• 한국토양비료학회지
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• 제46권5호
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• pp.359-364
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• 2013

This study was conducted to develop a model to estimate crop leaf surface temperature. The results were as following; A definition for the daily time based on elapsed time from the midnight (00:00) as "E&E time" with the unit of Kmin. was suggested. The model to estimate the scaled temperature ($T^*e$) of crop leaf surface temperature by scale factor ($T^*$) according to the "E&E time : Kmin."(X) was developed as eq. (1) $T^*e=0.5{\cdot}sin(X+780)+0.5$ (2) $T^*=(Tx-Tn)/(Tm-Tn)$, Tx : Daily leaf temperature, Tm : Daily maximum leaf temperature, Tn : Daily minimum leaf temperature. Relative sensitivity of the measured temperature compared to the estimated temperature of red pepper, soybean and persimmon was 1.078, 1.033 and 0.973, respectively.

• 한국기후변화학회지
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• 제6권3호
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• pp.209-221
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• 2015

기후변화와 기상조건의 영향을 가장 많이 받는 분야는 농업이며, 특히 온도는 작물 생육에 영향을 미치는 가장 중요한 요인 중 하나이다. 본 연구는 수원에서 관개 조건 콩, 한발조건 콩, 배추, 노지 고추 및 비닐멀칭 고추 등 5개 작물에 대하여 기온과 작물 잎 및 토양의 표면온도를 monitoring 하여 이들 온도의 일중 변화 양상과 생육기간 동안의 온도 변화 양상 및 온도 요인 별 상호관계를 분석하였다. 시기별 기온과 작물잎 및 토양 표면온도에 대한 scale factor[Tsc]의 일중 변화 양상은 $[Tsc]=0.5{\times}sin(X+C)+0.5$와 같이 일중 시각(X : E&E time)에 대한 sine 함수로 나타낼 수 있었으며, scaling technique과 시기별 일 평균기온(Tavg), 최고기온(Tm) 및 최저기온(Tn)의 값을 이용하여 아래 식에 의해 시기별 일중시각(X)별 기온을 추정(E[Ti])할 수 있다. $E[Ti]=Tn+(Tm-Tn){\times}[0.5{\times}sin\;\{X+(9.646Tavg+703.65)\}+0.5]$. 또한 2014년 6월 24일의 작물별 일평균잎 표면온도는 노지 고추 > 멀칭 고추 > 한발 콩 > 관개 콩 > 배추 순이었다. 작물의 잎 표면온도를 추정할 경우, 멀칭 고추와 관개 및 한발 콩의 경우는 기온을 이용하여 가능하였으나, 배추와 노지 고추의 경우는 기온과 토양표면 온도의 두 변량을 이용하는 경우가 기온 한 변량을 이용하는 경우보다 작물 잎 표면온도의 실측치에 대한 편차가 더 작았다. Scale factor를 이용한 시기별 일중시각별 기온을 추정하는 방법과 작물별 잎 표면온도의 변화 양상을 구명한 본 연구결과는, 온도 등 기상자료를 이용한 작물 수량 예측 모형의 입력자료 산정 등에 활용 될 수 있다.

• 한국작물학회지
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• 제33권4호
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• pp.353-359
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• 1988

두께가 서로 다른 $C_3$ 식물의 잎은 단위엽면적당 광합성 능력에 있어서도 차이가 나는 바 잎의 내부구조와 기체교환 사이의 관계를 바탕으로 그 원인을 구명하였다. 광합성의 2대 제한요인으로 기체확산과 생화학적 과정의 상대적인 중요도를 결정하기 위해 중엽세포의 표면은 기체확산 저항의, 그리고 세포의 체적은 탄소고정 능력의 지표로 가정하였다. 즉 세포의 표면적이 증가하면 이산화탄소의 액상확산 저항이 감소하며 체적이 증대되면 carboxylation, oxygenation, 그리고 dark respiration 반응속도가 증가한다고 간주하였다. 이러한 개념을 함축하는 광합성 모형을 작성하고 이 가설의 검증을 위해 대두 품종 Amsoy잎을 이용한 실험을 수행하였다. 생장조절실내에서 200, 400, 600$\mu$mol photons m$^{-2}$ s$^{-1}$ PAR을 공급하여 서로 다른 두께의 잎을 준비하였으며 제3 및 4본엽에 대해 1,000 $\mu$mol photons m$^{-2}$ s$^{-1}$ PAR 및 28 기온 환경하에서 이산화탄소 흡수속도를 측정한 결과 세포의 체적과 표면적의 영향을 동시에 고려한 광합성 모형이 세포 표면적만을 고려한 경우 보다 실측치에 가까운 예측치를 산출하였다. 이로 미루어 세포의 표면적과 체적은 잎의 두께 및 그에 따른 광합성 능력의 예측에 적절한 변수로 간주된다.

