• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.397-402
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• 2009

In Korea, salt stress is one of the major problems limiting crop production and eco-environmental quality in greenhouse soil. The objective of this study was to evaluate the effectiveness of organic residues (Chinese milk vetch, maize stalk, rice straw, and rye straw) for reducing salt activity in greenhouse soil. Organic residues was incorporated with salt-accumulated soil (EC, 3.0 dS $m^{-1}$) at the rate of 5% (wt $wt^{-1}$) and the changes of electrical conductivity (EC) was determined weekly for 8 weeks under incubation condition at $30^{\circ}C$. The EC, microbial biomass carbon (MBC), and water soluble ions in soil was strongly affected by C/N ratio of organic residues. After 8 weeks incubation, the concentration of water soluble $NO_3{^-},\;Ca^{2+}$, and $Mg^{2+}$ was significantly decreased in organic residues having high C/N ratio (maize stalk, rice straw, and rye straw) incorporated soil compared to organic residues having lower C/N ratio (Chinese milk vetch) incorporated soil. The EC value in Chinese milk vetch incorporated soil was higher than control treatment. In contrast, maize stalk, rice straw, and rye straw amended soil was highly decreased the EC value compared to control and Chinese milk vetch applied soil after 4 weeks incubation. Our results indicated that incorporation of organic residues having high C/N ratio (>30) could reduce salt activity resulting from reducing concentration of water soluble ions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.5
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• pp.368-372
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• 2004

The lignin contents between IR-29 and Pokkali were not significantly different in the absence of NaCl, but they were slightly increased at 40 mM NaCl. Although lignin contents were not relatively significantly different between salt treated and control plants, the total yields of alkaline nitrobenzene oxidation ranged from 17.4-20.0 mg/g of cell wall residue at 40 mM NaCl were significantly different compared with control plants (11.8-12.2 mg/g). The total amounts of ester-linked hydroxycin-namic acids in IR-29 were decreased from 14.5 to 9.9mg/g, while Pokkali is almost same levels (14.9-15.0 mg/g) under treated and control with 40 mM NaCl. In contrast, the total amounts of ether-linked hydroxycinnamic acids were increased from 9.4 to 13.9 mg/g together with an opposite trend in Pokkali as a decrease 10.9 to 8.8 mg/g under treated and control with 40 mM NaCl. These results revealed that IR-29 is more sensitive in response to 40 mM NaCl in terms of hydroxycinnamic acids than Pokkali.

• The Plant Pathology Journal
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• v.32 no.4
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• pp.329-339
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• 2016

The short-term effects of low-level contamination by heavy metals (As, Cd, Cu, and Pb) on the soil health were examined by analyzing soil nematode community in soils planted with tomatoes. For this, the soils were irrigated with five metal concentrations ([1, 1/4, $1/4^2$, $1/4^3$, and 0] ${\times}$ maximum concentrations [MC] detected in irrigation waters near abandoned mine sites) for 18 weeks. Heavy metal concentrations were significantly increased in soils irrigated with MC of heavy metals, among which As and Cu exceeded the maximum heavy metal residue contents of soil approved in Korea. In no heavy metal treatment controls, nematode abundances for all trophic groups (except omnivorous-predatory nematodes [OP]) and colonizer-persister (cp) values (except cp-4-5) were significantly increased, and all maturity indices (except maturity index [MI] of plant-parasitic nematodes) and structure index (SI) were significantly decreased, suggesting the soil environments might have been disturbed during 18 weeks of tomato growth. There were no concentration-dependent significant decreases in richness, abundance, or MI for most heavy metals; however, their significant decreases occurred in abundance and richness of OP and cp-4, MI2-5 (excluding cp-1) and SI, indicating disturbed soil ecosystems, at the higher concentrations (MC and MC/4) of Pb that had the most significant negative correlation coefficients for heavy metal concentrations and nematode community among the heavy metals. Therefore, the short-term effects of low-level heavy metal contamination on soil health can be analyzed by nematode community structures before the appearance of plant damages caused by the abiotic agents, heavy metals.

