Analysis of Minor Elements and Metals in Hog Manure by Field- portable Near-infrared Spectroscopy: Results for the Textron/Case NH ProSpectraTM Spectrometer

Executive Summary The overall purpose of this project was to develop a field protocol for testing two field-portable near-infrared (NIR) spectrophotometers as on-site, free-standing (not in-line), measurement tools for nutrients in hog manure at the time of application of manure to agricultural land. This project is a developmental step between the analysis of hog manure in the laboratory using near-infrared spectroscopy (NIRS) and the deployment of NIR instruments in the manure stream for real-time measurement of composition of manure during application to land. The field-portable instruments included a prototype of the Textron Systems Corp (USA)/Case NH (USA) ProSpectra™ Spectrometer and the Carl Zeiss (Germany) Corona® Spectrometer. The first step in this project was the design and construction of a mobile laboratory mounted on the bed of a 1/4-ton pickup truck. Considerations in designing and building this system included reliable power supply for the instruments and laptop computers, security of the equipment against movement during transit and against theft, protection from the elements, and worker safety. Secondly, the project involved sampling of manure at 13 application operations during September to November 2000. A total of 121 manure samples were collected. Using conventional physical and chemical methods, the samples were analyzed for moisture, pH, density, conductivity, nutrients, metals and minor elements. Thirdly, the project involved operating the two field-portable NIR instruments on the mobile laboratory for the scanning of the manure samples. As well, all of the samples were scanned with a laboratory instrument, the Foss NIRSystems Inc. (USA) Model 6500 visible/near-infrared scanning spectrophotometer. The NIR spectral data from the 6500 and field-portable instruments were statistically correlated with the chemical data on the same samples to develop calibrations, or statistical models, for each constituent on each instrument. The success of calibrations was evaluated statistically as a measure of the performance of the instruments and their suitability for on-site manure analysis. Successful calibrations can be used with the respective instruments in the field to predict composition of future manure samples. This is the fourth of six reports describing the results from the overall project. It reports the results from developing calibrations for the minor elements and metals from the spectra obtained with the prototype ProSpectra™ spectrometer. The ProSpectra™ is a solid state spectrometer using a Charge Coupled Device (CCD) Linear Array to detect the light and is equipped with a diffuse reflectance probe. The instrument records absorbance of the sample every 0.5 nm …