• Nuclear Engineering and Technology
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• v.24 no.2
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• pp.121-129
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• 1992

Radio-tracer experiments on the Sr-90 absorption by rice and soybean from a sandy-loam soil of pH 6.35 treated with 5.2 and 31.2Bq Sr-90 per g-soil were carried out through pot cultivations. Sr-90 absorption rates of both crops increased till the mature stage when the rates were about 1.0%. Concentrations in their whole tops, however, decreased or changed little as they grew. Sr-90 concentrations in plant parts of both crops increased with the increase of those in soil. Soil-to-plant transfer coefficients of Sr-90 for rice and soybean at mature stages ranged, on the dry weight basis, from 0.07(unpolished seed) to 3.67(lean and from 0.86(seed) to 9.26(leaf), respectively. Only the unpolished rice seed showed a significant difference in the coefficient with 0.17 in 5.2Bq treatment and 0.07 in 31.2Bq treatment. Sr-90 retention rates of the upper 15cm soil after crop harvests were about 80% Sr-90 absorptions had no effect on the plant growth and yield of the crops.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.227-232
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• 2009

Land application of animal manure, such as pig slurry(PS), has been considered as valuable organic source to supply necessary nutrients for crop growth. On the other hand, little information is available on the effect of consecutive application of PS on agricultural soils. This study was conducted to evaluate the influence on change in soil chemical properties and yield of Chinese cabbage in soils amended with slurry composting and bio-filtration pig slurry (SCB) for four consecutive crop cultivations (2007-2008). Among total application rates required, a basal fertilizer (35%) was applied with SCB or chemical fertilizer (CF). The CF was applied as a side dressing was applied in all treatments. There was no significant effect of SCB and CF on Chinese cabbage yield during four cropping seasons. In addition, soluble sugar, vitamin C contents and yields of Chinese cabbage between SCB and CF did not show statistically significant difference. During the experiment, soil chemical properties between SCB and CF treatment showed similar pattern, however, the contents of exchangeable sodium (Na) in soil has been increased (P<0.05) since the second cropping season because of higher Na contents in SCB. Therefore, the use of SCB as a substitute of CF is available for growth and yield of chinese cabbage while its long-term application might leads to an accumulation of Na in soil.

• Research in Plant Disease
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• v.14 no.2
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• pp.90-94
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• 2008

To investigate the severity of crown gall disease on grapevine, the ratio of healthy vs. galled grapevines and the presence of the pathogen of the disease in soil were measured in Korean vineyards. In field and greenhouse cultivations, the crown gall incidence of the cv. Kyoho grapevines was $0.4{\sim}97.9%$ and $1.4{\sim}3.8%$ and those of cv. Campbell Early was $1.2{\sim}2.1%$ and $0{\sim}1.8%$, respectively. The higher populations of Agrobacterium spp. were isolated from soils of grapeveins with crown gall than from soils of noninfected vineyards. Based on the colony shapes and growth on plates, 480 isolates of Agrobacterium spp. from 21 soil samples were collected. Only 13 isolates out of 480 developed the gall on inoculated grapevines.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.4
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• pp.247-262
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• 1979

Majority of reclaimable soils in hillside lands in Korea are red yellow soils, with exception in Jeju island, where most of reclaimable hillside lands are composed of volcanic ash soils. Songjeong, Yesan and Samgag series are the major soil series of red yellow soils which are available for the reclamation. When observed in the fields, they are distinguished as reddish brown clay loam, red yellow sand loam and yellowish brown sand loam. They have moderately good physical properties but their chemical properties are generally poor for crop cultivations. The chemical properties of red yellow soils, as compared to long time cultivated (matured) soils, are characterized by very low pH, high in exchangeable Al content and phosphorus fixation capacity. Also extraodinary low available phosphorus and organic matter contents are generally observed. On the other, the chemical properties of volcanic ash soils are characterized by high armophous Fe and Al hydroxides and organic matter contents, which are the causative factors for the extremely high phosphorus fixation capacity of the soils. The phosphorus fixation capacity of volcanic acid soils are as high as 5-10 times of that of red yellow soils. Poor growth of crops on newly reclaimed red yellow soils are mainly caused by very low available P and pH and high exchangeable Al. Relatively high P fixation capacity renders the failure of effective use of applied P when the amount of application is not sufficient. Applications of lime to remove the exchangeable Al and relatively large quantity of P to lower the P fixation capacity and to increase the available P are the major recommendations for the increased crop production on red yellow hillside soils. Generally recommendable amounts of lime and P to meet the aforementioned requirements, are 200-250kg/10a of lime and $30-35kg\;P_2O_5/10a$. Over doses of lime. frequently induces the K, B, arid Zn deficiencies and lowers the uptake of P. In volcanic ash soils, it is difficult to alter the exchangeable Al and the P fixation capacity by liming and P application. This may be due to the peculiarity of volcanic ash soil in chemical properties. Because of this feature, the amelioration of volcanic ash soils is not as easy as in the case of red yellow soils. Application of P as high as $100kg\;P_2O_5/10a$ is needed to bring forth the significant yield response in barley. Combined applications of appropriate levels of P, lime, and organic matter, accompanied by deep plowing, results in around doubling of the yields of various crops on newly reclaimed red yellow soils.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.61-70
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• 2000

