Effects of Perennial Biomass Grasses on Soil Quality in Bath, Ontario

Abstract

Perennial grasses have the potential to be important bioenergy crops, as they are fast-growing and produce large amounts of biomass. They can also help improve soil quality (e.g. soil organic matter) when established on marginal lands or degraded soils. In collaboration with Lafarge Cement, who are interested in replacing coal with biomass energy, I tested the impact of perennial grasses on soil quality in Bath, ON. I studied soil samples collected in 2015 from three replicates of perennial grass species and one replicate of native vegetation (as a control) established by Queen’s faculty and students in 2009. The three perennial grass species used were switchgrass (Panicum virgatum), little bluestem (Schizachyrium scoparium), and big bluestem (Andropogon gerardii). Soil carbon and nitrogen content were higher under switchgrass in the 0-10 cm layer, but otherwise did not differ by species. Both carbon and nitrogen levels declined with depth. Isotopic data suggests a replacement of original soil carbon with carbon derived from the C4 grasses. These data will be compared with data collected prior to grass establishment to see whether the grasses have altered soil quality and/or enhanced soil carbon. My research will show how management of perennial grasses can be used to enhance the climate benefits of replacing fossil fuels with perennial grass biofuel crops and provide insights into the comprehensive climate and soil quality benefits of using these crops to replace fossil fuels in the manufacturing of cement.