Connecting nitrogen transformations mediated by the rhizosphere microbiome to perennial
cropping system productivity in marginal lands

Authors: Lisa Tiemann, Sarah Evans and Maren Friesen

A major goal of bioenergy research is to identify how cropping systems can be used as an economically and environmentally low-cost energy source. Achieving this goal requires that plant productivity be maintained at a high level while ensuring soil and system sustainability. A key, but often overlooked, component to balancing productivity and sustainability is N and the factors controlling its availability. Nitrogen typically limits plant growth, but N additions can have detrimental impacts on the environment (e.g. NO3- leaching; N2O efflux) and hinder sustainability. Perennial bioenergy cropping systems utilizing microbial N-fixation as a N-source in underutilized marginal lands may be an ideal system to jointly maximize productivity and sustainability. Our project seeks to address gaps in our knowledge regarding N dynamics and sustainability, taking an integrated approach to plant-soil-microbiome systems with experimental work that spans the lab to the field and uses multiple -omics technologies to assess system function. Exciting evidence suggests that, once established, perennial bioenergy cropping systems can secure N and maintain productivity under low N inputs. This suggests that perennial bioenergy crops have multiple strategies for obtaining N, and that they possess physiological traits that allow them to manage trade-offs between biomass production and N acquisition. This project will, for the first time, describe how perennial bioenergy crop trade-offs between productivity and N acquisition relate to the function of the rhizosphere microbiome that mediates N transformations and SOM dynamics.

Please visit our project website: http://rhizosphere.weebly.com/

Check out the press release here: http://msutoday.msu.edu/news/2015/grant-to-help-increase-biofuel-yield-while-limiting-fertilizer-use/