The great thistle harvest of 2018

The field work for Brittany Lenze's research project on the effects of soil warming on the growth of Canada Thistle came to an end a little over 2 weeks ago when we harvested the plants that originally started out as rhizomes last June. This is the second phase of her research that included a greenhouse experiment last year. The preliminary results are, thus far, quite interesting. In addition to finding a potentially novel herbivore on this invasive plant species, we were able to demonstrate 1) that any system with pots above the ground won't mimic the amplitude of soil temperature variations seen in the surrounding soil and 2) that the the plastic sheeting (not temperature) resulted in increased plant biomass. We also found an interesting result (pictured to the right) where the roots of this species spread prolifically down through the pots, into the surrounding soil, and sprouted under the plastic. I am not an expert on this species, but our experience collecting rhizomes and the literature we reviewed suggested that root growth would be more modest. Great stuff!