• 생물환경조절학회지
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• 제24권3호
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• pp.217-225
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• 2015

본 연구에서는 동절기 시설원예 난방에너지 절감을 위해 방울토마토의 온도민감부인 생장부를 추종하면서 난방을 수행할 수 있는 국소난방 시스템을 개발하고자 하였다. 방울토마토 생장부 추종형 국소난방시스템은 온실하류로의 균일한 열분배를 위해 내/외부 덕트와 온풍난방기를 연결하는 이중덕트 분배장치, 정식 후 작물 유인에 따라 덕트를 토마토 줄기끝 생장점과 개화화방을 추종하여 상하로 이동시키기 위한 권취장치 등으로 구성되었다. 국소난방 시스템의 운용은 토마토 정식 직후에는 덕트를 작물 상부에 위치시키며 작물 생장에 따라 생장부 국소난방과 차광 회피를 위해 덕트를 상하로 이동시켰다. 방울토마토 수경재배 온실을 대상으로 생장부 국소난방구와 관행의 바닥덕트 난방구에 대해 난방성능과 작물생육 비교시험을 수행하였다. 그 결과 생장부 국소난방구는 야간 난방시간에 작물 군락내 상부 기온이 하부에 비해 $0.9{\sim}2.0^{\circ}C$ 높으며, 바닥덕트 난방구에 비해 군락상부 기온은 $0.3{\sim}1.8^{\circ}C$ 높고, 하부 기온은 $1.4{\sim}1.8^{\circ}C$ 낮게 나타나 온도에 민감한 상부 생장부를 상대적 고온으로 관리하고, 군락하부는 상대적 저온으로 관리 가능하며, 관행 바닥덕트 난방구의 높이별 온도분포를 역전시킬 수 있음을 확인하였다. 토마토 군락에 대한 적외선 열화상 측정을 통해 정식 직후부터 줄기내림 유인재배기간에 걸쳐 생장부 국소난방구는 군락내에 높이별 엽온의 온도성층화를 형성하여 생장부 추종 국소난방이 가능함을 확인하였다. 난방방식별 작물생육 분석결과 초장을 제외한 나머지 항목은 유의적인 차이가 없었으며, 수확량에서도 생장부 국소난방구가 초기 수량이 약간 우세하였으나 총 수확량은 동일한 수준으로 나타났다. 온풍난방비 경유소비량은 생장부 국소난방구가 군락의 높이별 최적 온도관리로 관행 바닥덕트 난방구에 비해 약 23.7% 절감되는 것으로 나타났다. 본 시스템은 길이 90m 온실에 대한 적용시험에서 열분배 성능의 한계로 온실 상/하류간 온도편차가 발생하였으며, 시스템 개선을 위해 내부덕트의 직경 또는 두께 상향, 열복사 억제 재질의 덕트 사용 등 열분배 성능 최적화를 위한 추가연구가 필요한 것으로 판단되었다.

• 한국작물학회지
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• 제34권s02호
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• pp.96-114
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• 1989

There are several meterorolgical stresses in the winter cereal crops. Among these stresses, cold injury is one of the most important stresses for wheat and barley production in Korea. The reduction in grain yield of the wheat and barley due to cold injury has occurred almost every year in Korea. The objective of the study was to get the basic information in relation to the cold injury and to detect the method minimizing the damage of cold injury. When the air temperature was the ranges of -13$^{\circ}C$ to -15$^{\circ}C$, the soil temperature at the crown part of the plant was very stable, whereas in the ranges of -2$^{\circ}C$ to -3$^{\circ}C$ the soil surface temperature was more unstable and cold than air and subterranean temperatures. The different parts of the plant in wheat and barley possess the different levels of cold hardiness. In comparison to the cold hardiness of plant parts, the leaf and crown are the less sensitive to cold injury than root and vascular transitional zone. The type and extent of stress is determined by the redistribution pattern of water during freezing. These types from freezing processes were three types: a) Equilibrium freezing pattern b) Non -equilibrium freezing pattern, c) Non-equilibrium freezing pattern typical of tender tissues. Cold hardiness in wheat plants were more harder than barley plants at vegitative stage, but inverted at the reproductive stage. Injuries by low temperature during the seasons of barley cultivation in Korea were occured mainly in four stage; in the first and third stage, frost injury occurs, the second stage, freezing injury, and the fourth stage, chilling injury.

