• 농촌계획
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• 제20권4호
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• pp.35-43
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• 2014

The purpose of this study is to analyze emergy flows of rice for evaluating the value of rice production and sustainability. Emergy analysis evaluates the sustainability of systems or processes considering all the inputs to make a product or a sevice. In this study, we analyzed the emergy flows and indices of rice productionand compared the regional emergy values using statisticcal analysis: input materials, hours per unit area(10a), and production costs. As the results, we found that the rates of external investment (EIR= 18.87) and environmental loading (ELR=21.7) are significantly high during the rice cultivation. However, emergy yield ratio(EYR) shows that rice is a valuable resource because EYR is 5.12 and environmental Sustainability IndexSI value is as low as 0.24 and it shows rice has low sustainability. This study also shows that Chungcheongnam-do has the highest SI value for rice production due to low environmental loading and abundant natural energy during rice cultivation. These results of rice emergy flows and sustainability assessments could provide a way of sustainable rice cultivation with decrease of environmental loading from fertilizer.

• 한국농공학회논문집
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• 제63권3호
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• pp.75-85
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• 2021

This study evaluated variations in the paddy rice water demand based on the continuous changing in rice transplanting period and ponding depth at the four study paddy fields, which represent typical rice producing regions in Korea. Total 7 scenarios on rice transplanting periods were applied while minimum ponding depth of 0 and 20 mm were applied in accordance with maximum ponding depth ranging from 40 mm to 100 mm with 20 mm interval. The weather data from 2013 to 2019 was also considered. The results indicated that the highest rice water demand occurred at high temperature and low rainfall region. Increased rice transplanting periods showed higher rice water demand. The rice water demand for 51 transplanting days closely matched with the actual irrigation water supply. In case of ponding depth, the results showed that the minimum ponding depth had a proportional relationship with rice water demand, while maximum ponding depth showed the contrary results. Minimum ponding depth had a greater impact on rice water demand than the maximum ponding depth. Therefore, these results suggest that increasing the rice transplanting period, which reflects the current practice is desirable for a reliable estimation of rice water demand.

• 한국수자원학회논문집
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• 제33권6호
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• pp.765-774
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• 2000

본 연구는 수계규모에서 과거의 수원공 운영자료를 이용하여 농업용 저수지, 취입보 및 관정 등으로부터 논 관개지구에 공급된 농업용수 공급량의 조사방법을 개발하는 데 그 목적이 있다. 농업용 저수지에 의해 공급된 관개량은 일별 혹은 순별 저수율 자료와 DIROM 모형을 이용하여 추정하였으며, 일별 양수량은 연간 총양수량으로부터 일별 양수패턴을 적용하여 산정하였다. 관정에 의해 취수된 일별 공급량은 논벼의 조용수량과 관정의 설계유량을 고려하여 계산하였으며, 취입보의 일별 공급량은 관개지구의 조용수량, 하천 유량 및 설계취수량 중에서 최소 유량으로부터 구하였다. 1993~1997년의 조사 기간동안에 한강수계에서 공급된 농업용수는 $569백만\;\textrm{m}^3/년부터\;709백만\;\textrm{m}^3/년$의 범위를 보였으며, 5개년 평균 공급량은 $640백만\;\textrm{m}^3/년$이었다.

• 한국농공학회논문집
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• 제56권3호
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• pp.55-64
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• 2014

While utilizing high resolution satellite image for land use classification has been popularized, object-oriented classification has been adapted as an affordable classification method rather than conventional statistical classification. The aim of this study is to extract the paddy field area using object-oriented classification with time series NDVI from high-resolution satellite images, and the RapidEye satellite images of Jaeryung-gun in North Korea were used. For the implementation of object-oriented classification, creating objects by setting of scale and color factors was conducted, then 3 different land use categories including paddy field, forest and water bodies were extracted from the objects applying the variation of time-series NDVI. The unclassified objects which were not involved into the previous extraction classified into 6 categories using unsupervised classification by clustering analysis. Finally, the unsuitable paddy field area were assorted from the topographic factors such as elevation and slope. As the results, about 33.6 % of the total area (32313.1 ha) were classified to the paddy field (10847.9 ha) and 851.0 ha was classified to the unsuitable paddy field based on the topographic factors. The user accuracy of paddy field classification was calculated to 83.3 %, and among those, about 60.0 % of total paddy fields were classified from the time-series NDVI before the unsupervised classification. Other land covers were classified as to upland(5255.2 ha), forest (10961.0 ha), residential area and bare land (3309.6 ha), and lake and river (1784.4 ha) from this object-oriented classification.

