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Microbially Mediated Perennial Rhizosphere Nitrogen Transformations (MMPRNT)

Posted by | February 21, 2021

Principal investigators: Dr. Sarah Evans; Dr. Lisa Tiemann; Dr. Maren Friesen; and Dr. Jim Cole

Associated with: US Department of Energy, Office for Biological and Environmental Research

Project Summary:

Nitrogen (N) transformations are largely mediated by microorganisms that can carry out specific functions (e.g., N-fixation or N-mineralization). The microbiome associated with the switchgrass rhizosphere is therefore a critical factor that influences the overall N-cycle in perennial biofuel cropping systems. While N is commonly thought to limit productivity in terrestrial systems emerging research suggests the aboveground biomass yields in unfertilized switchgrass plots closely match yields in fertilized plots.

Mechanisms driving similar biomass yields in fertilized vs. unfertilized switchgrass plots are currently not well understood, but are crucial to understanding the sustainability of switchgrass as a candidate feedstock to biofuel production. ​We will test the hypothesis that the switchgrass rhizosphere microbiome plays a critical role in alleviating plant N-limitation in unfertilized switchgrass plots. By coupling molecular techniques to characterize the rhizosphere microbiome and biogeochemical assays to understand the pools and fluxes of N in switchgrass plots over multiple field sites and growing seasons we will gain a better understanding of the influence of the rhizosphere microbiome on N-transformations and ultimately plant N-availability.