France 하천 수질 평가법으로 이용하는 규조류 지수에 관한 소개

정상옥 ( Sang Ok Chung ) 한국하천호수학회 2004 생태와 환경 Vol.37 No.4

Since, in 1970, diatoms and diatom indices was first used in measuring quality of streams and rivers at the Seine Water Agency in France, five other water agencies began to show interests since 1990. In 1994, associated with CEMAGREF (Centre National du Machinisme Agricole du Genie Rural et des Eaux et des Forets : environmental science and expertise for the sustainable management of land and water), the six French Water Agencies (Seine, Rhone-Mediterranee-Corse, Artois-Picardie, Loire-Bretagne, Rhin-Meuse and Adour-Garonne) developed a practical diatom index, which is liable to be used routinely in the territorial streams and rivers of whole France, and which is liable to promote and facilitate its use in monitoring water networks. In 1995, the first version of a biological diatom index (IBD) was generated by them. Since then, the software update for IBD calculation and the user`s network have led to numerous practical applications in France. Furthermore, the Water Agencies have run applicable programs on the National Basin Network from 1996, and the initial data set of IBD was completed. Re-examination of the complete data set was done at the end of 1998, and the tests on different calculation options of the IBD led to a third version of this index in June, 2000 (AFNOR NF T 90-354).

고해상도 기후예측자료를 이용한 우리나라 논 관개용수량 추정

정상옥 ( Chung Sang-ok ) 한국농공학회 2009 한국농공학회 학술대회초록집 Vol.2009 No.-

우리나라의 장래 기후변화가 논 용수량에 미치는 영향을 분석하였다. 기상연구소의 SRES A2 시나리오에 대한 가상자료와 기상관측소에서 관측한 기준년도 (1971-2000)에 대한 관측 자료를 이용하였다. 기상여구소가 전지구 기후모형인 ECHO-G 모형 출력값을 고해상도 (27 x 27 km)인 MM5 지역기후모형을 이용하여 역학적으로 상세화한 값을 이용하였다. 벼의 관개 요구량의 지역적 변동을 도시 하는 데는 GIS를 이용하였다. 공간적으로는 우리나라 벼 재배지역 전부를 포한하고 시간적으로는 30년간씩 평균한 2020s (2010-2039), 2050s (2040-2069) 및 2080s (2070-2099)에 대하여 분석하였다. 분석결과 벼 생육기간의 평균기온은 기준년도 보다 1.5℃ (2020s), 3.3℃ (2050s) 및 5.3℃ (2080s) 상승할 것으로 예측되었다. 벼생육기간의 평균 강우량은 0.1 % (2020s) 4.9 % (2050s) 및 19.3 % (2080s) 상승할 것으로 예측되었다. 작부체계와 영농방식이 변하지 않는다고 가정하면 논 관개요구량은 2.8 % (2020s) 4.9 % (2050s) 및 4.5% (2080s) 증가할 것으로 예측되었다. 벼 관개요구량의 공간적 및 시간적 변동이 큰 것으로 예측되었으며 이는 장차 농업용수 개발 및 관리계획에 반드시 고려되어야 할 것이다. 본 연구는 한 개의 전지구 기후모형과 한 개의 지역기후모형의 결과만 이용한 점, SRES A2 시나리오에 대하여만 분석한 점, 및 불확실성에 대한 분석을 수행하지 않은 점 등의 제약점이 있으며, 앞으로 다양한 시나리오에 대하여 다른 모형을 이용한 결과에 대한 분석도 이루어 져야 할 것이다.

관개수온과 벼의 냉수피해

정상옥 ( Chung Sang Ok ),오창준 ( Oh Chang Jun ) 한국농공학회 1998 한국농공학회 학술대회초록집 Vol.1998 No.-

In 1996, a cold-water damage occured in the paddy field at downstream of the Unmoon dam. To study the cause and the preventive measures of the cold-water damage a field study was performed during the growing season of 1997. Field measurements such as water temperatures at reservoir, irrigation canal and in the paddy field were made. As a result, there was no cold-water damage due to the right irrigation water management practice in 1997. The cold-water damage is passible to happen, however, and the preventive measures were provided.

