• Korean Journal of Organic Agriculture
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• v.22 no.2
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• pp.303-319
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• 2014

The study researched germination of the plants and growth of experimented bacteria according to concentration of water extract in order to provide basic data for developing natural agricultural resources by using naturalized plants including Solidago altissima, Amaranthus retroflexus and Sida spinosa. As concentration of water extract increased, most of test plants showed a decrease in relative germinability. Sida spinosa(r=-0.540, p<0.01), Physalis wrightii(r=-0.693, p<0.01), Amaranthus retroflexu(r=-0.724, p<0.01), Solidago altissima(r=-0.728, p<0.01) and Eclipta prostrata(r=-0.779, p<0.01) showed tendency of decrease in relative germinative power in order, respectively. For average germination period, as concentration of the processed group increased, the time for germination increased (r = 0.769, p<0.01) and according to donor plants and test plants, there was a little difference. Also, as concentration of water extract of donor plant, length of above-aerial part(r=-0.587, p<0.01), length of underground part(r=-0.741, p<0.01), fresh weight(r=-0.574, p<0.01) and generation of root hair decreased. An then, for growth of test fungi according to concentration of water extract of donor plants, growths of Botrytis cinerea(r=-0.266, p<0.05), Diaporthe citri(r=-0.323 p<0.01), Colletotrichum gloeosporioides(r=-0.512, p<0.01), Pythiumultimum(r=-0.581, p<0.01) and Rhizoctonia solani(r=-0.806, p<0.01) were repressed in order, respectively. For total amount of content of phenol with herbicidal and Antifungal activities, S. altissima $17.3{\pm}0.5mg/g$, A. retroflexus $13.1{\pm}0.3mg/g$, P. wrightii $12.0{\pm}0.4mg/g$, S. spinosa $9.5{\pm}0.1mg/g$ and E. prostrata L. $4.1{\pm}0.1mg/g$ showed in order, respectively. As these results are summarized, donor plants which were naturalized, have competitive advantage because they release phenolic compounds with allelopathic effect and affect on germination, growth and fungi growth on underground flora compared to native plants and they have eligibility for natural herbicide and germicide.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.51-58
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• 1999

Korean native plants and naturalized plants were analyzed for allelochemicals, and their antimicrobial effects were studied. The difference in soluble solid contents between Korean native plants and naturalized species was not significant, and the Korean native plant, Solanum nigrum showed the highest soluble solid content of 90 mg/ml. The ethanol extract of the Korean native plant, Solanum nigrum showed antifungal activity to Aspergillus phoenicis KCTC 1228, with a clear zone of 18 mm, and spore formation was not observed from the treatment. The naturalized plants Ambrosia artemisiifolia var. elatior and Erigeron canadensis showed inhibition of spore formation and the clear zones were at 24 mm and 22 mm, respectively. The clear zones of Aspergillus phoenicis KCTC 1228 treated with ethanol extrats of Phytolacca americana and Rudbeckia bicolor were 22 mm and 19 mm, respectively, and spore formation was observed from the treatment. The Korean native plant, Solanum nigrum and naturalized plants, Phytolacca americana and Ambrosia artemisiifolia var. elatior showed antimicrobial activity against Bacillus sphiaericus 2362, and Bacillus sphiaericus 2297, Bacillus thuringiensis var. subtilis and Baicillus thuringiensis var. cereus. The antimicrobial activity of Ambrosia artemisiifolia var. elatior showed the largest clear zone of 32 mm against Bacillus thuringiensis var. subtilis. In general, the more soluble the solid contents of the extracts, the greater were the antifungal and antimicrobial activities. The phenolic compounds from the Korean native plant, Solanum nigrum and the naturalized species, Phytolacca americana and Ambrosia artemisiifolia var. elatior were analyzed by high performance liquid chromatography. Three phenolic compounds including hydroquinone were identified in Solanum nigrum. In contrast, five and seven phenolic compounds were identified in Phytolacca americana and Ambrosia artemisiifolia var. elatior, respectively. The antifungal activity against Aspergillus phoenicis KCTC 1228 was found to be due to the coumaric and benzoic compounds.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.760-763
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• 2012

