Monitoring Tobacco Growth And Quality Based On Spectra

The nondestructive hyperspectral technology to monitor and detect crop growth status has demonstrated wide applicability in the field of remote sensing and informative agronomy. In this study, hyperspectral technology was applied to tobacco. A series of field experiments with flued-cured variety (FCV) tobacco and oriental tobacco types under nitrogen rates were conducted in Zhengzhou Henan and Baoshan Yunan, which belong to main tobacco production region in China. Leaf-scale and canopy-scale reflectance spectra were measured with ASD Fieldspec FR2500 over the growth stages at the field and laboratory. The objectives of this research were to determine the relationship between spectral characteristics and tobacco biophysical and biochemistry parameters, and to develop models for monitoring growth and quality traits based on spectral characteristics. Therefore, this work would provide theoretical basis for quantitative remote sensing and hyperspectral application on tobacco production. The results showed that:1. Spectral characteristics of tobacco were analyzed systemically corresponding to nitrogen rates, tobacco types, growth stages, leaf position at the stem, position within-leaf, adaxial and abaxial leaf surface, fresh and dry leaf. Tobacco has typical vegetation reflectance spectral characteristics. Range of reflectance variation coefficient of FCV tobacco leaf investigated was 32.8-58.7% at field in 350-2500nm. Leaf reflectance of burley tobacco was great than that of oriental tobacco and FCV tobacco in the visible and near-infrared regions. FCV tobacco leaf reflectance was, upper leaf >cutter leaf>lower leaf at the stem. The reflectance varied with positions within-leaf as well as adaxial and abaxial leaf surface in FCV tobacco. The reflectance of dry leaf was great than that of fresh leaf in FCV tobacco. Reflectance of FCV tobacco leaf and oriental tobacco canopy decreased at visible region and increased with nitrogen rates at near-infrared region. Reflectance of FCV tobacco leaf increased with growth progress at 400-1350nm region, of which reflectance varied greatly at visible region. While reflectance of oriental tobacco leaf decreased at visible regions and increased at near-infrared with growth progress. Spectra are the...