• Journal of Biosystems Engineering
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• v.10 no.1
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• pp.1-12
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• 1985

The two agricultural zones, mid-and-northen region and southern region, were established according to the possibility of double cropping in the paddy field. For each agricultural zone typically mechanized farming systems with a power tiller for cultivating rice, barley and soybean were established. A computer program, which determines the optimum size of power tiller for the given farm size, the ratio of paddy area to total area and the ratio of double cropping area to the paddy area, was developed. The computer program was executed for the farm sizes, 1 to 3 ha, and the ratios of paddy area to the total area, 60~80%, and the ratio of double cropping area to the total paddy area, 70%. The following conclusions were drawn from analyzing the computer outputs. 1. In the mid-and-northern region, a smaller power tiller (5 or 6 PS) appeared to be more economical for the farm size up to 3 ha. From the viewpoint of fuel consumption a 6 PS power tiller appeared to be more favorable. 2. In the southern region, a smaller tiller (5 or 6 PS) appeared to be more economical for the farm size up to 1.5 ha. But, a larger power tiller (8 or 10 PS) appeared to become more economical as the farm size and the barley planted area increased. 3. For the southern region where rotary tilling is heavily required due to double cropping, it is recommended to develop a power tiller which weighs light like the conventional 5 or 6 PS small power tiller but has lager power.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.1
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• pp.52-59
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• 1999

Paddy rice is semi-tropical crop and requires warmirrigation water. If mean water temperature at the water source during the growing period is below 18$^{\circ}C$, sime kinds of water warming mechanism should be taken. In this study irrigation water temperature is measured and preventive measures to cold water damage on paddy rice are suggested. Field observations were performed at 100ha field area downtream of the Unmoon reservoir during the growing season of 1997. Land use, canal system, water temperature at irrigation canals. reservoir, and paddy fields were observed. In addition, growth and yield of the rice at selected plots were observed. Accordingly to the record, cold water damage occurred in this area due to the cold irrigation water supply in 1996. It did not occur because of the effective irrigation water management practice in 1997. However, several preventive measures such as pontoon intake system, using existing weir and construting a new warming pond, are suggested to prevent cold water damage in the future. If a new warming pond is construted to raise irrigation water temperature by 2 $^{\circ}C$, a pond area of 2.94 ha is required.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.604-609
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• 2005

Runoff characteristics of organic matters and nutrients from greenhouse site in paddy field area were investigated during the irrigation period in 2004. The greenhouse selected which situated near the Nam river, Jinju, Korea used the ground water as the irrigation purpose. And, the rotating system of paddy field to upland was adapted as a cropping system which is a typical practice in this area. Various items such as total phosphorus(T-P), total nitrogen(T-N), dissolved oxygen(DO), BOD, etc. were observed to figure out the seasonal and spatial variation in the study sites. it was found that the risk of water pollution due to the contamination of nutrients in canals in green house sites, and their neighbouring small sized streams are much higher than those in ordinary paddy field areas. Further surveys and investigations are required to find out the counter measures to reduce water pollution occurred in greenhouse sites.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.79-79
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• 2022

옥수수(Zea mays L.)의 생육 및 수확량은 온도, 일장, 강수량 등에 의해 영향을 밭는다. 본 연구에서는 남부지역 유휴 논을 이용하여 파종시기를 달리하여 옥수수를 재배하였을 때 생육 특성과 수확량을 분석하여 적정 파종시기를 규명하고자 하였다. 3월 하순에서 6월 중순까지 6차로 구분하여 파종하였을 때 출사일수와 성숙일수는 파종기가 늦어질수록 짧아졌다. 옥수수는 단일 및 고온 조건에 의해 생식생장으로의 전환이 빨라지는데, 본 연구에서도 파종이 늦어짐에 따라 단일과 고온에 의해 출웅과 출사가 촉진되었다. 간장과 착수고는 4월 상순까지는 높으나 파종이 지연됨에 따라 짧아졌다. 옥수수의 수량구성요소 중에 이삭장은 5월 하순까지는 유의적인 차이가 없으나 6월에 파종하였을 때에는 짧아졌으며, 이삭직경과 착립장도 파종이 늦어짐에 따라 가늘어지고 짧아져, 파종이 지연되었을 때 생육이 부진함을 알 수 있다. 이삭의 수확량은 4월 상순까지 파종하였을 때에는 800kg/10a 이상으로 높으나, 파종시기가 늦어짐에 따라 점차 감소하여 6월 중순에는 40% 이상 크게 감소하였다. 이는 수량구성요소 중에 이삭장, 이삭직경과 착립장 등 이삭 발달의 부진한 결과이다. 그리고 이삭을 제거한 지상부의 무게는 5월 하순까지의 파종에서는 유의적인 차이가 없으나 6월에는 큰 폭으로 감소하였는데, 이는 영양생장 기간이 짧아짐에 따른 결과로 보인다. 이상의 결과를 토대로 남부지역 논에서 옥수수를 재배할 때에는 늦어도 5월 중·하순까지는 파종하여야 할 것으로 판단된다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.5
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• pp.55-63
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• 1996

The situation and cause of bund collapse in steep sloping paddy area by a heavy rainfall of Chungbuk Province were investigated by field surveys. Shapes of paddy plots are irregular and average size of them is 12.6a. Surface, groundwater and plot-to-plot irrigations are being carried out in the study plots. The type of bund collapse can be divided as follows: overflow type and inundation type. The overflow type generally occurs at the bund with slope lacking the design standard. The inundation type damages paddy plots more seriously than the overflow type. It induces continuous bund collapse from a inflow-plot to a outflow-plot and includes lots of type (inside paddy) collapse, which results in much subsoil erosion. The installation of mountain stream weir and maintenance of mountain stream are proposed to prevent the inundation type collapse.

