APEX-Paddy 모델을 이용한 기후변화에 따른 논벼 생산량 및 증발산량 변화 예측

최순군,김민경,정재학,최동호,허승오,Choi, Soon-Kun,Kim, Min-Kyeong,Jeong, Jaehak,Choi, Dongho,Hur, Seung-Oh 한국농공학회 2017 한국농공학회논문집 Vol.59 No.4

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.

APEX 모델의 국내 적용을 위한 데이터베이스 구축 및 고랭지 밭에 대한 적용성 평가

구자영,김종건,최순군,김민경,정재학,임경재,Koo, Ja-Young,Kim, Jonggun,Choi, Soon-Kun,Kim, Min-Kyeong,Jeong, Jaehak,Lim, Kyoung Jae 한국농공학회 2017 한국농공학회논문집 Vol.59 No.6

The Agricultural Policy/Environmental eXtender (APEX) model was developed to extend EPIC's capabilities of simulating land management impacts for small-medium watershed and heterogeneous farms. APEX is a flexible and dynamic tool that is capable of simulating a wide array of management practices, cropping systems, and other land uses across a broad range of agricultural landscapes. APEX have its own agricultural environmental database including operation schedule, soil property, and weather data etc., by crops. However, agriculture environmental informations the APEX model has is all based on U.S. As this can cause malfunction or improper simulation while simulating highland field. In this study, database for APEX model to be utilized for South Korea established with 44,814 agriculture fields in Pyeongchang-gun, Korea from 2007 to 2016. And assessed domestic applicability by comparing T-P unit load criteria presented by National Institution of Environmental Research and result of APEX model. As a result of APEX model simulation, average T-P value for decade was 6.18. Average T-P of every year except 2011 was in range of 5.37~10.43 and this is being involved into criteria presented by National Institution of Environmental Research. It is analyzed that adjusting slope factor can make the model applicable for domestic agricultural environment.

기후변화시나리오 다중모형 앙상블에 따른 논 질소 유출 부하량 변동 및 불확실성 평가

최순군 ( Choi Soon-kun ),정재학 ( Jeong Jaehak ),엽소진 ( Yeob So-jin ),김민욱 ( Kim Minwook ),김진호 ( Kim Jin Ho ),김민경 ( Kim Min-kyeong ) 한국농공학회 2020 한국농공학회논문집 Vol.62 No.5

Rice paddy accounts for approximately 52.5% of all farmlands in South Korea, and it is closely related to the water environment. Climate change is expected to affect not only agricultural productivity also the water and the nutrient circulation. Therefore this study was aimed to evaluate changes of nitrogen load from rice paddy considering climate change scenario uncertainty. APEX-Paddy model which reflect rice paddy environment by modifying APEX (Agricultural Policy and Environmental eXtender) model was used. Using the AIMS (APCC Integrated Modeling Solution) offered by the APEC Climate Center, bias correction was conducted for 9 GCMs using non-parametric quantile mapping. Bias corrected climate change scenarios were applied to the APEX-Paddy model. The changes and uncertainty in runoff and nitrogen load were evaluated using multi-model ensemble. Paddy runoff showed a change of 23.1% for RCP4.5 scenario and 45.5% for RCP8.5 scenario compared the 2085s (2071 to 2100) against the base period (1976 to 2005). The nitrogen load was found to be increased as 43.9% for RCP4.5 scenario and 76.0% for RCP8.5 scenario. The uncertainty analysis showed that the annual standard deviation of nitrogen loads increased in the future, and the maximum entropy indicated an increasing tendency. And Duncan’s analysis showed significant differences among GCMs as the future progressed. The result of this study seems to be used as a basis for mid- and long-term policies for water resources and water system environment considering climate change.

심층 연산자 네트워크를 활용한 중심대동맥 압력과 오실로메트릭 신호 사이의 연산자 학습

민창희(Changhee Min),정재학(Jaehak Jeong),이보미(Bomi Lee),홍준기(Junki Hong),박용화(Yong-Hwa Park) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11

APEX 모델을 이용한 콩 재배 밭 전환 논의 물수지 특성 평가

최순군 ( Choi Soon-kun ),정재학 ( Jeong Jaehak ),엽소진 ( Yeob So-jin ),김명현 ( Kim Myung-hyun ),김민경 ( Kim Min-kyeong ) 한국농공학회 2021 한국농공학회논문집 Vol.63 No.4

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 APEX 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.

