• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.3
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• pp.1-22
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• 2020

This study was conducted as a basic data for preparing future management alternatives by analyzing the status and characteristics of invasive alien plants by land-use type based on the formation of a new town in Goyang Siksa district. As a result, the invasive alien plants in the Goyang Siksa district were 20 families 46 genera 57 taxa; according to the land-use type, the residential area(Wi City apartment complex) is 7 families 10 genera 12 taxa, the public facilities area(Dongguk University campus) is 17 families 40 genera 47 taxa, the mixed forest is 5 families 10 genera 10 taxa, the rice paddy is 5 families 6 genera 7 taxa, river(Mt. Gyeondal creek) is 7 families 13 genera 15 taxa were appeared. The life-form of invasive alien plants in Goyang Siksa district is annuals, the origin is America, the introduction time is third period(1962~the present), and the diffusion grade is wide spread(5 grade) species. It was higher than other types. The naturalization index by location was 31.9% in river(Mt. Gyeondal creek), 21.2% in rice paddy, 16.7% in mixed forest, 15.5% in public facilities area(Dongguk University campus), and 8.5% in residential area(Wi City apartment complex). As a result of comparing the naturalization index by regions with the previous studies, it is judged that there are differences due to the environment such as urbanization progress, size, area, population inflow and location conditions. Although many new towns have been established to date, there is a lack of research on flora (including invasive alien plants) as a basic data for preparing management alternatives. Therefore, Through this study, basic data on the management of exotic plants by land use unit in urban areas can be provided.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.14-21
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• 1997

This experiment was conducted to identify the growth and yield differences in rice cultural types: Broadcasting on flooded paddy surface(BF), drilling on flooded paddy surface(DF), puddled-soil drill seeding(PD), drill seeding on dried paddy flat(DD), and machine transplanting of lO-day old seedling(MT) at National Honam Agricultural Experiment Station in 1995. Among the cultural types of direct seeding, the number of seedling stand showed high in order of DD>BF>DF>PD. Tillering at early growth stage was faster in MT and effective tiller showed higher in MT than in direct seeding. Growth duration from seeding to heading was longer in direct seeding than in MT for 2-13 days of Dongjinbyeo and 10-18 days of Nonganbyeo. Root distribution ratio at the surface soil revealed high in order of BF>DF>PD>DD and MT. Culm wall thickness of 4th internode was thicker in machine transplanting of 10-day old seedling than in direct seeding, and the depth of buried culm showed deep by turns of MT> DD>PD>DF and BF. The height of center gravity and moment related to lodging revealed higher in direct seeding than machine transplanting that resulted high lodging index by turns of BF>DF>DD> PD among the direct seeding cultural type. Lodging was occured seriously in the order of BF>DF>PD>DD =MT in Dongjinbyeo but wasn't significantly different in Nonganbyeo among the cultural type. The yield components and grain yield showed varietal differences but was not significantly different between in MT and in direct seeding, and among cultural types of direct seeding.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.240-255
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• 2012

The objectives of this study were to investigate the levels of phytotoxicity of rice varieties to HPPD (4-hydroxy phenylpyruvate dioxygenase)-inhibiting herbicides known for their efficiency to control the sulfonylureas-resistant weed species：mestrione, benzobicyclone, and tefuryltrione. The twenty-six rice varieties (8-Japonica ${\times}$ Indica-type varieties and 18-Japonica-type varieties) were grown for 25 days on seedling trays and then transplanted to paddy rice fields followed by herbicide treatment i.e. standard and double doses of there respective herbicides at 5, 10, and 15 days after transplanting. Although mestrione, benzobicyclone and tefuryltrione are all HPPD-inhibiting herbicides, the phytotoxicity symptoms of the different rice varieties based on the timing of application and doses of the herbicides were significantly different. The Japonica ${\times}$ Indica-type varieties showed much more phytotoxicity symptoms than Japonica-type varieties in all applied herbicides. Increasing herbicidal doses of mesotrione, and an earlier application of and increasing herbicidal doses of benzobicyclon caused severe phytotoxicity symptoms. On the other hand, phytotoxicity due to tefuryltrione did not exhibit significant differences between rice varieties in either the timing of application or dose of the herbicide. Regardless of timing of application and dose of the herbicides, Hangangchalbyeo-1, Hyangmibyeo-1 and high-yield rice varieties such as Namcheonbyeo, Dasanbyeo, Areumbyeo, and Hanareumbyeo, which belong to the Japonica ${\times}$ Indica-type varieties, showed 5 to 8 levels of phytotoxicity symptoms including albinism, browning, detached leaf, and necrosis to mesotrione and benzobicyclon whereas only 1 to 3 levels of phytotoxicity symptoms (chlorosis, albinism, and browning) were seen with to tefuryltrione application. The Japonica-type varieties exhibited only slight phytotoxicity symptoms (1~2 levels) in conformity with the timing of application and doses of the herbicides. However, there were significant differences among the Japonica-type rice varieties, depending on the type of herbicide. Thirteen-Japonica type rice varieties were sensitive to benzobicyclone while 4-Japonica-type and 7-Japonica-type varieties showed phytotoxicity symptoms such as chlorosis and albinism with mestrione and tefuryltrione application, respectively. Therefore, we suggest that the combined-type herbicides including mestrione, benzobicyclone and tefuryltrione should be rejected in paddy fields where rice is grown for either human consumption (functional or processed rice) or livestock feed because of severe phytotoxicity symptoms on the various rice varieties seen regardless of the timing of application and doses of the herbicides.