This study was conducted to investigate foliar treatment effects of organic agricultural materials for the environmentally-friendly cultivation of grape. The organic materials applied were chitosan, wood vinegar (pyroligneous acid), amino acid solution, and ginkgo leaf extract. All the organic materials were relatively strong acidic ranging lower than pH 4.6. when comparing with other organic materials, amino acid solution contained relatively high contents of selected plant nutrients, such as N, P, K, Ca, Mg, Cu, Fe, Mn, and Zn. As comparison of selected soil properties in the grape cultivating field, soil pH values were lower at the harvest stage than at the first stage of grape growing (before treating the organic materials), and electrical conductivity (EC) and soil organic matter content were higher at the harvest stage in the all plots. The concentrations of available phosphorus increased in most of the plot soils except in control plot (conventional treatment). The concentrations of exchangeable K decreased in the plot treated with ginkgo leaf extract and the control plot. The exchangeable Mg concentrations decreased in soils of all the plots. On the other hand, the concentrations of N and K in the grape leaves were higher with the treatments of chitosan and amino acid solution, P concentrations were higher with the applications of chitosan, wood vinegar and amino acid solution, and Ca and Mg concentrations were higher with chitosan and amino acid solution treatments, respectively, than with others. The yields of grape were higher, $1,581{\sim}1,583kg\;10a^{-1}$, in the control and wood vinegar treatment plots than others. Sugar contents of grape were not different among all the plots.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.11-22
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• 1994

The understory vegetation of a Chamaecyparis obtusa plantation is relatively sparse at a valley in Sangkwan-my6n, Wanju-gun, Chiinbuk, Korea, and that of the pure C. obtusa plantation is more sparse than in the C, obtusa-Larix leptolepis plantation. In order to investigate the causes of this difference, this study was carried out both in the field and in the laboratory. Total of 109 taxa, comprising 90 genera and 53 families, were identified in the plantation. But the average number of species above 10% frequency was only 27, and both the number of species and plants per quadrat in the pure C. obtusa plantation were lower than those in the C, obtusa-L. leptolepis plantation. Light intensity, soil pH, and the difference of soil minerals were supposed to be parts of the causes. Soils, litter extracts of C. obtusa and L. leptolepis, and leachates collected by vermiculite beneath C. obtusa canopy for 1 year were tested for the effect on germination and seedling growth of both inside species and outside species in the laboratory. Germination and seedling growth of outside species were more suppressed than those of inside species. Therefore it was found that allelopathic effect of C. obtusa would be responsible for the sparse understory vegetation in the C. oblusa plantation.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1114-1119
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• 2012

This study was conducted to assess the microbial toxicity of ionic silver solution ($Ag^+N$) and silver nanoparticle suspension ($Ag^0NP$) based on the Microtox bioassay. In this test, the light inhibition of luminescent bacteria was measured after 15 and 30 min exposure to aqueous solutions and soils spiked with a dilution series of $Ag^+N$ and $Ag^0NP$. The resulting dose-response curves were used to derive effective concentration (EC25, $EC_{50}$, EC75) and effective dose ($ED_{25}$, $ED_{50}$, $ED_{75}$) that caused a 25, 50 and 75% inhibition of luminescence. In aqueous solutions, $EC_{50}$ value of $Ag^+N$ after 15 min exposure was determined to be < $2mg\;L^{-1}$ and remarkably lower than $EC_{50}$ value of $Ag^0NP$ with $251mg\;L^{-1}$. This revealed that $Ag^+N$ was more toxic to luminescent bacteria than $Ag^0NP$. In soil extracts, however, $ED_{50}$ value of $Ag^+N$ with 196 mg kg-1 was higher than $ED_{50}$ value of $Ag^0NP$ with $104mg\;kg^{-1}$, indicating less toxicity of $Ag^+N$ in soils. The reduced toxicity of $Ag^+N$ in soils can be attributed to a partial adsorption of ionic $Ag^+$ on soil colloids and humic acid as well as a partial formation of insoluble AgCl with NaCl of Microtox diluent. This resulted in lower concentration of active Ag in soil extracts obtained after 1 hour shaking with $Ag^+N$ than that spiked with $Ag^0NP$. With longer exposure time, EC and ED values of both $Ag^+N$ and $Ag^0NP$ decreased, so their toxicity increased. The toxic characteristics of silver nanomaterials were different depending on existing form of Ag ($Ag^+$, $Ag^0$), reaction medium (aqueous solution, soil), and exposure time.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.223-235
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• 2006

Soil testing laboratories unfamiliar with turfgrasses will often overestimate the plant's need for phosphorus and underestimate the need for potassium. This is partly due to differences in rooting between grasses and many garden plants and crops. The grasses are generally more efficient in extracting phosphorus from the soil, reducing their need for phosphorus fertilizer. The fact that crop yield is often the primary objective in field crop production, and is usually of little interest in turfgrass management, may affect soil test interpretation for potassium. Potassium levels above those required for maximum tissue yield of grasses may improve stress tolerance and turfgrasses will usually benefit from higher applications of this element. There are also diffrrences in soil testing philosophies. Some laboratories use the sufficiency level of available nutrients(SLAN) approach, whereas others prefer the basic cation saturation ratio(BCSR) approach. Some will use a combination of the two methods. The use of the BCSR theory easily lends itself to abuse and questionable fertilizer applications and products are sometimes recommended citing imbalances in cation ratios. The usefulness of the BCSR ratio theory of soil testing varies with soil texture and interpretations on tests performed on sand-based media are particularly a problem. Other soil testing problems occur when sand-based media used on sports fields and golf greens contain free calcium carbonate. The ammonium acetate extractant at pH 7.0 dissolves excessive amounts of calcium that can bias cation exchange capacity measurements and measurements of cation ratios. Adjusting the pH of the extractant to 8.1 can improve the accuracy of the testing procedure for calcareous media.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.310-317
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• 2008

