Elemental Analysis of Nutrients in Dairy Manure by Automated X-rayFluorescence Spectrometry

We have determined that X-ray fluorescence (XRF) spectrometry can be used as a rapid and precise method for quantitative elemental analysis of macro and micro nutrients in dairy manure. The elements chosen for this study were N, P, K, Ca, Mg, S, Zn, Mn, Fe, Cu, Al, Na, B, and C. The wavelength-dispersive XRF spectrometer was calibrated by comparing its results with a panel of dried dairy manure samples with analyses from inductively coupled plasma (ICP) obtained from three independent certified laboratories. In addition, the XRF results for C, N, and S were compared with those from a high-temperature combustion (HTC) analyzer dedicated to measurements of these three elements. Then the performance of the calibrated XRF was tested against a separate panel of dairy manure samples collected at fifteen different sampling points at a manure processing plant. Subsamples from these samples were analyzed for the 14 elements of interest by a certified laboratory. The close agreement between the XRF results and those of the certified laboratory established that XRF can be used as a simple and precise method for the elemental analysis of dairy manure