquatic macrophyte that has been used for evaluating phytotoxicity of toxicants. In this study, we evaluated the responses of duckweed to PAHs and ammonium as toxicants that frequently affect the growth of plants in polluted industrial and agricultural areas. As the duckweed is growing in aquatic environment, the PAHs and ammonium were incorporated into nutrient solution and the fronds were cultured hydroponically. Frond growth was responded differentially to the concentration and type of PAHs. The severe inhibition of frond growth was observed in the treatment of fluorene. Fluoranthene and pyrene, however, showed weak inhibition of frond growth. The latter PAHs that showed weak inhibition did not reduced frond number at the low concentration of 30 ppm. Pigment contents were also responded differentially. Phenanthrene and fluorene reduced chlorophyll content more strongly than fluoranthene and pyrene. Carotenoids, well-known antioxidative compound, was relatively increased at the low concentration of PAHs up to 30 ppm by the treatment of fluoranthene and pyrene, suggesting an increased antioxidative activity in fronds. Ammonium treatment showed higher inhibitory effect even low concentration of 3 mM.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.81-88
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• 2000

Composting of N-rich wastes such as food waste and wastewater sludges can be associated loss of with substantial gaseous N, which means loss of an essential plant nutrient but may also lead to environmental pollution. We investigated the behavior of nitrogenous materials during the first high-rate phase in composting of food waste. Air dried food waste was mixed with shredded waste paper or wood chip and reacted in a bench scale composting reactor. Samples were analyzed for pH, ammonia, oxidized nitrogen and organic nitrogen. The volatilized ammonia nitrogen was also analyzed using sulfuric acid as an absorbent solution. Initial progress of composting reaction greatly influenced the ammonification of organic nitrogen. A well-balanced composting reaction with an addition of active compost as an inoculum resulted in the promoted mineralization of organic nitrogen and volatilization of ammonia. The prolongation of initial low pH period delayed the production of ammonia. It was also found that nitrogen loss was highly dependent on the air flow supplied. With an increase in input air flow, the loss of nitrogen as an ammonia also increased, resulted in substantial reduction of ammonia content in compost. The conversion ratio of initial nitrogen into ammonia was in the range of 28 to 38% and about 77~94% of the ammonia produced was escaped as a gas. Material balance on the nitrogenous materials was demonstrated to provide an information of importance on the behavior of nitrogen in composting reaction.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.860-868
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• 2015

The effect of Si supplied during plant cultivation on tolerance to high temperature stress in Euphorbia pulcherrima Willd. 'Ichiban' was investigated. Rooted cuttings were transplanted into 10-cm pots and a complete nutrient solution, containing 0 or $50mg{\cdot}L^{-1}$ Si as either $K_2SiO_3$, $Na_2SiO_3$, or $CaSiO_3$, was supplied through subirrigation or weekly foliar applications. After two months of cultivation, plants were placed in an environment-controlled chamber and subjected to $35{\pm}1^{\circ}C$ (high temperature) conditions for 18 days. Enhanced specific activities of enzymatic antioxidants (APX) and suppressed specific activities of non-enzymatic antioxidants (ELP) were observed in the high temperature-stressed plants with Si application. The Fv/Fm (maximum quantum yield of photosystem II), photosynthetic rate, and Si contents in the shoot increased in the treatments of $K_2SiO_3$ and $Na_2SiO_3$ supplied through subirrigation. The Si-treated plants had more tolerance of high temperature stress than the control plants. Of the Si sources and application methods tested, $K_2SiO_3$ and $Na_2SiO_3$ supplied through subirrigation were found to be the most effective in enhancing tolerance to high temperature stress.

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.501-505
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• 1996

Azimsulfuron [1H-pyrazole-5-sulfonamide,N-(((4,6-dimethoxy-pyridine-2-yl-aminocarbonyl-4-(2-methyl-2H-tetrazole-5-yl)] is a new sulfonamide herbicide that selectively controls a wide range of weeds in lowland rice (Oryza sativa). It effectively controlled Cyperus serotinus, Eleocharis kuroguwai, Sagittaria pygmaea, S. trifolia, and Scirpus juncoides at 7.5 - 30 g ai/ha. In the tolerance test on grasses carried out in a nutrient solution containing 0.3 - 30 ppm of azimsulfuron, greater inhibition occurred in roots of both rice and barnyardgrass (Echinochloa crus galli) than in shoots. However, rice root was approximately 5-fold more tolerant than that of barnyardgrass. The downward movements as determined by 50% growth inhibition of S. juncoides were 4-cm in clay loam and 6.5-cm in sandy loam soil with 3-cm/day leaching for 3 days. When incubated at 20 and $30^{\circ}C$, the residual effect in clay loam soil lasted for 30 and 21 days, respectively. In a soil column applied at 15 g ai/ha of azimsulfuron followed by 3-cm/day leaching for 3 days, dry weights of S. trifolia emerging at 5, 10, and 15-cm depth were reduced to 87, 85, and 79% of the corresponding untreated control, respectively. Susceptibility of S. trifolia to azimsulfuron did not greatly vary with the emergence depth.

