Submitted to: Soil Science Society of America Special Publication Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 11/21/2014
Publication Date: 7/10/2015
Citation: He, Z., Waldrip, H. 2015. Composition of whole and water extractable organic matter of cattle manure affected by management practices. Soil Science Society of America Special Publication, Madison, WI. Book Chapter. 382(2015):41-60. doi:10.2136/sssaspecpub62.2014.0034.
Technical Abstract: Organic matter (OM) is a major component of animal manure. In this chapter, we present two case studies on the multiple spectral features of whole and water extractable organic matter (WEOM) of cattle (beef and dairy) manure affected by differing management practices. Using wet chemistry and Fourier-transform infrared (FT-IR) and Ultraviolet-visible (UV-vis) spectroscopic techniques, Case study I demonstrated that the composition and content of OM and nutrients in beef cattle manure differ depending upon the location on a feedyard where it was collected (i.e., unconsolidated surface manure and the underlying manure pack in feedyard pens, settling basin and retention pond sediments), with a higher concentrations of available nutrients present in more recently excreted materials, and increased molecular weight and degree of humification as manure aged during its on-feedyard life cycle. Using multiple spectroscopic techniques, Case Study II compared the structural and functional groups in dairy manure between dairies under conventional and organic management, and found that cutin and cutan-related 13C nuclear magnetic resonance (NMR) peaks may be used for tracing the dietary management on dairy farms to distinguish grass-fed cows from grain-fed cows. Furthermore, veterinary pharmaceutical-related peaks found in manure with pyrolysis-gas chromatograph-mass spectroscopy (GC-MS) could be used to monitor the use of antibiotics and other pharmaceuticals in dairy cows. Thus, spectral features could be traceable markers to certify that dairy and beef cattle are managed according to standards for grass-fed or organic products. Further confirmation of the relation of the NMR and pyrolysis-GC-MS features with forage ingredients and pharmaceutical additives using manure from controlled studies where exact diet and management are known could help to provide a scientific basis for evaluation and authentication of organic and other alternative types of cattle management.