Open Source GIS를 활용한 QAPEX 분석 시스템 개발

구자영 ( Jayoung Koo ),정재학 ( Jaehak Jeong ),양동석 ( Dongseok Yang ),최순군 ( Soonkun Choi ),임경재 ( Kyoungjae Lim ) 한국농공학회 2018 한국농공학회 학술대회초록집 Vol.2018 No.-

Agricultural Policy/Environmental eXtender(APEX) 모델은 다양한 영농활동을 반영할 수 있어 최적관리기법 평가 적용 모형으로 분류되는 모델이다. APEX 모델에 대한 대표적인 사용자 인터페이스 개발 모델에는 윈도우 기반의 WinAPEX이 있으며, 이 후 ArcAPEX, i_APEX 등 다양한 형태로 개선되어왔다. 그러나 ArcGIS 소프트웨어에서 구동되는 ArcAPEX 인터페이스는 유료의 라이센스를 필요로 하여 폭넓은 활용에는 한계가 있다. 이에 본 연구의 목적은 오픈 소스 기반의 GIS 소프트웨어와 APEX 모델을 연계하여 APEX 모델의 새로운 인터페이스인 QAPEX 분석 시스템을 개발하는 데 있다. QAPEX 분석 시스템은 오픈 소스 기반의 GIS인 Quantum GIS(QGIS) 소프트웨어를 기반으로 개발되어 다양한 GIS 기능을 제공하며 활용할 수 있다. 본 연구에서 개발된 QAPEX 분석 시스템의 인터페이스에서는 ArcAPEX 인터페이스와 유사한 기능을 제공하고 있으며, 유역의 세분화 과정은 ArcAPEX 인터페이스보다 세분화되어 정밀한 수문 및 수질 모의가 가능하도록 하였다. 또한 최적관리기법의 적용이 가능한 인터페이스 기능이 추가되어 있으며, 유황곡선 및 오염부하지속곡선과 같이 시각적으로 모의 결과를 해석할 수 있는 기능이 추가되었다. 따라서 QAPEX 분석 시스템은 오픈 소스 기반으로 모델 확장성이 우수하며, 향후 최적관리기법 적용에 따른 비점오염물질의 저감 효과를 분석하는 등 비점오염원 관리를 위한 국가 정책자료를 도출하는 데 유용한 도구로 활용 될 것으로 기대된다.

APEX-paddy 모델을 활용한 SSPs 시나리오에 따른 논 필요수량 변동 평가

최순군 ( Choi Soon-kun ),조재필 ( Cho Jaepil ),정재학 ( Jeong Jaehak ),김민경 ( Kim Min-kyeong ),엽소진 ( Yeob So-jin ),조세라 ( Jo Sera ),오수당콰에릭 ( Owusu Danquah Eric ),방정환 ( Bang Jeong Hwan ) 한국농공학회 2021 한국농공학회논문집 Vol.63 No.6

Global warming due to climate change is expected to significantly affect the hydrological cycle of agriculture. Therefore, in order to predict the magnitude of climate impact on agricultural water resources in the future, it is necessary to estimate the water demand for irrigation as the climate change. This study aimed at evaluating the future changes in water demand for irrigation under two Shared Socioeconomic Pathways (SSPs) (SSP2-4.5 and SSP5-8.5) scenarios for paddy rice in Gimje, South Korea. The APEX-Paddy model developed for the simulation of paddy environment was used. The model was calibrated and validated using the H2O flux observation data by the eddy covariance system installed at the field. Sixteen General Circulation Models (GCMs) collected from the Climate Model Intercomparison Project phase 6 (CMIP6) and downscaled using Simple Quantile Mapping (SQM) were used. The future climate data obtained were subjected to APEX-Paddy model simulation to evaluate the future water demand for irrigation at the paddy field. Changes in water demand for irrigation were evaluated for Near-future-NF (2011-2040), Mid-future-MF (2041-2070), and Far-future-FF (2071-2100) by comparing with historical data (1981-2010). The result revealed that, water demand for irrigation would increase by 2.3%, 4.8%, and 7.5% for NF, MF and FF respectively under SSP2-4.5 as compared to the historical demand. Under SSP5-8.5, the water demand for irrigation will worsen by 1.6%, 5.7%, 9.7%, for NF, MF and FF respectively. The increasing water demand for irrigating paddy field into the future is due to increasing evapotranspiration resulting from rising daily mean temperatures and solar radiation under the changing climate.

