|Reeves iii, James|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/27/2006
Publication Date: 5/1/2007
Citation: Calderon, F.J., Reeves Iii, J.B. 2007. Drifts and Near Infrared Spectroscopy Analysis of Fresh and Decomposed Cattle Manure. Meeting Proceedings of the 12th International Conference on Near Infrared Spectroscopy in Auckland, New Zealand. April 10-15, 2005. Pages 45-48. Interpretive Summary: In this proceedings paper, we measured infrared and near infrared spectroscopic changes in cattle manure during decomposition in field soil. The aim was to determine what wavelengths change in manure as it decomposed. This information may be valuable for research about manure quality, and we hypothesize that the wavelengths which change during decomposition may be related to quality indicators such as manure mineralizable N. Our results show that near infrared spectra have more resolution that mid infrared in discerning between manures, especially at the early stages of decomposition. However, several wavelengths in the mid infrared were identified that show insight into specific changes in manure as it decomposes.
Technical Abstract: Determining the nitrogen fertilizer value of cattle manure remains an elusive problem due to the heterogeneity of manure N. Diffuse reflectance near infrared spectroscopy (NIRS) and Fourier-transformed mid infrared spectroscopy (DRIFTS) can be used to quickly and non-destructively determine the quality of manure N. As a first step to ascertain the usefulness of these technologies to measure manure N availability, we carried out a field experiment to test if these techniques are sensitive to changes in manure during decomposition. Two different cattle manures were incubated for 9 weeks in the field on soils that varied in their carbon content and field position. To allow for their retrieval , the manures were placed inside mesh bags before being buried in the soil. Manure samples were obtained at time zero, week 1, week 4, and week 9. The manures were then dried and scanned for DRIFTS and NIRS analysis. Principal Components analyses show that both the NIRS and DRIFTS spectra changed during decomposition in soil. However, NIRS spectroscopy was particularly sensitive to changes during the first four weeks of decomposition. Our results suggest that both spectroscopic techniques show promise as possible means to determine the fertilizer value of manure.