Chemistry and microbial functional diversity differences in biofuel crop and grassland soils in multiple geographies

• Published in: Bioenergy research Vol. 6; no. 2; pp. 601 - 619
• Main Authors: Watrud, Lidia S., Reichman, Jay R., Bollman, Michael A., Smith, Bonnie M., Lee, E. Henry, Jastrow, Julie D., Casler, Michael D., Collins, Harold P., Fransen, Steven, Mitchell, Robert B., Owens, Vance N., Bean, Brent, Rooney, William L., Tyler, Donald D., King, George A.
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01-06-2013; Springer; Springer Nature B.V
• Subjects: Agriculture; Bacteria; Biochemistry; Biodiesel fuels; Biofuels; Biomass; Biomass energy; Biomedical and Life Sciences; Cereal crops; Chemistry; Climate change; Crop production; Crops; DNA microarrays; Ecosystem services; Ecosystems; Energy crops; Fuels; Genes; Genetic diversity; Grasses; Grasslands; Life Sciences; Lignocellulose; Microorganisms; Panicum virgatum; Plant Breeding/Biotechnology; Plant Ecology; Plant Genetics and Genomics; Plant Sciences; Soil chemistry; Soil microbiology; Soil testing; Soils; Sorghum; Sorghum bicolor; Studies; Sustainable agriculture; Sustainable production; Taxonomy; Wood Science & Technology; United States > US; Sorghum; Functional gene array; GeoChip; Switchgrass; Soil ecosystem services
• ISSN: 1939-1234; 1939-1242
• DOI: 10.1007/s12155-012-9279-y

We obtained soil samples from geographically diverse switchgrass (Panicum virgatum L.) and sorghum (Sorghum bicolor L.) crop sites and from nearby reference grasslands and compared their edaphic properties, microbial gene diversity and abundance, and active microbial biomass content. We hypothesized that soils under switchgrass, a perennial, would be more similar to reference grassland soils than sorghum, an annual crop. Sorghum crop soils had significantly higher NO(3)(−)-N, NH(4)(+)-N, SO(4)(2−)-S, and Cu levels than grassland soils. In contrast, few significant differences in soil chemistry were observed between switchgrass crop and grassland soils. Active bacterial biomass was significantly lower in sorghum soils than switchgrass soils. Using GeoChip 4.0 functional gene arrays, we observed that microbial gene diversity was significantly lower in sorghum soils than grassland soils. Gene diversity at sorghum locations was negatively correlated with NO(3)(−)-N, NH(4)(+)-N, and SO(4)(2−)-S in C and N cycling microbial gene categories. Microbial gene diversity at switchgrass sites varied among geographic locations, but crop and grassland sites tended to be similar. Microbial gene abundance did not differ between sorghum crop and grassland soils, but was generally lower in switchgrass crop soils compared to grassland soils. Our results suggest that switchgrass has fewer adverse impacts on microbial soil ecosystem services than cultivation of an annual biofuel crop such as sorghum. Multi-year, multi-disciplinary regional studies comparing these and additional annual and perennial biofuel crop and grassland soils are recommended to help define sustainable crop production and soil ecosystem service practices.