• 대한원격탐사학회지
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• 제1권1호
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• pp.63-87
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• 1985

Considerable experience has been reported on the use of spectral data to measure the canopy biomass of dryland grain crops and the use of these estimates to forecast subsequent grain yield. These basic procedures were retested to assess the use of the general process to forecasting grain yield for paddy rice. The use of the ratio of a multiband radiometer simulation of Thematic Mapper band 4(.76 to .90 .mu.m) divided by band 3 (.63 to .69 .mu.m) was tested to estimate the canopy biomass of paddy rice as a function of the stage of development of the rice. The correlation was found to be greatest (R = .94) at panicle differentiation about midway through the development cycle of the rice canopy. The use of this ratio of two spectral bands as a surrogate for canopy biomass was then tested for its correlation against final grain yield. These spectral estimates of canopy biomass produced the highest correlations with final grain yield (R = .87) when measured at the canopy development stages of panicle differentiation and heading. The impact of varying the amounts of supplemental nitrogen on the use of spectral measuremants of canopy biomass to estimate grain yield was also determined. The effect of the development of a significant amount of weed biomass in the rice canopy was also clearly detected.

• Agricultural and Biosystems Engineering
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• 제6권1호
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• pp.8-14
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• 2005

This study was carried out to develop a real-time grouping system of chlorophyll contents of rice crop canopy for precision agriculture. The system measured reflected light energy of a rice canopy on a paddy field from visual to near-infrared range and analyzed the collected information of chlorophyll contents of rice crop canopy with given position data. The four filters, 560 nm $({\pm}10nm)$, 650 nm $({\pm}25nm)$, 700 nm $({\pm}12nm)$, and 850 nm $({\pm}40nm)$, were used for a multiple regression to estimate the chlorophyll contents of rice crop canopy. Every $0.2m^2$ area of the open field was inspected at a distance of 1 m above the rice canopy. According to the results of verification test, the chlorophyll content grouping by a commerical chlorophyll meter (SPAD) and by the developed system showed 58.7% match for five-stage chlorophyll contents of rice crop canopy grouping and 93.5% for the $five{\pm}1-stage$ grouping. In addition, the results showed 63.0% match for three-stage grouping and 100.0% for the $three{\pm}1-stage$ grouping.

• 대한원격탐사학회지
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• 제31권1호
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• pp.11-20
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• 2015

This study aimed to investigate the canopy growth conditions and the accuracy of phenological stages of paddy rice using ground-based remote sensing data. Plant growth variables including Leaf Area Index (LAI) and canopy reflectance of paddy rice were measured at the experimental fields of Chonnam National University, Gwangju, Republic of Korea during the crop seasons of 2011, 2012, and 2013. LAI values were also determined based on correlations with Vegetation Indices (VIs) obtained from the canopy reflectance. Three phenological stages (tillering, booting, and grain filling) of paddy rice could be identified using VIs and a spatial index (NIR versus red). We found that exponential relationships could be applied between LAI and the VIs of interest. This information, as well as the relationships between LAI and VIs obtained in the present study, could be used to estimate and monitor the relative growth and development of rice canopies during the growing season.

• 한국농림기상학회지
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• 제2권4호
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• pp.204-208
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• 2000

벼 군락의 기온 연직구조에 관한 연구는 일반적으로 출수 이후 등숙기에 완전히 형성된 군락을 대상으로 한 것이므로 병해충 예찰모형의 구동 등 실용적으로 많이 요구되는 생육중기의 미형성 군락에 관한 정보를 보완하기 위해 이앙 후 한 달째부터 출수 직전까지 기온을 연속 측정하였다. 별도의 차광 혹은 환기장치가 불필요한 직경 0.003mm E형 미세선 열전대를 관개수면 위 l0cm부터 100cm까지 10cm 간격으로 10개를 설치하였으며, 비교를 위해 150cm 위치에 1개를 추가설치 하였다. 자료는 10초 간격으로 측정하고 그 10분 평균값을 취하였으며 분석은 한 시간 단위로 수행하였다. 맑은 날 자료에 의하면 일출 이후 초관부(최대엽면적 부위) 기온은 외기온과 거의 같은 비율로 상승하나, 그 아래쪽으로 갈수록 태양고도가 높아지기 전까지는 온도 상승이 상대적으로 지연된다. 오후에 태양고도가 낮아지기 시작해도 군락 외부와 초관부의 기온은 관측노장의 일 최고기온 발생시각까지 상승을 지속하나, 그 아래쪽 기온은 상승폭이 둔화되며 수면 부근에서는 외기온 상승폭의 10%에 그쳐 오후 내내 거의 일정한 온도를 유지한다. 외기온의 하강이 시작되면 위치와 무관하게 같은 비율로 냉각되나, 일몰 후에는 초관 하부의 냉각이 지연되면서 자정 무렵에는 상하 중립인 구조를 갖는다.

