• The Korean Journal of Pesticide Science
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• v.7 no.4
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• pp.264-270
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• 2003

To control effectively and safely Phytophthora root rot caused by Phytophthora capsici on tomato in hydroponic culture, tank-mixing method was considered with two pesticides, metalaxyl copper oxychloride 50% WP and dimethomorph dithianon 38% WP. Forty days after transplanting of tomato seedlings, 4 mL of sporangia of P. capsici (about 25 sporangi/mL) per plot was inoculated around tomato plant roots, and at 5 days after inoculation, the pesticides tank-mixed at three dilution levels, 12,500, 25,000 and 50,000, were drenched 1, 2 or 3 times per plot on the culture cube every 15 days for metalaxyl copper oxychloride 50% WP and every 10 days for dimethomorph dithianon 38% WP. During the drenching period, the residue levels of metalaxyl and dimethomorph in hydroponic culture solution were similar to the initial levels but the level of dithianon was drastically decreased from one day after tank-mixing. In tomato drenched with metalaxyl copper oxychloride 50% WP, metalaxyl was detected $0.02\sim0.04$ mg/kg in all diluted plots. Dimethomorph was detected $0.012\sim0.021$, $0.001\sim0.006$ and $0.001\sim0.003$ mg/kg in 12,500, 25,000 and 50,000 times diluted plots, respectively, while dithianon was detected 0.005, 0.003 mg/kg in 12,500 and 50,000 times diluted plots, respectively. The detection levels of three pesticides were far below compared with the levels of Korean MRLs. Incidences of Phytophthora root rot were not found in all the plots, but phytotoxic responses were recognized in the 12,500 times diluted plots of both pesticides. Based on the above results, the drenching of the culture solution tank-mixed with these pesticides could be recommended as a very safe and effective method to control Phytophthora root rot in tomato in hydroponic culture.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.5
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• pp.160-168
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• 2012

This study generated regression models to estimate the carbon storage and uptake from the urban deciduous landscape trees through a direct harvesting method, and established essential information to quantify carbon reduction from urban greenspace. Tree species for the study included Acer palmatum, Zelkova serrata, Prunus yedoensis, and Ginkgo biloba, which are usually planted as urban landscape trees. Tree individuals for each species were sampled reflecting various diameter sizes at a given interval. The study measured biomass for each part including the roots of sample trees to compute the total carbon storage per tree. Annual carbon uptake per tree was quantified by analyzing radial growth rates of stem samples at breast height. The study then derived a regression model easily applicable in estimating carbon storage and uptake per tree for the 4 species by using diameter at breast height(dbh) as an independent variable. All the regression models showed high fitness with $r^2$ values of 0.94~0.99. Carbon storage and uptake per tree and their differences between diameter classes increased as the diameter sizes got larger. The carbon storage and uptake tended to be greatest with Zelkova serrata in the same diameter sizes, followed by Prunus yedoensis and Ginkgo biloba in order. A Zelkova serrata tree with 15cm in dbh stored about 54kg of carbon and annually sequestered 7 kg, based on a regression model for the species. The study has broken new grounds to overcome limitations of the past studies which substituted, due to a difficulty in direct cutting and root digging of urban landscape trees, coefficients from the forest trees such as biomass expansion factors, ratios of below ground/above ground biomass, and diameter growth rates. Study results can be useful as a tool or skill to evaluate carbon reduction by landscape trees in urban greenspace projects of the government.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.426-433
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• 1988

A pot experiment was conducted to find out the effects of application of slacked lime and fused super-phosphate on the lead uptake of upland crops in a lead added soil. Lead concentration of the soils were adjusted to 0, 150, 300mg/kg respectively. The slacked lime was applied at the equivalent amount of lime requirement with extra 150kg/10a, and 2 times for the fused superphosphate. The results obtained were as follows: 1. Lead contents in crops increased in the order: sesame > maize > potato > sweet potato > soybean > green perilla > peanut > red bean. 2. Lead contents in parts of crops were increased in the order; root > stem > leaf > grain. 3. Increasing lead concentration in soils, lead content in the plant was increased and crops yield were decreased. 4. Lead contents in soybean and green perlilla were decreased in slacked lime application treatment. 5. The lead contents in leaf and grain of soybean and green perllila decreased with decreasing in the ratio of Pb/Ca+Mg equivalent in soil. 6. Grain yield were increased in slacked lime, but were decreased in fused superphosphate application treatment. 7. With increasing the soil Pb contents, calcium and phosphate contents were increased in leaf and stem, but calcium was decreased in roots. 8. $1N-NH_4$ OAC soluble Pb contents in soil were 26-50 ppm and 42-70 ppm, respectively, for 150mg/kg and 300mg/kg lead treatments. 9. The soil pH was increased in the order of slacked lime, fused superphosphate and nontreatment.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.340-345
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• 2017

