Assessment of vegetation stress using reflectance or fluorescence measurements

J Environ Qual. 2007 May 7;36(3):832-45. doi: 10.2134/jeq2005.0396. Print 2007 May-Jun.

Abstract

Current methods for large-scale vegetation monitoring rely on multispectral remote sensing, which has serious limitation for the detection of vegetation stress. To contribute to the establishment of a generalized spectral approach for vegetation stress detection, this study compares the ability of high-spectral-resolution reflectance (R) and fluorescence (F) foliar measurements to detect vegetation changes associated with common environmental factors affecting plant growth and productivity. To obtain a spectral dataset from a broad range of species and stress conditions, plant material from three experiments was examined, including (i) corn, nitrogen (N) deficiency/excess; (ii) soybean, elevated carbon dioxide, and ozone levels; and (iii) red maple, augmented ultraviolet irradiation. Fluorescence and R spectra (400-800 nm) were measured on the same foliar samples in conjunction with photosynthetic pigments, carbon, and N content. For separation of a wide range of treatment levels, hyperspectral (5-10 nm) R indices were superior compared with F or broadband R indices, with the derivative parameters providing optimal results. For the detection of changes in vegetation physiology, hyperspectral indices can provide a significant improvement over broadband indices. The relationship of treatment levels to R was linear, whereas that to F was curvilinear. Using reflectance measurements, it was not possible to identify the unstressed vegetation condition, which was accomplished in all three experiments using F indices. Large-scale monitoring of vegetation condition and the detection of vegetation stress could be improved by using hyperspectral R and F information, a possible strategy for future remote sensing missions.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acer / drug effects
  • Acer / metabolism*
  • Acer / radiation effects
  • Carbon Dioxide / metabolism
  • Carbon Dioxide / pharmacology
  • Environmental Monitoring / methods
  • Glycine max / drug effects
  • Glycine max / metabolism*
  • Glycine max / radiation effects
  • Nitrogen / metabolism
  • Nitrogen / pharmacology
  • Ozone
  • Plant Leaves / drug effects
  • Plant Leaves / metabolism
  • Plant Leaves / radiation effects
  • Spectrometry, Fluorescence / methods*
  • Ultraviolet Rays / adverse effects
  • Zea mays / drug effects
  • Zea mays / metabolism*
  • Zea mays / radiation effects

Substances

  • Carbon Dioxide
  • Ozone
  • Nitrogen