• 한국작물학회지
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• 제42권4호
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• pp.473-482
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• 1997

Temperature, humidity and wetness duration were monitored for fully developed paddy rice canopies with 3 different structures induced by the seeding method(puddled-soil drill seeding, DS ; hand broadcasting, HB ; machine broadcasting, MB). Within-canopy air temperature averaged over "clear sky" hours during the study period(maximum tillering through heading) was lower than the screen temperature at a nearby standard weather station, especially in the night. The same trend was true for "overcast sky" hours except the diurnal distinction. Vapor pressure within the canopy was high during the daytime and low in the night, making the daytime deviation from outside the canopy more significant on clear days. Under the overcast sky, the canopy maintained a steady 5 to 10％ higher vapor pressure than the outside regardless of day or night. Daily maximum temperature was observed to be higher within the canopies with more leaf mass, making MB the highest, HB the lowest, and DS in between. Relative humidity was over 90％ in the night and dropped to 70％ in the mid-afternoon, but vapor pressure within the canopy was highest at around 13:00 LST. Dew point depression was lowest and, combined with the temperature, the relative humidity was highest in HB. Mean period of wetting duration was in the order of DS＞HB＞MB, while the dew point depression was greatest in DS.

• 한국농림기상학회지
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• 제3권4호
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• pp.199-205
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• 2001

넓은 지역에 걸친 병 예찰모형의 동시 다지점 적용은 지역특이적 식물 병 관리체계 구축을 위한 전제조건이다. 예찰모형의 구동변수로서 군락내부 기온자료 역시 충분한 공간해상도와 공간범위로 준비되어야 한다. 생육중기의 여 군락기온구조에 관한 실측정보를 토대로 만들어진 실용성 있는 광역 군락기온분포 예측 기법을 제시한다. 이앙 후 한 달째부터 출수기까지 벼 군락 내 기온 연직구조의 경시변화를 관측하여 맑은 날, 흐린 날, 비오는 날의 군락외부기온(250 cm)과 군락내부기온(10cm)간 편차의 경시변화양상을 정량화 하였고, 이를 토대로 군락외부 기온값이 주어지면 군락내부 임의높이의 기온을 추정할 수 있는 경험식을 작성하였다. 벼논의 경우 맑은 날 인근 관측노장 대비 전국적으로 0.6~1.2$^{\circ}C$ 낮다는 사실을 근거로 기온 공간내삽시 지표피복 특성이 벼논인 경우의 보정량을 결정하였다. 전라남북도 지역을 대상으로 기상청 정규관측소의 매 시간 관측값을 공간내삽 함으로써 초지로 덮여있는 가상지형상의 기온표면을 1km$\times$1km 해상도로 생성하였고, 위성영상자료의 분석을 통해 이들로부터 벼논에 해당되는 픽셀만 추출하여 기온 하강분을 보정함으로써 군락외부 기온을 준비하였다. 벼논특성을 가진 픽셀에 준비된 군락내부 기온추정식을 각각 적용하여 층위별 기온값을 추정하였다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.60-60
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• 2017

It is important to measure the gas exchange activity of the crops in canopy scale to understand the process of biomass production and yield formation. Thermal imaging of the canopy surface temperature is a powerful tool to detect the gas exchange activity of the crop canopy. The simultaneous measurement of the canopy temperature and the meteorological data enables us to calculate the canopy diffusive conductance ($g_c$) based on the heat flux model (Monteith et al. 1973, Horie et al. 2006). It is, however, difficult to realize the long-term and continuous monitoring of $g_c$ due to the occurrence of the calculation error caused by the fluctuation of the environmental condition. This is partly because the model assumption is too simple to describe the meteorological and aerodynamic conditions of the crop canopy in the field condition. Here we report the novel method of the direct measurement of the aerodynamic resistance ($r_a$) of the crop canopy, which enables us the stable and continuous measurement of the gas exchange capacity of the crop plants. The modified heat balance model shows the improved performance to quantify $g_c$ under the fluctuating meteorological condition in the field. The relationship between $g_c$ and biomass production of rice and soybean varieties is also discussed in the presentation.

