Journal / Book Title
20th International Meeting on Organic Geochemistry (IMOG), Nancy, France
The increasing practice of industrial-scale agriculture tends to concentrate large masses of animal waste in relatively compact areas, potentially leading to excessive release of polluting nutrients into waterways during major storms. Anaerobic treatment conditions are generally favored to conserve nitrate N as an agricultural commodity. However, overall N contents in waste are often in excess of crop fertilization needs: storing excess N in soluble nitrate form increases pollution potential. Thus the perceived needs of agriculture and society-at-large become at odds. Organic nitrogen forms (e.g., proteins) are more environmentally stable and are less subject to unintentional release. Although U.S. farmers tend to view it with disfavor, non-aqueous (aerobic) treatment such as composting holds potential for storing nitrogen in a more stable, environmentally-benign form.
Six dairy farm (DF) waste samples were collected. The two samples discussed herein, DF4 and DF6, were chosen as representative of two biochemically different waste treatment scenarios: anaerobic versus aerobic. DF4, taken from a six-week old pit sludge at a depth of 80 cm, was olive green and exhibited odor characteristic of anaerobic conditions. DF6 was taken from older, mixed-age, lot-edge spillover and was open to the air and well-drained, but partly sheltered. DF6 was browner in color than DF4 and had an earthy odor. Sub-samples were dried, crushed, and cryo-fractured as preparation for pyrolysis.
Significant differences between the two pyrolyzates were noted: DF4 is strongly enriched in fatty acids relative to DF6. As anaerobic systems tend to be lower in pH, this might be expected. A more detailed examination of the pyrograms reveals that, while both have many compounds in common, such as the methoxyphenols derived from the plant matter in the feed, relative proportions may vary considerably. The DF6 pyrolyzate appears to be relatively depleted in n-alkanes and enriched in organonitrogen compounds (indoles and dipeptides). This conservation of organic N lends support to the idea that aerobic manure management, such as by composting, could be a more desirable agricultural practice.
MSU Digital Commons Citation
Vaughn, Daniel L. and Kruge, Michael A., "Use of Py-GC/MS Analysis Techniques in Animal Waste Management: A Preliminary Survey of Dairy Manures" (2001). Department of Earth and Environmental Studies Faculty Scholarship and Creative Works. 92.
Vaughn D. L. and Kruge M. A. (2001) Use of Py-GC/MS analysis techniques in animal waste management: A preliminary survey of dairy manures. 20th Int. Meeting on Organic Geochemistry (IMOG), Nancy, France