Soil erosion in the hilly and mountainous uplands in the Daekwanryong area, Kangwon-Do, were investigated through a field plot experiment. The plot size was 15m long and 2.5m wide with the average slope of 12.5 percents. Soil erodibility factor (K), surface coverage (SC), soil aggregate percentage and wind erodibility (I) were evaluated in the mountainous soils under different management practices for corn and potato cultivations. Soil erodibility factor (K) was greater in upper part than in lower part of the plots. Surface coverage (SC) values ranged from 0.01 to 0.84 depending on the amounts of crop residues. Soils having a greater crop residue in surface were less subjected to soil erosion. SC values after corn harvest were 0.4 to 0.8, while those after potato harvest were 0.4 to 0.5, indicating potato might be better than corn for erosion control. Soil aggregate percentages of the experimental plots ranged from 49.7 to 79.8%. Those were higher in potato-cultivated plots with higher surface coverage, organic fertilizer treatment and contour tillage. Soil aggregate percentage of potato-cultivated plots was significantly correlated to crop residue coverage after harvest. The dried soil aggregate percentage, showing the ranges of 26.4 to 56.4%, were higher in the plots with the increased crop residue incorporation. Wind erodibility (I) of the soil was decreased with increasing surface coverage. When soil had 26.4% of the dried aggregate percentage, wind erodibility was estimated to be $183Mgha^{-1}$ which was equivalent to soil loss of $0.5Mg\ha^{-1}day^{-1}$.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.81-88
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• 2011

This study was carried out to provide basic information for standard cultivation guideline of Korean mountain cultivated ginseng (Panax ginseng). Environmental conditions, soil properties, growth process, cultivation methods and sowing timing were investigated in cultivations of Korean mountain cultivated ginseng in Korea (18 region in 9 province). Most of Korean mountain cultivated ginseng was cultivated to north, north-east, east or north-west direction in broad-leaved forest, IV age group, and 500~1,000 trees/ha. Elevation was below 500 m and slope was below $25^{\circ}$ in cultivation. There were significant differences in soil properties by region and cultivation based on organic matter (3.43~24.07%) and pH level (3.8~5.7). Sprouting, leaf unfolding, flowering, fruiting, red ripening, fruit drop and leaf drop of Korean mountain cultivated ginseng was investigated in cultivation. The results show that it took 98 days on average for the whole growth process. There were two methods, sowing and transplant for cultivation. Sowing methods were classified in sowing after opening-testa treatment and direct sowing. and it was 70% and 30%, respectively.

• Korean Journal of Environmental Agriculture
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• v.31 no.3
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• pp.205-211
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• 2012