• Current Research on Agriculture and Life Sciences
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• v.15
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• pp.7-16
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• 1997

The effects of liming and inoculation of nodule bacteria on the growth and yield of soybeans in the 1st and 3rd year paddy-upland rotated paddy fields was investigated. Compared with the 1st rotated field, the degree of nodulation was much higher in the 3rd rotated one with greater difference at flowering stage than at the early stage of soybean growth. At the same time, greater difference in the degree of nodulation was also recognized between soybean varieties. In the 3rd year rotated field, a great deal of nodulation effect was recognized in the no-limed field but not in the limed one. The growth of soybean was not much affected by liming and nodulation at early stage but it was much increased by liming at flowering stage, especially in Williams 79, indeterminate type variety. Most of yield components and yield of soybean at maturity was much increased by liming with greater in Williams 79 than in Namhaekong. Nodulation effect on the yield components and yield was great in the no-limed filed but not in the limed one for both varieties. The yield and yield components of soybean, without no relation with liming and nodulation, was much great in the 3rd year rotated paddy fields than in the 1st year one, which was inferred that the more rotated fields the more yield and better growth of soybeans could be possible in the paddy-upland rotatonal soybean croppings.

• Korean Journal of Environmental Agriculture
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• v.18 no.4
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• pp.384-387
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• 1999

The residue of imidacloprid in hulled rice and paddy soil was investigated. In laboratory conditions, the degradation of imidacloprid in the soils followed first-order reaction kinetic. The rate of degradation was influenced by soil temperature and soil type. The half-life of imidacloprid at $18-28^{\circ}C$ was 66.7-96.3 days in the heavy clay soil and 56.8-117.5 days in the clay loam soil. Arrhenius activation energy obtained from the temperature experiment was 25.5 KJ/mol in heavy clay soil and 50.3 KJ/mol in clay loam soil. In paddy field, the degradation of imidacloprid was fast during the initial period but the degradation rate was gradually slow. About 10 % of the initial amount remained in the soil 120 day after the application. The residual amount of imidacloprid in rice was below the detection limit, 0.01 ppm. The residue level in rice was lower than MRL 0.05ppm in Korea.

• Resources Recycling
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• v.7 no.1
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• pp.50-56
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• 1998

Basic oxygen furnace @OF) slag. a by-pradud of thc iron and steelmaking industry produced in largc quantities in Korea, poszs a subslantial disposal challenge. The BOF slag used in this study was if3 CaCO, in total n e u ~ ~ pnowger and application of 7-8 Mgha' was needed to bring soil pH to 6.5 horn pH 5.0-5.5 m silly clay or clay loam sod wnlained about 10% orgaoic matter. A field assay was conducted to shldg whether BOP slag could bc used as a dolomitic k i n g agent for agricullural soils. Four slag rates (0, 4, 8, 12 Mgha-')were investigated for their effcfect on soil pmperti~, mineral concentralions in leaf tissues of rice and soybean, and yield of the crops. Slag application at 8 Mgha-' rate in paddy field increased pH, Ca Mg, P, Si and Fe wntenl in sail and rice yield by 4.3-14.25 depending an the soil type. h upland field the 8 Mghaf ratc increa3ed pH, Ca and Fe wntent m soil and soybean yield by 36.6%. Thus, BOF slag appears to be a useful liming mate&\ulcornerl for corrzch~gs oil acidity on both paddy and upland ficld soils and for innwing Ca, Mg, P, Si, and Fe wncenhation in plants.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.275-289
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• 2011

