ABSTRACT
Near infrared (NIR, 750 to 2500 nm wavelength) spectroscopy is a well-known analytical technique and has been adopted by many agricultural and manufacturing industries. In agriculture it is commonly used to measure the nutritional components of forage and animal feeds (Norris et al., 1976; Shenk and Westerhaus, 1994; Fahey and Hussein, 1999), and to measure secondary metabolites in plants (Clark et al., 1987; Windham et al., 1988). This method has obtained certified status (AOAC, 1990) to measure moisture, crude protein and acid detergent fiber in forages. NIR spectroscopy is known for its rapidity, convenience, accuracy and ability to analyze many constituents at the same time (Stark et al., 1986). It is now believed that this technique has the capacity to be used to study complex functional attributes of natural systems, for example, the susceptibility of plants to insect attack (Rutherford and van Staden, 1996), the yield of pulp from trees (Wright et al., 1990) and the biological degradability of sawlogs (Hoffineyer and Pedersen, 1995; Schimlecketal., 1996). It is still being tested for its usefulness to analyze soils, other biological materials and ecological parameters (Ben-Dor and Banin, 1995; Foley et al., 1998).
