• 한국농공학회지
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• 제44권7호
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• pp.14-24
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• 2002

The effect of reclaimed water irrigation on paddy rice culture was evaluated by pilot study at the experimental field of Konkuk University in Seoul, Korea. The sewage was treated by constructed wetland system, and its effluent was used as irrigation water for four treatments and one control plots with three replications. Irrigation of reclaimed water onto paddy rice cultures did not adversely affect the growth and yield of rice. Instead, experimental rice plots of reclaimed water irrigation displayed about 10 to 50% more yield on average than controls. This implies that reclaimed water irrigation might be beneficial rather than harmful to rice culture as long as the sewage is treated adequately and used properly. The amount of irrigation water had little effect on experimental rice cultures, but its strength was important. The strength of treated sewage was not a limiting factor in this study, and no lodging was observed even with a relatively high nitrogen concentration (up to 160mg/L). In general the paddy soil was not affected by reclaimed water irrigation. However, there was an indication that continuous irrigation with high strength of reclaimed water might cause salt accumulation in the soil. Supplemental use of reclaimed water with existing sources of irrigation water is recommended rather than irrigation with a single source of reclaimed water. Overall, the results demonstrated that reclaimed water could be reused as a supplemental source of irrigation water for paddy rice culture without causing adverse effects as long as it is properly managed. For full-scale application, further investigation should be done on environmental risks, tolerable water quality, and fraction of supplemental irrigation.

• 한국응용곤충학회지
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• 제44권4호
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• pp.337-339
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• 2005

익산지역에서 벼 줄점팔랑나비(Parnara guttata)는 1년에 3세대를 경과하며, 5월중 하순부터 월동처에서 우화하여 논으로 이동한 다음 벼 잎에 산란하기 시작하였다. 유충에 의한 벼의 피해는 7월 하순부터 증가하여 8월 중 하순 사이에 가장 많은 것으로 관찰되었으며, 3세대 성충이 우화하기 시작하는 시기는 9월 중순이었다. 벼의 이망시기와 줄점팔랑나비에 의한 피해는 만식한 논에서 켰다. 살충제를 유충발생 최성기 약 1주일 전인 7월 하순에 처리하였을 때 91.2%의 방제효과를 나타낸 반면 8월 초순에 처리할 경우에는 방제효과가 57.2%로 낮았다.

• 한국농공학회논문집
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• 제59권4호
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• pp.27-42
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• 2017

The global rise in atmospheric $CO_2$ concentration and its associated climate change have significant effects on agricultural productivity and hydrological cycle. For food security and agricultural water resources planning, it is critical to investigate the impact of climate change on changes in agricultural productivity and water consumption. APEX-Paddy model, which is the modified version of APEX (Agricultural Policy/Environmental eXtender) model for paddy ecosystem, was used to evaluate rice productivity and evapotranspiration based on climate change scenario. Two study areas (Gimjae, Icheon) were selected and the input dataset was obtained from the literature. RCP (Representitive Concentration Pathways) based climate change scenarios were provided by KMA (Korean Meteorological Administration). Rice yield data from 1997 to 2015 were used to validate APEX-Paddy model. The effects of climate change were evaluated at a 30-year interval, such as the 1990s (historical, 1976~2005), the 2025s (2011~2040), the 2055s (2041~2070), and the 2085s (2071~2100). Climate change scenarios showed that the overall evapotranspiration in the 2085s reduced from 10.5 % to 16.3 %. The evaporations were reduced from 15.6 % to 21.7 % due to shortend growth period, the transpirations were reduced from 0.0% to 24.2 % due to increased $CO_2$ concentration and shortend growth period. In case of rice yield, in the 2085s were reduced from 6.0% to 25.0 % compared with the ones in the 1990s. The findings of this study would play a significant role as the basics for evaluating the vulnerability of paddy rice productivity and water management plan against climate change.

• 한국토양비료학회지
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• 제4권2호
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• pp.177-186
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• 1971

벼생육기간에 있어서 논토양에 시용된 퇴비 생집 등의 유기물 효과를 밝히기 위하여 시험했든 기존성적들을 요약하면 다음과 같다. 1. 토양개량제의 면에서 배수가 양호한 토양에서는 퇴비의 효과가 인정되었고 습답이나 배수불량한 논토양에서의 효과는 보지 못했다. 2. 생집의 효과는 토양조건에 따라 퇴비의 효과보다 한정되어 있으며 생집은 초기 벼생육을 억제하고 후기양분 보존 면에서 효과가 있었다. 3. 생집시용시의 수종문제점도 역시 논의되었다.