Carrot leaves have many nutrients as well as roots, which will increase the demand for carrot leaves in the future. This study was carried out by dividing into two stages: high temperature and low temperature periods, in order to investigate the possibility of cultivation of carrot leaves and the composition and EC of the nutrient solution for growth and quality of carrot leaves. Composition of nutrient solution($NO_3-N:16.0$, $NH_4-N:1.0$, P: 1.0, K: 11.0, Ca: 2.0, Mg: 1.0, $SO_4-S:1.0mM{\cdot}L^{-1}$) developed by analysis of plant. In the high temperature range (From June $29^{th}$ to Sep. $8^{th}$, 2016), the concentration of the developed nutrient solution (JNU) were 1.0, 2.0, 3.0, and $4.0dS{\cdot}m^{-1}$ and the concentration of nutrient solution of Japanese Horticultural Station(JHS) $2.0dS{\cdot}m^{-1}$ was used for comparison. In the low temperature range (From Dec. $31^{st}$, 2015 to Feb. $29^{th}$, 2016), the concentration of the developed nutrient solution 1.0, 2.0, and $3.0dS{\cdot}m^{-1}$ were used. Growth was investigated in root fresh and dry weights, shoot fresh and dry weights, leaf number, and leaf area of carrot. In the high temperature range, the leaf area and shoot fresh and dry weights were good at 1.0 and $2.0dS{\cdot}m^{-1}$. The sugar content of the root was the highest at the EC $2.0dS{\cdot}m^{-1}$, and the chlorophyll content was the highest at the EC $4.0dS{\cdot}m^{-1}$. In the low temperature range, The shoot fresh and dry weights were the highest at EC 1.0 and $2.0dS{\cdot}m^{-1}$. There was no significant difference in sugar content and chlorophyll content. As a result, from the viewpoint of growth and quality of carrot, it is good to cultivate EC 1.0 and $2.0dS{\cdot}m^{-1}$ in high temperature period and low temperature period, but EC $1.0dS{\cdot}m^{-1}$ is economical perspective such as fertilizer input.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.829-846
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• 2015

This study was conducted to determine the effects of organic fertilization rates on the nutrient accumulation and recovery in radish (Raphanus sativus L.) as well as growth and yield of radish in Jeju island. An understanding the relationships between organic fertilization rate, crop nutrient recovery and crop yield can assist in making organic fertilizer recommendation which balances crop value and environmental risk in organic cultivation. Nitrogen (T-N), phosphate ($P_2O_5$) and potassium ($K_2O$) were applied at 0, 115-35-40, 230-70-80 (standard application rate), 460-140-160, 230-200-100 (recommended application rate) and 158-53-35 kg/ha (customary application rate), respectively as the broadcast application of mixed organic fertilizer (N 4.5% - $P_2O_5$ 1.5% - $K_2O$ 1%) in combination with langbeinite ($K_2O$ 22%), 100% at sowing period. The organic fertilizer was made of organic materials like oil cakes. Total yield of radish, as fresh weight of roots, increased with increasing organic fertilizer doses to a maximum at rate of standard or soil-testing application. Nitrogen, phosphate and potassium accumulations of radish increased curvilinearly with increasing organic fertilization rate to a maximum at rate of N 460 - $P_2O_5$ 140 - $K_2O$ 160 kg/ha. However, nitrogen, phosphate and potassium use efficiency of applied organic fertilizer decreased curvilinearly or linearly with increasing organic fertilization rate. Application of organic fertilizer in combination with langbeinite (as a potassium source) had significant effect on the yield of radish. Organic fertilization on a basis of standard or soil-testing application rate is recommended for maximun radish yield in organic cultivation.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.223-227
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• 2008

