SIMULTANEOUS DETERMINATION OF MOISTURE, ORGANIC-CARBON, AND TOTAL NITROGEN BY NEAR-INFRARED REFLECTANCE SPECTROPHOTOMETRY

Near infrared diffuse reflectance spectrophotometry, within the wavelength range 1,100 to 2,500 nm, was investigated for use in the simultaneous prediction of the moisture, organic C, and total N contents of air-dried soils. An infraAlyzer 500 C (Technicon Instruments Corp. ) scanning spectrophotometer was used to obtain near infrared reflectance of soils at 2-nm intervals. Calibration equations for each of the soil constituents studied were based upon selection of the best combination of three wavelengths in a multiple regression analysis.