• Title/Summary/Keyword: 변환계수

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Comparison of Microscopy and Pigment Analysis for Determination of Phytoplankton Community Composition: Application of CHEMTAX Program (식물플랑크톤 군집조성 파악을 위한 현미경관찰법과 지표색소분석법 비교 연구: CHEMTAX 프로그램 활용)

  • Kim, Dokyun;Choi, Jisoo;Oh, Hye-Ji;Chang, Kwang-Hyeon;Choi, Kwangsoon;Shin, Kyung-Hoon
    • Korean Journal of Ecology and Environment
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    • v.54 no.4
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    • pp.303-314
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    • 2021
  • To understand how to efficiently observe the biomass and community of phytoplankton, phytoplankton sampling was carried out from June to October 2019 at the Yeongju dam sediment control reservoir(YJ) and Bohyeonsan dam reservoir(BH1 and BH2). The results derived from microscopic observation, such as the conventional phytoplankton qualitative/quantitative analysis, and from the CHEMTAX method based on the pigments, were compared. The relative contribution of phytoplankton, calculated by the microscopy and CHEMTAX methods, showed a significant difference in all four classes: cryptophyta, chlorophyta, cyanobacteria, and diatoms. In addition, the correlation between the two observation methods was poor. This might be caused by methodological differences in microscopy that do not consider the varying cell sizes among phytoplankton species. In this study, by converting the cells into carbon, the slope between both carbon biomasses based on microscopy and CHEMTAX was improved close to the 1 : 1 line, and the y-intercept was closer to 0 for cryptophyta and diatoms. For cyanobacteria, the slope increased, the y-intercept decreased, and the plot approached 1 : 1 although the correlation coefficients were not improved in all classes. The present study suggests that application of CHEMTAX based on pigment analysis could be a possible approach to efficiently determine the relative carbon proportions of individual classes of phytoplankton community composition.

Estimation of Rice Canopy Height Using Terrestrial Laser Scanner (레이저 스캐너를 이용한 벼 군락 초장 추정)

  • Dongwon Kwon;Wan-Gyu Sang;Sungyul Chang;Woo-jin Im;Hyeok-jin Bak;Ji-hyeon Lee;Jung-Il Cho
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.25 no.4
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    • pp.387-397
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    • 2023
  • Plant height is a growth parameter that provides visible insights into the plant's growth status and has a high correlation with yield, so it is widely used in crop breeding and cultivation research. Investigation of the growth characteristics of crops such as plant height has generally been conducted directly by humans using a ruler, but with the recent development of sensing and image analysis technology, research is being attempted to digitally convert growth measurement technology to efficiently investigate crop growth. In this study, the canopy height of rice grown at various nitrogen fertilization levels was measured using a laser scanner capable of precise measurement over a wide range, and a comparative analysis was performed with the actual plant height. As a result of comparing the point cloud data collected with a laser scanner and the actual plant height, it was confirmed that the estimated plant height measured based on the average height of the top 1% points showed the highest correlation with the actual plant height (R2 = 0.93, RMSE = 2.73). Based on this, a linear regression equation was derived and used to convert the canopy height measured with a laser scanner to the actual plant height. The rice growth curve drawn by combining the actual and estimated plant height collected by various nitrogen fertilization conditions and growth period shows that the laser scanner-based canopy height measurement technology can be effectively utilized for assessing the plant height and growth of rice. In the future, 3D images derived from laser scanners are expected to be applicable to crop biomass estimation, plant shape analysis, etc., and can be used as a technology for digital conversion of conventional crop growth assessment methods.