Spectroscopy and hyperspectral imagery for monitoring summer barley

Abstract

The potential of field spectroscopy is shown by the quantitative assessment of summer barley canopy properties. A data set was acquired, comprising top of canopy reflectance (0.4–2.4 μm) and the corresponding canopy parameters of summer barley stands for two phenological stages. Canopy variables (leaf area index, canopy chlorophyll, water, and fresh matter contents) were predicted by partial least squares regression (PLSR) from field spectra resampled to HyMap spectral resolution with very high accuracy (r ² _cv  > 0.88). PLSR models obtained from field spectra were applied to HyMap data to allow spatial prediction of summer barley canopy properties. Subsequently, to assess accuracy of the spatially distributed estimates, predictions obtained from the image data were validated with reference to the vegetation samples taken in the field. The predicted values reflect the spatial conditions of the investigated plot. The results indicate the potential of this method as a quick screening tool for spatial assessment of canopy variables.

Acknowledgements

This research was supported in part by a Sam & Cecilia Neaman Fellowship at the Technion – Israel Institute of Technology – and the Forschungsfonds of Trier University. The author would like especially to thank Matthias Mohn, the landowner of the study plot, for his cooperation and Michael Vohland, who generously supported data acquisition and preprocessing. The author thanks the following people who assisted in data collection and harvesting: Henning Buddenbaum, Sebastian Mader, Erik Mohr, Franz Ronellenfitsch, and Martin Schlerf. The author also thanks Antje Heuer for providing the data on soil depth, and the two anonymous referees for their valuable comments on the article.