벼의 냉수피해 감소를 위한 관개수온 조사와 대책수립

정상옥 ( Chung Sang Ok ),오창준 ( Oh Chang Jun ) 한국농공학회 1999 韓國農工學會誌 : 전원과 자원 Vol.41 No.1

Paddy rice is semi-tropical crop and requires warm irrigation water. If mean water temperature at the water source during the growing period is below 18℃, some kinds of water warming mechanism should be taken. In this study irrigation water temperature is measured and preventive measures to cold water damage on paddy rice are suggested. Field observations were performed at 100ha field area downstream of the Unmoon reservoir during the growing season of 1997. Land use, canal system, water temperature at irrigation canals, reservoir, and paddy fields were observed. In addition, growth and yield of the rice at selected plots were observed. According to the record, cold water damage occurred in this area due to the cold irrigation water supply in 1996. It did not occur because of the effective irrigation water management practice in 1997. However, several preventive measures such as pontoon intake system, using existing weir and constructing a new warming pond, are suggested to prevent cold water damage in the future. If a new warming pond is constructed to raise irrigation water temperature by 2℃, a pond area of 2.94 ha is required.

부분적(部分的)인 멀칭이 토양수분(土壤水分)의 이동에 미치는 영향(影響)

정상옥 ( Chung Sang Ok ) 한국농공학회 1990 韓國農工學會誌 : 전원과 자원 Vol.32 No.2

Soil surface mulch cover in upland crop field affects soil heat and moisture movement significantly. The mulch cover decreases not only surface evaporation but also soil loss from surface runoff. A numerical model using alternating direction implicit(ADI) finite difference scheme is developed to study the effects of mulch cover on soil moisture flow. To study two-dimensional soil moisture flow with partial surface mulch, the change of soil water content is observed by tensiometers at an experimental plot with chopped corn crop residue mulch cover. The model is tested using the field data, then is used to predict soil surface energy partitioning and soil moisture movement. The model can analyze the effects of mulch cover on soil moisture flow satisfactorily. The mulch cover reduced water content variation underneath and the soil surface evaporation. The partial surface mulch cover induced horizontal water flow near the soil surface. The present model can be applied successfully in soil science and groundwater hydrology, and also can be extended to include crops.

기준작물(잔디)의 증발산량 실측치와 모형 추정치의 비교

정상옥 ( Chung Sang-ok ),박기중 ( Park Ki Jung ) 한국농공학회 1999 한국농공학회 학술대회초록집 Vol.1999 No.-

Evapotranspiration is one of the important water budget components. An experiment was conducted to measure evapotranspiration. Three lysimeters were used to measure daily evapotranspiration. Lysimetrically measured values were compared with estimated values of various methods in REF -ET model, and then crop coefficient was computed.

논지대 수계환경에서 농약의 노출위험도 분석

정상옥 ( Chung Sang-ok ),박기중 ( Park Ki-jung ) 한국농공학회 2007 한국농공학회 학술대회초록집 Vol.2007 No.-

Exposure risk assessment of pesticide molinate in rice paddy areas was performed to see the effects of various water and pesticide management scenarios and then best management practices were proposed to prevent adverse effects on populations. The results of the RICEWQ model simulation from the previous studies were analyzed. The pesticide risk for aquatic organisms is evaluated by the ratio of the predicted environmental concentration (PEC) and the predicted no-effect concentration (PNEC). To assess the exposure risk to the aquatic organisms, predicted molinate concentrations were grouped into four risk classes. The no risk concentration range is lower than 0.002 mg/L, the low is from 0.002 mg/L to 0.01 mg/L, the moderate is from 0.01 mg/L to 0.1 mg/L, and the high is above 0.1 mg/L. The critical values for each category were calculated from the toxicity endpoint value (median lethal concentration, LC50) divided by the assessment factor (AF). The results showed that the very shallow ponding depth in rice paddies showed lower pesticide exposure risk than the deep ponding depth, and the higher application rate showed greater exposure risk to the aquatic organisms. The results of this study can be used for the non-point source pollution control and environmental policy making regarding pesticides.

