• 한국작물학회지
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• 제57권4호
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• pp.430-435
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• 2012

밭전환 1년차 논의 토양물리성 악화를 개선하고 사료용 옥수수 생육을 증진시키기 위한 심토파쇄의 효과를 살펴본 결과 다음과 같은 결과를 얻었다. 1. 심토파쇄에 의해 토심 25~35 cm 층위의 토양의 경도가 크게 감소하였고 토층 15~30 cm에서 가밀도, 공극율 및 고상비율 등 하층토의 토양물리성이 개선되는 것으로 나타났다. 2. 심토파쇄 추가 시 옥수수의 간엽 및 이삭의 생육이 크게 증가하였으며, 특히 이삭당 립수의 증가가 이삭중을 크게 증가시키는 것으로 나타났다. 3. 심토파쇄 추가 시 옥수수는 이삭 및 간엽의 수량증가에 의해 TDN 수량이 19~39% 증가하였으며, 특히 습해에 의해 생육이 불량한 2011년도의 옥수수의 생육촉진 효과가 컸다.

• 한국토양비료학회지
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• 제43권6호
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• pp.911-916
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• 2010

농업활동 중 경종분야인 벼재배와 작물잔사 소각은 온실가스인 메탄의 주 발생원이다. 이번 연구는 1990년부터 2008년까지 우리나라 경종분야에서 발생하는 메탄 배출량을 평가하기 위해 수행되었다. 우리나라에서 벼 재배에 의한 메탄 배출량은 1990년 395 천 톤에서 2008년 297 천 톤으로 벼 재배면적의 감소에 따라 지속적으로 감소하는 경향을 보였다. 작물잔사 소각에 의한 메탄 배출량은 1990년 2,502 톤에서 2008년 2,726 톤으로 작물별 차이는 있었으나 연도별 전체 배출량에는 큰 변화없이 일정한 값을 유지하였다. 작물잔사 소각에 의한 메탄 배출은 경종부분 전제 배출량에는 큰 영향을 미치지 않았다. 벼재배와 작물잔사 소각에 의한 총 메탄 배출량을 이산화탄소로 환산한 값은 1990년 8,356 천 톤 $CO_2$-eq.에서 2008년 6,287 천 톤$CO_2$-eq.로 나타났다. 농업부문의 온실가스 배출량 평가의 정확도 제고를 위해서는 활동자료의 신뢰성 확보가 무엇보다도 중요하다. 2010년부터 농촌진흥청과 통계청이 공동으로 활동자료의 공식적인 조사를 시작하였으며, 이러한 체계적인 활동량 조사는 농업부문 온실가스 배출량 평가의 신뢰도 향상과 불확도 저감에 크게 기여할 것으로 예상된다.

• 한국약용작물학회지
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• 제21권5호
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• pp.380-387
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• 2013

This study was carried out to investigate the difference of the content of soil chemical components and growth characteristics in five years old ginseng affected by application of manure in paddy-converted field. As all livestock manure regardless of kinds increased along with the whole soil chemical component, including the pH and EC in 2008. Change in the EC of control plot was slightly increased but not exceeded 1 ds/m over the years. However, the changes in the EC of livestock manure regardless of kinds and amounts were highly increased and irregularly exceeded 1.5 ds/m in 2012. The 5 years old ginseng root fresh weight, treatment of fertilizing pig manure compost 4 ton per 10 areas (PMC 4t on/10a) and fowl manure compost 4 ton per 10 areas (FMC 4 ton/10a), were superior to the others. But there were no difference between PMC 4 ton/10a, FMC 4 ton/10a and control. The standing crop rate 39.6%, treatment of fertilizing cattle manure compost 4 ton per 10 areas (CMC 4 ton/10a), was best in all livestock manure. However that was relatively lower than control. Physiological disorder occurrence rates of livestock manure related with leaf and root of ginseng were also higher than that of control. If excessively using non-decomposed livestock manure, It would be caused physiological disorder in many ways. It is a big problem to be producing the quality ginseng. More research is needed to find out the economic and effective fertilizer.