• 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.

• 한국농공학회논문집
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• 제54권1호
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• pp.47-54
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• 2012

Agriculture is dependable to weather condition and its change so that it is necessary to understand the impacts of climatic change. The aim of this study is to analyze the change of consumptive use of water and rice yield due to climate change using CERES-Rice. In this study, the weather data of three emission scenario of A1B, A2 and B1 created from CGCM (Coupled General Circulation Model) were used from 2011 to 2100, and downscaled daily weather data were simulated using LARS-WG (Long Ashton Research Station Weather Generator). The input data for cultivated condition for simulating CERSE (Crop-Environment Resource Synthesis)-Rice were created referring to standard cultivation method of paddy rice in Korea. The results showed that consumptive uses of water for paddy rice were projected decreasing to 4.8 % (2025s), 9.1 % (2055s), 12.6 % (2085s) comparing to the baseline value of 403.5 mm in A2 scenario. The rice yield of baseline was 450.7 kg/10a and projected increasing to -0.4 % (2025s), 3.9 % (2055s), 17.5 % (2085s) in A1B scenario. The results demonstrated relationships between consumptive use of water and rice yields due to climate change and can be used for the agricultural water resources development planning and cultivation method of paddy rice for the future.

• 한국작물학회지
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• 제54권1호
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• pp.119-123
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• 2009

최근 활발한 발굴에 따른 곡물의 출토가 많아짐에 따라, 벼의 한반도(韓半島) 전래(傳來) 경로(經路)에 대한 재검토가 필요하다고 생각된다. 특히 한반도(韓半島) 최고(最古) 벼인 청원 소로리(小魯里) 벼의 전래경로에 대하여 제4기 자연환경(自然環境), 생태적(生態的), 작물학적(作物學的)면을 검토한 결과는 다음과 같다. 1. 소로리(小魯里) 볍씨는, 최대빙하기(最大氷河期)이후 한반도가 중국대륙과 하나의 대륙으로 연결되었을 당시 한국조상(韓國祖上) 중 남방계(南方系)의 한 부류가 볍씨를 가지고 중국대륙 남부지역에서 해안을 따라 동북진(東北進)하다가 당시 옛 금강하류(錦江下流)를 거쳐 소로리(小魯里)로 이동하였다고 추정된다. 이를 "옛 금강-소로리 볏길(Old Geumgang-Sorori Rice Road)"이라 명명한다. 2. 유전적(遺傳的) 변이(變異)가 큰 소로리(小魯里)벼는 빙하기이후 지리적(地理的), 생식적(生殖的) 격리(隔離)가 발생함에 따라 한반도(韓半島)의 자연환경(自然環境)에 적응(適應)(자연선택(自然選擇))하게 되어 변이가 적은 고대(古代)벼(가와지(家瓦地)벼)로 종(種)의 분화(分化)(논벼, 수도(水稻))가 이루어졌다고 추정된다. 즉 한반도에서 순화단계(馴化段階)인 소로리(小魯里)벼가 재배(栽培)벼로 발전(發展)하였다고 판단된다.

• 한국농공학회논문집
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• 제53권4호
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• pp.67-74
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• 2011

The objectives of this study were to assess the rice yields and evaluate fertilizer reduction effect of reclaimed wastewater irrigation in paddy fields using the Decision Support System for Agrotechnology Transfer (DSSAT) v4.5 model. The experimental plots were designed, which was located near the Suwon wastewater treatment plant in Gyeonggi-do, Korea. The rice yield, irrigation amount, irrigation water quality and soil data were monitored and collected between 2006 and 2009. The DSSAT model was calibrated and validated with observed data. The methods that were used to evaluate this model were the root mean square error (RMSE), normalized root mean square error (nRMSE), and index of agreement (d). The values of RMSE, nRMSE, and d ranged from 145 to $789\;kg\;ha^{-1}$, 3.0 to 13.3 %, and 0.90 to 0.95 for the calibration period, respectively and represented from 91 to $538\;kg\;ha^{-1}$, 2.0 to 10.4 %, 0.94 to 0.98 for the validation period, respectively. Overall, this model showed good agreement with observed data of rice yields irrigated with reclaimed wastewater. The fertilizer reduction effect in paddy field of reclaimed wastewater irrigation was assessed about 60 % in 2008 and 40 % in 2009.