• 한국작물학회지
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• 제55권2호
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• pp.98-104
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• 2010

논을 밭으로 1년 전환 후 다시 논으로 복원한 논에서의 벼의 생육촉진 및 질소흡수 증가의 효과를 살펴보기 위하여 복원논 1년 및 2년차인 2006년 및 2007년에 복원논 및 연작논을 대상으로 질소비료를 0, 3, 6 kg $10a^{-1}$ 시용하여 벼의 생육량, 질소흡수량, 쌀의 수량 및 단백질 함량 등을 조사하였는데 결과는 다음과 같다. 연작논에 비해 복원논에서 복원 1년 및 2년차 모두 벼의 초기생육이 크게 증가하여 유수형성기 건물중 및 질소함량이 증가하였으며, 복원논에서도 질소시비량 증가에 따라 건물중 및 질소량이 증가하여 질소시비량 6 kg $10a^{-1}$까지 질소시비 효과가 뚜렷이 나타났는데, 복원논 1년차 및 2년차의 질소무비구의 건물중 및 질소흡수량은 각각 연작논의 질소시비량 6 및 3 kg $10a^{-1}$와 동일한 값을 나타내었다. 수확기에서의 벼의 건물중 및 질소흡수량도 유수형성기와 비슷한 경향을 보였으며, 질소시비 방법으로는 같은 량의 질소시비량이라도 전량을 기비로 시용한 것보다 유수형성기에 추비로 3 kg $10a^{-1}$를 시용한구가 질소흡수량이 다소 높았다. 수량구성요소에서는 연작논에 비해 복원논에서 벼의 수당립수가 증가하는 경향이었으며, 질소시비량이 많아질수록 등숙율이 감소하였는데, 특히 질소흡수량이 많았던 복원논-질소시비량 6 kg $10a^{-1}$ 구에서의 등숙비율이 많이 감소하였다. 벼의 수량도 복원논이 연작논에 비해 복원 1년차 및 2년차 모두 연작논보다 증가하였는데, 복원 1년차는 질소시비량간 벼수량의 차이가 없었지만, 복원 2년차에는 무질소시비구에서 벼의 수량이 다소 감소하였다. 현미 및 백미의 단백질 함량은 복원논이 연작논보다, 질소시비량이 증대할수록 높아졌는데, 질소시비방법에서는 질소시비량 모두 3, 6 kg $10a^{-1}$ 모두 유수형성기에서 추비로 3 kg $10a^{-1}$를 준 구에서 높아 질소흡수량이 많은 복원논에서 질소를 추비로 줄 때 단백질함량이 증대할 위험성이 높았다.

• 한국환경농학회지
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• 제30권1호
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• pp.1-8
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• 2011

BACKGROUND: With increasing public awareness to environment-friendly agriculture, many efforts have been run to develop organic farming technologies in Korea as of late 90s. The objective of this study was to investigate the effects of different organic farming practices on soil chemical properties and water quality in paddy fields. METHODS AND RESULTS: Total nitrogen (TN) and total phosphorus (TP) were monitored for a two-year period (2006 to 2007) from the study organic paddy fields located in Wan-ju, Jeonbuk Province in Korea. TN and TP of organic paddy water were gradually increased for 2~3 weeks after organic manure application and then gradually decreased afterward. The overall variation of TP in the paddy fields was much greater than that of TN. The phosphorus content in organic paddy field appeared to increase with the organic farming period. CONCLUSION(s): This indicates that long-term organic farming is likely to cause phosphorus accumulation in soils and increase vulnerability to rainfall runoff. Thus, appropriate phosphorus management needs to be implemented, particularly, to reduce excessive phosphorus supply owing to nitrogen-based determination of organic manure application amount.

• 한국농공학회논문집
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• 제60권5호
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• pp.41-54
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• 2018

A method to account a detention in a rice paddy field in hydrologic modeling was tested at plot and watershed scales. Hydrologic Simulation Program - Fortran (HSPF) and its one of surface runoff modeling method, i.e Surface-Ftable, were used to simulate a inundated condition in a rice paddy culture for a study plot and basins in Saemangeum watershed. Surface-Ftable in HSPF defines surface runoff ratio with respect to surface water depth in a pervious land segment, which can be implemented to the feature of water management in a rice paddy field. A Surface-Ftable for paddy fields in Saemangeum watershed was developed based on the study paddy field monitoring data from 2013 to 2014, and was applied to Jeonju-chun and Jeongeup-chun basins which comprise 12% and 22% of paddy fields in the basins, respectively. Four gaging stations were used to calibrate and validate the watershed models for the period of 2009 and 2013. Model performed 7.13% and 9.68% in PBIAS, and 0.94 and 0.90 in monthly NSE during model calibrations at Jeonju and Jeongeup stations, respectively, while the models were validated its applicability at Hyoja and Gongpyung stations. The comparison of results with and without considering detention effect of paddy fields confirmed the validity of the Surface-Ftable method in modeling watersheds containing rice paddy fields.