논 환경 영향평가를 위한 APEX-Paddy 모형 개발

최순군 ( Soonkun Choi ),김민경 ( Minkyeong Kim ),정재학 ( Jaehak Jeong ),방혜선 ( Hea Son Bang ) 한국농공학회 2015 한국농공학회 학술대회초록집 Vol.2015 No.-

Rice is the predominant grain crop of South Korea with the total paddy fields estimated to be 55 % of the cultivated lands, which is equivalent to 1 million hectares. In Korea, paddy fields are often flooded or semi-flooded during growing seasons between April and September and often serve as sources of water pollution. In this study, we develop national scale APEX model(s) that will be used to assess water consumption and pollutant discharge by rice paddies in South Korea. The Agricultural Policy/Environmental eXtender model is enhanced for simulating biophysical processes in paddy fields under flooding or dry conditions. Environmental effects of paddy managements such as puddling, fertilizer application, transplanting, and irrigation are assessed by simulating scheduled operations during cropping periods. For modeling the whole country at the field scale, national APEX database is being developed for soils, weather stations, and scheduled agricultural managements including planting/harvesting schedule, fertilizer application amount, and other paddy operations. A total of 376 soil types were compiled and formatted for APEX soil database. Daily weather data including precipitation, min/max temperature, solar radiation, humidity, and wind speed measured at 58 national weather stations for up to 30 years. A case study was conducted using field data in Icheon, Korea on water balance and Nitrogen load for two years.

환경보전 농법을 고려한 논에서의 질소유출 모의

박나영 ( Na-young Park ),최순군 ( Soon-kun Choi ),김민경 ( Min-kyeong Kim ),정재학 ( Jaehak Jeong ),최동호 ( Dongho Choi ),홍성창 ( Seong-chang Hong ),엽소진 ( Sojin Yeob ),허승오 ( Seung-oh Hur ) 한국환경농학회 2018 한국환경농학회 학술대회집 Vol.2018 No.-

국내에서 논 재배면적은 전체 농경지 면적의 55%를 차지하고 있으며 이는 전 국토의 11%에 해당한다. 논은 재배기간 동안(5~10월) 대부분 담수생태계를 유지하며 7~8월 중 2주간 벼의 유효분얼을 위해 중간낙수(물떼기)를 한다. Agricultural Policy/Environmental eXtender (APEX) 모델은 농업활동이 농경지 토양 및 하류수계에 미치는 영향을 평가하는 모델로서 US EPA (United States Environmental Protection Agency)의 지원을 받아 작성되었다. 그러나 APEX 모델은 논에서의 농업활동과 논의 물리적 특성을 반영하지 못한다. 농촌진흥청과 Texas A&M은 국제공동연구를 통해 APEX 모델 내 논 모듈(써레질, 담수관개, 이앙 등)을 추가하여 APEX-paddy 모델을 개발하였다. 본 연구에서는 APEX-paddy 모델을 이용하여 환경보전 농업에 따른 논 질소부하량의 변화를 모의 하였다. 분석기간은 향후 기후변화 영향평가를 수행하기 위하여 GCMs (General Circulation Model)의 기준인 1976년~2005년으로 설정하였다. 논의 환경보전 농법으로서 유출구 물꼬 높이 조절과 시비량 조절 시나리오를 적용하였다. 물꼬 높이를 중간낙수 이후 관행 80 mm에서 150 mm로 높여 빗물을 최대한 이용할 경우 배수량은 약 14.0%가 감소하는 것으로 나타났으며 이에 따라 질소부하량이 약 3.3%가 감소하는 것으로 나타났다. 빗물 이용량이 증가함에 따라 관개요구량은 약 9.3%가 감소하는 것으로 모의되었다. 질소비료 시비량을 관행 110 kg-N/ha에서 최고품질 벼생산 기준인 70 kg-N/ha로 줄일 경우 관개량과 배수량은 변화가 없으나 질소부하량이 33.9%가 감소하는 것으로 나타났다. 한편, 논벼 생산량은 10.8%가 감소하는 것으로 모의되었다.