ARS | Publication request: NEAR-INFRARED REFLECTANCE ANALYSIS OF SOIL MATERIALS

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 9, 2000
Publication Date: N/A

Technical Abstract: Near-infrared reflectance spectroscopy (NIRS) is a rapid and nondestructive analytical technique that potentially can be used to quantify C and N in soils. The objective of this study was to evaluate the ability of NIRS to quantify the C and N content of diverse soil materials. Samples analyzed were obtained by mixing soils with CaCO3, humic acid, and/or compost materials. NIR spectra of these samples (n=108) were correlated with measured values of organic C, inorganic C, total N, and C:N ratios using partial least square regression. The r2s between the measured and predicted values were higher than 0.96 for all tested properties. The results indicate that NIRS can be used to analyze soil organic C, inorganic C, and total N simultaneously for soils with diverse C and N compositions. In addition, the successful prediction of total N and C:N ratios for the studied samples indicates that NIRS prediction of total N for soils is not based on the strong correlation between C and N, which is observed in most soils, rather the results indicate the NIRS is responding to vibrational modes for N containing organic functional groups.