Near-infrared diffuse reflectance spectroscopy for the analysis of poultrymanures

The objective was to evaluate near-infrared diffuse reflectance spectroscop y (NIRS) for determining the composition of poultry manures. Poultry manure samples were obtained from a commercial testing laboratory along with conv entionally determined analyte values for total N, NH4+-N, organic N (comput ed as total minus NH4+-N), minerals, and moisture. Samples were blended in a food blender and scanned in polyethylene bags on a FOSS-NIRSystems model 6500 scanning monochromator. Initial results indicated that changes had occ urred in NH4+-N contents from the time of analysis, and samples were reanal yzed for NH4+-N. Using the new analyses, NIPS was able to accurately determ ine NH4+-N, organic N, total N, and moisture in 128 poultry manures. Result s were more accurate when determinations were made on an "as is" as opposed to dry matter basis. Finally, results indicated that NIPS was not suitable for the determination of minerals (P, K, Ca, etc.) in poultry manures.