SOIL SPECTRAL IMAGING: MOVING from PROXIMAL SENSING to SPATIAL QUANTITATIVE DOMAIN

Imaging spectroscopy (IS) is a relatively new technique that has attracted the attention of workers in many fields. In the soil sciences, this technology is not well developed and additional research is required - despite the fact that a large number of soil properties in the soil environment have already been studied from a reflectance perspective with much success (e.g. organic matter, cation exchange capacity, carbonate content and specific surface area). Going from proximal sensing to image spectrometry is not only a journey from the micro to macro scales; it is a lengthy one that is fraught with problems, such as dealing with data having a low signal-to-noise level, contamination of the atmosphere, large data sets, the Bidirectional Reflectance Distribution Function (BRDF) effect and more. In this paper, provide a brief history of both near infrared spectroscopy (NIRS) and IS approaches and attempt to understand why, despite its promise, IS has not yet been well developed for the soil sciences. We assume that research, education, exposure of the technology to end-users and governmental involvement are the major factors that require attention in this venue. Also provide some personal thoughts on the future of IS in soil and conclude that in 5 to 10 years, this application will have matured into one that is ready to use and well-known among soil scientists, end-users and decision-makers.