This study was carried out to investigate the factors of desalinization of the rainfall interception culture soils of Rubus sp. in Gochang-gun, Jeollabuk-do. Soil samples were collected from 85 different sites of the rainfall interception culture soils of Rubus sp. in Gochang-gun, Jeollabuk-do. The electrical conductivity in paste saturation of rainfall interception culture soils ranged from $1.0\sim28.4dS\;m^{-1}$ (average: $4.8dS\;m^{-1}$) and salt affected soil which EC was higher than $4dS\;m^{-1}$, covered nearly 55% of all field surveyed. Salts in rainfall interception culture soils were accumulated by increasing the cultivation period. Electrical conductivity in rainfall interception culture soils was positively correlated with water soluble anions such as chloride ion ($r=0.85^{**}$), nitrate ion ($r=0.94^{**}$), phosphate ion ($r=0.88^{**}$), and sulfate ion ($r=0.84^{**}$), respectively. As a result of desalinization experiments carried out by water management practices, the rinsing method was more effective than leaching method.

• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.331-337
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• 1990

An antitumor antibiotic named B-1123 substance was isolated from the culture filtrate of a new isolate fungus identified as Aspergillus terreus. The fermentation yield reached about 23 mg per liter of the broth. The B-1123 substance, chlorine containing antibiotic, has the molecular formular of $C_{17}H_{12}0_7C_{12}$. Its structure was determined to be geodin by spectroscopic data. It is active against some Gram-positive bacteria and it prolongs the life span of mice inoculated with Ehrlich carcinoma.

• Economic and Environmental Geology
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• v.55 no.2
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• pp.209-217
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• 2022

The purpose of this study was to confirm the dissolution of arsenic from the stabilized soil around abandoned coal mines by cultivation activities. Experimental soils were collected from the agricultural field around Okdong and Buguk coal mines, and the concentration of arsenic in the soil and the geochemical mobility were confirmed. The average arsenic concentration was 20 mg/kg. The soil with relatively high geochemical mobility of arsenic in the soil was used in the batch and column experiment. The limestone was mixed with soil for soil stabilization, and the mixing ratio was 3% of limestone, based on the soil weight. The phosphoric acid fertilizer (NH₄H₂PO₄) was added to the soil to simulate a cultivation condition according to the Rural Development Administration's rules. Comparative soil without mixing limestone was prepared and used as a control group. The arsenic extraction from soil was increased following the fertilizer mixing amount and it shows a positive relationship. The concentration of phosphate in the supernatant was relatively low under the condition of mixing limestone, which is determined to be result of binding precipitation of phosphate ions and calcium ions dissolved in limestone. Columns were set to mix phosphoric acid fertilizers and limestone corresponding to cultivation and stabilization conditions, and then the column test was conducted. The variations of arsenic extraction from the soil indicated that the stabilization was effectible until 10 P.V.; however, the stabilization effect of limestone decreased with time. Moreover, the geochemical mobility of arsenic has transformed by increasing the mobile fractions in soil compared to initial soil. Therefore, based on the arsenic extraction results, the cultivation activities using phosphoric fertilizer could induce a decrease in the stabilization effect.

• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.137-142
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• 1998

Helicobacter pylori is a Gram-negative bacterium which causes chronic gastritis and is associated with gastric ulcer, duodenal ulcer and gastric carcinoma. In the process of screening of antibacterial activities against H. pylori from soil microorganisms, fungus No. 60686 was isolated. After fermentation of No.60686, the antibacterial compound was isolated, purified and followed by extraction of mycelium with organic solvents, acetone and ethyl acetate, through silica gel chromatography, LH-20 gel chromatography and HPLC. As a result of the structural analyses of the compound by IR, $^1$H- and $^{13}$C-NMR, FAB/Mass spectrophotometer, the compound having the antimicrobial activity was identified as chaetoglobosin A ($C_{32}H_{36}N_2O_5$), a cytochalasan derivative. The antimicrobial activity of chaetoglobosin A was tested against Gram-positive and negative bacteria by paper disk method. Among the test strains of 9 Gram-positive bacteria and 18 Gram-negative bacteria containing 4 H. pylori strains, the growth of 4 H. pylori strains and 3 S. aureus strains (SG 511, 285 and 503) was only inhibited by chaetoglobosin A. Also it was shown that its growth inhibition against H. pylori strains was stronger than that against S. aureus strains at the treatment of the same concentration. Therefore it was concluded that chaetoglobosin A has a specific growth inhibition against H. pylori of the tested bacteria.