• Journal of Biosystems Engineering
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• 제26권3호
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• pp.221-228
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• 2001

Chemical application, one of the most important crop management processes happened to cause spray drift, that would threaten farmers in field as well as dwellers in rural region. Spray drift was affected by micro-meteorological parameters. A study to evaluate short distance drift characteristics of a boom sprayer in paddy fields has been undergoing. This study is the first step of the research. Main purpose of the was conducted to develop a mean wind profile and to get information on turbulence intensities above and within rice canopy. Wind in rice paddy field were measured at every 10cm from 10 to 180cm above the ground using a 2-dimensional probe and a hot wire anemometer system. Main results were summarized as follows. 1. Mean wind profile was modeled as; Equations. see full-text 2. Roughness length and zero-displacement in rice canopy were analyzed to be respectively 0.04 and 0.7∼0.72 times of the canopy height. The values are smaller comparing to those of other crops because rice canopy is flexible and uniform comparing to other crops. 3. Turbulence intensities (Tl) was greater as close to the ground and became constant at heights greater than 1.5Hc. where Tl’s were 0.4 and 0.15 in horizontal and vertical direction respectively.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.805-809
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• 2008

Measurement of leaf area index (LAI) is useful for understanding rice growth, water use, and canopy light interception. The top nitrogen content(TNC) per unit area is an important quantitative index of the condition of nitrogen nutrition in rice production. The rapid and simple method of estimation of TNC, with the use of the existing nondestructive analyzing instruments chlorophyll meter SPAD-502 and plant canopy analyzer (PCA) LAI-2000, was scrutinized. Destructive measurement is time consuming and labor intensive. Our objective was to evaluate sampling procedures using the Li-Cor LI-1800, LAI 2000 plant canopy analyzer (PCA) for nondestructive estimation of rice LAI, and SPAD-502 on the Northern Plains of Cheongju. The LAI estimated by PCA tended to underestimate the LAI determined by actual measurement by about 20%. The estimation of LAI by PCA was judged to have a sufficient accuracy as a practical technique. A high positive correlation was obtained between the values of the SPAD reading and LAI. NDVI and LAI also showed a very high correlation. The values of the SPAD reading and LAI, and NDVI gave a high positive correlation. These results indicated that the method described in this study was effective as a simple and rapid method for the estimation of rice growth.

• 한국육종학회지
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• 제40권2호
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• pp.143-152
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• 2008

1913년부터 2000년까지 국내에서 육성된 70품종에 대한 초형형질에 관련된 주경, 분지 및 엽형질의 특성을 파악하여 다수성 콩 품종개발의 기초자료로 이용코자 하였다. 1. 초형형질의 변이는 주경과 분지관련형질의 12개 형질 중에서 초형폭, 분지장 및 초형폭/장 비율이 컸으며, 엽관련 8개형질 중에서는 엽병각, 엽장폭비 및 엽건물중이 컸다. 2. 용도별로 초형폭/장 비율은 밥밑콩이 장류 및 두부용콩과 나물콩에 비하여 높았고 장류 및 두부용콩과 나물콩은 큰 차이가 없었다.총분지장/주경장 비율은 나물콩과 밥밑콩이 높았고 장류 및 두부용콩이 낮았다. 3. 주경과 분지형질은 초형폭/장 비율과 총분지장/ 주경장 비율에 의하여 각각 그룹으로 분류되어졌고, 협초폭형이며 주경의존형은 단원콩, 금강콩, 셀비 및 신팔달콩이었고, 협초폭형이며 분지의존형은 소명콩이었다. 광초폭형이면서 주경의존형은 강림, 금강대립 및 진율콩이었으며, 광초폭형이면서 분지의존형은 검정콩 2호이었다. 4. 용도별로 소엽장/폭 비율은 밥밑콩이 작았고 장류 및 두부용콩과 나물콩과는 큰차이가 없었으며, 복엽의 엽면적은 밥밑콩이 가장 컸고 나물콩이 가장 작았다. 엽병장은 나물콩이 작았으며 장류 및 두부용콩과 밥밑콩은 큰 차이가 없었고, 엽병각은 밥밑콩이 가장 컸고 나물콩이 가장 작았다. 5. 엽형태는 엽장폭비와 엽면적에 의하여 각각 4그룹으로 분류 되어졌고, 소엽장폭비가 큰 원엽이면서 엽면적이 큰 대형엽은 부석과 대황콩이었고, 엽장폭비가 극세엽이면서 엽면적이 작은 소형엽은 은하콩과 소호콩이었다. 6. 엽병의 특성은 엽병장과 엽병각에 의하여 각각 3그룹과 4그룹으로 분류 되어졌고, 엽병장이 짧고 엽병각이 작은 품종은 은하콩이었고, 엽병장이 짧고 엽병각이 큰 품종은 알찬콩, 무한콩 및 푸른콩이었으며, 엽병장이 길고 엽병각이 작은 품종은 신팔달콩 2호이었다. 7. 은하콩은 전 시험품종 중에서 엽장폭비가 가장 큰 극세엽이면서 엽면적이 가장 작은 소형엽이었고, 엽병장이 가장 짧으며 엽병각이 가장 작은 품종이었다.