|Reeves Iii, James|
|Van Kessel, Jo Ann|
Submitted to: Pittsburgh Conference
Publication Type: Abstract Only
Publication Acceptance Date: March 7, 1999
Publication Date: N/A
Technical Abstract: The objective was to investigate the feasibility of using near-infrared or visible-shortwave near-infrared fiber optic based spectrometers to determine constituents of dairy manures. Manures (107) collected from dairy farms in the northeastern US were assayed conventionally and spectroscopically for total C and N, ammonia, moisture, P and K. Samples were scanned (64 co-added scans) on a NIRSystems Model 6500 scanning monochromator equipped with a fiber optic probe from 400 to 2498 nm, and on an Ocean-Optics model S2000 CCD spectrometer from 430 to 1100 nm (1000 scans/sample, integration time of 41 ms). Calibrations were developed using the one-out cross validation procedure under PLS. Results demonstrated that: 1. Accurate calibrations for ammonia, moisture, and Total C and N can be developed, but are not as accurate as those developed using a sample transport device; 2. Limitations in the spectra produced by presently available fiber optic bundles are at least partially responsible for the reduced accuracy found when compared to non-fiber optic means of sample presentation; 3. Spectra produced by fiber optic systems appear to be more diverse than those for non-fiber optic systems; 4. While determinations based on spectra covering the region from 400 to 2300 nm appear to be a viable alternative to other available quick tests for manure, those using only the 400 - 1100 nm spectral region do not; and 5. Further efforts with larger data sets are needed to determine the limitations and requirements for developing accurate and robust calibrations for manure constituents using fiber optic based spectrometers.