This experiment was conducted to describe the distribution of stable isotope Cd in the mine tailing and uncultivated soils derived from different parent rocks (Igneous rock, Metamorphic rock, and Sedimentary rock) as well as the movement of Cd isotopes from soil to plants, soybean and pepper. The results showed that there was no significant difference in isotopic ratios in soil among the eight kinds of stable isotope of Cd. However the relationship among isotopic ratios of stable isotope of Cd in soils were classified to four types, linear type between $Cd^{106}/Cd^{111}$ and $Cd^{108}/Cd^{111}$, quadratic type between $Cd^{114}/Cd^{108}$ and $Cd^{111}/Cd^{110}$, reverse quadratic type between $Cd^{110}/Cd^{116}$ and $Cd^{108}/Cd^{116}$, and cluster type between $Cd^{110}/Cd^{113}$ and $Cd^{116}/Cd^{113}$. While the individual stable isotopes of Cd in root were remained except on the plot of pepper without mine tailing application. $Cd^{116}$, $Cd^{114}$, and $Cd^{112}$ played active roles among other stable isotopic Cds in bean and red pepper, and $Cd^{116}$ was ranked the highest abundance ratio. Contrary to crop itself, the abundance ratios of $Cd^{116}$ in bean and read pepper roots were decreased, and the ones of other Cds were relatively increased.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.85-98
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• 1995

Six malformin B's produced by Aspergillus niger van Tiegh. were separated by HPLC. Their structures determined by the methods of amino acid analyses, mass spectrometry, and two-dimensional NMR were revealed as cyclic pentapeptides structurally related to malformin $A_1$. Both the NMR and MS/MS data suggest that the respective structures of separated malformin B's were as follows; cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-allo-Ile for $B_{1a}$, cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-Leu for $B_{1b}$, cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Leu for $B_2$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Leu for $B_3$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Ile for $B_4$, and cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Ile for $B_5$. Among the malformin B's, the structure of $B_{1b}$ was the same as that of malformin $A_3$ or C. All the malformin B's showed physiological activities in the two assay systems using corn(Zea mays L.) roots and mung bean(Phaseolus aureus Roxb.) hypercotyl segments. The malformin B's with molecular weight 529 were more effective for inducing corn root curvature than those with molecular weight 515. The difference in molecular weight of malformin B's, i.e., the retention time on HPLC, results in the polarity change of the whole malformin molecule which affects the revealation of the malformin activities. In addition, the disulfide form of the malformin B's gives the rigidity of the molecule, whereas the combination of the fourth and the fifth amino acid residues provides the optimal three-dimensional configuration to the malformin receptor of plants. Presumably, these two factors are appeared to be essential for the greatest physiological activity of malformin B's. malformin $B_{1a}$ caused the corn root curvature by 90% at a concentration of $0.25{\mu}M$. However, such differential activities with molecular weight of 529 or 515 of malformin B's were not found in the mung bean hypercotyl segment test. Maximum stimulation of mung bean hypercotyl growth was observed at $0.1{\mu}M$ concentration of malformin B's. The growth of the segments treated with $B_5$ was 154% greater than that of the control.

• Korean Journal of Organic Agriculture
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• v.19 no.1
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• pp.65-82
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• 2011