• 한국약용작물학회지
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• 제22권2호
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• pp.140-146
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• 2014

This study was carried out to investigate the difference of the content of soil chemical components and growth characteristics in six years old ginseng affected by application of decomposing plant residues in paddy-converted field. The results show that aerial parts of ginseng are no difference between press cake (PC) 200 kg/10a and control but subterranean parts of ginseng PC 200 kg/10a, especially quantity related root fresh weight and tap root diameter, are statically about 1.6 times heavier and about 1.2 times thicker than the ginseng control. Furthermore, the survival rate of PC 200 kg/10a is 67.1% rise significantly compare with the control 50.7%. But compared with the PC 200 kg/10a and the PC 400 kg/10a, ginseng root growth and survival rate of PC 400 kg/10a get worse and that increase physiological disorder occurrence rate than PC 200 kg/10a. Even though there are no significant differences between the ginseng of decomposing plant residues except press cake treatment and the ginseng of control in growth characteristics, it does tend to increase the survival rate and decrease the physiological disorder occurrence rate in most fertilizer treatment except for RSC 2 ton/10a, RSC 4 ton/10a and RH 4 kL/10a. Noted that EC is highly increased and exceeded 1.7 ds/m in RSC 2 ton/10a, RSC 4 ton/10a and RH 4kL/10a. It would be caused physiological disorder in many ways and affected ginseng growth characteristics, survival rate.

• 한국농공학회논문집
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• 제63권6호
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• pp.27-37
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• 2021

Conversion of rice paddy field to upland has been accelerated as the central government incentivizes more profitable upland crop cultivation. The objective of this study was to investigate the current status and conversion trend from paddy to upland for the reservoir irrigation districts. Total 605 of reservoir irrigation districts whose beneficiary area is greater than 200 ha were selected for paddy-to-upland conversion analysis using the land cover maps provided by the EGIS of the Ministry of Environment. The land cover data of 2019 was used to analyze up-to-date upland conversion status and its correlation with city proximity, while land cover change between 2007 and 2019 was used for paddy-to-upland conversion trend analysis. Overall 14.8% of the entire study reservoir irrigation area was converted to upland cultivation including greenhouse and orchard areas. Approximately the portion of paddy area was reduced by 17.8% on average, while upland area was increased by 4.9% over the 12 years from 2007 to 2019. This conversion from paddy to upland cultivation was more pronounced in the Gyoenggi and Gyeongsang regions compared to other the Jeolla and Chungcheong provinces. The increase of upland area was also more notable in proximity of the major city. This study findings may assist to identify some hot reservoir districts of the rapid conversion to upland cultivation and thus plan to transition toward upland irrigation system.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2011년도 추계학술발표회
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• pp.366-367
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• 2011

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.308-308
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• 2017

The low and unstable yield of soybean has been a major problem in Japan. Excess soil moisture conditions are one of the major factors to restrict soybean productivity. More than 80 % of soybean crops are cultivated in converted paddy fields which often have poor drainage. In central and eastern regions of Japan, the early vegetative growth of soybean tends to be restricted by the flooding damage because the early growth period is overlapped with the rainy season. Field observation shows that induced excess water stress in early vegetative stage reduces dry matter production by decreasing intercepted radiation by leaf and radiation use efficiency (RUE) (Bajgain et al., 2015). Therefore, it is necessary to evaluate the responses of soybean growth for excess water conditions to assess these effects on soybean productions. In this study, we aim to modify the soybean crop model (Sinclair et al., 2003) by adding the components of the restriction of leaf area development and RUE for adaptable to excess water conditions. This model was consist of five components, phenological model, leaf area development model, dry matter production model, plant nitrogen model and soil water balance model. The model structures and parameters were estimated from the data obtained from the field experiment in Tsukuba. The excess water effects on the leaf area development were modeled with consideration of decrease of blanch emergence and individual leaf expansion as a function of temperature and ground water level from pot experiments. The nitrogen fixation and nitrogen absorption from soil were assumed to be inhibited by excess water stress and the RUE was assumed to be decreasing according to the decline of leaf nitrogen concentration. The results of the modified model were better agreement with the field observations of the induced excess water stress in paddy field. By coupling the crop model and the ground water level model, it may be possible to assess the impact of excess water conditions for soybean production quantitatively.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.315-315
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• 2017

