• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.2
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• pp.118-127
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• 1984

In order to find an appropriate model for rice crop-season, the possibility to utilize the geographical conditions instead of meteorological factors was examined on the data from the Local Adaptability Test(LAT) conducted over the country from 1962 to 1980. The mutiple regression model, $Y={\Upsilon}={\ss}{\sum}_{i=1}^n{\beta}^1X^iwas applied on seeding, transplanting, heading and marginal heading date, and multiple regression coefficients(\beta) and multiple correlation coefficients (R) were tested. Two varietal groups, japonica(1962-l971) and indica/japonica(l972-1980) were separately tested. The application of these established models, growth duration in nursery and paddy field, cultural season, and the relation between heading date and yield are reviewed.

• Korean Journal of Agricultural Science
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• v.2 no.1
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• pp.151-177
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• 1975

To obtain the informations on the checking factors of the effecient utilization of paddies in chungnam province and study on the effecient working system and high productive cropping system in paddies, the utilization state of paddies including environmental conditions were investigated at sample 1,500 farms. The results obtained are summarized as follows; 1. The difficulty of drainage in paddies was the most important factor checking the utility of paddies. Delayed transplanting of rice and lack of labour were also important checking factors on the efficient utilization of paddies. 2. The utilization of paddies was rather effecient at small size farms of which farmers were almost poor, and most of them cultivated barley for their own food. 3. Considering climatic conditions, pre-crops of rice must be harvested before June 10 tho and the marginal transplanting date of rice plant is June 25 th. 4. In case of planting barley as a post-crop after rice, the spread seeding by rotary before plowing was most efficient with lowest cost. 5. Considering rice cultivation, yield of barley and net income, the most efficient cropping system was "Josaengtongil + Olbori".

• Journal of Climate Change Research
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• v.7 no.4
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• pp.383-390
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• 2016

According to the "Framework Act on Low Carbon, Green Growth", publication of annual national greenhouse gas (GHG) inventory report is mandatory. This annual GHG inventory report is used as basal data for GHG mitigation strategies. In the livestock sector, GHG emission trends from year 1990 to 2013 were estimated based on the 1996 IPCC guidelines with the Tier 1 methodology. GHG emissions from the livestock sector in 2013 were 9.9 million tons $CO_2-eq$., where emissions from enteric fermentation were 4.4 million tons $CO_2-eq$, increased by 47.4% over 1990 mainly due to the increase in non-dairy cattle population. On the other hand, GHG emissions from livestock manure in 2013 were 5.5 million tons $CO_2-eq$, increased by 75.5% over 1990 mainly due to the increase in non-dairy cattle, swine and poultry populations. Additional research is required to develop country-specific emission factors to estimate GHG emissions precisely from livestock in South Korea.

• Korean journal of applied entomology
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• v.21 no.1 s.50
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• pp.38-48
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• 1982

This study was conducted to investigate the changes in moth occurrence of striped rice barer, Chilo suppressalis (Walker), in relation to climatic factors, rice varieties, and cultural practices. The light trap data from 41 forecasting stations for 14 years from 1966 to 1979 were analyzed by means of the changes in the time and amount of borer occurrence in connection with the introduction of new rice varieties, the accumulated effective day-degree and its variation for completing one generation, and the climatic factors affecting the moth occurrence. The total number of moths caught by light traps in both spring and summer generations were considerably decreased with the wide cultivation of new rice varieties. In fact, the spring moths were remarkably decreased since the new varieties were introduced in 1972. The occurrence ratio of summer moths against the preceeding spring moths was higher in the middle region and middle southern mountainous area than the other regions. Its high ratio of regions was annually expanded from the middle region to the southern region. The $50\%$ emergence dates of both generations were later in the southeastern region than in the middle region. The ecological characteristics were clearly shown between the northern and southern region of Chupungryeong in terms of the occurrence of summer moths, the ratio of occurrence of summer moths to the preceeding spring moths, and $50\%$ emergence dates of the summer moths during the years of $1977\~1979$. The ratio of the summer moth occurrence to the preceeding generation was negatively correlated with the average temperature in lune and July, respectively, and the average precipitation in late June. The ratio of spring moth occurrence over the preceeding generation was positively correlated with the average temperature in September, October, November, and March, respectively, whereas it was negatively correlated with the average precipitation in early September and March, and the average humidity in early May. The effective day-degree for one generation was in the range from 600 to 900 DD at upper threshold $30^{\circ}C$ and lower threshold $10^{\circ}C$.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.4
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• pp.303-308
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• 2015

