Author
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Reeves Iii, James |
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Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/7/2001 Publication Date: 11/10/2001 Citation: N/A Interpretive Summary: Spectroscopy uses the interaction between light and various materials to determine the composition of the material in question. Near-infrared and mid-infrared diffuse reflectance spectroscopy (NIRS) use the reflection of light beyond the range of human vision and have been used to determine the composition of animal feeds, human foods and other materials. The objective was of this work was to determine if accurate determinations for mineral content in dried poultry manures could be developed using near- or mid-infrared spectra. Samples (n = 124) were obtained from a commercial testing laboratory along with conventionally determined values for Ca, Cu, K, Mg, Mn, P, S, Zn. Samples were blended in a food blender, dried at 60o C, ground to 20 mesh and scanned in the near-infrared and mid-infrared. Results showed neither calibrations based on near- or mid-infrared spectra to be satisfactory for the accurate determination of Ca, Cu, K, Mg, Mn, P, S or Zn in dried poultry manures. At best, most of the calibrations would be suitable for only gross estimates, although the mid-infrared calibration for P might be suitable for some needs where only a limited degree of accuracy was needed. Either spectral range could be used to separate dried poultry manure samples into those containing less than 3% and greater than 8% Ca, but not to accurately differentiate samples within those two groupings. Technical Abstract: The objective was to determine if accurate calibrations for mineral content in dried poultry manures could be developed using near- or mid-infrared spectra. Samples (n = 124) were obtained from a commercial testing laboratory along with conventionally determined values for Ca, Cu, K, Mg, Mn, P, S, Zn. Samples were blended in a food blender, dried at 60o C, ground to 20 mesh and scanned in the near-infrared (rotating sample cup) on a FOSS- NIRSystems model 6500 scanning monochromator. Samples were also scanned in the mid-infrared on a Digi-Lab FTS60 Fourier Transform spectrometer using a custom made sample transport. Results showed neither calibrations based on near- or mid-infrared spectra to be satisfactory for the accurate determination of Ca, Cu, K, Mg, Mn, P, S or Zn in dried poultry manures. At best, most of the calibrations would be suitable for only gross estimates, although the mid-infrared calibration for P might be suitable for some needs where only a limited degree of accuracy was needed. Either spectral range could be used to separate dried poultry manure samples into those containing less than 3% and greater than 8% Ca, but not to accurately differentiate samples within those two groupings. Finally, while the mid- infrared calibrations were the more accurate for five of the eight minerals studied, the differences between the two sets of calibrations were so varied that it would be difficult to say that one region is better for mineral content measurement. |