In order to evaluate the weed suppressing effect of Solanum viarum Dunal. In this study species diversity in patch of S. viarum and allelopathic effects of the aqueous extracts on S. viarum were investigated. Number of species and species diversity in site close to patch of S. viarum were decreased gradually 1site ($7.7{\pm}2.0,\;1.5{\pm}0.2$), 2site ($5.3{\pm}1.2,\;1.2{\pm}0.2$) and 3site ($4.0{\pm}1.7,\;0.9{\pm}0.1$). And total phenolic compounds of soil in survey area were increased gradually site1 ($0.16{\pm}0.01mg\;g^{-1}$), site2 ($0.17{\pm}0.01mg\;g^{-1}$) and site3 ($0.22{\pm}0.02mg\;g^{-1}$). So the number of species and species diversity (r=-0.692, P<0.05) were negatively correlated with increased total phenolic compounds of soil in the survey area. The relative germination ratio, the mean germination time, the relative elongation ratio, the fresh weight and the dry weight of receptor plants are generally getting decreased while the concentration of the aqueous extracts from S. viarum escalate. But every ratio was various depending on the growing regions, the kind of receptor plants and the treatment of the aqueous extracts. Especially, the radicle by injection of the aqueous extracts concentration of S. viarum was influenced more than the shoot on the same condition. The total phenolic compounds on region of S. viarum was gradually increased in stems (fresh $0.56{\pm}0.02mg\;g^{-1}$, dry $1.58{\pm}0.08mg\;g^{-1}$), roots (fresh $1.77{\pm}0.07mg\;g^{-1}$, dry $2.64{\pm}0.06mg\;g^{-1}$), leaves (fresh $6.01{\pm}0.14mg\;g^{-1}$, dry $7.04{\pm}0.29mg\;g^{-1}$), seeds (fresh $6.21{\pm}0.17mg\;g^{-1}$, dry $9.08{\pm}0.73mg\;g^{-1}$) in order. On the contrary, the negative correlation on germination and growth of receptor plants was shown by total phenolic compounds on the each parts of S. viarum. We think that the aqueous extracts of S. viarum showed allelopathic effects on other plants. Therefore, S. viarum holds the higher competitiveness in plant community in Jeju Island and makes possibility of application as natural herbicide.

• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.174-181
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• 1998

In four citrus grow of Satsuma mandarin (rootstock of trifoliate orange) including two grove of organical management and two groves of conventional management, spores of arbuscular mycorrhizal(AM) fungi were identified and seasonal changes in spore density in soils and AM colonization of citrus roots were investigated. AM colonization in weeds found in the groves were also examined. Three species of Glomus (G.deserticola, G. vesiculiferum, G. rubiforme ) and one unknown species of Acaulospora were observed in all of the groves. Annual mean density of AM fungal spores were in the range of 10,000${\sim}$40,000 per 100g soil with more spores in the organically-managed groves. The least spores were observed in December in all groves, and the most spores in April in the organically-managed groves while in February or April in the conventionally- managed. Annual mean AM colonization more 27% of citrus root were observed in the organically-managed with the high peaks in April and October and the minimum in August, while mean colonization less than 15% in the conventionally-managed with the peak in February and the minimum in different times depending on groves and years. AM colonization corresponded to a sigmoidal curve consisting of a laf phase during winter and a subsequent increase in spring, then succeeded by a maximum, and then a decrease at the end of vegetation. Fungal spore density and AM colonization showed a parallel pattern during the sample period. The seasonality appeared to be related more to the phenology of the plant than to the soil factors. Generally more spore density and AM colonization were found in organically managed groves. AM colonization was not correlated with available P and organic matter content in soil in this field investigation. Among sixteen weed species found in the groves, Astrogalus sinicus of Leguminosae, Portulaca oleracea of Portulacaceae showed high colonization in all groves and they can be considered as a source of inoculumn and host plants for propagation of AM fungi.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.38-45
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• 2017

We investigated the effects of rising temperatures on the photosynthesis, mineral composition, and growth of radish (Raphanus sativus var. hortensis) in a winter cropping system using a temperature gradient tunnel to predict the impact of rising global temperatures. Vegetative growth, including shoot and root fresh and dry weights, shoot length, and root length and diameter, was high under elevated temperatures (ambient $+4^{\circ}C$ and $+7^{\circ}C$) compared with ambient temperature. At elevated temperatures, the N, P, Ca, Mg, and Fe contents were high in shoots, whereas in roots, the K, Ca, Mg, and Fe contents were high and the Cu content was low. The maximum photosynthetic rates ($22.1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at ambient temperature $+4^{\circ}C$ and $22.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at ambient temperature $+7^{\circ}C$) at elevated temperatures were more than twice that ($9.7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) at ambient temperature, whereas the water use efficiency was lower at elevated temperatures. These results suggest that rising global temperatures will lead to increased mineral absorption and photosynthesis in radish in winter cropping systems, subsequently favoring plant growth, although the water requirements will be high.