We investigated the hydrological and geomorphological characteristics of small irrigation ponds in civilian control zone of Paju city in Korea. Among 85 small irrigation ponds, water level of 52 ponds changed seasonally and that of 33 was constant. Water sources of 12 ponds were surface water, 29 surface water and ground water, and 44 ground water. 4 ponds locate in the edges of forests, 33 in flat-lands, and 48 in valleys. Water in 45 ponds was exchanged with paddy fields and 40 ponds were isolated from paddy fields. Endangered or endemic species were inhabited in 26 ponds, which have ground water as water source and constant water level. Based on these characteristics, we suggested 4 types of small irrigation ponds: spring, water exchanging, stagnant/spring, stagnant water. This classification system will help ecosystem managers to investigate ponds systematically and manage them based on pond type.

• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.255-263
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• 2013

Purpose: It is not easy to drive a rice-transplanter avoiding underlapped or overlapped transplanting in paddy fields. An automated guidance system for the riding-type rice-transplanter would be necessary to operate the rice-transplanter autonomously or to assist the beginning drivers as a driving aid. Methods: A prototype of guidance system was composed of embedded computers, RTK-GPS, and a power-steering mechanism. Two Kalman filters were adopted to overcome sparse positioning data (1 Hz) from the RTK-GPS. A global Kalman filter estimated the posture of rice-transplanter every one second, and a local Kalman filter calculated the posture from every new estimation of the global Kalman filter with an interval of 200 ms. A PID controller was applied to the row-following mode control. A control method of U-turning mode was developed as well. A stepping motor with a reduction gear set was used to rotate the shaft of steering wheel. Results: Test trials for U-turning and row-following modes were done in a paddy field after some parameters have been tuned at the ground speed range of 0.3 ~ 1.2 m/s. The minimum RMS error of offset was 3.13 cm at the ground speed of 0.3 m/s while the maximum RMS error was 13.01 cm at 1.2 m/s. The offset RMS error tended to increase as the ground speed increased. The target point distance, LT also affected the system performance and PID controller parameters should be adjusted on different ground speeds. Conclusions: A target angle-based PID controller plus stationary steering angle controller made it possible for the rice-transplanter to steer autonomously by following a reference line accurately and even on U-turning mode. However, as condition in paddy fields is very complicated, the system should control the ground speed that prevents it from deviating too much due to ditch and slope.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.2
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• pp.192-205
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• 2012

This study estimates how much climate variables affect the land price and acreage of rice paddy and dry farm field in agriculture with the case of Gangwon-do in Korea. To this end, we capitalize upon the Ricardian approach based upon the panel data on climate, soil and geography, farmland prices and acreage, other economic and social variables for 11 municipal units comprising Gangwon-do during the period of 1992-2010. Our empirical analysis shows that the temperature variable has negative economic impacts on the price and acreage of rice paddy and dry farm field, confirming that the temperature variable is much significant than that of precipitation in global warming. On the other hand, the other determinants of farmland price and acreage are different with the type of farmland in Gangwon-do.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.3
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• pp.31-46
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• 1978

In order to secure the proper use of herbicides that are frequently used in Korea, the behavior of herbicides in various type of soil were studied. This study includes the variation of phytotoxicity, leaching and movement, and residual activity period of herbicides depending upon the type of soil etc. Experiments were also conducted to establish a guideline for the selection of herbicides according to the type of soil and the proper use of each herbicide in various type of soil in Korea. Experimental results showed that the behavior of herbicides could be characterized based on the series or kind of herbicides and devided into two major groups. One group (nitrofen. CNP, benthiocarb and butachlor) of herbicides showed relatively little crop injury and was very dependable. The action of this group was not remarkably influenced by soil components, rainfall and the quantity of herbicide used with the type of soil that had small adsorption capacity such as most of soil in Korea. The other group(simazine, 2, 4-D. linuron, alachlor and simetryne) showed a wide variation in it's action and retained potentially injurious effect. This group was very susceptable to using condition as well as the type of soil itself. Based on the results of various experiments the disappearance of the residual activity period of major herbicides used in upland and paddy field and the related factors were explained. It is believed that the results of this study can be used as a base for the establishment of a guideline for the proper use of each herbicide and can suggest a direction of developing new herbicides.