Fall Green Roof Research Intro

My focus of our project is on soil carbon content. I have two experimental questions. First: will added live versus sterile inoculum promote an increase in soil carbon? Second: do sedum species versus native prairie plants lead to higher soil carbon levels? To answer these questions I must be able to accurately measure the carbon in the soil. My goal this semester is just that: get reliable soil carbon data for our experimental trays by using the Flash CN Analyzer. 

Before I can run our real samples, I have to practice preparing samples and running standards and samples with the analyzer using excess soil. This coming week, Susanna and I will collect the end-of-season soil samples for our experiment. From there I will need to grind the soil, finalize the Flash analyzer protocol, and begin running samples.  The Flash Analyzer, which I described in detail in a previous post, is intimidating, but I am excited about the potential data sets we could get; that is if I can get good at using the machine.

This semester, I also want to work on scoring the MIP root slides for our mychorrizal data, but this is secondary because the slides are easily preserved where as I need the carbon data to continue my project. I am also looking forward to helping Susanna with her project which deals in part with soil water retention. 

Summer Green Roof Research explanation

Susanna and I assisted with Kelly Ksiazek’s experiment that had two main questions. The first: does adding live versus sterilized prairie inoculum increase mycorrhizal fungal relationships and promote plant growth. The second: do native prairie plants function better as green roof organisms than traditional sedum species in terms of growth and green roof services provided.

We set up a grid of forty trays filled with soil substrate on the Quinlan Life Science terrace. Life prairie inoculum was added twenty trays and sterilized prairie inoculum to the remaining twenty trays. The inoculum was collected from a local prairie, half of which was sterilized to kill all bacteria and fungi.

Of the forty trays, ten were planted with sedum species, ten with prairie species mix A, ten with prairie species mix B, and ten remained unplanted as the control group. The ten trays of sedum were ordered from the green roof distributer and re planted in the experimental trays. Prairie mixes A and B contain different species of native prairie plants, grown in a greenhouse before planted in the trays. The control trays contain live and sterile inoculum but no plants.

Over the course of the summer we took measurements of plant growth, substrate temperature, soil stability, and soil carbon content. For the plant growth data, we measured month to month the individual plant’s max height, tray coverage area, and flower and fruit number. To measure the tray substrate temperature we inserted a thermochron in the center of each tray. These thermochrons were calibrated to take a temperature reading every hour for an extended period of time. Soil stability was measured using the soil slake test procedure. Soil carbon content was measured by ashing the samples in a muffle furnace. Future soil samples will be measured using the Flash soil carbon and nitrogen analyzer.