• The Plant Pathology Journal
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• 제32권6호
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• pp.508-518
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• 2016

Early blight of tomato caused by Alternaria solani, is responsible for severe yield losses in tomato. The conidia survive on soil surface and old dry lower leaves of the plant and spread when suitable climatic conditions are available. Macroclimatic study reveals that highest inoculum concentration of Alternaria spores appeared in May 2012 to 2013 and lowest concentration during January 2012 to 2013. High night temperature positively correlated and significantly (P < 0.01) involved in conidial spore dispersal and low relative humidity (RH) displayed significant (P < 0.05) but negative correlation with conidial dispersal. The objective of the study was to modify microclimatic conditions of tomato crop canopy which may hamper conidial dispersal and reduce disease severity. We evaluated effect of marigold intercropping and plastic mulching singly and in consortia on A. solani conidial density, tomato leaf damage and microclimatic parameters as compar to tomato alone (T). Tomato-marigold intercropping-plastic mulching treatment (T + M + P) showed 35-39% reduction in disease intensity as compared to tomato alone. When intercropped with tomato, marigold served as barrier to conidial movement and plastic mulching prevented evapotranspiration and reduced the canopy RH that resulted in less germination of A. solani spores. Marigold intercropping and plastic mulching served successfully as physical barrier against conidial dissemination to diminish significantly the tomato foliar damage produced by A. solani.

• 대한원격탐사학회지
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• 제22권3호
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• pp.175-182
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• 2006

Because of the phenological variation of vegetation growth in temperate region, it is often difficult to accurately assess the surface conditions of agricultural croplands, grasslands, and disturbed forests by multi-spectral remote sensor data. In particular, the spectral similarity between soil and dry vegetation has been a primary problem to correctly appraise the surface conditions during the non-growing seasons in temperature region. This study analyzes the spectral characteristics of the mixture of dry vegetation and soil. The reflectance spectra were obtained from laboratory spectroradiometer measurement (GER-2600) and from EO-1 Hyperion image data. The reflectance spectra of several samples having different level of dry vegetation fractions show similar pattern from both lab measurement and hyperspectral image. Red-edge near 700nm and shortwave IR near 2,200nm are more sensitive to the fraction of dry vegetation. The use of hyperspectral data would allow us for better separation between bare soils and other surfaces covered by dry vegetation during the leaf-off season.

• 한국약용작물학회지
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• 제3권3호
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• pp.181-186
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• 1995

본(本) 연구(硏究)는 고추냉이의 광합성(光合成) 효율증진(效率增進)을 위한 기상환경(氣象環境)에 조건(條件)을 알아내어 재탑적지(栽培適地)의 선정(選定)과 재배관리(栽培管理)에 대한 기초적(基礎的)인 자료(資料)를 제공(提供)하고자 온도(提供)와 광도(光度), 그리고 $CO_2$의 농도(農度)에 대한 광합성(光合成), 청호흡(晴呼吸) 그리고 광호흡(光呼吸)의 반응(反應)을 조사(調査)하였다. 1. 고추냉이의 광합성(光合成)에 최적온도(最適溫度)는 $17{\sim}20^{\circ}C$이었고 최적온도(最適溫度) 이상(以上)에서 광합성(光合成)이 크게 감소(減少)하였으며, 암호흡(暗呼吸)은 $15^{\circ}C$에서 $30^{\circ}C$까지 온도(溫度)가 높아질수록 증가(贈加)하였다. 2. 광보상점(光補償點)은 고추냉이가 $6.0 {\mu}E\;m^{-2}s^{-1}$으로 옥수수의 $36.7{\mu}E\;m^{-2}s^{-1}$보다 낮았으며 광포화점(光飽和點)은 고추냉이와 옥수수 모두 $600{\mu}E\;m^{-2}s^{-1}$로 비슷하였다. 3. $CO_2$ 보상점(補償點)은 고추냉이가 67. 3 ppm으로 옥수수 11.6 ppm보다 높았으며 암호흡(暗呼吸)은 $CO_2$의 농도(濃度)가 낮을수록 높았다. 4. 고추냉이의 광호흡(光呼吸)은 광도(光度) $l000{\mu}E\;m^{-2}s^{-1}$에서 $3.3 mg\;CO_2\;dm^{-2}\;hr^{-1}$이었으며 광도(光度)가 낮아짐에 따라 감소(減少)하였다. 5. 기공(氣孔)의 분포(分布)는 잎의 표면(表面)에 약 76개/$mm^{-2}$, 뒷면에 623개/$mm^{-2}$이었으며 기공(氣孔)의 크기는 표면(表面)의 것이 $12{\mu}m$이고 뒷면의 것이 $17{\mu}$로 나타났다.

