This material in this section first appeared as an article in the Australian Soil Club Newsletter 1(3) in February 2004 by Craig Russell (The University of Western Australia) and Les Janik (Infrared Analytical Services).
This section contains three questions.
Infrared spectroscopy is based on the fact that individual materials are defined and therefore identified by their reflectance or absorbance of infrared light. Infrared spectroscopy is currently used routinely for the rapid characterisation of a wide range of materials. It is used in Australia in the areas of grain quality and leaf tissue testing, food chemistry and mining.
The advantages of infrared techniques for soil analyses over other analytical techniques include:
Infrared technology offers the potential of a more precise and standardised soil testing service. Soil analyses derived from standard chemical methods from different laboratories, or at different times from the same laboratory, can be difficult to compare. This can be due to operator error and, or, differences in analysis conditions across laboratories, or even across batches within a laboratory. Infrared techniques will support the further development of precision agriculture by providing information at higher spatial resolutions cheaper and faster. They may also be available for on site analysis in the near future.
All of these advantages contribute to a reduced cost of analysis. Consequently, infrared spectroscopy is being rapidly adopted across Australiaʼs primary industries.
Laboratory research has demonstrated the capacity of infrared spectroscopy to predict soil physical, chemical, and biological properties. Quantitative predictions of several important soil properties have been made. These properties are important in assessing soil fertility, agricultural practices and land degradation. They include:
Other soil properties that have been predicted with infrared technology are total nitrogen, carbonate, lime requirement, cation exchange capacity and soil texture (i.e. percentage sand, silt and clay).