• 한국농공학회지
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• 제26권4호
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• pp.37-51
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• 1984

The purpose of this study is to find out the determination method of designed duty of water in the rice fields through the comparison of the net unit duty of water at the late reduction division to heading stage with that at the planting stage. The data used for analysing this problem are the data of precipitation and gauge evaporation observed by Cheong-ju Meterological Center, the coefficient of evapotranspiration by College of Agriculture, Chung Buk University and the data of transplanting progressing in Boun area. The results obtained from this analysis are summarized as follows. 1.The occurring year of 1/10 probability value for available precipitation, gauge evaporation and mean maximum daily evapotranspiration during growing season is the year of 1977. 2.The 1/10 probability values of mean maximum evapotranspiration per day under the production rate of 1, 400kg/l0a and 1, 500kg/10a based on the weight of dry matters are 9. 2mm/day and 9. 6mm/day, respectively. 3.The net unit duty of water required in the fields that the maximum planting rate exists is more than the one in the fields that the planting rate is uniform in the planting stage. 4.The determination of net unit duty of water in the late reduction division to heading stage or the planting stage depends upon the daily evapotranspiration and percolation rate in the late reduction division to heading stage or the water depth required for planting and daily consumptive use of water after planting at the planting stage. Therefore the use of figure 5-(1) to figure 5-(6) can easily make the determination of the designed net unit duty of water out of above two kinds of net unit duty of water.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.437-437
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• 2012

현재 우리나라에는 63,000개가 넘는 농업수리시설 구조물이 있으며, 그 중 70%가 넘는 시설물이 저수지이다. 이러한 저수지의 주 목적은 갈수시 안정적인 관개용수 공급과 하류의 생활용수를 공급함에 있다. 특히, 농업용 저수지의 경우에는 농번기에 물을 충족하게 공급함과 동시에 생활용수 및 유지용수의 공급이 동시에 이루어 질 수 있도록 고려하여야 하는 특수성을 가지고 있다. 그러나, 20세기 후반부터 우리나라에는 기후변화에 따른 전 지구적인 온난화 추세를 상회하는 경향을 보이고 있고, 강수량 및 집중호우의 증가추세도 보고되고 있다. 기온과 강수량이 과거와 다른 변화를 보임에 따라 물 공급의 안정성을 확보하기 위해 저수지를 통한 수자원 확보가 이루어지고 있으나, 용수공급능력이 어떻게 변화할 것인지에 대한 정량적 정보가 부족한 상태이다. 또한, 논벼의 생육에 있어 저수지의 적절한 용수공급은 필수적이기 때문에 저수지의 효율적 운영이 필요한 시점이다. 따라서 농업용수에 대한 기후변화의 영향을 이해하고 안정적이고 지속가능한 작물생산에 부정적인 역할을 최소화하기 위한 연구가 필요하다. 이에 본 연구에서는 1981년부터 2100년까지 기후변화에 따른 농업용 저수지의 용수공급능력을 평가하고자 하였다. 본 연구를 위하여 각 도별 대표 저수지를 한발빈도 10년을 기준으로, 그 이상인 저수지와 그 미만인 저수지로 각각 선정하였다. 다음으로 미래 기상자료는 IPCC 5차 보고서에서 제시할 RCP(Representative Concentration Pathways) 기반의 GCM/RCM 자료를 기상청으로부터 제공받아 활용하였다. 이 기상자료를 이용하여 물수지방법으로 현재저수량을 산정하고, 기준저수량을 현재저수량 중 하위 10% 저수량으로 가정하여 기준저수량에 미치지 못하는 기간과 저수량을 도출하였다. 산정된 자료를 활용하여 한발빈도별 농업용 저수지의 용수공급능력 불능을 파악하고자 하였다.