In Japan, more than 80 % of soybean growing area is converted fields and excess water is one of the major problems in soybean production. For example, recent study (Yoshifuji et al., 2016) suggested that in the fields of shallow groundwater level (GWL) (< 1m depth), rising GWL even in a short period (e.g. 1 day) causes inhibition of soybean growth. Thus it becomes more and more important to predict GWL and soil moisture in detail. In addition to conventional surface drainage and underdrain, FOEAS (Farm Oriented Enhancing Aquatic System), which is expected to control GWL in fields adequately, has been developed recently. In this study we attempted to predict GWL and soil moisture condition at the converted field with FOEAS in Biwa lake reclamation area, Shiga prefecture, near the center of the main island of Japan. Two dimensional HYDRUS model (Simuinek et al., 1999) based on common Richards' equation, was used for the calculation of soil water movement. The calculation domain was considered to be 10 and 5 meter in horizontal and vertical direction, respectively, with two layers, i.e. 20cm-thick of plowed layer and underlying subsoil layer. The center of main underdrain (10 cm in diameter) was assumed to be 5 meter from the both ends of the domain and 10-60cm depth from the surface in accordance with the field experiment. The hydraulic parameters of the soil was estimated with the digital soil map in "Soil information web viewer" and Agricultural soil-profile physical properties database, Japan (SolphyJ) (Kato and Nishimura, 2016). Hourly rainfall depth and daily potential evapo-transpiration rate data were given as the upper boundary condition (B.C.). For the bottom B.C., constant upward flux, which meant the inflow flux to the field from outside, was given. Seepage face condition was employed for the surrounding of the underdrain. Initial condition was employed as GWL=60cm. Then we compared the simulated and observed results of volumetric water content at depth of 15cm and GWL. While the model described the variation of GWL well, it tended to overestimate the soil moisture through the growing period. Judging from the field condition, and observed data of soil moisture and GWL, consideration of soil structure (e.g. cracks and clods) in determination of soil hydraulic parameters at the plowed layer may improve the simulation results of soil moisture.

• 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.

• 한국작물학회지
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• 제55권2호
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• pp.91-97
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• 2010

The growth, yield and chemical properties of waxy corn $Sonjajang{\times}KNU-7$ and $Asan{\times}KNU-7$ planted in different dates and mulch types in a converted paddy field was investigated. Experiment was carried out in a randomized complete block design in a split split-plot arrangement with four replications. Planting dates (D) [May 16 (D1, early), June 1 (D2, middle), June 6 (D3, late)] represented main plots, plastic mulch (M) [(BM, black mulch; TM, transparent mulch)] for subplots while waxy corn crosses [$Sonjajang{\times}KNU-7$ (‘Sonja’) and $Asan{\times}KNU-7$ (‘Asan’)] for sub-subplots. Results showed that D had a significant effect on growth characters except emergence, ear quality except ear diameter, and yield whereas M showed significant effect on growth characters only. Superior growth and ear quality performance were recorded in D1 and BM. In terms of crosses, ‘Sonja’ had better growth performance than ‘Asan’ regardless of D and M, but performed better at D1 and BM. Highest yield was obtained in D1 for BM (2,131 kg $10a^{-1}$) and TM (1,655 kg $10a^{-1}$) but no significant difference in the yield across V was recorded. In terms of starch and sugar contents, a decreasing trend was observed from D1 to D3 regardless of M and V.