• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.4
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• pp.76-84
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• 2010

Darangyi paddy in Namhae Gachon village provides natural beauty with its distinct location. Darangyi is a traditional Korean landscape, shaping a circular form to serve continuous cultivation. Despite the paddy's landscape, it is difficult to preserve its natural scenery due to many factors such as inadequate visual analysis. Under the belief that there is a necessity to preserve Darangyi paddy, the research in visual features of the paddy began to illustrate the relevance between its viewpoint and landscape objects. First, we researched typical view structures. When considering the visual features, Darangyi paddy landscape objects has a viewpoint from the horizontality to its below, which its center area is about $-5^{\circ}{\sim}-30^{\circ}$. From the analyzed data, the scenary of Darangyi paddy, which most people agree its decency, is formed in a visually decent location. The above type of measure of visual structure in Darangyi paddy is expected to be applied in maintenance of foothold of views in the future. Second, the surrounding elements play important parts to form the whole landscape of Gachon Darangyi paddy. Although Darangyi paddy is the principal part of the scenary, the landscape analysis showed a high relevance with the paddy's identity, forest around the paddy, sky, ocean, settlements, and the roads in terms of visual perception. It was affirmed that those elements around the paddy play important parts in structuring and providing the beauty of the whole landscape. Various viewy objects are seen obvious especially in a long distance, and the splendid scenary proved that those viewy objects are in indispensable location. In order to preserve the paddy, it seems necessary to consider the surrounding envrionment of Darangyi paddy, not just the paddy's sole landscape form. Third, Darangyi paddy has a distinct seasonal characteristics. According to the survey analysis, the full heading time in spring and time when people can take a picture against the sun light proved magnificence of Darangyi paddy. Thus, it would be ideal to maintain Darangyi paddy by securing the sunlight condition with decent landscape view and the views from its surrounding environments or researching the ways to principally maintain the surrounding environments.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.3
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• pp.150-161
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• 2017

This study was conducted with the data of monitoring on soil chemical properties of rice paddy soils in Gyeongbuk Province. The selected soil chemical properties were analyzed every 4 year from 1999 to 2015. The soil pH measured in 2015 was higher than pH 6.0, which was 0.3-0.4 pH unit higher than data until 2007 survey year. The mean content of organic matter was greater than $24g\;kg^{-1}$ since 2003, but 35% of soil samples remained below the recommended level ($20-30g\;kg^{-1}$) in 2015. The mean concentration of available phosphate was maintained at $40mg\;kg^{-1}$ higher than the upper recommendation level ($80-120mg\;kg^{-1}$), and more than 40% of paddy soils tested were found to have less than the recommendation level during the survey period. The exchangeable K concentration ranged from 0.25 to $0.39cmol_c\;kg^{-1}$. Exchangeable Ca showed an average at the optimum range ($5.0-6.0cmol_c\;kg^{-1}$) during the monitoring period. Exchangeable Mg decreased linearly ($0.02cmol_c\;kg^{-1}\;year^{-1}$) from $1.55cmol_c\;kg^{-1}$ as of 1999 to below the lower level of the recommendation range ($1.5-2.0cmol_c\;kg^{-1}$). The amount of available $SiO_2$ was increased significantly from 2011 to over the recommendation level (${\geq}157mg\;kg^{-1}$). It was revealed that the soil chemical properties of rice paddy fields was influenced by topology, soil texture, type and region as result of principal component analysis or cluster analysis. Therefore, an assessment on chemical properties of rice paddy soils should be performed to consider various soil physical conditions and agronomic practices such as fertilization, cropping system, and so on. Because of the high variability of nutrient levels across Gyeongbuk Province, nutrient management based on soil fertility test is required by respective farm land unit.

• Korean Journal of Environmental Agriculture
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• v.19 no.5
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• pp.433-441
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• 2000

A feasibility study was performed to examine the agronomic application of treated sewage on paddy rice culture by field experiment for two consecutive years. The domestic sewage was treated by the constructed wetland system which was in subsurface flow type and consisted of sand and macrophyte. The effluent of the wetland system was used for irrigation water. The effluent was diluted to maintain the total nitrogen concentration below $26mg{\cdot}L^{-1}$ in the first year and used without dilution in the second year experiment. Growth components and yields were compared against the CONTROL plot where conventional method was applied. And also, soil characteristics of the plots before and after reclaimed sewage irrigation were analyzed. Generally, addition of the treated sewage to the irrigation water showed no adverse effects on paddy rice culture, and even enhancement was noticed in both growth and yield. Irrigation of treated sewage after concentration adjusted with conventional fertilization showed the better result, and the yield exceeded that of CONTROL case where clean water was irrigated. Soil characteristics changed after irrigation, and significant EC increasing was observed for the reclaimed sewage irrigation plots. From this study, it appears that reuse of treated sewage, as supplemental irrigation water could be a feasible and practical alternative. For full-scale application, further study is recommended on the specific guideline of major water quality components in treated sewage for irrigation and public health.

