Estimating Zn Content of Pepper under Different Fertilizer Applications Using a Handheld Spectrometer

Basayigit L., Ozkul M.

INTERNATIONAL JOURNAL OF AGRICULTURE AND BIOLOGY, vol.17, no.1, pp.97-104, 2015 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 17 Issue: 1
  • Publication Date: 2015
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.97-104


In this study, the zinc content of pepper plants was determined when different doses of zinc sulphate (ZnSO4 center dot 7H(2)O) or ethylene diamine tetraacetic acid (Zn-EDTA) were applied using the hyperspectral method. This study was performed in greenhouse and two different fertilizers (ZnSO4 center dot 7H(2)O and Zn-EDTA) were applied at five doses to the plants. There were fifty pots that had five recurrences, and each pot contained three pepper plants. Three leaf samples from each pot were taken at five different growing stages for analysis. An ASD Field Spec Handheld spectroradiometer and a plant probe were used to obtain data from the leaves. The zinc (Zn) concentrations were determined by stepwise multiple linear regression analysis of first degree derivation of spectral reflectance peaks with maximum R-2; possible wavelengths for zinc (Zn) measurements were determined. Reflectance peaks, its first order derivatives and the equation of prediction models for zinc sulphate heptahydrate (ZnSO4 center dot 7H(2)O) and ethylene diamine tetraacetic acid (Zn-EDTA) were compared. To reveal the relationships between Zn concentration of the leaf samples fertilized with either ZnSO4 center dot 7H(2)O or Zn-EDTA, the correlation analysis of the vegetation index was performed. The relationships between plant vegetation indices and zinc concentration were visualized by diagrams. The reflectance peaks at 640 nm wavelength were significant for both fertilizers. The highest accuracies were obtained at 400-500 nm for ZnSO4 treatments, whereas the 900-1000 nm wavelengths were better for Zn-EDTA treatments. In conclusion, different spectral wavelengths should be used for the determination of zinc concentration from hyperspectral reflectance peaks, but the vegetative index of the plants cannot be determined by the hyperspectral reflectance method. (C) 2015 Friends Science Publishers