Spectral response of potassium content in flue-cured tobacco leaves under different degree of water stress
LI Mengzhu1,2, YE Hongchao3, WANG Hui2, JIA Fangfang4, LIU Guoshun1
1 National Tobacco Cultivation&Physiology&Biochemistry Research Center, Henan Agricultural University, Zhengzhou 450002, China; 2 Yiyang Branch of Luoyang Municipal Tobacco Company, Yiyang 471600, China; 3 Luoyang Municipal Tobacco Company, Luoyang 471000, China; 4 Shangqiu Normal University, Shangqiu 476000, China
Abstract [Objective] This study aims to realize accurate, rapid and nondestructive monitoring of the potassium nutrition level of flue-cured tobacco leaves. [Methods] The experiment of different degree of drought and waterlogging stress was designed. K326 and zhongyan100 were used as the test varieties to explore the change rule of potassium content and spectral information of flue-cured tobacco leaves under different degree of water stress. By screening the sensitive spectral characteristic variables and spectral parameters of potassium content of flue-cured tobacco leaves, the prediction model of potassium content in tobacco leaves was constructed. [Results] (1) With the aggravation of water stress, the K content and spectral reflectance of flue-cured tobacco leaves showed an increasing trend at the root extension stage, and a decreasing trend at the vigorous growth and mature stages. (2) The BP neural network model based on the eight best sensitive spectral indexes (msr705, SDR, DVI, msavi2, λ g, Dr, NDSI (2275, 1875), rdvi) had the best effect, R2 (decision coefficient) was 0.9336, RMSE (root mean square error) was 0.1348. [Conclusion] The BP neural network model of potassium content in flue-cured tobacco can be constructed by using spectral parameters and such constructed model is more stable and accurate. This study provides technical support for real-time and accurate monitoring of potassium content in flue-cured tobacco leaves and timely understanding of soil moisture environment.
LI Mengzhu, YE Hongchao, WANG Hui, JIA Fangfang, LIU Guoshun. Spectral response of potassium content in flue-cured tobacco leaves under different degree of water stress[J]. Acta Tabacaria Sinica, 2020, 26(4): 86-92.