• Korean Journal of Medicinal Crop Science
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• v.18 no.5
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• pp.345-360
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• 2010

This study was conducted to investigate the content of sulfur dioxide residues in medicinal herbs in Seoul in 2009. Sulfur dioxide in the samples were determined by Monnier-Williams's modified method. A total of 1,821 samples of 205 different types of herbs were collected from Kyung-Dong Herb markets and Oriental medicine hospitals in Seoul. Of these samples, 642 samples were domestic, and 1,179 samples were imported. Of the 1,821 samples, 61 (3.3%, 31 types) failed to meet the regulations for sulfur dioxide residues of KFDA in medicinal herbs. Among these 61 unsuitable samples, 17 (7 types) were domestic, and 44 samples (26 types) were imported. The content of sulfur dioxide in the domestic medicinal herbs ranged from 0 to 809 mg/kg, while those in imported medicinal herbs ranged from 0 to 4,481 mg/kg. Approximately 84.6% of the samples contained less than 10 mg/kg of sulfur dioxide and about 10.0% of samples contained more than 30 mg/kg of sulfur dioxide.

• The Plant Pathology Journal
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• v.35 no.5
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• pp.538-542
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• 2019

In 2017, two new tomato mosaic virus (ToMV) isolates were collected from greenhouses in Buyeo, Chungcheongnam-do, South Korea. Full-length cDNAs of the new ToMV isolates were cloned into dual cauliflower mosaic virus 35S and T7 promoter-driven vectors, sequenced and their pathogenicities investigated. The nucleotide sequences of isolates GW1 (MH507165) and GW2 (MH507166) were 99% identical, resulting in only two amino acid differences in nonconserved region II and the helicase domain, Ile668Thr and Val834Ile. The two isolates were most closely related to a ToMV isolate from Taiwan (KJ207374). Isolate GW1 (Ile668, Val834) induced a systemic hypersensitive response in Nicotiana benthamiana compared with the isolate GW2, which a single residue substitution showed was due to Val834.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.77-84
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• 2005

Three new rice farming systems, i.e. (1) straw-mulched no-till rice cropping system(SMNTRCS), (2)straw-mulched no-till rice-vetch cropping system (SMNTRWCS), (3)conventional rice-barley cropping system(CRVCS) have been established and compared with (4)conventional rice cropping system(CRCS). Grain appearance of brown rice of Korean native rice cultivars in SMNTRCS and SMNTRVCS were better than those in CRBCS and CRCS. Grain appearance of milled rice in SMNTRCS was better than those of other cropping systems. Korean native rice cultivars showed more white belly and broken rice than those of recommended rice cultivars. Mg and K contents of Korean native rice cultivars were the highest in SMNTRVCS. Protein contents of all the cultivars tested were the highest in SMNTRCS. Protein contents of Korean native cultivars were higher than those of recommended cultivars. Amylose contents of the cultivars tested were from 16 to 22 percent, while those of Aedal and Jenmjo were significantly higher than those of the other cultivars. Alkali digestibility values(ADV) of milled rice grain, tested in $1.2\%$ potassium hydroxide for 23 h at $30^{\circ}C$, showed varietal differences and the cultivars grown in CRBCS were the highest and the lowest in CRCS.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.454-459
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• 2010

This study was conducted to investigate the phytotoxic reaction and the impact on the growth of apple fruit included the yield amount by misuse of non-selective herbicide, glufosinate-ammonium in apple field and for the study, 4 cultivars of apple were tested. The results showed that the highest phytotoxic degree was observed on Sansa-cultivar and then the degree was diminished on Tsugaru, Hongro and Fuji in order in the application year. In one year after application, the highest phytotoxic degree was showed on Fuji and then diminished on Tsugaru, Hongro and Sansa in order. However, in one year after application, the phytotoxic symptom was negligible in comparison with the degree in the year of application and the flowering and fruiting were reduced 30% only in Fuji, but in the other cultivars, the phytotoxic symptoms were not observed. Meanwhile, the residue of glufosinate-ammonium was below the detection limit as 0.04ppm in all tested cultivars and in 2years after application, the phytotoxic symptom was not observed in all cultivars of the apple.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.275-282
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• 2020