BACKGROUND: Generally, nitrogen (N) fertilization higher than the recommended dose is applied during vegetable cultivation to increase productivity. But higher N fertilization also increases the concentrations of nitrate ions and nitrous oxide in soil. In this experiment, the impact of N fertilization was studied on nitrous oxide ($N_2O$) emission to standardize the optimum fertilization level for minimizing $N_2O$ emission as well as increasing crop productivity. Herein, we developed $N_2O$ emission inventory for upland soil region during red pepper and Chinese milk vetch cultivation. METHODS AND RESULTS: Nitrogen fertilizers were applied at different rates to study their effect on $N_2O$ emission during red pepper and Chinese milk vetch cultivation. The gas samples were collected by static closed chamber method and $N_2O$ concentration was measured by gas chromatography. The total $N_2O$ flux was steadily increased due to increasing N fertilization level, though the overall pattern of $N_2O$ emission dynamics was same. Application of N fertilization higher than the recommended dose increased the values of both seasonal $N_2O$ flux (94.5% for Chinese cabbage and 30.7% for red pepper) and $N_2O$ emission per unit crop yield (77.9% for Chinese cabbage and 23.2% for red pepper). Nitrous oxide inventory revealed that the $N_2O$ emission due to unit amount of N application from short-duration vegetable field in fall (autumn) season (6.36 kg/ha) was almost 70% higher than that during summer season. CONCLUSION: Application of excess N-fertilizers increased seasonal $N_2O$ flux especially the $N_2O$ flux per unit yield during both Chinese cabbage and red pepper cultivation. This suggested that the higher N fertilization than the recommended dose actually facilitates $N_2O$ emission than boosting plant productivity. The $N_2O$ inventory for upland farming in temperate region like Korea revealed that $N_2O$ flux due to unit amount of N-fertilizer application for Chinese cabbage in fall (autumn) season was comparatively higher than that of summer vegetables like red pepper. Therefore, the judicious N fertilization following recommended dose is required to suppress $N_2O$ emission with high vegetable productivity in upland soils.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.292-300
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• 1996

This experiment was conducted to investigate the factor of phytotoxicity for herbicides(bensulfuron methyl, pyrazosulfuron-ethyl, dimepiperate, molinate) on flood direct-seeded rice. The phytotoxicity of herbicides was evaluated under controlled environment condition. Bensulfuron methyl and pyrazosulfuron-ethyl reduced more rice growth, especially root growth on low temperature(20/$11^{\circ}C$) than high temperature(30/$22^{\circ}C$) cultivations. The phytotoxicity of bensulfuron methyl and pyrazosulfuron-ethyl were increased relatively by non-nutrient and nutrient solution. cultivation, respectively. The rice applied bensulfuron methyl and pyrazosulfuron-ethyl with pH 3.5, 5.5, 7.5 and 9.5 solution became low growth rate on low pH of pH 3.5 and 5.5 solution cultivation. Bensulfuron methyl application with pH 5.5 and pH 7.5 solution, and pyrazosulfuronethyl application with pH 7.5 and 9.5 solution reduced rice growth inhibition. The root growth of rice seeded in 6cm depth of water solution applied herbicides was suppressed by bensulftuon methyl and pyrazosulfuron-ethyl, the growth of shoot was suppressed heavily by dimepiperate and molinate, in particular dimepiperate suppressed about the growth of 90%. The phytotoxicity of pyrazosulfuron-ethyl became high on light clay soil of non-fertilizer condition and sand loam soil of fertilizer condition, bensulfuron methyl became high on sand loam soil.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.132-138
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• 2023

The Gymnocalycium mihanovichii has been an important export item of Korean flower industry for a long time. Although there is a high demand for grafted cactus from overseas, its production for export is limited. In this study, the growth and marketable yield characteristics of Gymnocalycium mihanovichii 'I-Hong' were compared between soil culture and ebb-and-flow hydroponic system with single- or double-tier bench. As a result, hydroponic methods with single-tier bench resulted in higher fresh weight and glove diameter compared to other cultivation methods. In the ebb-and-flow hydroponic system, hydroponic system with double-tier bench of grafted cactus traits has a lower growth rate than other cultivations. However, the hydroponic system with double-tier bench of grafted cactus significantly increased the yield. In conclusion, the yield from hydroponic system with double-tier bench was better than soil cultivation method. Although there were some differences in color depending on the cultivation method, it was considered that there was no difference in appearance of Gymnocalycium mihanovichii 'I-Hong'. Our results suggest the cultivation methods to overcome production constraints, expand their exports, and improve the value-added characteristics of grafted cactus.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.13-19
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• 2014

The management of non point sources was marked by the need for clean water environments. It was proposed the fundamentals to promote the reasonable land management in this study. We monitored rainfall events at two non point sources with different crop cultivations such as a sweet potato and a cherry tree for three years. Because the most important factor was rainfall, the rainfall runoff and pollutant loads were generated 100% in the case of rainfall ranges with 50 < rainfall (mm). However the frequency of rainfall runoff was interacted with the crop cultivation and soil characteristics in the case of rainfall ranges such as 30 < rainfall (mm) ${\leq}50^a$ and 10 < rainfall (mm) ${\leq}30^b$. The frequency of rainfall runoff was a : 60% and b : 5% in the cherry tree cultivation with growing significantly and pollutant loads were lower than that of the sweet potato cultivation. Meanwhile the frequency of rainfall runoff was a : 60% and b : 5% in the sweet potato cultivation.