Cultivating genetically modified (GM) crops is believed to be a practical solution to meet the increasing food demand, but GM crops are not legal in Korea mainly due to food safety issues. Even though the general public might not be ready to consume GM food, GM crops are imported and consumed as food and feed. To analyze farmers's willingness to grow GM crops for feed, a survey was conducted among crop farmers and 640 valid responses were collected by mail. In the questionnaire, the farmers were asked to select either 'yes' or 'no' if they were willing or not willing to cultivate GM rice and GM grass, respectively, under the given hypothetical income increase rate (i.e., 10%, 20%, 30%, 40%, 50%, 60%, or 70%). Logit regression was used to estimate the two dichotomous choices by explanatory variables including hypothetical income increase rate. The results show that farmers are willing to cultivate GM rice and grass when their income is expected to increase by 47% and 43%, respectively.

• Journal of Animal Environmental Science
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• v.15 no.1
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• pp.69-74
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• 2009

A survey questionnaire that addressed the issues to manure compost producers and users was prepared. The questionnaire addressed three main topics as follows: 1) types of manure treatment and composting facilities are being operated, 2) quantity of manure compost produced and used, 3) problems experienced in producing and using manure compost. A total of 30 manure compost producers and 10 manure compost users were interviewed. Solid manure are applied to composting. Slurry and wastewater are simplified aeration method to produce liquid fertilizer. The open elongated type manure composting are generally used on manure compost centers jointly used by several farms. The amount of annually manure compost production was most common in the range of $5{\sim}10$ thousand tons per manure compost center. The manure compost utilization and cucumber yield were mostly $6{\sim}15$ tons and $20{\sim}27$ tons per 10a of cucumber farmland, respectively. Environmentally friendly use both of manure compost and chemical fertilizer are recommended for natural recycling agriculture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.459-466
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• 2021

The present study was conducted to propose future research directions for weed management by examining the current trends of research on weed occurrence according to cropping systems. The cropping systems are developed for the efficient use of arable land, and the weed flora changes according to the management practices of a given cropping system. In particular, weed occurrence can be reduced by altering the soil environment. In addition, cultivation methods, such as tillage, affect the weed seed bank in the soil, thus altering the pattern of weed occurrence. Here, we propose three weed management practices according to the cropping system. First, it is necessary to develop a model that can classify weed species by analyzing young seedlings and can predict the flora in the field. Second, it is important to manage the cropping system history and establish a database of agricultural information, which can be linked to meteorological and geographic data. Third, it is critical to estimate the weed occurrence and soil seed bank dynamics, based on which a cropping system platform and digitalization technology can be developed. In the future, the prediction of weed occurrence and control according to the cropping system will contribute to sustainable agriculture by reducing the use of herbicides and solving the problems of resistant weeds.

• Journal of Practical Agriculture & Fisheries Research
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• v.10 no.1
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• pp.43-58
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• 2008

This research was conducted to determine the alternative tool of chemical spray for rice cultivation using the unmanned helicopter(Yamaha, R-Max Type 2G-remote controlled system) at farmer's field in Korea. The unmanned helicopter tested was introduced form Japan. In Korea the application of chemicals by machine sprayer for pest management in rice cultivation has been ordinarily used at the farmer's level. However, it involved a relatively high cost and laborious for the small scale of cultivation per farm household. Farm population has been highly decreased to 7.5% in 2002 and the population is expected to rapidly reduce by 3.5% in 2012. In Japan, pest control depending on unmanned helicopter has been increased by leaps and bounds. This was due in part to the materialization of the low-cost production technology under agricultural policy and demand environmentally friendly farm products. The practicability of the unmanned helicopter in terms of super efficiency and effectiveness has been proven, and the farmers have understood that the unmanned helicopter is indispensable in the future farming system that they visualized. Also, the unmanned helicopter has been applied to rice, wheat, soybean, vegetables, fruit trees, pine trees for spraying chemicals and/or fertilizers in Japan Effect of disease control by unmanned helicopter was partially approved against rice blast and sheath blight. However, the result was not satisfactory due to the weather conditions and cultural practices. The spray density was also determined in this experiment at 0, 15, 30, and 60cm height from the paddy soil surface and there was 968 spots at 0cm, 1,560 spots at 15cm, 1,923 spots at 30cm, and 2,999 spots at 60cm height. However, no significant difference was found among the treatments. At the same time, there was no phytotoxicity observed under the chemical stray using this unmanned helicopter, nor the rice plant itself was damaged by the wind during the operation.