• Horticultural Science & Technology
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• v.17 no.3
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• pp.355-360
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• 1999

This study was carried out to investigate the effect of irrigation frequency, particle size and depth of perlite medium on the growth of Dendranthema grandiflorum (Ramat.) Kitamura 'Shuhouno-chikara' grown on recycling system. In Exp 1, the irrigation frequency (IF) was designed as 3 (IF3), 9 (IF9), and 18 (IF18) times a day. Fine and coarse particle size (PS) of perlite was used as a media, and depth of media (DM) was 15 and 10 cm contained in $34{\times}120{\times}15cm$ styrofoam bed. In Exp 2, the IF was 3 (IF3), 6 (IF6), and 9 (IF9) times a day with the same amount of nutrient solution. Fine and coarse PS were used, and DM was 15 and 7.5 cm. In this study, high IF and fine PS was favorable for plant growth. However, as the IF became frequent, difference of plant growth between fine and coarse PS became smaller. Also, shallow media showed little difference with deep media in plant growth. Thus, decreasing the amount of media was recommended to reduce the production cost.

• Horticultural Science & Technology
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• v.16 no.3
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• pp.347-349
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• 1998

Slow sand filtration was modified and applied for the determination of eliminating efficacy of various fungi and for recommending an easy approach to growers. After 1,500 liter filtration, Fusarium oxysporum was eliminated by several substrates such as activated charcoal (92.5% elimination), silica (90.8%), vermiculite (90.5%), sand (82.3%), perlite (50.4%), and hydroball (21.2%). Silica was able to eliminate several fungi by maximal ratio, which was corresponded to Fusarium oxysporum 120 cfu/mL. Collectotrichum lagenarium 98 cfu/mL. Phytophthora capsici 82 cfu/mL, Botrytis cinerea 62 cfu/mL, Pythium spp. 42 cfu/mL, and Sclerotinia ssp. 52 cfu/mL. In this case, the change of EC was minor and pH was maintained to about 7. In deep flow culture of 'Ddooksum Cheokchookmyeon' lettuce and 'Seokwang' tomato, silica-, activated charcoal-, and vermiculite-based filtration system successfully eliminated Fusarium oxysporum and Phytophthora capsici from the nutrient solution. As a result, these plants were not diseased by ten weeks after inoculation. With this system, growers can easily control the root-zone fungi in the recirculating hydroponic system.

• Journal of Bio-Environment Control
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• v.8 no.3
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• pp.192-201
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• 1999

This study was aimed to introduce the measurement of $CO_2$ concentration and leaf area index in the phytotron for predicting the effect of CO.E, light and leaf area index on the instantaneous photosynthetic rate of sweet pepper with the existing ASKAM model. Measurements were made in 2 semi-closed phytotron compartments in which three different $CO_2$ concentrations were applied at random. Plants were grown on containers with circulating nutrient solution at 21$^{\circ}C$ and 80-95% relative humidity. The model estimates crop net $CO_2$ uptake for short time intervals during the day based on short-term data of daily radiation, temperature and $CO_2$ concentration. During the photosynthesis measurements, $CO_2$ concentrations in both compartments and in the basement were measured every minute. This was also done for the flow of pure $CO_2$ into the compartment, global radiation, photosynthetic active radiation inside the compartment, temperature and relative humidity. Crop growth models summarize our knowledge on crop behavior and have as such a wide range of applications in analysis, crop management and thus as a farm management tool.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.197-203
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• 2011

This experiment was carried out to investigate the growth characteristics of virus-free sweetpotato in hydroponic bag culture. The rooted one-node and upper-shoot cuttings of 'Yeonhwangmi' and 'Mannamiwere' transplanted into the plastic bag (0.5 mm of thickness, $W300{\times}L1,200{\times}H120mm$) culture system filled with commercial horticultural media (TKS-2, Flora Gard Co.) and cocopeat + perlite (3 : 7, 5 : 5, 7 : 3, (v/v). Nutrient solution of National Horticultural Research Station in Japan was separately irrigated $3times{\times}30minutes$ per day (10:00, 14:00 and 20:00 with timer control) by the drip irrigation. The growth of two varieties was not significantly different among four substrates in 15 days, but it was excellent in commercial horticultural media (TKS-2) and cocopeat 3 : perlite 7 (v/v) in 20 days. The growth in 'Yeonhwangmiwas' promoted than that in 'Mannami', and the upper-shoot cuttings of 'Yeonhwangmi' and 'Mannami' showed a significant vine elongation (over 10 and 2 cm, respectively) compared to the one-node cuttings. Fresh weight and dry weight in cocopeat 3 : perlite 7 (v/v) were significant increased than that in cocopeat 7 : perlite 3 (v/v). Therefore, the bag culture system filed with cocopeat 3 : perlite 7 (v/v) was successfully applied on propagation of virus-free sweetpotato seedling, and the result expected that the bag culture system could be commercialized without high financial costs for farmers.