• 한국농공학회논문집
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• 제63권4호
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• pp.55-64
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• 2021

The expansion of upland crop cultivation in rice paddy fields is recommended by the Korean government to solve the problem of falling rice price and reduction of rice farmer's income due to oversupply of rice. However, water use efficiency is significantly influenced by the land use change from paddy field to upland. Therefore, this study aimed to evaluate the water budget of soybean grown in using APEX (Agricultural Policy and Environmental eXtender) model. The amount of runoff was measured in a test bed located in Iksan, Jeollabu-do and used to calibrate and validate the simulated runoff by APEX model. From 2019 to 2020, the water budget of soybean grown in uplands were estimated and compared with the one grown in paddy fields. The calibration result of AP EX model for runoff showed that R² (Coefficient of determination) and NSE (Nash-Sutcliffe efficiency) were 0.90 and 0.89, respectively. In addition, the validated results of R² and NSE were 0.81 and 0.62, respectively. The comparative study of each component in water budget showed that the amounts of evapotranspiration and percolation estimated by APEX model were 549.1 mm and 375.8mm, respectively. The direct runoff amount from upland was 390.1 mm, which was less than that from paddy fields. The average amount of irrigation water was 28.7 mm, which was very small compared to the one from paddy fields.

• 한국농공학회논문집
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• 제53권4호
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• pp.11-19
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• 2011

PADDIMOD2 was deloped to estimate nonpoint source pollution from paddy rice fields. The PADDIMOD2 was enhanced to estimate runoff and pollutant load during non-growing as well as growing season and to be easily used for public by development of Excel based system. Nutrient concentration and hydrology were based on Dirac delta function and continuous source function, and tank model for growing season and Event Mean Concentrations (EMCs) and SCS-Curve Number method for non-growing season. The PADDIMOD2 consists of three main component (input data, parameters data, and output data) by including eight Excel spread sheets. As a result of model application, total precipitation and irrigation were 1,051.7 mm and 439.2 mm, respectivley and surface runoff and water loss including infiltration and evapotranspiration were 463.0 mm and 947.9 mm, respectively. Annual nutrient loadings of T-N and T-P from study area were 6.7 kg/$km^2$/day and 0.5 kg/$km^2$/day, respectively. Development of PADDIMOD2 was focused on minimizing input data and maximizing user friendly system and is expected to be useful tool to evaluate various non-structure BMPs and estimate unit load from paddy rice fields for application at Korean TMDL.

• 한국작물학회지
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• 제46권6호
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• pp.429-433
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• 2001

경종조건에 따른 벼 이형주의 발생양상과 특성은 다음과 같다. 1.벼 이형주의 발생량은 종자의 자가 채종년수가 증가할수 록 많았고, 직파재배 포장에서 이앙재배 포장보다 2배 가량 많았다. 2. 재배벼의 재배포장에 장립적미와 단립적미를 인위적으로 산파 하였을 때 담수표면산파 재배에서 기계이앙 재배보다 발생량이 많고 간장이 길고 주당 유효경수가 많았으며, 장립적미가 단립적미보다 이런 특성들을 많이 지녔다. 3. 이앙재배 포장에서 이형주가 재배벼의 포기 밖에서 발생하는 비율은 농가관행재배의 경우 0∼6%인 반면, 장립적미와 단립적미를 인위적으로 산파하였을 때는 70.6∼91.1% 이기 때문에 농가포장에서 발생하는 이형주군의 대부분은 종자흔입에 의해 발생하는 것으로 보아진다.

• The Plant Pathology Journal
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• 제36권3호
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• pp.297-302
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• 2020

Root-knot nematodes (Meloidogyne spp.) are the most destructive group of plant-parasitic nematodes. Plants infected by Meloidogyne spp. develop above-ground symptoms, stunting, yellowing, nutrient deficiencies, and gall formations with typical hook-shaped root tips. Infected plants experience yield losses. During 2018-2019 survey, leaf chlorosis rice plants were found in 206 fields of 67 counties in Guangxi, China, around 30 days after transplanting. Galls and hooked tips on the roots and pear-shaped females were observed. About 32.04% of fields were infested with the nematode. The nematodes were identified as Meloidogyne graminicola base on morphological and molecular analysis. To the best of our knowledge, this is the first report of M. graminicola on rice plants in Guangxi, China. The results of this study urge the discovery of resistant cultivars and the development of management strategies.

• 농업과학연구
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• 제42권2호
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• pp.111-116
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• 2015

Combined applications of rice bran with pine leaves were tested to examine the inhibitory effects to paddy weeds and increased yield of rice for developing techniques of environment-friendly weed management in paddy rice fields. Weed control efficacy at 60 days after treatment was improved to 88.8% by combined application of rice bran with pine leaves, while weed control efficacy by single application of rice bran showed 67.5%. The other weed control efficacy combined with chestnut leaves and barley straws were 76.3% and 69.9% respectively. Combined application of rice bran with pine leaves was more effective to broadleaf weeds such as Monochoria vaginalis. Weed control efficacy by combined application with pine leaves was 100% until 70 days after rice transplanting and maintained weed control effect up to 90 days after transplanting. Rice yield by combined application of rice bran with pine leaves was 526 kg/10 a, which was higher yield than by combined application with barley straws, single application of rice bran, natural snail application and hand weeding.