As pesticide safety was extended to agricultural environments and Positive List System was carried out, Pesticide safety management in soils has become even more important. To improve pesticide safety in soils needs the degradation technology of the residues in soils and reduce plant uptake of pesticides. In this study, biochars and quicklime as the degradation methods of pesticides (azoxystrboin, procymidone and tricyclazole) were used to identify the reduction effects. The experimental methods were putting biochars and quicklimes (0, 0.5, 1.0, 2.0% per 15 cm soil weight) in soils and analyzing the pesticide residues at 0, 10, 20, 35, 50 day. To identify the reduction effects of uptake from soil to korean cabbages (roots, leave, stems) by biochar treatment, the residues in samples were analyzed. As a results, azoxystrobin (36-96%), procymidone (40-117%) and tricyclazole (26-83%) were reduced in soils when treated with 2.0% quicklime (p<0.05). There were no reduction effect in soils when treated with 1.0% or less biochar. However, the amounts of residues translocated to roots (0.11-1.62 mg/kg), leave (0.05-0.29 mg/kg), stems (0.06-0.1 mg/kg) were reduced treated with 2.0% biochar treatments. The biochar and quicklime can be applicable to agricultural field to improve pesticide safety in soils.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.147-156
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• 1981

Most of the currently available rice threshers in Korea are of head-feeding type originally developed for threshing paddy at grain moisture content of 15 to 17% on wet basis. And prevailing rice harvesting system is swathing or cutting and bundling upright rice crop at a maturity stage of grain moisture content of ca. 28 to 20%, followed by transient natural drying in the field and threshing at grain moisture content of about 17%. The system often allows rather high field loss of rice both quantitatively and qualitatively. These necessitate use of a preharvest desiccant, and diquat has been registered recently as a rice desiccant. Aim of the present study is to determine the best time and rate of diquat application and to evaluate its utility as a rice desiccant under its optimal usage conditions in Korea. Diquat was not so effective for japonica rice varieties while it was very effective for the new varieties bred from indica x japonica crosses. The best time of application was the period from 2 days before to 3 days after physiological maturity of grain (moisture content of 28% w.b.) and the optimal rate was about 330g of diquat ion/ha. Applying diquat at the right time and rate dropped grain moisture to 15 to 16% (w.b.) within a week after treatment in contrast to that of 20 to 24% in untreated rice. Desiccation of rice crop with diquat resulted in 10 to 15% increase in grain resistance to shattering and significant reduction in percent green rice. However, there was no reduction in milled rice yield and percent whole kernel and was no change in the percent chalky rice and percent tinted rice. Diquat use appears highly desirable, if there is no residue problem which has not been studied in the present study.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.1
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• pp.1-13
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• 2009

Understanding the net nutrient balance in a farming system is crucial in assessing the system's sustainability. We quantified N, P and K balances under vegetable organic farming in a Eutric Haplud and in West Java, Indonesia in five planting seasons from 2005 to 2007. The ten treatments and three replications, arranged in a completely randomized block design, included single or combined sources of organic fertilizers: barnyard manure, compos ts or green manures. The organic matter rates were adjusted every planting season depending on the previous crop responses. The result sshowed that the application of ${\geq}20$ t $ha^{-1}$ barnyard manure per crop resulted in positive balances of N, P, and K, except in the second crops of 2006 where potassium balance were -25 to -11 kg $ha^{-1}$ under the treatments involving cattle barnyard manure, because of low K content of these treatments and high K uptake by Chinese cabbage. Application of 20 to 25 t $ha^{-1}$ of plant residue or 5 t $ha^{-1}$ of Tithonia compost also resulted in a negative K balance. Soil available P increased significantly under ${\geq}25$ t $ha^{-1}$ barnyard manure and that under chicken manure had the highest available P. Accordingly, chicken barnyard manure gave the highest crop yield because of relatively higher N, P, and K contents. Plant residues gave the lowest yield due to the lowest nutrient content among all sources. Reducing the use of barnyard manure to 12.5 t $ha^{-1}$ and substituting it with Tithonia compost, Tithonia green manure or vegetable plant residue compost gave insignificantly different yield compared to the application of 25 t $ha^{-1}$ barnyard manure singly. In the long run, application of 25 t ha-1 cattle, goat, and horse manure or about 20 t $ha^{-1}$ chicken manure is recommendable for sustaining the fertility of this Andisol for vegetable production.