• Research in Plant Disease
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• v.15 no.1
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• pp.41-45
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• 2009

In order to study a relationship between soil nutrients and rice brown spot occurrence, paddy field soils, rice grains and straws collected from different paddy fields with different disease degrees of brown spots were analyzed for inorganic nutrients. Brown spot was prevalent in the rice grown in nutrient-deficient soils, which is especially low in macronutrient elements (phosphoric acid, potassium, silicic acids) and micronurients (calcium, magnesium). The soil, however, was high in sodium while organic nutrients and pH level were similar to others. The rice straws with severe brown spot were low in inorganics such as ferrous, copper, T-N, and $P_{2}O_{5}$ while the rice grains with brown spot were low in ferrous, MgO, Zn, and Mn. In the analysis of field type and nitrogen level, the highest disease severity was found in sandy-type field soil, followed by salty-type field soil and disease severity decreased as application level of nitrogen fertilizer increased. As a summary, the most important factor for effective brown spot control in rice is maintenance of proper nutrients in sandy-type field and control of sodium level in salty-type field soil.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.331-344
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• 2022

This study analyzed the characteristics of the soil and hydrological environment of abandoned paddy wetlands examined the changes in land cover type in the ecological affect area, analyzed the environmental factors of abandoned paddy wetlands, and examined the changes in land cover type in the ecological impact area. The ecological environment characteristics of the reference abandoned paddy wetlands were investigated through literature research, environmental spatial information service, and preliminary exploration of the abandoned paddy wetlands, and the basic data for the restoration of abandoned paddy wetlands ware provided by examining the changes in land cover type in the ecological impact area for 40 years. Through this study, it will be possible to manage the rapidly increasing number of abandoned farmland to be converted into wetlands so that it can perform functions equivalent to or greater than that of natural wetlands. In particular, as we checked the clues that abandoned paddy wetlands could spread to surrounding ecological influences through land cover changes, the study sites are highly likely to be reference wetlands, and if the topography, soil, water circulation system, and carbon reduction performance are analyzed carefully, it will be possible to standardize the development process. In addition, through the change in land cover, clues were confirmed that the abandoned paddy wetlands could spread to the surrounding ecological affect areas. The land cover type in the ecological impact area, forests was mainly distributed, but generally decreased rapidly in the last 10-20 years, and forests were changing from coniferous forests to broad-leaved forests, mixed forests, or grassland. It has not yet been fully called to the wetland, and it is found that it has maintained the form of barren or grassland, and as can be seen in the case of natural wetlands after more than 30 years after abandoned, it is expected that the transition will gradually proceed to wetlands that are structurally and functionally similar to natural wetlands.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2001.02a
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• pp.207-212
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• 2001

• Korean journal of applied entomology
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• v.4
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• pp.33-38
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• 1965

1. This survey was conducted to make a basis for the cause of severe epidemic and disease control to the losses due to bacterial leaf blight of rice in Chun-Nam rice paddy field areas in the first part of October in 1965. The severe epidemic areas were included Taijun-Myun, Tamyang-Eup, riverside in Youngsanpo and seaside in the suburbs of Mokpo. 2. A drought in the period of rice transplanting and flooding due to a heavy rain in July were resulted reasonable weather conditions that the disease occurred more early and severe epidemic. 3. In Tamyang area, frist outbreak of the disease was on the middle part of July in the paddy flooded after heavy rainfall of the first fart of July. It is recognized to farmers that the disease is known as a now serious one. 4. The more date of transplanting is followed, the more serious damage is happened and especially, in the paddy field flooded, too. 5. Flooded areas showed more serious epidemic. 6. Varietal difference to the disease was surely noticed, and Kumnampoong and Chunbonwuk were susceptible, whereas Norin 6 was resistant. 7. Damage was occurred more in plant paddy area than tile slopping paddy area. 8. Fallow paddy field was more serious than the field using double cropping a year. 9. Moist and semimoist paddy field were more serious damage, while light damage in dry paddy field. 10. Near part of flood gate for drainage of submerge paddy was more serious damage than inside part of the field. 11. Soft type is often seen in the mode of the disease occurrences. 12. The most farmers insisted that dropping water is caused to promote disease dissemination when disease occurred.