• Journal of People, Plants, and Environment
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• v.24 no.4
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• pp.389-401
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• 2021

Background and objective: The purpose of this study is to investigate the ecological status of six areas around Geumgang River that used to be farmlands before they were restored as a riverine ecobelt. This study aims to analyze the correlation between the location environment and ecological status of the sites to identify the environmental factors affecting them. Methods: The sites are classified into four types according to restoration: terraced paddy fields, flat paddy fields, artificial wetland, and landscape forest. The survey items were divided into land use status, plant ecology, and animal ecology. Results: In terms of plant ecology, terraced paddy fields showed favorable naturality with the rate of native species above 90% and the naturalization index below 10%. In terms of animal ecology, the total number of species found in these areas was biggest in terraced paddy fields, followed by flat paddy fields, artificial wetland, and landscape forest. Regarding species diversity, terraced paddy fields also showed abundant species with an average of 1.05 to 1.09. The results of the correlation analysis showed that the forest area around the sites had the most significant effect on species diversity. The grassland and open water area showed a positive correlation with the total number of animal species and the number of dragonflies, confirming that the marshy grassland had a positive effect. As the cultivated land and urbanized area around the sites increased, it had a negative effect on the distribution of native species and the number of animal species that appeared, and a positive effect on the naturalization index. Conclusion: It is necessary to establish preemption and restoration plans for sites such as grasslands adjacent to the forest and terraced paddy fields in order to promote resilience of the diverse species returning to the purchased lands.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1943-1947
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• 2007

The objective of this research was to find a direct and indirect method to estimate land surface temperature (LST) efficiently, using Landsat images and in-situ measurement. Agricultural fields including paddy fields have long been known to have multi-functions beneficial to the environment and ecology of the urban surrounding areas. Among these functions, the ambient temperature cooling (ATC) effect are widely acknowledged. However, quantitative and regional assessment of such effect has not had many investigations. Thermal remote sensing has been used over urban areas to assess ATC effect, to perform land cover classifications and as input for models of urban surface atmosphere exchange. Here, we review the use of thermal remote sensing in the study of paddy fields and urban climates, focusing primarily on the ATC effect. Landsat satellite images were used to determine the surface temperatures of different land cover types of a $441km^2$ study area in Cheongju, Korea. The results show that the ATC are a function of paddy area percentage in Landsat pixels. Pixels with higher paddy area percentage have more significant cooling effect.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.5
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• pp.39-48
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• 2006

The objective of this research was to find an indirect method to estimate land surface temperature (LST) efficiently, using Landsat images. Agricultural fields including paddy fields have long been known to have multi-functions beneficial to the environment and ecology of the urban surrounding areas. Among these functions, the ambient temperature cooling (ATC) effect is widely acknowledged. However, quantitative and regional assessment of such effect has not been performed. Thermal remote sensing has been used over urban areas to assess the ATC effect, Thermal Island Effect(TIE), and as input for models of urban surface atmosphere exchange. Here, we review the use of thermal remote sensing in the study of paddy fields and urban climates, focusing primarily on the ATC effect. Landsat satellite images were used to determine the surface temperatures of different land cover types of a $44km^{2}$ study area in Cheongiu, Korea. The results show that the ATC is a function of paddy area percentage in Landsat pixels. Landsat pixels with higher paddy area percentage have much more cooling effect. The use of satellite data may contribute to a globally consistent method for analysis of ATC effect.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.3
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• pp.146-156
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• 2002

The objective of this study was to develop a modified CREAMS model for paddy field conditions. The model simulates daily balance of water and nutrient from irrigated paddies using meteorological, irrigation, and agricultural management data. The model simulates daily evapotranspiration of paddy using Penman equation and determines daily flooding depth changes. Total nitrogen and phosphorus concentrations within flooding water, surface runoff, and leaching water from a paddy field also can be simulated. Parameters of the model were calibrated using observed data of the Agricultural Experiment Station of the Seoul National University in Suwon Korea. The model was applied for the irrigation period of paddy field in Gicheon area when 1,234 mm annual rainfall was occurred. The simulated losses of the total nitrogen and total phosphorous were 11.27 kg/ha and 0.98 kg/ha, respectively. There was a good agreement between observed and simulated data. It was found that CREAMS-PADDY model was capable of predicting runoff and nutrient losses from irrigated paddy fields.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.132-139
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• 2010

To manage the effluent nutrients amounts from rice paddy fields using free range ducks or rice bran, we evaluated the effects of a purifying paddy field which is no fertilizer, no pesticides, and dense rice seedling having a concept of constructed wetland. The experimental paddy field was located at downstream in the watershed of ducks using rice culture area in Milyang. The purifying paddy of land design were treated with seeding method, and vegetation type. As land design, direct seeding on plane, and direct seeding on high-ridge field in 2007. Planting rice only, and planting rice with water hyacinth were treated as vegetation type in purifying paddy in 2008. The purifying paddy fields were effective to reduce amount of T-N and T-P contents in effluent to 33.2~45.3%, and 53.1~55.4%, respectively. The direct seeding on high-ridge treatment, having long residence time of effluent water was more effective than plane plot as T-N 0.29 $g^{-1}m^{-2}d^{-1}$, and T-P 0.031 $g^{-1}m^{-2}d^{-1}$. The planting rice with water hyacinth treatment was effective than planting rice only as T-N 0.23 $g^{-1}m^{-2}d^{-1}$, and T-P 0.049 $g^{-1}m^{-2}d^{-1}$. The optimum area of purifying paddy field to treats all effluent were found out 3.2~4.7% of rice culture area using free range ducks, and rice bran at upper stream.