Portable spectrometers can be used in a variety of real-world and experimental scenarios to estimate important physiological, chemical, and genetic information about plants. Prior to collecting reflectance spectra – in a lab, greenhouse, or in the field – it is important to consider the viewing geometries, ambient light and atmospheric conditions, limitations of the instrument, and finally, how light interacts with plants at the leaf and canopy levels.
High spectral resolution in vivo leaf-level contact measurements provide a valuable alternative to destructive sampling, but even these data require interaction with plants that takes time, requires very specialized and expensive equipment, and can potentially affect the plant's physical and chemical state. Canopy-level spectroscopic measurements can be made relatively quickly and do not affect plant state, but require characterization and understanding of contemporaneous light conditions. Here we demonstrate field application of the Piccolo Doppio, a dual-field-of-view tandem spectrometer system (Mac Arthur et al, 2014) that we have configured to measure reflected light at 400-950 nm @ ~1.4 nm resolution, and 900-1700 nm @ ~3.1 nm resolution. The spectrometer system has been fitted to an adjustable tractor-mounted boom in order to make fast and consistent spectral measurements in agro- and similar low-stature ecosystems.
Results/Conclusions
We demonstrate the utility of a canopy scanning dual-field-of-view tandem spectrometer system – the Piccolo Doppio – for collecting reflectance spectra from a tractor-mounted boom. An existing experiment, one designed to assess the interactions of seed treatment and planting date on soybean yield as well as apparent symptoms of Sudden Death Syndrome (SDS), was the testbed for the Piccolo Doppio capabilities. Specifically, we established a workflow to determine if and when (i.e. time after planting) the canopy-level spectra could pre-visually identify plants affected by SDS. This method can be used for assessment of ecosystems and plant-pest-pathogen interactions across a range of applications.