ARS | Publication request: Short-term plant species impact on microbial community structure in soils with long-term agricultural history

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 21, 2009
Publication Date: May 1, 2010
Citation: Maul, J.E., Drinkwater, L.E. 2010. Short-term plant species impact on microbial community structure in soils with long-term agricultural history. Plant and Soil Journal. 330(1):369-382.

Interpretive Summary: Plant-microbial interactions influence a wide range of biological processes governing the cycling of biologically important elements. These processes include the sequestration of carbon, denitrification and the re-cycling of phosphorous. A better understanding of the how different plant species interact with the soil microbial community structure will contribute to the predictability of soil biology and environmental nutrient retention. The goal of our study was to capture the short term effects of different plant species on the soil microbial community. To achieve this goal we conducted a greenhouse experiment using field soil from a site that has been managed as a Corn (Zea mays) monoculture for over 50 yrs. Using molecular methods that involve analysis of the DNA from soil microbes growing close to each plant species roots, we quantified the differences in the soil microbial community composition for each crop species used. We found that in a short time frame (8 weeks) plant species appear to influence the soil microbial community in unique ways. Some plants (buckwheat and triticale) appear to be “permissive” to microbial growth, resulting in increased total microbial community richness, and diversity. Other plants (vetch and Italian ryegrass) tend to be “restrictive” to microbial growth and suppress microbial community richness, diversity and do not support many unique microbial species. It appears that root surface area may be a good general predictor of rhizospehre microbial community diversity. These results suggest that choice of plant species used in an agroecosystem can influcence the soil microbial community structure, which in turn may impact important soil biological and chemical processes such as carbon sequestration, denitrification and the re-cycling of phosphorous.

Technical Abstract: Plant-microbial interactions influence a wide range of biogeochemical processes governing the cycling of biologically important elements. Plant species have distinct impacts on biogeochemical processes and plant-microbial interactions in the rhizosphere account for many of the observed differences in process rates of carbon, nitrogen and phosphorous. A better understanding of the role plant species play in determining soil microbial community structure will contribute to the predictability of soil biogeochemical cycling. The goal of our study was to capture the short term effects of individual plant species on an established microbial community in a soil with a well-defined plant history. We quantified the effects of individual plant species on changes in the soil MCC over an 8 week time-course. To achieve this goal we conducted a greenhouse experiment using field soil from a site that has been managed as a Corn (Zea mays) monoculture for over 50 yrs. We assumed the 50 yrs of corn monoculture has established a stabile microbial community structure and the conditioned soil provided a baseline from which to determine changes in MCC induced by the rhizosphere effects of newly introduced plant species. Using terminal restriction fragment length polymorphisms (TRFLP) targeting the 16S rDNA gene, coupled with AMMI multivariate analysis of whole community profiles we quantified the differences in the soil MCC for each cover crop species through determination of the microbial community at the scale of individual Operational Taxonomic Units (OTU). We found that in a short time frame (8 weeks) plant species appear to influence the soil microbial community in unique ways. Some plants (buckwheat and triticale) appear to be “permissive” to microbial growth in the corn background, resulting in increased total microbial community richness, diversity, as well as stimulate growth of unique microbial species. Other plants (vetch and Italian ryegrass) tend to be “restrictive” to microbial growth and suppress microbial community richness, diversity and do not support many unique microbial species. It appears that root surface area may be a good general predictor of rhizospehre microbial community diversity in but in some cases other plant may have dominant influence on plant induced changes in microbial community composition.