• 한국농공학회논문집
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• 제62권3호
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• pp.51-61
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• 2020

Drought events are not clear when those start and end compared with other natural disasters. Because drought events have different timing and severity of damage depending on the region, various studies are being conducted using satellite images to identify regional drought occurrence differences. In this study, we investigated the applicability of drought assessment using the Evaporative Stress Index (ESI) based on Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images. The ESI is an indicator of agricultural drought that describes anomalies in actual and reference evapotranspiration (ET) ratios that are retrieved using remotely sensed inputs of Land Surface Temperature (LST) and Leaf Area Index (LAI). However, these approaches have a limited spatial resolution when mapping detailed vegetation stress caused by drought, and drought hazard in the actual crop cultivation areas due to the small crop cultivation in South Korea. For these reasons, the development of a drought index that provides detailed higher resolution ESI, a 500 m resolution image is essential to improve the country's drought monitoring capabilities. The newly calculated ESI was verified through the existing 5 km resolution ESI and historical records for drought impacts. This study evaluates the performance of the recently developed 500 m resolution ESI for severe and extreme drought events that occurred in South Korea in 2001, 2009, 2014, and 2017. As a result, the two ES Is showed high correlation and tendency using Receiver Operating Characteristics (ROC) analysis. In addition, it will provide the necessary information on the spatial resolution to evaluate regional drought hazard assessment and and the small-scale cultivation area across South Korea.

• 한국잡초학회지
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• 제12권3호
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• pp.200-222
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• 1992

The results of recent researches for improvement of seedling stand in direct seeded rice on the dry paddy in Korea were summarized as the following ; a variety to be cultivated should be chosen the characteristics of high percentage germination under low temperature, shorter period of shoot emergence, and better growth of the mesocotyl and shoots. Meanwhile, there was 40% increase in seedling stand at the treatment of removal of the seed awn under using the drill seeder. After seeding the rice seed covered with soil of 3cm depth was better seedling emergence and also there was the hightest seedling emergence at the 70% of moisture content of the soil. In addition, the application of the Release containing GA 10% enabled to increase the seedling stand and furthermore it was effective under deep seeding depth. The optimum seeding date should be seeded around May 10 when mean air temperature is above 12-13$^{\circ}C$ so that may establish more less 70% in seedling stand. Based on an appropriate seedling stand of 150/$m^2$, the optimum seeding rate was 5kg/10a. It was the best in seeding method using drill seeder and the most desirable recommended seeding method was the drill seeder in terms of seedling stand. In order to improve seedling stand water management was more effective in canal irrigation and in drainage at 6hr after irrigation following by the seeding process. On the other hand, for the increase of seedling stand under flooded condition a variety might have characters being better germination at low concentration of dissolved oxygen and vertically deeper growing of the crown root. Also, seedling stand was able to increase with the seed coating of $CaO_2$in the flooded soil. It was possible to be seeded on the early part of May being mean air temperature of avove 10$^{\circ}C$ and the optimum seeding rate was 5kg/10a. For an effective water management water would be flooded up to 3cm depth for 2-3 weeks after seeding. The rice plant grown under the direct seeded cultivation might be not so much strong in lodging resistance compared to that grown under the transplanting and moreover direct seeded rice cultivation under flooded condition would be more weak growth of the rice plant than that on dry paddy. Meanwhile, the lodging would be affected by the seeding rate, the soil depth after seeding. and seeding method even in the same variety. In particular, roots in the lodging pattern of direct seeded rice cultivation under flooded condition were largely distributed on the soil surface so that resulted easily in the lodging. In general, the lodging resistance would be greater as seeding rate and amount of N fertilizer application are lower and soil depth after seeding is higher. Among the introduction of different seeding method the high ridged drill seeding method on dry paddy soil resulted in the lowest in the lodging index and also it was lower in the drill seeding method than in the scattering seeding method under flooded condition. In case of more than 150 seedlings per $m^2$ there was a severe lodging due to high lodging index at the 3rd and 4th internodes. The effective lodging prevention was able to at the treatment of the Inabenfide at 45 days before heading and the Uniconazol at 15 days before heading which caused the shortage by 10-15cm in culm length. Also, fertilizer management using split application of nitrogen would be contributed the reduction of lodging at the rate of 20-30-20-20-10%(basal-5th leaf stage-7th leaf stage-panicle initiation stage-heading stage) on the dry paddy soil.