• 한국토양비료학회지
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• 제50권6호
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• pp.520-529
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• 2017

In Korea, the largest agricultural lands are paddy fields which have poor infiltration and drainage properties. Recently, Korean government pursuits cultivating upland crops in paddy fields to reduce overproduced rice in Korea. In order to succeed this policy, it is critical to set criteria suitability classification for upland crops cultivating in paddy field soils. The objective of this study was developing guideline of suitability classification for sesame cultivation in paddy field soils. Yields of sesame cultivated in paddy field soils and soil properties were investigated at 40 locations at nationwide scale. Soil properties such as topography, soil texture, soil moisture contents, slope, and drainage level were investigated. The guideline of suitability classification for sesame was determined by multi-regression method. As a result, sesame yields had the greatest correlation with topography, soil moisture content, and slope. Since sesame is sensitive to excessive soil moisture content, paddy fields with well drained, slope of 7-15% and mountain foot or hill were best suit for cultivating sesame. Sesame yields were greater with less soil moisture contents. Based on these results, area of best suitable paddy field land for sesame was 161,400 ha, suitable land was 62,600 ha, possible land was 331,600 ha, and low productive land was 1,075,500 ha. Compared to existing suitability classification, the new guideline of classification recommended smaller area of best or suitable areas to cultivate sesame. This result may suggest that sesame cultivation in paddy field can be very susceptible to soil moisture contents.

• Journal of Biosystems Engineering
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• 제33권2호
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• pp.83-93
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• 2008

In order to save labor and cost, direct seeding has been considered as an important alternative to the machine transplanting in rice cultivation. Current direct seeding machines for rice in Korea drill irregularly under various operating conditions. This study was conducted to develope a precision seeder which enables the accurate, even-spaced in row placement of rice seeds at uniform depths of 3-4 cm on dry paddy. Design, construction and performance evaluation of the precision seeder were carried out. The tractor rear-mounted type 8-rows precision seeder which performs seeding in addition to fertilizing, ditching, and rotary tilling works on dry paddy was developed. Main components of the seeder were ditcher and leveller, rotary tiller, powered roller type furrow opener, seeding device, powered roller type furrow covering and firming device, hydraulic unit, seeding speed control system, power transmission system, hitch and frame. Ditching, furrow opening, and seed covering and firming performances were good and seeding depths of 2-4 cm could be maintained. Planting accuracies and planting precisions were within 13.6%, and 31.2%, respectively, for planting space of 15 cm, and seeding velocity of 0.5 m/s. These mean variations of average planting space were within 2.1 cm, and 90% of seeds in a hill were seeded within 4.7 cm of hill length, respectively. Error ratios between setting planting space and measured average planting space were shown within 6.7%. Therefore the seeder showed good planting performance up to seeding velocity of 0.5 m/s in field tests. And field capacity of the seeder was about 0.28 ha/hour.

• 한국토양비료학회지
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• 제30권1호
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• pp.35-40
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• 1997

담수된 논 토양에서는 산소공급의 차단으로 환원상태가 조장되어 메탄가스가 생성되는데, 생성된 메탄은 확산이나 벼 식물체를 통하여 대기로 배출되어 지구온난화 가스로 작용된다. 본 연구는 메탄가스 저감방법을 구명하고자 벼 재배양식별 메탄가스 배출특성을 조사한 결과를 요약하면 다음과 같다. 1. 벼 재배양식에 따른 메탄 배출량은 이앙재배, 담수직파, 건답직파순으로 많았으며 볏짚을 시용한 건답직파의 평균메탄 배출량($mg{\cdot}m^2{\cdot}h^{-1}$)은 10.27, 담수직파는 21.94, 그리고 이앙재배는 24.05였다. 2. 출수기의 시간별 메탄발생 양상은 오전 9시에서 오후7시까지 메탄배출량이 많았으며 밤에는 낮보다 메탄 배출량이 낮았다. 3. 메탄 배출량은 기온과 Eh와 높은 상관을 보였다. 4. 시기별 메탄 배출정점은 유수형성기와 출수기 무렵에 두번 보였다.