• Journal of Ecology and Environment
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• 제33권2호
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• pp.149-155
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• 2010

This study was conducted to investigate the feeding efficiency of the cattle egret (Bubulcus ibis) and the intermediate egret (Ardea intermedia) in relation to the stage of rice culture during two breeding seasons, 2006 and 2007, in Asan city, Chungcheongnam-do, South Korea. Cattle egrets caught mainly small invertebrate prey (insects and spiders, 98.4%) during all stages of rice cultivation, and had a higher prey capture rate in the plowing stage (14.98 prey/min) than in other stages (2.82-3.51 prey/min). Therefore, the biomass intake rate of cattle egrets was highest in the plowing stage. The intermediate egret captured both loaches (43.4%) and small invertebrates (50.6%). The prey capture rates of intermediate egrets increased gradually from the flooding stage (0.38 prey/min) to the planting stage (1.09 prey/min), and decreased in the growing stage (1.04 prey/min). However, intermediate egrets had the highest biomass intake rates in the plowing stage because more loaches were caught in the plowing stage (0.54 loaches/min) than other stages (0.23-0.36 loaches/min). Consequently, both intermediate egrets and cattle egrets had high energy intakes in the plowing stage and rice fields provided an important feeding habitat for both species.

• 한국식물병리학회지
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• 제13권2호
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• pp.79-84
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• 1997

Incidence of rice blast on new rice cultivars and elite lines was observed from 194 to 1996 in Icheon, Chuncheon, Jecheon and Naju areas. The observations were made in the nuseries and in the fields. In the nurseries, only cultivars Daesanbyeo and Hyangmibyeo 2 showed moderate levels of resistance to leaf blast, with the disease index 0 to 6. From the field observations, it was found that cultivars Hyangmibyeo 2 and Suwon 414 were highly resistant to leaf blast, but susceptible to neck blast. the fields, leaf blast was not observed. In general, there was great yearly and regional variation in the incidence of neck blast within the same cultivars, some times ranging from 0 to 100% of incidence. However, the range of fluctuation in the disease incidence were relatively small in the cultivars Daejinbyeo (0∼17.5%), Daesanbyeo (0∼4.0%), Donganbyeo (0∼21.4%) and Hwasambyeo (0∼13.9%). Hyangmibyeo 2 and Seojinbyeo were rarely infected with neck blast in Chuncheon and Naju all of the years, the same cultivars were severely infested with neck blast; 45.1 and 45.5%, respectively, in Jecheon in 1995. The occurrence of different races of rice blast fungus were different at different areas. However, it was found that in Icheon, Chuncheon, Jecheon and Naju areas, the dominant races were KI-409, KJ-201 and KJ-301.

• 한국농공학회지
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• 제42권3호
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• pp.5-17
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• 2000

The story of route of wet-rice diffusion to Korean peninsular is so far known only piecemeal. It is however commonly agreed that wet-rice technology may have spread the western coastal area in Korea from the lower and middle reaches of the yangzi river in China and to the Shandong peninsular and Bohai Bay region and was then transmitted overland to the area in Korea. Recently excavated three prehistoric paddy fields in Korea provide crucial evidence that helps to solve many of the important problems associated with technological diffusion. Research on the paddy field system and irrigation technology of prehistoric wet-rice has been so far especially productive in Japanese archaeology. Judging from the fact that the Yayoi wet-rice agricultural technology in Japan was transmitted by the Korean Strait from the southern part of Korea it is assumed that people in both regions may have practiced the same technology in prehistoric time. This paper examines three prehistoric paddy fields system(the Majon-ri site the Kwanchang-ri site and the Mujon-dong site) in relation to those of japanese data. The conclusions are as follows ; First early wet-rice agriculture in korea was limited by the level of technology and the size of labour. Secondly the location of field itself was restricted to the lower land and valley bottom area. Thirdly the layout of channel and field network is not very much different from the modern paddy field system.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.374-383
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• 2021

Rhizoctonia solani is one of the major pathogens that cause sheath blight disease in rice. Sheath blight is one of the most difficult diseases to control. Biological control (with the use of rhizobacteria) is one of the ways to control this disease. Plant Growth Promoting Rhizobacteria (PGPR) is a rhizosphere bacterium that can be used to enhance plant growth. The composition of the rhizobacteria in organic and nonorganic soil is affected by the chemical characteristics of the soil - which influences plant physiology and root exudation patterns. This study aimed to obtain a species of rhizobacteria which shows PGPR activity, from organic and nonorganic rice fields and test their capability to suppress R. solani growth. Out of 23 isolates screened for PGPR activity, the following isolates showed high PGPR activity and were selected for in vitro antagonistic activity testing against R. solani: ISO6, ISO11, ISO15, ISN2, ISN3, and ISN7, The six isolates produced 43,42-75,23 ppm of IAA, possessed phosphorus solubilization capability, and chitinase-producing activity. ISO6 (54.88%) and ISN7 (83.33%) displayed high inhibition capacities against R. solani, in vitro. ISO6 and ISN7 inhibited the growth of R. solani lesions on rice leaves by 89% and 100% (without lesion), respectively, after 7 days of incubation. Analysis of their 16S rRNA sequences revealed that the ISO6 isolate was Citrobacter freundii and ISN7 isolate was Pseudomonas aeruginosa.

• 한국전자파학회논문지
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• 제18권7호
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• pp.819-827
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• 2007

본 논문은 논에 대한 전파 산란 특성을 측정하고, 수치적 계산 결과와 비교함으로써 벼의 수치적 모델링에 대한 전파 산란 알고리즘을 제시하고자 한다. 임피던스 경계 조건과 dyadic 그린함수로부터 임피던스 표면 위(수면)의 손실 있는 유전체(벼)에 대한 적분 방정식을 유도하였고, 모멘트 법을 이용하여 유전체의 체적 전류를 계산하였다. 또한, 몬테 카를로 방법을 적용하여 입사 각도 및 편파에 따른 후방 산란 계수를 수치적으로 계산하였다. 1.85 GHz의 측정 시스템을 이용하여 논의 후방 산란 계수를 측정하였으며, 본 논문에서 제시한 알고리즘의 계산 결과와 비교, 검증하였다.