• Journal of Wetlands Research
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• v.24 no.2
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• pp.93-101
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• 2022

This study was conducted to analyze the distribution characteristics of abandoned paddy wetlands according to topography and land cover. In Seosan-si, Dangjin-si, Boryeong-si, and Taean-gun, Chungcheongnam-do, abandoned rice wetlands were found through GIS and field surveys, and the distribution status according to slope, elevation and land cover type was analyzed. As a result of the study, a total of 106 abandoned paddy wetlands were identified, and the average elevation of each abandoned paddy wetlands was 38.85m (S.D.32.76), the average slope was 6.27˚ (S.D.5.39), and the total area was 24,200km². 90 sites (84.9%) of abandoned paddy wetlands were distributed on flat land with less than 5˚ slope, 63 sites (12,121.07km²), and 27 sites(9,524.15km²) at 5-10˚ (9,524.15km²) on flat land with less than 10˚. The area is 21,645.22km²(89.5%) of the total area of abandoned paddy wetlands. 48 sites(12,326km²) in the lowlands with an altitude of less than 25 m, 29 sites(4,909.4km²) below 50m. It accounts for 71.2% of the total area of abandoned paddy wetlands. Among environmental factors of abandoned paddy wetlands, there was no statistically significant correlation between slope and altitude. According to the land cover classification, it was widely distributed in artificial grasslands (38), paddy fields (33), and fields (22).

• Journal of Biosystems Engineering
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• v.10 no.1
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• pp.13-23
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• 1985

Spraying method from the paddy-field levee is known to give insufficient penetration of the spray droplets to the rice stem of the densely grown plants, which is generally encountered at the last stage of rice growth. This study was intended to investigate the spraying system to solve this existing problem. As an approach, it was attempted to develop the boom-with-nozzle, between-the-row application system. Several types of nozzles and their different arrangements in the boom were tested in the field to measure the penetration-reaching distance and the uniformity of spray droplet distribution. The results of the study are summarized as follows: 1. Field experiments by the spraying method from the paddy-field levee showed to have practically no penetration of the spray droplets to the portion of the plant stem with the normal flow volume generally applied and thus need for improving present spraying method. 2. It was found that, considering both the uniformity of the spray droplet distribution and performance rate, the most efficient type of nozzle in the between-the-row boom-type spraying system was one that has core-insert hollow-cone with some clearance between the cone and tip. 3. When tested by applying the spraying method of between-the-row, the nozzle pressure did not affect the uniformity of spray droplet distribution. However, the nozzle pressure had a positive effect on the penetrating-reaching distance of the facing side of the rice stem and did not affect much on that of the opposite face of the stem. It was also found that the maximum pressure to affect the penetration-reaching distance was about $10kg/cm^2$. 4. The uniformity of the spray droplet distribution in the between-the-row system was greatly affected by the height and orientation of the nozzles in the boom. Based on experimental work for the different type of the boom-with-nozzle arrangements, it is recommended that the position of nozzle is set at about 0.45 m above the ground and two nozzles in the boom are oriented to be faced with each other with some angle such that the droplet stream from the nozzle would not directly face with each other.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.887-894
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• 2011

To evaluate the effects of abiotic factors of paddy fields on greenhouse gases (GHGs) emissions from rice paddy fields, $CH_4$ emission amounts were investigated from rice paddy fields by different soil organic matter contents, paddy types, and agricultural climatic zone in Yeongnam area during 3 years. $CH_4$ emission amounts according to soil organic matter contents in paddy field were conducted at having different contents of 5 soil organic matters fields (23.6, 28.7, 31.0, 34.5, and $38.0g\;kg^{-1}$), The highest $CH_4$ emission amount was recorded in the highest soil organic matters plot of $38.0g\;kg^{-1}$. High correlation coefficient (r=$0.963^{**}$) was obtained between $CH_4$ emissions from paddy fields and their soil organic matter contents. According to paddy field types, $CH_4$ emission amounts were investigated at 4 different paddy fields as wet paddy, sandy paddy, immature paddy, and mature paddy. The highest $CH_4$ emissions was recorded in wet paddy (100%) and followed as immature paddy 64.0%, mature paddy 46.8%, and sandy paddy 23.8%, respectively. For the effects of temperature on $CH_4$ emissions from paddy fields, 4 agricultural climatic zones were investigated, which were Yeongnam inland zone (YIZ), eastern coast of central zone (ECZ), plain area of Yeongnam inland mountainous zone (PMZ), and mountainous area of Yeongnam inland mountainous zone (MMZ). The order of $CH_4$ emission amounts from paddy fields by agricultural climatic zone were YIZ (100%) > ECZ (94.6%) > PMZ (91.6%) > MMZ (78.9%). The regression equation between $CH_4$ emission amounts from paddy fields and average air temperature of Jul. to Sep. of agricultural climatic zone was y = 389.7x-4,287 (x means average temperature of Jul. to Sep. of agricultural climatic zone, $R^2=0.906^*$)