• 한국환경과학회지
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• 제9권2호
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• pp.109-114
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• 2000

The purpose of the present study is to develope the estimation scheme for sensible heat flux by semi-empirical approach using routine meteorological data such as solar radiation and air temperature. To compare observed sensible heat flux with estimated sensible heat flux, the sensible heat fluxes were measured by three dimensional sonic anemometer-thermometer. The field observation was performed during 1 year from December 1, 1995 to November 30, 1996 on a rice paddy field in Chunchon basin. The heat fluxes were measured at a heights of 5m and mean meteorological variables were obtained at two levels, 2.5m(or 1.5m) and 10m. Since condition of rice paddy field such as, wetness of the field, roughness length, vary widely, we devided annual data to 5 periods. Comparing with two sensible heat fluxes, the results showed that the correlation coefficients were more than 0.86. Thus, we can conclude that the estimation method of sensible heat fluxes using routine meteorological data is practical and reliable enough.

• 한국잡초학회지
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• 제3권2호
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• pp.246-251
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• 1983

In recent years weed flora have been changed to perennial dominance in paddy field being affected by the cropping systems and cultural practices. The perennial weeds are difficult to be controlled with annual herbicides which occupy 94% of total consumption of herbicides. The weeds competed more with rice plants in early tillering stages in machine transplanted field. For the reasonable and effective weed control, it is advisable to use single ai herbicides in hand transplanting field, but combined and mixed herbicides should be applied in machine transplanting field.

• 한국환경농학회지
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• 제19권5호
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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.

• 한국환경농학회지
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• 제31권4호
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• pp.359-367
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• 2012

본 연구는 논습지를 이용하는 수조류의 서식지 이용과 개체군 특성을 파악하기 위해 수행되었다. 2009/2010년과 2011/2012년에 걸쳐 아산만 일대의 논을 대상으로 매월 2회씩 조사를 수행한 결과 총 35종의 수조류가 관찰되었다. 수조류의 논이용은 분류군에 따라 시기적으로 차이가 있지만, 분류군에 상관없이 대부분 논을 취식지로 이용하였다. 도요물떼새류는 봄철이동시기(4월-5월)에 담수화된 본답을 주로 이용하였다. 백로류는 논을 4월에서 10월까지 이용하였으며, 논의 상태변화에 따라 본답, 논둑, 수로 등을 고루 이용하였다. 논은 백로류의 번식에 필요한 충분한 먹이를 제공하는 서식지이다. 오리기러기류는 월동기간(11월-3월)동안 추수 후 떨어진 낙곡을 취식하기 위해 논을 이용하였다. 결과적으로 주기적으로 뚜렷한 환경변화를 갖는 논 생태계는 시기에 따라 다양한 수조류의 서식지를 제공하고 있다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.61-67
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• 2005

Agricultural water for rice growing is the important factor of water resources in Korea. so, it is imperative to know the practice of water management in paddy field. The experimental site has been operated in order to investigate water management practice and water supply discharge since 2001. There are 8 irrigation areas which are observed the water supply discharge in this site. We have investigate the water management practice in this site and we know that the practical date of rice growing stages and the date for calculating the water demand in paddy field. So, There is much differences between the calculated water demand and practical water supply. We could reduce the differences by calculating the water demand using the practical date of rice growing stages.

• 한국물환경학회지
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• 제25권1호
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• pp.69-75
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• 2009

Water stress has become a major concern in agriculture. Korea suffers from limited agricultural water supply, and wastewater reuse has been recommended as an alternative solution. A study was performed to examine the effects of microorganism concentration in the ponded-water of a paddy rice field with reclaimed-water irrigation for evaluating the microbial risk to farmers and neighborhood children. Most epidemiological studies were performed based on an upland field, and they may not directly applicable to paddy fields. Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion. Their risk value increased significantly high level after irrigation and precipitation. It implies that agricultural activities such as plowing, and fertilizing, and precipitation need be practiced a few days after irrigation considering health risks. The results about field application of the microbial risk assessment using E. coli showed difference according to monitoring time and treatment plot. Result of the microbial risk assessment showed that risk values of ground-water and reclaimed secondary wastewater irrigation were lower than directly use of wastewater treatment plants' effluent. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of E. coli to wastewater reuse in a paddy rice farming.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.611-616
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• 2000

Effect of reclaimed sewage on the paddy rice culture was examined by field experiment for two consecutive years. The domestic sewage was treated by the comstructed wetland, and the effluent of the treatment wetland was used for irrigation water. Growth components and yields were compared against the CONTROL plot where conventional fertilization was applied. In general, addition of the reclaimed sewage irrigation which contained high nutrient concentration didn＇t affect paddy rice culture adversely, and even better growth and more yields were observed. Overall, reclaimed sewage irrigation was thought to be one of practical alternatives for irrigation water.