A Comparison between Fatty Acid Methyl Ester Profiling Methods As a Soil Health Indicator for Microbial Community Composition.

Soil health serves as an important foundation for increased crop yields in agriculture and animal livestock in the United States. Well-established soil health indicators which measure the biological, chemical, and physical properties of soil can be used to evaluate the current state of a soil. The ideal soil health indicator must be reproducible, inexpensive, and accessible to the public to serve in appropriate soil management decisions. An important indicator for soil microbial community composition is through fatty acid methyl ester (FAME) profiling. Two methods have been developed to measure FAMEs: 1) phospholipid fatty acid (PLFA) and 2) ester-linked fatty acid methyl ester (EL-FAME). Although both methods provide information on microbial composition in relation to soil management, the accuracy of certain FAME extraction capacities can vary between methods, especially between different regions and soil types. The objective of this research is to compare PLFA and EL-FAME extraction methods in soil samples taken across the nation by the Natural Resource Conservation Service (USDA-NRCS). These samples were used to represent multiple soil types and properties, management practices and climatic zones. Results from this study will optimize FAME soil health indicators which are valuable in soil health assessments that provide helpful information and recommend better soil management options for agricultural producers.