• 한국토양비료학회지
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• 제49권4호
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• pp.335-340
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• 2016

Soil organic carbon plays an important role on soil physico-chemical properties and crop yields in paddy soil. However, there is little information on the soil organic carbon under different forage cultivation during winter season in rice paddy. In this study, we investigated the soil organic carbon and physico-chemical properties in 87 fields of paddy soil cultivated with Barley, rye, and Italian ryegrass (IRG) as animal feedstock during winter season. Organic carbon was 12.9, 14.3, and $16.9g\;C\;kg^{-1}$ in soil with barley, rye, and IRG cultivation, respectively. Among rice-forage cultivation systems, the rice+IRG cropping system was 19.5% higher than in the mono-rice cultivation. Bulk density ranged from 1.17 to $1.28g\;cm^{-3}$ irrespective of cropping systems, and had strongly negative correlation with the soil organic carbon in the rice+IRG cropping system. Carbon storage in rice+IRG cropping systems was average $29.6Mg\;ha^{-1}$ at 15 cm of soil depth, which was 20.4 and 10.3% higher than those of barley and rye cultivation. Increasing carbon storage in paddy soil contributed to the fertility for following rice cultivation. This results indicated that IRG cultivation during winter season could be an alternative and promising way to enhance soil organic carbon content and fertility of paddy soil.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.319-319
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• 2017

Methane is the main greenhouse gas released from rice paddy field. Methane from paddy fields accounts for 11 % of the global total methane emission. The global warming potential (GWP) of methane is 25 times more than that of carbon dioxide on a mass basis. It is well known that most effective practice to mitigate methane in paddy is related to the water management during rice growing season and the use of organic matters. This study was conducted to investigate the effects of tillage and cultivation method on methane emission in paddy. Tillage (tillage and no-tillage) and cultivation methods (transplanting and direct seeding) were combined tillage-transplanting (T-T), tillage-wet hill seeding (T-W), tillage-dry seeding (T-D) and no-till dry seeding (NT-D) to evaluate methane mitigation efficiency. Daily methane emission was decreased on seeding treatments (T-W, T-D, NT-D) than transplanting treatment (T-T). Amount of methane emission during rice growing season is highest in T-T ($411.7CH_4\;kg\;ha^{-1}y^{-1}$) and lowest in NT-D treatment (89.7). In T-W and T-D treatments, methane emissions were significantly decreased by 36 and 51 % respectively compared with T-T. Methane emissions were highly correlated with the dry weight of whole rice plant ($R^2=0.62{\sim}0.93$). T-T treatment showed highest $R^2$ (0.93) among the four treatments. Rice grain yields did not significantly differ with the tillage and cultivation methods used. These results suggest that direct seeding practice in rice production could mitigate the methane emissions without loss in grain yield.

• 한국토양비료학회지
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• 제51권1호
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• pp.61-70
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• 2018

This study was carried out to review and compare crop cultivations upon chemical properties of paddy soil and qualitative characteristics of rice in Sejong-city from a point of view of farming extension to rice farmers and to utilize the result of the study as a basic guideline for precise agricultural practice. The pH in soils of Sejong was about 6.1-6.6 and had no difference with an average pH of paddy soils in Chung-Nam with pH 6.1. However, the average of organic matter, calcium (Ca) and available silicate in Sejong was lower than the average of them in Chung-Nam. The yields of rice were higher in 2010 than in 2011 and 2012, and the protein contents of rice were the highest in 2011 while the lowest water contents of rice in 2011. The protein contents upon regions were the highest in 2011 with 6.1%, and the amylose contents were the highest in Yeondong-myun, Jeoneu-myun, and Yeonseo-myun in 2010 while Kumnam-myun and Jeondong-myun were the highest in 2012. With the increase of precipitation, the protein content level in rice was increased while the amylose content level tended to decrease. Correlations between the chemical properties of paddy soil and the quality of rice and between level of organic matter in soil and amylose contents were negative (r = -0.507), and the correlation between the moisture contents and amylose contents (r = 0.419) and between the water contents and whiteness (r = 0.485) were positive. Because the quantity and quality of rice yield is determined by the soil characteristics, the consultation to farmers for the proactive soil analysis and for the maintenance of stable level of pH, organic matter and available silicate based on historical results of analysis is highly recommended. Also, the analysis on the effect of the weather and the soil characteristics affecting the quality and quantity of rice would be another good way.