Soil Microbial Community Response to Corn Stover Harvesting Under Rain-Fed, No-Till Conditions at Multiple US Locations

• Published in: Bioenergy research 2014-06, Vol.7 (2), p.540-550
• Main Authors: Lehman, R. Michael, Ducey, Thomas F, Jin, Virginia L, Acosta-Martinez, Veronica, Ahlschwede, Carla M, Jeske, Elizabeth S, Drijber, Rhae A, Cantrell, Keri B, Frederick, James R, Fink, Darci M, Osborne, Shannon L, Novak, Jeff M, Johnson, Jane M. F, Varvel, Gary E
• Format: Article
• Language: English
• Subjects: Agricultural land; Agricultural practices; Agricultural research; Analysis; Bacteria; Biomedical and Life Sciences; By products; Carbon content; Climate change; Climatic changes; Climatic conditions; Communities; Community structure; Corn; corn stover; Cover crops; Crop residues; DNA; Ecosystem services; Ecosystems; Ethanol; ethanol production; Ethyl alcohol; fatty acids; Harvest; Harvesting; Laboratories; Life Sciences; Microbial activity; Microorganisms; No-tillage; Organic matter; Plant Breeding/Biotechnology; Plant Ecology; Plant Genetics and Genomics; Plant protection; Plant Sciences; Protection and preservation; Rain; Residues; Soil (material); Soil aggregates; Soil erosion; Soil fertility; soil fungi; Soil microbiology; Soil microorganisms; Soil organic matter; Soil properties; Soil structure; Soil types; Soils; Stover; Studies; Sustainable energy; Vegetables; weather; Weather patterns; Wood Science & Technology
• ISSN: 1939-1234; 1939-1242
• DOI: 10.1007/s12155-014-9417-9

Harvesting of corn stover (plant residues) for cellulosic ethanol production must be balanced with the requirement for returning plant residues to agricultural fields to maintain soil structure, fertility, crop protection, and other ecosystem services. High rates of corn stover removal can be associated with decreased soil organic matter (SOM) quantity and quality and increased highly erodible soil aggregate fractions. Limited data are available on the impact of stover harvesting on soil microbial communities which are critical because of their fundamental relationships with C and N cycles, soil fertility, crop protection, and stresses that might be imposed by climate change. Using fatty acid and DNA analyses, we evaluated relative changes in soil fungal and bacterial densities and fungal-to-bacterial (F:B) ratios in response to corn stover removal under no-till, rain-fed management. These studies were performed at four different US locations with contrasting soil-climatic conditions. At one location, residue removal significantly decreased F:B ratios. At this location, cover cropping significantly increased F:B ratios at the highest level of residue removal and thus may be an important practice to minimize changes in soil microbial communities where corn stover is harvested. We also found that in these no-till systems, the 0- to 5-cm depth interval is most likely to experience changes, and detectable effects of stover removal on soil microbial community structure will depend on the duration of stover removal, sampling time, soil type, and annual weather patterns. No-till practices may have limited the rate of change in soil properties associated with stover removal compared to more extensive changes reported at a limited number of tilled sites. Documenting changes in soil microbial communities with stover removal under differing soil-climatic and management conditions will guide threshold levels of stover removal and identify practices (e.g., no-till, cover cropping) that may mitigate undesirable changes in soil properties.