용수절약형 논관개 기법

정상옥 ( Chung Sang Ok ),안태홍 ( Ahn Tae Hong ) 한국농공학회 2000 한국농공학회 학술대회초록집 Vol.2000 No.-

A field study was performed to investigate the effect of water saving irrigation method on water use efficiency and rice yield. The field plot was 40a (40 × 100m) in size and located at Buryangmyun, Kimjae city, Chonbuk province. Field measurements were made during the growing seasons, May to September of the year 1998 and 1990. Irrigation water volume, drainage water volume, rainfall and ponding depth were measured. Irrigation water management practice employed was such that to keep the ponding depth about 3 to 4cm by intermittent irrigation with drying the soil surface until hair cracks emerge before the next irrigation. The amounts of water volume irrigated and drained were measured by pipe flow meter and ponding depth was observed by using a partly buried 120mm diameter PVC pipe. The results showed that the irrigation water depths, the rainfalls, and the drainage depths were 379mm, 458mm, and 448mm in 1988, and 274mm, 819mm, and 736mm in 1990, respectively. The average yield was 590kg per 10a. The water saving irrigation method saved irrigation water by about 20% with higher yield compared with the traditional method.

대표농도경로 시나리오에 의한 한반도 주요 평야지역 논벼 소비수량 추정

정상옥 ( Sang-ok Chung ) 한국농공학회 2012 한국농공학회 학술대회초록집 Vol.2012 No.-

The paddy rice consumptive use in the six plains of the Korean peninsula was projected with changing climate under the representative concentration pathway (RCP) scenarios. High resolution climate data for the baseline (1961-1990) was obtained from the International water management institute (IWMI) and future high resolution climate projection was obtained from the Korea Meteorological Administration. Reference evapotranspiration (ET) was calculated by using Hargreaves equation. The results of this study showed that the average annual mean temperature would increase persistently in the future. Temperatures were projected to increase more in RCP8.5 than those in RCP4.5 scenario. The rice consumptive use during the growing period was projected to increase slightly in the 2020s and then more significantly in the 2050s and 2080s. It showed higher values for RCP8.5 than for RCP4.5. The rice consumptive use after transplanting in the study areas would increase by 2.2%, 5.1% and 7.2% for RCP4.5 and 3.0%, 7.6%, and 13.3% for RCP8.5, in the 2020s, 2050s, and 2080s, respectively, from the baseline value of 534mm. The results demonstrated the effects of climate change on rice consumptive use quite well, and can be used in the future agricultural water planning in the Korean peninsula.

직파재배 벼의 영농기법 및 비용 절감 효과 - 현장 사례 연구

정상옥 ( Chung Sang Ok ),김지용 ( Kim Ji Yong ),안태홍 ( Ahn Tae Hong ) 한국농공학회 2000 한국농공학회 학술대회초록집 Vol.2000 No.-

A field case study was performed to investigate optimum cropping technique of direct seeded rice. In addition, an economic analysis was made to see the effect of this method. Field study was performed at a 2.1㏊ paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding method such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Optimum cropping techniques such as when and how to manage the rotary till, water supply, herbicide application, and ponding depth were developed for different cropping methods. Based on this study ￦640,000 per ㏊ can be saved by direct seeding due to no nursery cost, and ￦1,220,000 per ㏊ can be saved by no-till and no nursery cost. With further study these cropping techniques including the no-till direct deeding proves to be advantageous these can be adopted for the most of the paddy fields in Korea.